Day: August 10, 2026

How Hyperbaric Oxygen Therapy May Support Healing in Tissues Injured Months or Years After Radiation Treatment

Radiation therapy plays a critical role in the treatment of many cancers. Modern planning techniques allow clinicians to target tumors more precisely, but nearby healthy tissue may still receive enough radiation to produce long-term changes.

Some radiation effects occur during treatment and resolve afterward. Late radiation complications are different. They may develop months or years after radiation has ended and can become progressively more difficult to manage. Depending on the treatment field, patients may experience bleeding, pain, fibrosis, ulceration, tissue breakdown, impaired organ function, or bone exposure.

Hyperbaric oxygen therapy, commonly abbreviated as HBOT, may be considered for selected forms of delayed radiation injury. The Undersea and Hyperbaric Medical Society recognizes delayed radiation injury involving soft tissue and bone as an accepted indication for HBOT. Medicare also covers HBOT as an adjunct to conventional treatment for soft tissue radionecrosis and osteoradionecrosis. (UHMS)

HBOT is not appropriate for every symptom that develops after cancer treatment. Its clinical role depends on the affected tissue, severity of injury, exclusion of recurrent malignancy, previous treatments, and whether impaired vascularity is contributing meaningfully to the problem.

What Are Late Radiation Complications?

Late radiation tissue injury, sometimes called delayed radiation injury or radiation necrosis, refers to tissue damage that becomes clinically apparent after the acute effects of radiation have resolved.

Radiation can injure the endothelial cells lining small blood vessels. Over time, affected vessels may narrow, thrombose, or disappear. The surrounding tissue becomes less vascular, less cellular, and chronically hypoxic. Fibrosis may increase while the tissue’s ability to remodel, resist infection, and heal after minor trauma declines. (PubMed Central (PMC))

This process may remain clinically silent until an additional stress exposes the limited reserve of the irradiated tissue. Symptoms can begin after dental extraction, surgery, infection, pressure, instrumentation, or a minor wound. In other patients, tissue breakdown develops without an obvious triggering event.

Late radiation injury can affect:

• The bladder
• The rectum and lower bowel
• The jaw and other bones
• Oral and pharyngeal tissues
• The larynx
• The skin and chest wall
• Breast and axillary tissues
• Pelvic and gynecologic tissues
• Surgical wounds located within a previous radiation field

The symptoms depend on the organ involved, but the underlying tissue frequently shares a pattern of vascular damage, hypoxia, fibrosis, and reduced healing capacity.

Why Radiation Injury Can Progress Years Later

Radiation treatment may eliminate or control cancer while also initiating long-term changes in nearby normal tissue. Unlike an acute wound that moves through a predictable healing process, irradiated tissue may undergo continuing vascular and fibrotic remodeling.

As small-vessel density decreases, less oxygen reaches the tissue. Fibroblasts and other repair cells may function less effectively, while collagen becomes increasingly dense and disorganized. The tissue may become stiff, fragile, painful, and susceptible to breakdown.

A patient may appear fully recovered from cancer treatment and then develop hematuria, rectal bleeding, exposed jawbone, a nonhealing wound, or increasing fibrosis years later. The delayed timing can be confusing and distressing, particularly when the symptoms raise concern about cancer recurrence.

Late symptoms should never be attributed automatically to radiation history. Recurrent malignancy, infection, vascular disease, medication effects, and unrelated conditions must be considered before a diagnosis of delayed radiation injury is established.

Soft Tissue Radionecrosis

Soft tissue radionecrosis describes delayed radiation damage involving tissue other than bone. It may affect mucosa, skin, muscle, connective tissue, blood vessels, or internal organs.

Possible presentations include:

• Chronic ulceration or tissue breakdown
• Recurrent bleeding
• Pain and tissue induration
• Poor healing after surgery or instrumentation
• Fibrosis and restricted movement
• Fistula formation
• Recurrent infection
• Necrosis of skin, muscle, or mucosal tissue

Radiation cystitis and radiation proctitis are organ-specific forms of delayed soft tissue radiation injury. Other examples include laryngeal radionecrosis, chest-wall injury, vaginal or pelvic soft tissue necrosis, and nonhealing wounds within a previously irradiated field.

The diagnosis requires more than confirming that a tissue was exposed to radiation. Clinicians must evaluate the location and dose of the original radiation, the timing of symptoms, physical and imaging findings, infection status, and the possibility of persistent or recurrent cancer.

Osteoradionecrosis and Radiation-Damaged Bone

Osteoradionecrosis occurs when irradiated bone becomes devitalized and fails to heal adequately. It is most commonly discussed in the jaw after treatment for head and neck cancer, but radiation-associated bone injury may occur at other sites.

Patients may develop:

• Exposed bone
• Persistent oral or facial pain
• Drainage or fistula formation
• Infection
• Pathologic fracture
• Difficulty chewing or swallowing
• Trismus
• Failure of a dental extraction site to heal

Management may include oral hygiene measures, antimicrobial therapy when infection is present, limited debridement, medical antifibrotic regimens, resection, and reconstructive surgery. HBOT has historically been incorporated into some preventive and treatment protocols.

The role of HBOT in jaw osteoradionecrosis is now more controversial than its broader recognition as a hyperbaric indication might suggest. A 2024 joint guideline from the International Society of Oral Oncology, the Multinational Association of Supportive Care in Cancer, and the American Society of Clinical Oncology concluded that evidence supporting HBOT for the prevention or management of jaw osteoradionecrosis remains limited. (ASCO Publications)

This does not mean HBOT has no role in every case. It means treatment should not be applied automatically based on an older protocol alone. Decisions should consider the stage of disease, planned surgery, available reconstructive options, previous medical management, and the experience of the multidisciplinary team.

How HBOT Affects Irradiated Tissue

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. The increased oxygen partial pressure substantially raises the amount of oxygen dissolved in plasma.

This oxygen-rich plasma can move through functioning vessels at the edge of the radiation field and create a stronger diffusion gradient into hypoxic tissue. Each exposure temporarily increases tissue oxygen tension, but the objective of a full treatment course is broader than temporary hyperoxygenation.

Repeated treatments may support:

• Angiogenic signaling and new capillary formation
• Improved oxygen delivery between treatments
• Fibroblast activity and collagen remodeling
• Mucosal and epithelial repair
• Improved leukocyte function
• Modulation of chronic inflammation
• Healing after surgical debridement or reconstruction

HBOT cannot restore tissue that has already been completely destroyed. It also cannot remove necrotic bone, correct a fixed obstruction, close every fistula, or treat recurrent cancer. Its purpose is to improve the biologic environment of viable but compromised tissue and complement the necessary medical or surgical treatment.

A 2023 Cochrane review found evidence that HBOT may improve outcomes in selected late radiation injuries, including some injuries involving the bladder, rectum, bone, and head and neck tissues. The review also emphasized that many studies were small, clinically varied, or at risk of bias, leaving uncertainty about which patients benefit most and which protocols are optimal. (PubMed Central (PMC))

Radiation Cystitis and Bladder Injury

Chronic radiation cystitis may cause urinary frequency, urgency, pain, incontinence, reduced bladder capacity, and recurrent hematuria. Severe bleeding can produce clot retention, anemia, transfusion requirements, and repeated hospitalization.

HBOT is intended to improve the vascular condition of the bladder wall rather than simply stop one visible bleeding vessel. It is commonly considered after urologic evaluation has excluded recurrent malignancy and other causes of hematuria.

The strongest randomized evidence for HBOT in late pelvic radiation injury comes from radiation cystitis. The RICH-ART trial found improvement in patient-reported urinary symptoms after HBOT, and five-year follow-up published in 2025 reported that meaningful improvements were sustained in many initial responders. Some patients required another treatment course after symptoms recurred. (PubMed)

Patients with active clot retention, major blood loss, or urinary obstruction still require immediate urologic stabilization. HBOT is a restorative treatment, not a substitute for catheterization, clot evacuation, transfusion, cystoscopy, or other urgent interventions.

Radiation Proctitis and Bowel Injury

Chronic radiation proctitis may cause rectal bleeding, urgency, tenesmus, mucus discharge, pain, diarrhea, or fecal incontinence. Telangiectatic vessels in the irradiated rectal lining can rupture repeatedly, while fibrosis may reduce tissue compliance.

HBOT may be considered when symptoms persist after medical or endoscopic care, particularly when disease is diffuse, ulcerative, or difficult to treat without causing additional tissue injury.

The evidence is mixed. Some randomized and observational studies have reported improvement in bleeding and other symptoms, while another sham-controlled trial did not demonstrate a significant benefit for a broader group of chronic bowel symptoms. The 2023 Cochrane review concluded that HBOT may help selected patients but that certainty remains limited by differences in study populations and outcomes. (PubMed Central (PMC))

This variation reinforces the need to define the treatment target clearly. A patient with confirmed hemorrhagic radiation proctopathy is clinically different from a patient with nonspecific bowel symptoms caused by altered motility, malabsorption, pelvic floor dysfunction, or another gastrointestinal disorder.

Breast, Chest Wall, and Soft Tissue Fibrosis

Late radiation effects after breast cancer treatment may include pain, edema, skin changes, fibrosis, restricted shoulder movement, and tissue tightness. These symptoms can interfere with clothing, exercise, sleep, work, and daily activities.

A 2024 randomized clinical trial evaluated HBOT for late local toxic effects after breast irradiation. In the intention-to-treat analysis, being offered HBOT was associated with reduced fibrosis but not a statistically significant reduction in pain. Among participants who completed HBOT, both pain and fibrosis improved, although treatment uptake was low and the trial design requires careful interpretation. (JAMA Network)

These findings are promising but do not establish HBOT as routine treatment for all post-radiation breast symptoms. Lymphedema, shoulder dysfunction, recurrent disease, neuropathic pain, and musculoskeletal conditions should also be assessed and treated appropriately.

When a Hyperbaric Consultation May Be Appropriate

A hyperbaric evaluation may be reasonable when a patient has a documented history of therapeutic radiation and a clinically significant tissue complication consistent with delayed radiation injury.

Potential reasons for referral include:

• Persistent bladder or rectal bleeding
• Chronic radiation-associated ulceration
• Nonhealing wounds in an irradiated field
• Soft tissue necrosis
• Selected cases of osteoradionecrosis
• Tissue breakdown after surgery or dental treatment
• Radiation-associated pain and fibrosis in selected settings
• Planned reconstruction involving compromised irradiated tissue
• Failure of appropriate conventional treatment

The consultation should answer several questions:

• Is the current problem truly caused by delayed radiation injury?
• Has recurrent malignancy been evaluated appropriately?
• Is infection present?
• Is surgery, endoscopy, vascular care, or another intervention more urgent?
• Is the affected tissue viable enough to respond?
• What functional outcome is the treatment intended to improve?
• Can the patient complete a prolonged treatment schedule safely?

HBOT should be integrated into a defined clinical plan rather than added because symptoms have been difficult to treat.

What an HBOT Course May Involve

Treatment protocols vary by anatomy, severity, prior care, and whether surgery is planned. Many delayed radiation injury protocols involve treatment five days per week for several weeks.

A course often includes approximately 30 to 40 sessions, although additional treatments may be considered when the patient is improving or when HBOT is coordinated with surgery. Treatment pressures commonly fall between approximately 2.0 and 2.5 atmospheres absolute, with prescribed oxygen periods and air breaks determined by the hyperbaric physician. Clinical trials and systematic reviews have used varying pressures, durations, and treatment numbers, and no single schedule applies to every radiation complication. (PubMed Central (PMC))

Clinical response should be evaluated throughout treatment. Measures may include:

• Frequency and severity of bleeding
• Wound dimensions and tissue quality
• Pain and medication requirements
• Urinary or bowel function
• Range of motion
• Need for transfusion or hospitalization
• Progress toward surgery or reconstruction
• Patient-reported quality of life

Improvement may occur during the treatment course or continue afterward as vascular and tissue remodeling progresses.

HBOT Remains an Adjunct to Multidisciplinary Care

Late radiation complications often require more than one specialty. Depending on the tissue involved, care may include radiation oncology, urology, colorectal surgery, gastroenterology, oral and maxillofacial surgery, otolaryngology, plastic surgery, wound care, physical therapy, and hyperbaric medicine.

Conventional treatment may include:

• Endoscopic control of bleeding
• Debridement or removal of necrotic tissue
• Antimicrobial therapy
• Dental or oral surgical care
• Medical treatment of fibrosis
• Wound dressings and reconstructive surgery
• Bladder irrigation or clot evacuation
• Nutritional and anemia management
• Pelvic floor or physical rehabilitation

CMS coverage language specifically describes HBOT for soft tissue radionecrosis and osteoradionecrosis as adjunctive treatment. This reflects the clinical reality that oxygen therapy is most useful when paired with appropriate management of the structural, infectious, oncologic, and functional components of the injury. (Centers for Medicare & Medicaid Services)

Risks and Practical Considerations

HBOT is generally well tolerated in appropriately screened patients, but it carries recognized risks. These include middle-ear or sinus barotrauma, temporary myopic vision changes, claustrophobia, blood glucose changes, pulmonary oxygen effects, and rare oxygen-induced seizure.

An untreated pneumothorax is generally considered an absolute contraindication. Pulmonary disease, difficulty equalizing ear pressure, unstable cardiac disease, seizure risk, implanted medical devices, and medication concerns require individualized assessment.

The treatment schedule can also be burdensome. Patients may attend daily sessions for six to eight weeks while continuing cancer surveillance, specialist visits, wound care, or other treatments. Transportation, work, caregiving responsibilities, fatigue, urinary urgency, bowel symptoms, and mobility limitations can affect whether the plan is realistic.

These considerations should be discussed before treatment begins. A technically appropriate therapy still needs to be practical, safe, and connected to outcomes that matter to the patient.

Setting Realistic Expectations

HBOT should not be presented as a universal remedy for radiation damage. Evidence is stronger for certain conditions, such as chronic radiation cystitis, than for others. Research involving rectal injury, breast toxicity, skin necrosis, and head and neck complications is promising in some areas but inconsistent or limited in others. Jaw osteoradionecrosis remains a particularly important area of clinical debate. (PubMed)

Treatment success may mean complete resolution of bleeding or wound closure, but it can also mean fewer procedures, improved tissue quality, reduced pain, greater function, or a safer reconstructive operation.

For patients who believed their cancer treatment was behind them, the appearance of a delayed complication can feel like an unexpected return to illness. Compassionate care requires acknowledging that burden while providing a careful, evidence-based explanation of what HBOT may and may not accomplish.

When the diagnosis is clear, recurrent cancer has been appropriately evaluated, and chronic tissue hypoxia is contributing to the problem, HBOT may provide a meaningful opportunity to improve the healing capacity of previously irradiated tissue.

How Hyperbaric Oxygen Therapy May Reduce Rectal Bleeding and Support Healing After Pelvic Radiation

Radiation therapy is an important treatment for prostate, rectal, cervical, uterine, anal, bladder, and other pelvic cancers. Although modern radiation planning helps limit exposure to surrounding organs, part of the rectum may still receive radiation because of its proximity to the treatment field.

Some patients develop rectal symptoms during treatment, while others experience problems months or years after radiation has ended. Chronic radiation proctitis may cause rectal bleeding, urgency, mucus discharge, diarrhea, pain, tenesmus, fecal leakage, or difficulty controlling bowel movements. Severe cases can lead to anemia, repeated transfusions, ulceration, strictures, fistulas, or substantial disruption of daily life.

Hyperbaric oxygen therapy, commonly abbreviated as HBOT, may be considered for selected patients with persistent radiation-related rectal injury. Its purpose is not simply to cauterize a bleeding vessel. HBOT is intended to improve oxygen delivery within chronically hypoxic tissue and support vascular and mucosal repair.

Medicare generally recognizes radiation proctitis within the broader covered indication of soft tissue radionecrosis when HBOT is used as an adjunct to conventional treatment. Coverage requirements vary, and coverage alone does not determine whether treatment is medically appropriate for an individual patient. (Centers for Medicare & Medicaid Services)

Acute and Chronic Radiation Proctitis Are Different

Acute radiation proctitis develops during pelvic radiation or shortly after treatment. It primarily reflects injury to rapidly dividing cells within the rectal lining. Symptoms may include diarrhea, urgency, mucus discharge, rectal discomfort, and occasional bleeding.

These acute symptoms often improve after radiation is completed, although infection, medication effects, and other gastrointestinal conditions should still be considered.

Chronic radiation proctitis is a delayed tissue injury. It may appear months or years after radiation and can continue to evolve long after the original cancer treatment has ended. The delayed condition is driven less by temporary mucosal inflammation and more by progressive vascular damage, tissue hypoxia, fibrosis, and abnormal healing.

The American Society of Colon and Rectal Surgeons identifies rectal bleeding as the most common presentation of chronic radiation proctitis. Fecal urgency, tenesmus, and mucus drainage are also common. (ASCRS U)

Because the underlying biology differs, therapies used for acute symptoms are not necessarily effective for chronic radiation injury.

Why Irradiated Rectal Tissue Becomes Fragile

Radiation can damage the endothelial cells lining small blood vessels within the rectal wall. Over time, these vessels may narrow, thrombose, or disappear. The surrounding tissue receives less oxygen and fewer nutrients, limiting its ability to maintain a healthy mucosal surface.

The tissue may gradually develop:

• Reduced capillary density
• Chronic hypoxia
• Submucosal fibrosis
• Mucosal thinning and ulceration
• Fragile telangiectatic blood vessels
• Reduced elasticity and impaired healing

Telangiectasias are dilated, fragile vessels that can rupture when stool passes through the rectum. Bleeding may begin as an occasional streak of blood and progress to frequent hematochezia, clot passage, iron-deficiency anemia, or transfusion dependence.

Fibrosis and neuromuscular injury can also affect rectal compliance and bowel control. This helps explain why some patients experience urgency, frequent bowel movements, tenesmus, or incontinence even when bleeding is not the dominant symptom.

The injury is often diffuse rather than limited to one visible vessel. A focal endoscopic treatment may stop a particular bleeding point without fully correcting the hypoxic condition of the surrounding tissue.

How HBOT May Help Radiation Proctitis

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. The increased pressure raises arterial oxygen tension and substantially increases the amount of oxygen dissolved directly in plasma.

This oxygen-rich plasma can reach functioning vessels surrounding the irradiated area and create a stronger diffusion gradient into hypoxic tissue.

Repeated hyperbaric treatments may support:

• Increased oxygen delivery to damaged rectal tissue
• Angiogenic signaling and new capillary formation
• Fibroblast activity and collagen remodeling
• Repair of the rectal mucosal lining
• Modulation of chronic inflammatory activity
• Improved tissue resistance to recurrent injury
• Healing of selected radiation-associated ulcers

The immediate increase in tissue oxygen lasts for a limited period after each treatment. The longer-term goal is to stimulate structural repair, particularly the development of a more functional microvascular supply.

The American Society of Colon and Rectal Surgeons recommends HBOT as an effective option for reducing bleeding in chronic radiation proctitis. The recommendation is classified as strong and based on moderate-quality evidence. (ASCRS U)

Rectal Bleeding After Radiation Requires Evaluation

A history of pelvic radiation does not mean that every episode of rectal bleeding is caused by radiation proctitis.

Other possible causes include:

• Recurrent or new colorectal malignancy
• Hemorrhoids
• Anal fissures
• Diverticular bleeding
• Inflammatory bowel disease
• Ischemic or infectious colitis
• Angiodysplasia
• Colorectal polyps
• Medication-related bleeding

The evaluation should document the amount, duration, and frequency of bleeding, along with bowel urgency, mucus discharge, pain, tenesmus, continence changes, weight loss, medication use, and the patient’s original cancer history.

At minimum, ASCRS recommends a disease-specific history, physical examination, digital rectal examination, and proctoscopic evaluation. Colonoscopy may be required when the full extent of disease cannot be determined, another form of colitis must be excluded, or the patient is due for colorectal cancer evaluation. (ASCRS U)

Laboratory assessment may include a complete blood count, iron studies, metabolic testing, and coagulation evaluation when bleeding is clinically significant.

The objective is not merely to confirm that radiation changes are present. It is to determine whether those changes explain the symptoms and whether another condition requires treatment.

Conventional Treatment Usually Precedes HBOT

Management depends on the severity and dominant symptoms. Mild bleeding may be observed or treated medically, while persistent hemorrhage may require endoscopic intervention.

Therapies used in chronic radiation proctitis include:

• Sucralfate retention enemas
• Formalin application
• Argon plasma coagulation
• Correction of iron deficiency or anemia
• Treatment of diarrhea and bowel dysfunction
• Dietary modification when clinically appropriate
• Review of anticoagulant or antiplatelet therapy
• HBOT for selected refractory or diffuse disease

ASCRS considers sucralfate retention enemas moderately effective for rectal bleeding. Formalin application and argon plasma coagulation are also recognized treatments for hemorrhagic chronic radiation proctitis. (ASCRS U)

Argon plasma coagulation, commonly called APC, is frequently used when telangiectatic vessels can be treated endoscopically. ASCRS reports that APC produces cessation or a meaningful reduction in bleeding in many treated patients, although more than one session may be required. Rectal pain, mucus discharge, and ulceration may occur after treatment, while strictures and fistulas are less common but important complications. (ASCRS U)

HBOT may be particularly relevant when:

• Bleeding persists after medical or endoscopic treatment
• Radiation injury is extensive or diffuse
• Repeated cauterization could increase tissue damage
• Rectal ulceration accompanies the bleeding
• The patient has multiple pelvic radiation injuries
• A tissue-restorative approach is preferred before more invasive surgery

The sequence should be individualized. Not every patient needs to undergo every available medical and endoscopic therapy before receiving a hyperbaric consultation.

Which Patients May Be Considered for HBOT?

Potential candidates include patients with documented delayed radiation injury who continue to experience clinically meaningful symptoms despite appropriate evaluation and conventional management.

Reasons for referral may include:

• Persistent or recurrent hematochezia
• Iron-deficiency anemia caused by ongoing rectal bleeding
• Repeated blood transfusions or iron infusions
• Failure or recurrence after endoscopic therapy
• Radiation-associated rectal ulceration
• Chronic urgency, pain, tenesmus, or mucus discharge
• Diffuse tissue injury that is difficult to treat focally
• Concern about progression to more destructive interventions
• Concurrent radiation cystitis or other pelvic soft tissue injury

The patient’s overall cancer status should be reviewed. HBOT treats delayed radiation tissue injury, not the malignancy itself. New bleeding, pain, unexplained weight loss, obstruction, or suspicious endoscopic findings require appropriate oncologic and colorectal evaluation.

A patient is less likely to benefit when symptoms are primarily caused by a fixed mechanical problem, untreated malignancy, severe stricture, established fistula, active inflammatory bowel disease, or another condition that requires a different intervention.

What an HBOT Course May Involve

The treatment protocol is prescribed by a hyperbaric physician after review of the radiation history, endoscopic findings, previous treatments, current symptoms, and medical risks.

A typical course may involve:

• Treatment five days per week
• Approximately 30 to 40 sessions
• Pressure commonly between 2.0 and 2.5 atmospheres absolute
• Around 80 to 90 minutes of oxygen exposure at treatment pressure
• Air breaks when included in the prescribed protocol

Protocols vary, and additional sessions may be considered when the patient is improving but has not reached the treatment objective.

The randomized Clarke trial used oxygen at 2.0 ATA and followed patients for as long as five years. The HOT2 trial used 40 exposures at 2.4 ATA, with 90-minute sessions delivered five days per week over eight weeks. (ASCRS U)

During the course, clinicians should monitor:

• Frequency and volume of rectal bleeding
• Hemoglobin and iron status
• Transfusion or iron-replacement requirements
• Stool frequency
• Fecal urgency and continence
• Rectal pain and tenesmus
• Treatment tolerance
• Need for additional endoscopic or surgical care

Improvement may occur during treatment, but tissue remodeling can continue after the final session. Patients should understand that HBOT is generally not an immediate hemostatic procedure.

What the Evidence Shows

Clinical evidence for HBOT in chronic radiation proctitis is supportive but not uniform.

A randomized, double-blind crossover trial led by Clarke evaluated patients with refractory radiation proctitis. Among evaluable participants, the HBOT group demonstrated greater improvement and a higher responder rate than the control group. The investigators reported an absolute risk reduction of 32 percent and a number needed to treat of approximately three after the initial treatment allocation. (PubMed)

Observational studies summarized by ASCRS have also reported reductions in bleeding, diarrhea, rectal pain, urgency, and endoscopic ulceration. Treatment courses in these reports commonly involved approximately 36 to 40 sessions, although patient selection and outcome definitions varied. (ASCRS U)

The HOT2 trial produced a different result. This double-blind, sham-controlled phase 3 trial enrolled 84 patients with chronic gastrointestinal symptoms after pelvic radiation. At 12 months, investigators found no statistically significant benefit in the primary bowel-function outcome or rectal-bleeding score. (PubMed)

The trials studied related but not identical clinical populations and used different eligibility criteria, endpoints, treatment pressures, and methods of measuring response. These differences may partly explain the conflicting results, but they do not eliminate the uncertainty.

The evidence supports a selective rather than universal approach. HBOT should not be presented as an effective treatment for every chronic bowel symptom following radiation. Its strongest clinical rationale is generally in well-characterized delayed radiation tissue injury, particularly persistent bleeding or ulcerative proctopathy that has not responded adequately to conventional care.

Risks and Contraindications of HBOT

HBOT is generally well tolerated in appropriately screened patients, but it has recognized risks.

Potential adverse effects include:

• Middle-ear or sinus barotrauma
• Temporary myopic vision changes
• Claustrophobia or confinement anxiety
• Pulmonary oxygen effects
• Blood glucose changes in patients with diabetes
• Rare oxygen-induced seizure

In the HOT2 trial, ear pain and refractive vision changes were among the more common treatment-associated events. (PubMed)

An untreated pneumothorax is generally considered an absolute contraindication. Pulmonary disease, difficulty equalizing ear pressure, seizure risk, unstable heart failure, implanted devices, and medication concerns require individualized review.

Patients with frequent diarrhea or fecal urgency may also worry about remaining in the chamber for the full treatment period. The hyperbaric team should discuss bowel timing, dietary triggers, medication schedules, and what will happen if a treatment must be stopped.

Surgery Is Reserved for Severe or Refractory Disease

Surgical intervention may become necessary when a patient develops uncontrolled bleeding, obstruction, severe stricture, fistula, perforation, necrosis, or symptoms that remain disabling despite less invasive treatment.

Possible procedures include fecal diversion, resection, reconstruction, or more extensive pelvic surgery. Operations in previously irradiated tissue carry increased risks because blood supply and healing capacity may already be compromised.

HBOT may sometimes be considered before a major operation or as part of a broader strategy to improve irradiated tissue, but it cannot reverse every structural complication. A mature fistula, fixed obstruction, or severely contracted segment may still require surgery.

The decision should involve colorectal surgery, gastroenterology, radiation oncology, hyperbaric medicine, and the patient. Preserving bowel function is important, but symptom control, cancer status, surgical risk, and quality of life must all be considered.

Measuring Meaningful Improvement

Complete cessation of rectal bleeding is an important goal, but it is not the only outcome that matters.

Meaningful improvement may include:

• Fewer bleeding episodes
• Reduced blood volume or clot passage
• Stabilization of hemoglobin
• Reduced need for transfusions or iron replacement
• Less urgency or tenesmus
• Improved continence
• Reduced rectal pain
• Fewer endoscopic procedures
• Greater confidence leaving home or returning to work

Radiation proctitis can profoundly affect dignity and independence. Patients may plan their days around restroom access, avoid travel, stop exercising, or withdraw socially because of bleeding and urgency.

These effects deserve the same clinical attention as endoscopic appearance. The most appropriate treatment plan should address tissue injury while recognizing the practical and emotional burden of living with unpredictable bowel symptoms.

HBOT offers a tissue-restorative option for selected patients with chronic radiation proctitis, particularly when bleeding or ulceration persists despite appropriate conventional treatment. It should be integrated into a multidisciplinary plan that confirms the diagnosis, excludes recurrent malignancy, treats anemia, addresses bowel dysfunction, and reserves invasive procedures for situations in which they are truly necessary.

How Hyperbaric Oxygen Therapy May Support Bladder Healing After Pelvic Radiation

Radiation therapy is an essential component of care for many pelvic cancers, including prostate, bladder, cervical, endometrial, rectal, and other malignancies. While modern treatment planning limits exposure to surrounding organs, the bladder may still receive enough radiation to produce tissue injury.

Radiation cystitis can cause urinary frequency, urgency, pain, burning, incontinence, and blood in the urine. In more severe cases, bleeding may become persistent, produce clots, obstruct urinary drainage, require transfusion, or lead to repeated hospitalizations and invasive procedures.

Hyperbaric oxygen therapy, commonly abbreviated as HBOT, may be used to treat selected patients with chronic radiation injury of the bladder. Its role is different from bladder irrigation, cauterization, embolization, or other interventions intended to stop active bleeding immediately. HBOT is intended to improve the underlying health of radiation-damaged tissue by increasing oxygen delivery and supporting vascular repair.

In the United States, radiation cystitis is generally treated within the recognized HBOT indication of delayed radiation injury or soft tissue radionecrosis. Medicare identifies soft tissue radionecrosis as a covered condition when HBOT is used as an adjunct to conventional treatment. (Centers for Medicare & Medicaid Services)

Acute and Chronic Radiation Cystitis Are Different

Urinary symptoms can develop during radiation treatment or appear months to years later. These presentations reflect different patterns of tissue injury.

Acute radiation cystitis occurs during or shortly after pelvic radiation. It is primarily an inflammatory response involving the bladder lining. Patients may experience urinary frequency, urgency, discomfort, or burning with urination. Symptoms often improve after radiation is completed, although infection and other causes must still be considered.

Chronic radiation cystitis is a delayed injury that may not become apparent until months or years after treatment. Radiation can progressively damage small blood vessels supplying the bladder wall. This process, sometimes described as obliterative endarteritis, leads to tissue hypoxia, reduced capillary density, fibrosis, mucosal atrophy, and fragile abnormal vessels that bleed easily. (eviQ)

Late radiation injury may produce:

• Visible or microscopic hematuria
• Recurrent bleeding or passage of clots
• Urinary urgency and frequency
• Dysuria or bladder pain
• Reduced bladder capacity
• Urinary incontinence
• Difficulty emptying the bladder
• Recurrent catheterization or hospitalization

The term hemorrhagic radiation cystitis is often used when bleeding is the dominant symptom. Not every patient with chronic radiation cystitis develops severe hematuria. Some experience persistent urgency, frequency, pain, or impaired bladder function without major bleeding.

Why Radiation-Damaged Bladder Tissue Does Not Heal Normally

Radiation injury can continue to evolve long after cancer treatment has ended. The initial exposure damages cellular DNA, vascular endothelium, and connective tissue. Over time, progressive narrowing and loss of small blood vessels reduce the tissue’s ability to deliver oxygen and nutrients.

The bladder wall may become chronically hypoxic and fibrotic. Normal repair is limited because the tissue lacks the vascular supply needed to support cellular metabolism, collagen remodeling, and mucosal regeneration.

New vessels that form spontaneously within irradiated tissue may be thin, irregular, and fragile. These telangiectatic vessels can rupture as the bladder fills and empties, causing recurrent hematuria.

Radiation injury can also affect bladder compliance. Fibrosis may make the bladder less elastic, producing urgency, frequent urination, pain during filling, and reduced functional capacity. Severe injury can occasionally contribute to ulceration, necrosis, fistula formation, or obstruction.

This is why simply cauterizing visible bleeding vessels may not provide lasting control. Fulguration can stop a specific bleeding point, but it does not necessarily correct the diffuse hypoxia and vascular injury affecting the surrounding bladder wall.

How HBOT May Help Radiation Cystitis

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. The elevated pressure increases arterial oxygen tension and substantially raises the amount of oxygen dissolved directly in plasma.

This oxygen-rich plasma can reach functioning vessels at the margins of irradiated tissue and establish a strong diffusion gradient into hypoxic areas. Repeated treatments are intended to create more than temporary hyperoxygenation.

Potentially relevant effects include:

• Increased oxygen delivery to hypoxic bladder tissue
• Stimulation of angiogenic signaling
• Formation and maturation of new capillary networks
• Support for fibroblast function and collagen remodeling
• Improved epithelial and mucosal repair
• Modulation of chronic inflammation
• Improved resistance of repaired tissue to recurrent injury

HBOT does not simply seal an actively bleeding vessel. The clinical objective is to improve the vascularity and biologic condition of the bladder wall so that the tissue becomes more capable of maintaining itself after the treatment course ends.

This distinction also explains why benefits may develop gradually. Some patients notice reduced bleeding during treatment, while others improve over the weeks or months that follow as vascular and tissue remodeling continue.

Hematuria After Radiation Still Requires a Urologic Evaluation

A history of pelvic radiation does not establish that every episode of hematuria is caused by radiation cystitis.

Blood in the urine may also result from:

• Recurrent or new urinary tract malignancy
• Urinary tract infection
• Kidney or bladder stones
• Prostatic bleeding
• Anticoagulant or antiplatelet therapy
• Renal disease
• Trauma or recent instrumentation
• Other inflammatory bladder conditions

The evaluation should establish that radiation injury is the likely cause and identify any immediate threat from bleeding or obstruction.

Depending on the presentation, the workup may include urinalysis, urine culture, blood counts, renal function testing, coagulation assessment, urine cytology, upper urinary tract imaging, and cystoscopy. Cystoscopic evaluation helps identify characteristic radiation changes, locate active bleeding, remove clots, and exclude bladder tumors or other pathology. (PubMed Central (PMC))

Biopsy may be considered when a suspicious lesion is present, but it should be approached carefully because irradiated bladder tissue can heal poorly. The decision belongs with the treating urologist and should reflect the risk of malignancy and the appearance of the lesion.

Severe Bleeding Must Be Stabilized Before or Alongside HBOT

HBOT is not a substitute for emergency management of significant blood loss, clot retention, or urinary obstruction.

A patient with heavy hematuria may require:

• Placement of a large-bore urinary catheter
• Manual clot evacuation
• Continuous bladder irrigation
• Intravenous fluids
• Correction of a clinically significant coagulopathy
• Blood transfusion
• Cystoscopic clot evacuation
• Fulguration or coagulation of bleeding sites
• Hospital admission and close monitoring

If bleeding remains uncontrolled, additional options may include intravesical agents, selective arterial embolization, urinary diversion, or surgery. The choice depends on bleeding severity, bladder condition, kidney function, previous treatments, and the patient’s overall medical status. (PubMed Central (PMC))

HBOT may be introduced once the patient is sufficiently stable to undergo daily chamber treatments. It can sometimes begin while other supportive measures continue, but it should not delay urgent clot removal, stabilization, or evaluation for recurrent cancer.

The Canadian Urological Association best practice report recommends considering HBOT relatively early after cystoscopy and fulguration have failed, rather than reserving it only for patients who have undergone multiple destructive or highly invasive therapies. (PubMed Central (PMC))

Which Patients May Be Considered for HBOT?

HBOT may be appropriate for patients with confirmed or strongly suspected delayed radiation injury of the bladder who continue to experience clinically meaningful symptoms.

Potential candidates include patients with:

• Persistent or recurrent radiation-related hematuria
• Bleeding that returns after cystoscopic treatment
• Chronic urinary urgency, frequency, or dysuria associated with radiation injury
• Transfusion-dependent or hospitalization-producing hemorrhagic cystitis
• Diffuse cystoscopic radiation changes that are difficult to treat focally
• A desire to preserve the bladder and avoid more invasive procedures
• Combined pelvic soft tissue radiation injury affecting nearby structures

The decision should consider the severity of symptoms, the degree of bladder damage, prior interventions, cancer status, medical comorbidities, and the patient’s ability to complete a daily treatment schedule.

Earlier referral may be beneficial. Retrospective studies have reported better responses when HBOT begins relatively soon after the onset of radiation-related hematuria, although the available data do not establish one universal referral deadline. The practical point is that patients do not necessarily need to exhaust every invasive option before receiving a hyperbaric evaluation.

HBOT is less likely to correct symptoms caused primarily by a fixed anatomic problem, such as severe urethral obstruction, a large fistula, extensive bladder contraction, an untreated tumor, or another condition requiring surgery.

What an HBOT Course for Radiation Cystitis May Involve

A treatment course is prescribed by a hyperbaric physician after reviewing the urologic evaluation, radiation history, current symptoms, medical risks, and previous treatments.

Protocols commonly involve treatment five days per week for several weeks. Treatment is often delivered at approximately 2.0 to 2.5 atmospheres absolute, with around 80 to 90 minutes of oxygen breathing at treatment pressure. Many patients receive 30 to 40 sessions, although additional treatments may be considered based on clinical response and treatment tolerance.

The RICH-ART randomized trial used 30 to 40 treatments with 100 percent oxygen at 240 to 250 kPa, approximately 2.4 to 2.5 ATA, for 80 to 90 minutes per session. (ScienceDirect)

A typical visit includes:

1. Review of current symptoms and interval medical changes.
2. Assessment of ear-pressure equalization and treatment readiness.
3. Removal of prohibited items under hyperbaric fire-safety protocols.
4. Gradual chamber compression.
5. Oxygen breathing at the prescribed pressure.
6. Air breaks when included in the protocol.
7. Controlled decompression and post-treatment assessment.

Patients may be treated in either a monoplace or multiplace chamber. The clinical oxygen dose and safety of treatment are more important than the chamber configuration.

How Response to HBOT Is Measured

Visible hematuria is an important outcome, but it should not be the only measure of treatment success.

Radiation cystitis can affect several areas of urinary function and quality of life. Clinical monitoring may include:

• Frequency and severity of hematuria
• Number of clot-retention episodes
• Need for transfusion
• Emergency visits or hospitalizations
• Need for cystoscopy or fulguration
• Urinary frequency and urgency
• Dysuria and pelvic pain
• Incontinence
• Nighttime urination
• Patient-reported quality of life

A patient may experience meaningful improvement even when occasional mild hematuria persists. Conversely, cessation of visible bleeding does not necessarily mean that urgency, pain, or bladder-capacity limitations have resolved.

Standardized patient-reported instruments can help capture changes that are not reflected by laboratory values or cystoscopic findings alone. The RICH-ART study used the urinary domain of the Expanded Prostate Cancer Index Composite to evaluate urinary symptoms and the degree to which they affected daily life. (University of Michigan Medical School)

What the Clinical Evidence Shows

The evidence for HBOT in radiation cystitis includes case series, cohort studies, systematic reviews, and a multicenter randomized controlled trial.

A 2024 systematic review and meta-analysis reported improvement in symptoms among approximately 90 percent of included patients, with complete remission of hematuria in a pooled 55 percent. The studies varied in patient selection, severity, treatment protocols, and outcome definitions, so these figures should not be interpreted as a guaranteed individual response. (PubMed Central (PMC))

The RICH-ART randomized phase 2 to 3 trial found that HBOT improved patient-reported urinary symptoms compared with standard care in patients with chronic radiation cystitis. The trial evaluated a broader range of urinary problems rather than focusing only on visible bleeding. (ScienceDirect)

A 2025 five-year follow-up reported that benefits were sustained among patients who responded initially. Of 70 patients included in the long-term analysis, 68.6 percent met the study’s responder definition after HBOT. Their improvements remained clinically meaningful at five years. Nine patients received a second HBOT course because symptoms recurred. (PubMed Central (PMC))

These findings provide stronger evidence for durable symptom improvement, but important limitations remain. Not every patient responds, study populations may not represent the most severe cases of life-threatening hemorrhage, and the optimal pressure, number of sessions, and timing of treatment have not been established for every presentation.

HBOT should therefore be presented as a tissue-restorative treatment with meaningful evidence, not as a guaranteed cure or immediate method of hemostasis.

Risks and Contraindications of HBOT

HBOT is generally well tolerated when delivered in a medically supervised facility, but treatment has recognized risks.

Potential adverse effects include:

• Middle-ear or sinus barotrauma
• Temporary myopic vision changes
• Claustrophobia or confinement anxiety
• Pulmonary oxygen effects
• Blood glucose changes in patients with diabetes
• Rare oxygen-induced seizure

An untreated pneumothorax is generally considered an absolute contraindication. Patients with pulmonary disease, difficulty equalizing ear pressure, uncontrolled fever, unstable heart failure, seizure risk, or implanted medical devices require individualized assessment.

Cancer history also requires thoughtful evaluation. HBOT is used to treat complications of previous radiation, not active malignancy itself. A patient should have an appropriate oncologic and urologic assessment to determine whether recurrent or persistent cancer may be contributing to the symptoms.

Practical Considerations for Patients

A full course of HBOT requires a significant time commitment. Patients commonly attend treatment five days per week for six to eight weeks, in addition to urology, oncology, primary care, or other appointments.

Transportation, work obligations, urinary urgency, catheter care, mobility limitations, and fatigue can affect attendance. Some patients are also understandably anxious about entering a chamber after already enduring cancer treatment and repeated urologic procedures.

Clear preparation can make the experience more manageable. Patients should understand:

• Why HBOT is being recommended
• What symptoms it is intended to address
• That improvement may occur gradually
• How long each visit may take
• What sensations to expect during compression
• How treatment response will be evaluated
• What symptoms require urgent urologic care

The emotional burden of recurrent hematuria should not be underestimated. Seeing blood or clots in the urine can create persistent fear that the cancer has returned, even after testing identifies radiation injury as the likely cause. Compassionate care includes explaining the diagnosis clearly and maintaining appropriate cancer surveillance without dismissing the patient’s concern.

HBOT as Part of Coordinated Bladder-Preservation Care

The most effective management of radiation cystitis is multidisciplinary. Urologists address bleeding, obstruction, malignancy surveillance, and structural complications. Radiation oncologists help clarify the original treatment field and expected late effects. Hyperbaric clinicians evaluate whether increased tissue oxygenation may support recovery. Primary care and other specialists help manage anticoagulation, cardiopulmonary disease, diabetes, and treatment logistics.

HBOT occupies a distinctive position within this care pathway. Unlike therapies that cauterize, constrict, embolize, or chemically treat bleeding surfaces, HBOT is intended to improve the vascular environment of the irradiated bladder.

For an appropriately selected patient, that restorative approach may reduce hematuria, improve urinary symptoms, decrease reliance on repeated procedures, and support preservation of bladder function. The decision should be made after other causes of hematuria have been excluded and immediate bleeding risks have been controlled.

How Hyperbaric Oxygen Therapy May Support Tissue Survival After Severe Traumatic Ischemia

A crush injury occurs when sustained or high-energy force damages muscle, blood vessels, nerves, connective tissue, and sometimes bone. The visible wound may represent only part of the injury. Beneath the skin, bleeding, endothelial damage, microvascular obstruction, and progressive edema can reduce tissue perfusion long after the original force has been removed.

As swelling increases, oxygen must travel farther from functioning capillaries to reach injured cells. Rising tissue pressure may further restrict arterial inflow and venous drainage, creating a cycle of edema, ischemia, cellular dysfunction, and additional swelling. Without timely intervention, viable tissue can progress to necrosis, infection, functional loss, or amputation.

Hyperbaric oxygen therapy, or HBOT, may be used as an adjunct in selected crush injuries and other forms of acute traumatic peripheral ischemia. It does not replace trauma resuscitation, vascular repair, fracture stabilization, fasciotomy, or surgical debridement. Its purpose is to increase oxygen availability within threatened tissue while definitive surgical and medical care addresses the underlying injury.

The Undersea and Hyperbaric Medical Society recognizes crush injury, compartment syndrome, and other acute traumatic ischemias as accepted clinical indications for HBOT. Medicare also covers chamber-based HBOT for crush injuries and acute traumatic peripheral ischemia when loss of function, limb, or life is threatened and treatment is used alongside accepted standard measures. (UHMS)

What Happens to Tissue During a Crush Injury?

Crush injuries range from localized hand or foot trauma to extensive limb injuries involving open fractures, disrupted vessels, contaminated wounds, and severe muscle damage.

The initial mechanical force can rupture cells and blood vessels directly. Damaged vessels leak fluid into the surrounding tissue, while clotting, vascular spasm, endothelial swelling, and microthrombi reduce effective circulation. Inflammatory cells then accumulate within the injured area, contributing to additional endothelial dysfunction and fluid leakage.

This can create a self-perpetuating sequence:

• Trauma damages muscle and the microcirculation.
• Bleeding and inflammation increase tissue edema.
• Edema compresses small blood vessels and increases diffusion distance.
• Reduced perfusion produces tissue hypoxia.
• Hypoxic cells lose the ability to regulate fluid and energy normally.
• Cellular swelling and endothelial injury increase edema further.

Even after a damaged artery is repaired or external compression is removed, tissue may remain at risk. Restoration of blood flow can trigger ischemia-reperfusion injury, during which activated leukocytes, inflammatory mediators, and reactive oxygen species contribute to secondary endothelial and cellular damage. (NCBI)

The clinical objective is not merely to restore a palpable pulse. It is to preserve the microcirculation and maintain oxygen delivery at the cellular level.

Crush Injury, Compartment Syndrome, and Crush Syndrome Are Different

These terms are related but should not be used interchangeably.

A crush injury describes direct tissue damage caused by compression or high-energy force. It may remain localized to one body region or involve multiple structures.

Acute compartment syndrome occurs when pressure rises within a closed fascial compartment enough to impair tissue perfusion. It most commonly affects the extremities and represents a surgical emergency. Pain out of proportion to the apparent injury, pain with passive stretch, tense swelling, sensory changes, and motor dysfunction may raise concern, but no single examination finding should be used to exclude the diagnosis.

When acute compartment syndrome is present, urgent fasciotomy is the definitive treatment. HBOT must not be used as an alternative to surgical decompression or as a reason to delay it.

Crush syndrome is a systemic consequence of extensive muscle destruction, often after prolonged compression. When pressure is released, potassium, myoglobin, acids, and other intracellular substances may enter the circulation. The patient can develop hyperkalemia, metabolic acidosis, shock, cardiac arrhythmia, and acute kidney injury.

Crush syndrome requires emergency resuscitation, cardiac and electrolyte monitoring, renal protection, and critical care. HBOT may address threatened local tissue in an appropriately selected patient, but it does not replace management of the systemic metabolic consequences.

How HBOT Increases Oxygen Delivery to Crushed Tissue

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. The elevated oxygen partial pressure substantially increases the quantity of oxygen dissolved directly in plasma.

This dissolved oxygen can travel through the remaining functional microcirculation and establish a stronger diffusion gradient between capillary blood and hypoxic tissue. Oxygen may therefore reach viable cells located farther from an intact capillary than it could under ordinary atmospheric conditions.

This effect is particularly relevant when edema and microvascular damage have impaired oxygen delivery without eliminating perfusion completely.

HBOT cannot push blood through a completely obstructed major artery. Vascular disruption, thrombosis, or inadequate arterial inflow still requires urgent vascular evaluation and repair when feasible. Hyperbaric treatment is most biologically plausible when some circulation remains or has been restored, but surrounding tissue continues to be threatened by edema, microvascular dysfunction, or reperfusion injury.

Hyperoxic Vasoconstriction May Reduce Edema

One of the important physiologic effects of HBOT is hyperoxic vasoconstriction. Elevated oxygen tension causes arterioles in certain tissues to constrict, reducing plasma filtration into the injured area.

Ordinarily, vasoconstriction could reduce oxygen delivery. Under hyperbaric conditions, however, plasma contains substantially more dissolved oxygen. Tissue oxygenation can remain elevated even as regional blood flow decreases.

This combination may help reduce edema without worsening local hypoxia. As swelling decreases, pressure on small vessels may fall and the distance between capillaries and viable cells may shorten.

HBOT may also reduce neutrophil adhesion to injured vascular endothelium, potentially limiting part of the inflammatory microvascular obstruction associated with ischemia-reperfusion injury. These mechanisms help explain why HBOT is considered for acute traumatic ischemia rather than simply for the external wound. (NCBI)

HBOT Does Not Replace Fasciotomy or Vascular Repair

A patient with a severe crush injury requires immediate trauma assessment. Priorities may include hemorrhage control, airway and hemodynamic stabilization, vascular examination, fracture management, wound exploration, and evaluation for compartment syndrome.

Urgent interventions may include:

• Surgical decompression through fasciotomy
• Arterial or venous repair
• Thrombectomy or bypass
• Fracture reduction and stabilization
• Debridement of contaminated or nonviable tissue
• Repair or reconstruction of tendons, nerves, and soft tissue
• Replantation of an amputated part
• Antibiotic prophylaxis or treatment
• Tetanus prevention
• Management of rhabdomyolysis and electrolyte abnormalities

Emergency surgical treatment should generally occur before HBOT when delay would threaten the limb or patient. Hyperbaric therapy and surgery are complementary, not competing, interventions. Current clinical reviews emphasize that revascularization, fracture stabilization, and necessary decompression should precede hyperbaric treatment when urgently indicated. (NCBI)

HBOT should also never be used to avoid necessary debridement. Tissue that is irreversibly necrotic can become a focus for infection and must be managed surgically.

Which Crush Injuries May Be Considered for HBOT?

Not every contusion, fracture, or soft-tissue injury requires hyperbaric treatment. HBOT is generally considered when the injury threatens meaningful tissue, limb function, or survival.

Potential candidates may include patients with:

• Severe soft-tissue crush injury and progressive edema
• Acute traumatic peripheral ischemia
• High-grade open fractures with substantial soft-tissue damage
• Persistent tissue hypoxia after vascular repair
• Compartment syndrome after appropriate surgical decompression
• Replanted or revascularized extremities with threatened viability
• Extensive hand or foot injuries in which small areas of tissue loss could cause major functional impairment
• Traumatic wounds with a high risk of necrosis, infection, or reconstructive failure
• Compromised tissue in a patient with diabetes, vascular disease, tobacco exposure, or other host factors that limit healing

Patient selection should involve direct communication between the trauma, orthopedic, vascular, plastic or hand surgery, and hyperbaric teams.

The presence of normal large-vessel pulses does not always mean the tissue is safe. A limb can have macroscopic arterial flow while the microcirculation remains impaired. Conversely, HBOT cannot compensate for an unrepaired major vascular injury.

Clinical assessment may include serial examination, Doppler evaluation, vascular imaging, compartment-pressure measurement when appropriate, laboratory testing, tissue appearance, and direct operative findings. Transcutaneous oxygen measurements may provide additional information in selected cases, although they should not delay necessary treatment.

Timing of HBOT After a Crush Injury

When HBOT is selected, treatment is generally most relevant during the early period when tissue is hypoxic but still viable.

The objective is to intervene before progressive edema, microvascular failure, and cellular injury become irreversible. Treatment should be coordinated promptly after stabilization and necessary surgery rather than reserved automatically for a wound that has already declared extensive necrosis.

European consensus recommendations support early HBOT as an adjunct to surgery for open fractures with crush injury. A current clinical review similarly emphasizes early assessment and close coordination between the surgical and hyperbaric teams. (PubMed Central (PMC))

Timing still depends on the individual patient. HBOT should not interrupt active resuscitation, delay vascular repair, postpone fasciotomy, or prevent a necessary return to the operating room.

What a Hyperbaric Treatment Course May Involve

Protocols vary according to the injury, surgical findings, chamber capability, and patient stability.

Clinical studies have used pressures around 2.4 to 2.5 atmospheres absolute with approximately 90 minutes of oxygen exposure per session. Treatments may be delivered twice daily during the early phase of a severe injury and then reduced as edema, perfusion, and tissue viability improve.

The 1996 randomized trial of crush injuries used 12 sessions delivered twice daily over six days after surgical management. The more recent Hyperbaric Oxygen for Lower Limb Trauma trial evaluated a planned course of 12 treatments at approximately 2.4 ATA, beginning within 48 hours of injury. These study protocols provide clinical context, but they should not be treated as a universal prescription for every crush injury. (PubMed)

Treatment planning should account for:

• Timing of repeat surgical exploration
• Vascular and neurologic status
• Compartment decompression
• Fracture stability
• Wound contamination
• Ventilation and critical care needs
• Intravenous medications and blood products
• Glucose management
• Chest injuries and pneumothorax risk
• Implanted or external medical devices
• The patient’s ability to equalize middle-ear pressure

The limb should be reassessed throughout the course. HBOT should not continue automatically when tissue is deteriorating or a surgical problem remains unresolved.

Evidence for HBOT in Crush Injury

The clinical evidence is smaller than the evidence base for many common trauma interventions, but randomized and observational studies suggest potential benefit in selected severe injuries.

A double-blind randomized trial published in 1996 included 36 patients with crush injuries who received either HBOT or sham treatment after surgery. Complete healing was reported more frequently in the HBOT group, and patients receiving HBOT required fewer repeat surgical procedures. The study was small, and some of its subgroup analyses were not prespecified, so its findings should be interpreted with appropriate caution. (PubMed)

The international HOLLT randomized trial enrolled 120 patients with open tibial fractures and severe soft-tissue injury. Its combined primary outcome of necrosis or infection within 14 days was not statistically different between the assigned groups. Tissue necrosis considered separately occurred in 29 percent of patients assigned to HBOT and 53 percent of controls. The investigators also reported fewer late complications and better functional outcomes in the HBOT group. (ResearchGate)

These findings are encouraging, but they do not establish that HBOT is necessary or effective for every traumatic limb injury. Trauma mechanisms, wound severity, surgical quality, treatment timing, and actual HBOT exposure vary considerably among studies.

The most defensible role remains adjunctive treatment for carefully selected, limb-threatening acute traumatic ischemia within a multidisciplinary trauma system.

Monitoring Tissue Viability During Treatment

The response to HBOT should be evaluated alongside the overall surgical course. Clinicians may monitor:

• Skin color and temperature
• Capillary refill
• Doppler signals and palpable pulses
• Edema and tissue tension
• Sensory and motor function
• Wound bleeding and tissue appearance
• Development or progression of necrosis
• Infection and drainage
• Need for additional debridement
• Viability of replanted or reconstructed tissue
• Renal function, creatine kinase, potassium, and urine output when muscle injury is extensive

Improvement may appear as stabilization of tissue margins, decreased swelling, improved wound-bed appearance, or clearer demarcation between viable and nonviable tissue.

A concerning examination should trigger surgical reassessment rather than simply an additional chamber session. Progressive pain, tense swelling, neurologic deterioration, absent flow, systemic toxicity, or advancing necrosis may indicate a problem that requires urgent operative intervention.

Risks and Logistical Challenges

HBOT is generally well tolerated in appropriately screened patients, but acute trauma introduces additional complexity.

Potential HBOT complications include middle-ear barotrauma, sinus pressure injury, temporary visual changes, oxygen toxicity, and rare oxygen-induced seizure. An untreated pneumothorax is generally considered an absolute contraindication.

Trauma patients may also have pulmonary contusions, chest tubes, unstable fractures, mechanical ventilation, vascular access devices, external fixation, drains, or continuous infusions. Each device and treatment must be assessed for pressure compatibility and fire safety.

Safe treatment of a critically ill trauma patient requires:

• Chamber-compatible monitoring and support equipment
• Personnel trained in hyperbaric critical care
• Reliable communication with the patient and treatment team
• A plan for deterioration under pressure
• Rapid access to surgery and intensive care
• Coordination of analgesia, sedation, ventilation, and glucose management

These requirements can limit the practicality of HBOT even when a physiologic rationale exists. Transfer to a hyperbaric facility should not expose an unstable patient to greater risk or separate the patient from essential surgical care.

Limb Salvage Includes Long-Term Function

Survival of the limb is not the only outcome that matters. Severe crush injuries can produce chronic pain, sensory loss, muscle weakness, stiffness, contracture, infection, delayed bone healing, and repeated reconstructive procedures.

A technically preserved extremity may still have limited function. Conversely, amputation may occasionally offer a better functional path than prolonged attempts to preserve severely damaged tissue. These decisions require honest, patient-centered discussion among the trauma, reconstructive, rehabilitation, prosthetic, and hyperbaric teams.

When HBOT is used, its purpose should be clearly defined. The goal may be to preserve muscle, limit necrosis, support a replantation, improve the reconstructive options available to the surgeon, or reduce the extent of tissue loss.

For patients and families, the period after a severe crush injury can be frightening and uncertain. Clear explanations are essential. HBOT should be presented neither as a rescue that guarantees limb survival nor as an experimental afterthought. It is a time-sensitive adjunct that may help protect viable tissue when integrated appropriately with surgery, vascular care, critical care, and rehabilitation.

The Adjunctive Role of Hyperbaric Oxygen in a Time-Critical Surgical and Infectious Disease Emergency

Necrotizing soft tissue infections, commonly abbreviated as NSTIs, are rapidly progressive infections that cause tissue destruction along the fascia, subcutaneous tissue, or muscle. This clinical category includes necrotizing fasciitis, clostridial myonecrosis, commonly called gas gangrene, and Fournier gangrene involving the perineal or genital region.

These infections can progress from localized pain and swelling to septic shock, multiorgan dysfunction, limb loss, or death. Successful treatment depends on immediate surgical source control, broad-spectrum antimicrobial therapy, and intensive physiologic support. Hyperbaric oxygen therapy, or HBOT, may be considered as an adjunct at appropriately equipped centers, but it must never delay resuscitation, operative exploration, or debridement.

The Undersea and Hyperbaric Medical Society recognizes HBOT as an adjunct to surgery, antibiotics, and goal-directed critical care for necrotizing soft tissue infections. Medicare also lists progressive necrotizing infections and gas gangrene among its covered conditions for chamber-based HBOT. These classifications do not mean every patient with an NSTI should receive hyperbaric treatment. The decision remains dependent on clinical urgency, surgical timing, transport risk, chamber availability, and the patient’s physiologic stability. (UHMS)

Necrotizing Soft Tissue Infection Is a Surgical Emergency

The most important intervention for a suspected NSTI is prompt surgical evaluation. The infection can spread beneath skin that initially appears only mildly inflamed, making early recognition difficult.

Clinical findings that should increase concern include:

• Severe pain that appears disproportionate to the visible skin findings
• Rapidly increasing swelling, erythema, or tenderness
• Firm or wooden-feeling subcutaneous tissue
• Edema extending beyond the apparent area of redness
• Bullae, ecchymosis, skin discoloration, or necrosis
• Crepitus or gas within the soft tissues
• Altered mental status, hypotension, or other systemic toxicity
• Failure to improve with treatment for presumed cellulitis

Severe pain may occur before substantial cutaneous changes become visible. As tissue and superficial nerves are destroyed, pain may later diminish and the affected area can become anesthetic. IDSA recommends prompt surgical consultation whenever an aggressive soft tissue infection is associated with systemic toxicity or suspected necrotizing fasciitis or gas gangrene. (Infectious Diseases Society of America)

Laboratory tests and imaging can assist with diagnosis, define the extent of disease, and identify gas or fluid collections. They should not postpone surgical exploration when clinical suspicion is high. The definitive findings are often established in the operating room, where the surgeon may observe necrotic fascia, abnormal tissue fluid, poor bleeding, loss of normal fascial resistance, or tissue planes that separate easily with blunt dissection. (Infectious Diseases Society of America)

Why Necrotizing Infections Cause Severe Tissue Hypoxia

NSTIs create an environment in which oxygen demand rises while oxygen delivery deteriorates.

Bacterial proliferation, inflammatory activity, edema, thrombosis, and microvascular injury can reduce local perfusion. Pressure within swollen tissue may further compress small vessels. As oxygen tension falls, leukocyte function becomes less effective, antibiotic delivery may become impaired, and viable tissue surrounding the infection becomes increasingly vulnerable.

Some organisms produce enzymes and toxins that accelerate tissue destruction or contribute to shock. Clostridial organisms can produce rapidly progressive myonecrosis accompanied by gas formation and profound systemic toxicity. Other infections are polymicrobial, involving combinations of aerobic and anaerobic organisms. Monomicrobial disease may be caused by group A streptococci, methicillin-resistant Staphylococcus aureus, or other invasive pathogens. (Infectious Diseases Society of America)

The resulting injury is not limited to the bacteria themselves. The host inflammatory response, endothelial dysfunction, impaired microcirculation, and tissue hypoxia can continue to drive damage even after antimicrobial treatment begins.

How Hyperbaric Oxygen May Support NSTI Treatment

During HBOT, the patient breathes medical oxygen while exposed to increased atmospheric pressure inside a hyperbaric chamber. This raises arterial oxygen partial pressure and substantially increases the amount of oxygen dissolved directly in plasma.

The oxygen-rich plasma can reach functioning microvessels surrounding the infected area and create a stronger diffusion gradient into hypoxic tissue. Proposed and observed effects relevant to NSTIs include:

• Increased oxygen tension in viable but hypoxic tissue
• Support for oxygen-dependent leukocyte microbial killing
• Direct inhibition of selected anaerobic organisms
• Improved activity of certain antimicrobial agents
• Reduction of edema through hyperoxic vasoconstriction
• Modulation of inflammatory and endothelial responses
• Support for demarcation between viable and nonviable tissue
• Improved oxygen availability for later wound repair

Hyperbaric oxygen may reduce hypoxia-related leukocyte dysfunction and improve oxygenation in ischemic tissue surrounding the infection. These effects provide the physiologic rationale for its use as an adjunct, particularly when microvascular injury and severe tissue hypoxia are prominent. (UHMS)

HBOT does not penetrate or revive completely necrotic tissue in a way that eliminates the need for surgery. Dead fascia, muscle, foreign material, and infected fluid collections still require removal or drainage.

Surgical Debridement Must Never Be Delayed for HBOT

The central treatment for an NSTI is early and aggressive surgical source control. All clearly necrotic and infected tissue must be excised until viable tissue is reached. Depending on the extent and location of the infection, this may require fasciotomy, muscle excision, removal of infected hardware, bowel or urologic procedures, amputation, or extensive perineal debridement.

One operation is frequently not enough. IDSA notes that many patients should return to the operating room within approximately 24 to 36 hours after the initial debridement and continue to undergo reassessment and additional debridement until no further necrotic tissue remains. (Infectious Diseases Society of America)

Hyperbaric treatment should be coordinated around surgery, not placed ahead of it. A patient should not be transferred away from an available operating room or critical care team merely to receive HBOT.

A practical sequence may include:

1. Immediate resuscitation and broad-spectrum antibiotics.
2. Urgent operative exploration and debridement.
3. Postoperative stabilization and critical care.
4. HBOT when available without compromising another operation or essential support.
5. Repeated surgical assessment and additional debridement as needed.

At centers with established emergency hyperbaric capability, HBOT may sometimes be delivered soon after the first operation and repeated during the period of active source control. The exact sequence must remain flexible because surgical findings and physiologic stability take priority.

Broad-Spectrum Antibiotics and Critical Care Remain Essential

Empiric antimicrobial therapy should begin promptly and provide broad activity against gram-positive, gram-negative, aerobic, and anaerobic organisms. IDSA recommendations include an anti-MRSA agent combined with broad gram-negative and anaerobic coverage while microbiology remains uncertain. Documented group A streptococcal necrotizing fasciitis is generally treated with penicillin plus clindamycin, while clostridial myonecrosis requires urgent surgery and appropriate toxin-suppressing antimicrobial therapy. (Infectious Diseases Society of America)

Antibiotic treatment should be refined when operative cultures, blood cultures, Gram stain findings, and susceptibility results become available. Superficial wound cultures may not accurately represent the organisms driving infection within the fascia or muscle. Deep operative tissue is generally more clinically useful.

Critical care management may include:

• Aggressive fluid resuscitation
• Vasopressor support
• Mechanical ventilation
• Renal support
• Correction of electrolyte, glucose, and acid-base abnormalities
• Blood-product administration
• Nutritional support
• Pain management
• Thromboembolism prevention
• Management of concurrent cardiac, pulmonary, or renal disease

HBOT cannot replace any of these interventions. Its potential value exists within a coordinated system capable of delivering surgery, infectious disease care, anesthesia, critical care, wound management, and hyperbaric treatment without dangerous delay.

Which Patients May Be Considered for HBOT?

There is no single test that determines whether HBOT should be added. The decision is made by the surgical, critical care, infectious disease, and hyperbaric teams based on the entire clinical situation.

HBOT may be considered when:

• Necrotizing infection has been confirmed surgically or is strongly suspected
• Initial surgical source control has been performed
• Additional debridement remains available whenever needed
• The infection involves extensive hypoxic or ischemic tissue
• Clostridial myonecrosis or another anaerobic component is suspected
• The patient can be transported and monitored safely
• A medically staffed hyperbaric program can provide timely treatment
• HBOT will not interfere with resuscitation, antibiotics, or repeat surgery

Patients with severe shock, unstable airways, active hemorrhage, uncontrolled arrhythmia, or other immediate threats may require further stabilization before chamber treatment. In some hospital-based multiplace chambers, critically ill and mechanically ventilated patients can be treated with trained personnel and chamber-compatible equipment. Other facilities may not have this capability.

An untreated pneumothorax is generally considered an absolute contraindication to HBOT. Pulmonary air trapping, implanted devices, seizure risk, hemodynamic instability, glucose abnormalities, and the ability to manage infusions or ventilation under pressure also require assessment.

The appropriate question is not simply whether HBOT might help. It is whether it can be integrated safely without weakening the interventions that have the clearest lifesaving role.

HBOT Protocols for Necrotizing Soft Tissue Infections

Treatment protocols vary according to the organism, disease severity, surgical course, chamber capability, and patient stability.

Clinical hyperbaric oxygen treatments are generally delivered at pressures between 2.0 and 3.0 atmospheres absolute. For necrotizing infections, treatment may be provided more frequently during the early, rapidly progressive phase and reduced as infection control and physiologic stability improve. Oxygen-breathing periods and air breaks are selected by the hyperbaric physician. (UHMS)

Treatment planning must account for:

• Timing of the next operative exploration
• Ventilator and airway requirements
• Vasopressor and infusion needs
• Hemodynamic stability
• Chest tubes and other drains
• Chamber-compatible monitoring
• Glucose management
• Ear-pressure equalization
• Fire-safety requirements
• Safe transport between the ICU, operating room, and chamber

The number of sessions is not standardized for every NSTI. Treatment should be guided by surgical findings, clinical response, control of systemic toxicity, progression of tissue necrosis, and the ongoing judgment of the multidisciplinary team.

Evidence for HBOT Remains Promising but Inconclusive

The role of HBOT in NSTIs remains debated because randomized controlled trial evidence is lacking. Existing studies are primarily retrospective cohorts, registry analyses, case series, and observational comparisons. These designs are vulnerable to selection bias, differences in disease severity, variation in surgical timing, and differences between hospitals that do and do not have hyperbaric capability.

A 2024 analysis of more than 60,000 surgically treated NSTI admissions in the United States found that fewer than 1 percent received HBOT. After statistical adjustment, HBOT was associated with lower in-hospital mortality and amputation risk, but it was also associated with longer hospitalization and higher cost. The study could not identify treatment pressure, number of sessions, or timing in relation to surgery, and its authors called for a multicenter randomized trial. (PLOS)

A 2025 Scandinavian prospective observational cohort also reported an association between HBOT and lower 30-day mortality. Because treatment was not randomly assigned, the authors still considered a randomized trial necessary to establish whether HBOT itself caused the observed difference. (PubMed)

Professional guidance reflects this uncertainty. UHMS recognizes HBOT as an accepted adjunct to surgery, antibiotics, and critical care for NSTIs. In contrast, the IDSA guideline does not recommend HBOT for clostridial gas gangrene because benefit had not been proven and treatment could delay resuscitation and debridement. (UHMS)

These positions are less contradictory than they initially appear. Both place immediate surgery and resuscitation first. The difference is whether HBOT should be incorporated after those priorities have been protected.

Recovery Often Continues After Infection Control

Surviving the acute infection is only the first stage of recovery. Extensive debridement may leave large wounds, exposed structures, functional impairment, or loss of a limb. Patients may require negative-pressure wound therapy, additional debridement, skin grafting, flap reconstruction, ostomy care, rehabilitation, prosthetic services, or long-term wound management.

The psychological impact can also be substantial. A patient may awaken after emergency surgery with a dramatically altered body, prolonged hospitalization, or uncertainty about future function. Clear communication, pain control, rehabilitation planning, and mental health support should be treated as core components of care.

HBOT may support oxygenation and host response during the active infection, but it is only one part of a much larger clinical effort. The strongest treatment plan remains one that moves quickly, prioritizes source control, coordinates multidisciplinary care, and introduces hyperbaric oxygen only when it can be delivered without compromising lifesaving treatment.

The Clinical Role of HBOT in Refractory Bone Infection

Osteomyelitis is an infection involving bone or bone marrow. It may develop through bloodstream spread, direct contamination after trauma or surgery, extension from a nearby wound, or infection associated with orthopedic hardware. Treatment can be difficult because infected bone may contain poorly perfused tissue, necrotic fragments, bacterial biofilm, and structural areas that systemic antibiotics cannot easily reach.

Most cases of osteomyelitis are treated with antimicrobial therapy, surgical source control, or a combination of both. Hyperbaric oxygen therapy, commonly abbreviated as HBOT, is not a first-line treatment for uncomplicated bone infection. Its recognized role is primarily as an adjunct for chronic refractory osteomyelitis that persists or recurs despite appropriate medical and surgical management. Medicare coverage similarly identifies chronic refractory osteomyelitis that has not responded to conventional treatment as a covered HBOT condition. (UHMS)

What Is Refractory Osteomyelitis?

Refractory osteomyelitis generally refers to a bone infection that persists or returns after appropriate treatment has been attempted. It may also describe an acute infection that continues to progress despite accepted management.

The term should not be applied simply because osteomyelitis requires several weeks of antibiotics. Bone infections commonly need prolonged treatment, and radiographic abnormalities may remain visible after the patient has begun to improve. Persistent imaging changes alone do not necessarily establish treatment failure.

A refractory infection is more likely to involve evidence such as:

• Continued or recurrent drainage
• Persistent exposed or necrotic bone
• Recurrent abscess formation
• Failure of a surgical site or wound to progress
• Ongoing positive cultures
• Persistent systemic or local signs of infection
• Worsening pain or structural instability
• Inflammatory markers that fail to improve in the appropriate clinical context

Definitions and monitoring methods vary according to the anatomic site. For native vertebral osteomyelitis, the Infectious Diseases Society of America recommends interpreting symptoms, examination findings, inflammatory markers, microbiology, and imaging together. Persistent pain, neurologic deficits, elevated inflammatory markers, or abnormal imaging findings considered individually do not necessarily prove that treatment has failed. (Infectious Diseases Society of America)

Before labeling an infection refractory, the clinical team should determine whether the original diagnosis was correct, whether the causative organism was identified, whether the antimicrobial regimen was appropriate, and whether residual infected or necrotic tissue remains.

Why Bone Infections Can Be Difficult to Eradicate

Healthy bone is living, vascular tissue that continually remodels. Osteomyelitis can disrupt that environment by damaging the microcirculation and separating devitalized bone from its blood supply.

A fragment of necrotic bone, known as a sequestrum, may serve as a protected surface for microorganisms. Antibiotics delivered through the bloodstream may have limited access to this nonviable tissue. Infections involving plates, screws, prosthetic material, or other implanted hardware may also develop biofilm, a structured microbial community that adheres to a surface and becomes more tolerant of antimicrobial therapy and host immune defenses.

Several clinical factors can further complicate treatment:

• Peripheral artery disease
• Diabetes and impaired glucose control
• Tobacco exposure
• Malnutrition
• Chronic edema
• Immune suppression
• Renal disease
• Extensive trauma or soft-tissue loss
• Prior radiation exposure
• Inability to remove infected hardware
• Infection involving the spine, skull, sternum, or another surgically challenging site

These factors do not automatically establish an indication for HBOT. They help explain why some infections remain active even after an apparently appropriate course of care.

How HBOT May Affect Infected Bone

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. The elevated oxygen partial pressure substantially increases the amount of oxygen dissolved in plasma and can raise oxygen tension in tissues supplied by functioning blood vessels.

In refractory osteomyelitis, several physiologic effects may be clinically relevant.

HBOT may improve oxygen availability in hypoxic bone and surrounding soft tissue. This matters because immune cells use oxygen-dependent mechanisms to kill certain microorganisms. Severe local hypoxia can impair this oxidative activity even when circulating leukocyte numbers are normal.

Controlled hyperoxia may also support:

• Leukocyte oxidative killing
• Angiogenic signaling and development of new microvessels
• Osteoblast and osteoclast activity involved in bone remodeling
• Collagen formation and soft-tissue repair
• Reduction of edema around compromised tissue
• Activity of selected antimicrobial agents
• Host response in areas with impaired local perfusion

These mechanisms are complementary rather than curative on their own. HBOT does not remove sequestra, drain an abscess, stabilize an infected fracture, restore flow through an obstructed artery, or eliminate a colonized implant. Reviews from the Undersea and Hyperbaric Medical Society emphasize that the best outcomes are generally obtained when HBOT is delivered alongside culture-directed antibiotics and appropriate surgical management. (PubMed)

Surgery Remains Central to Source Control

When necrotic bone, purulent material, unstable tissue, or infected hardware is present, surgery often remains an essential part of treatment.

Depending on the location and severity of the infection, surgical management may include:

• Drainage of an abscess
• Excision of sinus tracts
• Debridement of necrotic soft tissue
• Resection of infected or nonviable bone
• Removal or exchange of orthopedic hardware
• Stabilization of the affected bone
• Dead-space management
• Soft-tissue coverage or reconstructive surgery
• Partial amputation when tissue cannot be preserved safely

HBOT should not be used to postpone urgent source control. A patient with sepsis, progressive neurologic compromise, an undrained abscess, extensive necrosis, or mechanical instability requires prompt evaluation by the appropriate surgical and infectious-disease teams.

There are circumstances in which extensive surgery or hardware removal may carry substantial risk. Cranial, spinal, sternal, and pediatric osteomyelitis can present situations in which aggressive resection is technically difficult or potentially disabling. In selected cases, a coordinated trial of limited surgery, culture-directed antibiotics, and HBOT may be considered when the expected harm of more extensive intervention is high. (PubMed)

Culture-Directed Antibiotic Therapy Is Still Required

HBOT is not an antibiotic and should not be used as a substitute for microbiologic diagnosis or systemic antimicrobial therapy.

Whenever clinically feasible, deep tissue or bone cultures should be obtained to identify the causative organism and guide treatment. Superficial wound swabs may not accurately represent organisms within infected bone. The most useful specimen is generally obtained from bone or deep tissue using a technique that minimizes contamination.

Antibiotic selection depends on:

• The identified organism
• Susceptibility results
• The anatomic site
• Bone penetration and bioavailability
• Renal and hepatic function
• Allergies and medication interactions
• Presence of hardware or biofilm
• Surgical findings
• Previous antimicrobial exposure

The required duration varies considerably. IDSA guidance for native vertebral osteomyelitis recommends approximately six weeks of parenteral or highly bioavailable oral antimicrobial therapy for most bacterial cases. For diabetes-related foot osteomyelitis, guideline recommendations distinguish between infections managed with bone resection or amputation and those treated without bone removal. These examples illustrate why treatment duration must be based on the infection site and clinical scenario rather than a universal osteomyelitis schedule. (Infectious Diseases Society of America)

When HBOT May Be Considered

A hyperbaric consultation may be reasonable when osteomyelitis has continued or recurred despite a coordinated treatment plan that includes appropriate antimicrobial therapy and surgical evaluation.

Potential candidates may include patients with:

• Chronic refractory osteomyelitis after conventional treatment
• Recurrent infection following apparently adequate surgery and antibiotics
• Compromised local tissue oxygenation or vascularity
• Extensive disease with significant host or local risk factors
• Infection in a location where radical debridement would create major morbidity
• Persistent infection associated with hardware that cannot be removed safely
• Complex post-traumatic osteomyelitis
• Selected diabetic foot wounds with associated bone infection
• Osteomyelitis complicated by difficult soft-tissue reconstruction

The decision should be made by a multidisciplinary team whenever possible. The team may include orthopedic surgery, podiatric surgery, infectious disease, plastic surgery, vascular surgery, wound care, radiology, and hyperbaric medicine.

The presence of osteomyelitis alone is not enough. The team should identify why conventional treatment has failed and whether HBOT addresses a meaningful component of that failure.

Diabetic Foot Osteomyelitis Requires Careful Classification

Osteomyelitis associated with a diabetic foot ulcer deserves particular attention because HBOT may be considered under more than one clinical framework.

A patient may qualify for HBOT because of chronic refractory osteomyelitis. A different patient may qualify because of a sufficiently advanced diabetic lower-extremity wound that has not responded to standard wound care. These pathways overlap, but they are not identical.

The IWGDF/IDSA diabetic foot infection guideline advises against using HBOT solely for the purpose of treating a diabetic foot infection. This does not mean HBOT can never be used when a diabetic foot ulcer also contains infected bone. It means that HBOT should not replace surgical drainage, debridement, systemic antibiotics, vascular assessment, or other established infection treatment. (Infectious Diseases Society of America)

For a diabetic foot ulcer with osteomyelitis, the treatment plan should also address:

• Pressure offloading
• Peripheral artery disease
• Glucose management
• Wound debridement
• Soft-tissue infection
• Nutritional status
• Edema
• Foot deformity
• Appropriate footwear and recurrence prevention

When infection and peripheral artery disease occur together, urgent surgical and vascular consultation may be required to coordinate drainage, debridement, and revascularization. (Infectious Diseases Society of America)

Evaluating a Patient Before Hyperbaric Treatment

A hyperbaric evaluation should confirm both the clinical indication and the patient’s ability to tolerate treatment safely.

The medical review commonly includes:

• History of the infection and previous treatment
• Surgical and pathology reports
• Culture and antimicrobial records
• Imaging findings
• Presence and status of orthopedic hardware
• Vascular assessment
• Current wounds, drainage, or exposed bone
• Inflammatory-marker trends
• Diabetes and glucose-management needs
• Pulmonary and cardiovascular history
• Ear and sinus pressure-equalization ability
• Medication and implanted-device review

MRI is frequently used to define the extent of osteomyelitis and associated soft-tissue disease, although postoperative changes and chronic abnormalities can complicate interpretation. Other imaging methods may be selected when MRI is contraindicated or when the clinical question requires a different modality. IDSA guidance for suspected vertebral osteomyelitis recommends MRI as the preferred initial imaging study and identifies nuclear imaging, CT, or PET as possible alternatives in selected circumstances. (Infectious Diseases Society of America)

The evaluation should also determine whether the patient is receiving adequate nutrition, antimicrobial therapy, pressure relief, vascular care, and wound management. HBOT is less likely to help when these foundational issues remain unresolved.

What an HBOT Course May Involve

HBOT protocols for refractory osteomyelitis are individualized according to infection severity, anatomic location, surgical timing, comorbidities, and response.

A commonly described approach involves treatment once daily, five to seven days per week, at approximately 2.0 to 3.0 atmospheres absolute. Oxygen exposure commonly lasts 90 to 120 minutes, with air breaks incorporated when appropriate. A course may continue for approximately four to six weeks, although some patients require fewer or additional sessions. (PubMed)

HBOT may be started after debridement, delivered during an extended antimicrobial course, or coordinated around staged reconstructive procedures. There is no single protocol appropriate for every bone infection.

During treatment, clinicians should continue to evaluate:

• Wound appearance and drainage
• Pain and functional status
• Evidence of recurrent abscess
• Inflammatory-marker trends
• Antimicrobial tolerance
• Vascular status
• Surgical or reconstructive progress
• Treatment attendance and tolerance
• New signs of systemic infection

A predetermined number of sessions should not prevent reassessment. Lack of meaningful progress should prompt the team to reconsider residual necrotic bone, inadequate source control, resistant organisms, biofilm, impaired blood flow, nonadherence, or an alternative diagnosis.

Risks and Practical Considerations

HBOT is generally well tolerated when patients are appropriately screened, but treatment is not risk free.

Potential complications include:

• Middle-ear or sinus barotrauma
• Temporary myopic vision changes
• Claustrophobia or anxiety
• Blood glucose instability
• Pulmonary oxygen effects
• Rare oxygen-induced seizure

An untreated pneumothorax is generally considered an absolute contraindication. Significant pulmonary disease, inability to equalize ear pressure, unstable heart failure, seizure risk, medication interactions, and implanted devices require individualized evaluation.

The treatment schedule can also be demanding. A patient may need daily chamber sessions while receiving intravenous antibiotics, undergoing dressing changes, attending surgical appointments, and managing limited mobility. Transportation, caregiver support, employment obligations, and treatment fatigue should be considered before beginning a lengthy course.

These practical barriers are not secondary concerns. A clinically appropriate treatment can only be effective when the patient can participate in the complete care plan.

What the Evidence Shows

The evidence supporting HBOT for refractory osteomyelitis is based largely on physiologic studies, animal research, observational cohorts, case series, and systematic reviews of nonrandomized data.

No randomized clinical trials have directly established the effect of HBOT in refractory osteomyelitis. Published reports generally describe favorable outcomes when HBOT is added to surgery and culture-directed antimicrobial therapy, but differences in infection location, patient selection, treatment protocols, follow-up, and definitions of remission limit certainty. (PubMed)

More recent observational research continues to evaluate outcomes and factors associated with treatment failure, but it does not remove the need for controlled trials. HBOT should therefore be presented as an evidence-supported adjunct for selected refractory cases, not as a guaranteed cure or routine treatment for every bone infection. (PubMed)

Medicare recognizes chronic refractory osteomyelitis that is unresponsive to conventional medical and surgical management as a covered indication for chamber-based HBOT. Coverage requirements and documentation standards may vary among insurers and do not independently establish that treatment is appropriate for a particular patient. (Centers for Medicare & Medicaid Services)

The strongest clinical rationale exists when the infection remains active despite appropriate care, viable tissue can still be preserved, and increased tissue oxygenation can complement a clear surgical and antimicrobial strategy.

Hyperbaric therapy works best as part of a disciplined effort to control infection, preserve function, and restore healthy tissue. For patients facing repeated procedures, prolonged antibiotics, or the possibility of losing bone or limb function, that coordinated approach should remain clinically rigorous while recognizing the significant personal burden of living with a persistent bone infection.

How Hyperbaric Oxygen Therapy May Support Healing in Selected Complex Diabetic Foot Wounds

A diabetic foot ulcer is rarely caused by one problem alone. Peripheral neuropathy may prevent a person from feeling repetitive pressure or minor trauma. Foot deformity can concentrate mechanical stress in a small area. Peripheral artery disease may reduce blood flow, while impaired immune function, infection, edema, and metabolic dysfunction further limit tissue repair.

Once an ulcer develops, these factors can reinforce one another. Continued pressure causes additional tissue damage, ischemia limits oxygen delivery, and infection increases local oxygen demand. The result may be a wound that remains open despite appropriate care and places the patient at risk for hospitalization, osteomyelitis, tissue loss, or amputation.

Hyperbaric oxygen therapy, or HBOT, may be considered for a carefully selected subset of these wounds. It is not intended for every diabetic foot ulcer, and it does not replace revascularization, debridement, offloading, antimicrobial therapy, or diabetes management. Its role is adjunctive: to improve oxygen availability within viable but hypoxic tissue while the underlying causes of the wound are addressed.

Why Diabetic Foot Ulcers Become Hypoxic

Wound healing depends on an adequate supply of oxygen. Oxygen supports cellular energy production, collagen synthesis, fibroblast activity, angiogenesis, epithelial migration, and the oxidative mechanisms used by leukocytes to kill certain microorganisms.

In a diabetic foot ulcer, oxygen delivery may be impaired at several levels. Peripheral artery disease can reduce blood flow into the foot. Microvascular dysfunction can affect the distribution of oxygen within tissue. Edema can increase the distance oxygen must diffuse between functioning capillaries and cells. Infection and inflammation can raise metabolic demand at the same time that supply is falling.

Neuropathy creates an additional challenge. Because protective sensation is diminished, the patient may continue to walk on the injured area without experiencing the pain that would normally limit activity. Repeated pressure and shear can damage newly forming tissue faster than the wound can repair itself.

A normal pulse oximetry reading does not rule out local wound hypoxia. Pulse oximetry measures hemoglobin saturation in arterial blood, not oxygen tension in the tissue surrounding a foot ulcer. A patient may have normal systemic oxygen saturation while the wound bed and adjacent tissue remain poorly oxygenated.

How Hyperbaric Oxygen Therapy Affects a Diabetic Foot Wound

During HBOT, the patient breathes oxygen while exposed to increased atmospheric pressure inside a medical hyperbaric chamber. Increased pressure raises the partial pressure of oxygen in the lungs and substantially increases the amount of oxygen dissolved directly in plasma.

This oxygen-rich plasma can reach functioning microvessels and create a stronger diffusion gradient between capillary blood and hypoxic tissue. Oxygen may then travel farther from the capillary than it can under normal atmospheric conditions.

For a diabetic foot ulcer, the relevant physiologic effects may include:

• Temporary elevation of oxygen tension in hypoxic tissue
• Support for oxygen-dependent fibroblast and collagen activity
• Promotion of angiogenic signaling and capillary development
• Improved oxygen-dependent leukocyte function
• Modulation of inflammation and leukocyte-endothelial adhesion
• Hyperoxic vasoconstriction that may help reduce edema
• Support for metabolically stressed but still viable tissue

The treatment does not force blood through a completely obstructed artery. Some degree of perfusion is still necessary to transport oxygen toward the wound. Significant arterial disease must therefore be identified and corrected when feasible before HBOT is expected to support healing.

The International Working Group on the Diabetic Foot notes that oxygen is involved in angiogenesis, collagen deposition, and epithelialization. Its 2023 wound-healing guideline conditionally recommends considering HBOT for neuro-ischemic or ischemic diabetes-related foot ulcers when standard care has failed and appropriate treatment resources already exist. The certainty of evidence supporting that recommendation was rated low. (IWGDF Guidelines)

Which Diabetic Foot Ulcers May Be Appropriate for HBOT?

The presence of diabetes and an open foot wound does not, by itself, establish an indication for HBOT. The wound should be thoroughly evaluated to determine its depth, perfusion, infection status, mechanical causes, healing trajectory, and response to standard care.

In the United States, Medicare coverage for diabetic lower-extremity wounds generally requires all three of the following:

• The patient has type 1 or type 2 diabetes and a lower-extremity wound caused by diabetes
• The wound is classified as Wagner grade 3 or higher
• The wound has failed an adequate course of standard wound therapy

For coverage purposes, failure of standard care is defined as no measurable signs of healing for at least 30 consecutive days. HBOT must be provided in addition to continued standard wound care, and the wound must be reassessed at least every 30 days during treatment. (Centers for Medicare & Medicaid Services)

A Wagner grade 3 ulcer typically extends into deeper structures and may involve an abscess, tendon, joint, or bone infection. Grade 4 describes localized gangrene, while grade 5 describes extensive gangrene of the foot.

The Wagner system is useful for describing wound depth and tissue loss, but it does not fully characterize ischemia or infection severity. Clinicians may also use the Wound, Ischemia, and foot Infection classification, known as WIfI, and the IWGDF/IDSA infection classification to guide vascular, surgical, and infectious-disease decisions.

The Undersea and Hyperbaric Medical Society clinical practice guideline suggests HBOT for Wagner grade 3 or higher ulcers that have not shown significant improvement after 30 days of standard care. It also addresses selected acute postoperative wounds following surgical treatment of an infected diabetic foot. HBOT is not generally suggested for Wagner grade 2 or lower ulcers solely to promote healing. (UHMS)

Standard Diabetic Foot Ulcer Care Must Come First

HBOT is most appropriately considered after the fundamentals of diabetic foot care have been implemented and any correctable barriers to healing have been addressed.

Standard care should include:

• Vascular assessment and revascularization when indicated
• Effective offloading of the ulcerated area
• Debridement of devitalized or infected tissue
• Diagnosis and treatment of clinically significant infection
• Moisture-balanced wound management
• Optimization of glucose management
• Nutritional assessment and support
• Management of edema and other comorbid conditions
• Regular measurement and documentation of wound progress

CMS specifically identifies vascular assessment, correction of vascular problems when possible, nutritional optimization, glucose management, debridement, moist wound care, offloading, and infection treatment as components of standard diabetic wound care. (Centers for Medicare & Medicaid Services)

Offloading is particularly important. Even an advanced wound product or adjunctive therapy may fail when the patient continues to place excessive pressure on a plantar ulcer. The offloading plan must be clinically effective and realistic for the patient’s mobility, balance, home environment, and daily responsibilities.

Similarly, HBOT should not delay revascularization. A patient with clinically significant ischemia requires prompt vascular evaluation. Oxygen delivered under pressure may improve diffusion from vessels that are still functioning, but it cannot substitute for restoring adequate macroscopic blood flow.

HBOT Is Not a Stand-Alone Treatment for Infection

Many advanced diabetic foot ulcers are complicated by soft-tissue infection or osteomyelitis. HBOT may improve tissue oxygenation and support oxygen-dependent leukocyte activity, but it is not a substitute for infection source control.

An infected diabetic foot may require urgent:

• Surgical drainage
• Excisional debridement
• Bone resection or limited amputation
• Culture-directed antimicrobial therapy
• Vascular intervention
• Hospitalization and systemic support

The IWGDF/IDSA guideline recommends diagnosing diabetic foot infection clinically, based on local or systemic signs of inflammation, and grading its severity using the IWGDF/IDSA system. It also advises against using antibiotics for clinically uninfected ulcers solely to prevent infection or promote healing. (OUP Academic)

HBOT should not be prescribed simply because an ulcer culture contains bacteria. Chronic wounds are commonly colonized, and a positive culture alone does not establish invasive infection. The clinical team must distinguish colonization from infection and determine whether soft tissue, bone, or systemic structures are involved.

Vascular Assessment and Tissue Oxygen Testing

Peripheral artery disease is common in patients with diabetes-related foot ulcers and strongly influences healing potential. Assessment may include pedal pulse examination, Doppler waveforms, ankle pressures, toe pressures, ankle-brachial index, skin perfusion pressure, transcutaneous oxygen measurement, or vascular imaging.

The ankle-brachial index can be difficult to interpret in diabetes because medial arterial calcification may make vessels poorly compressible and produce falsely elevated measurements. Toe pressure and waveform-based assessment may provide additional information.

Transcutaneous oxygen measurement, often abbreviated TcPO₂ or TCOM, may be used by some programs to assess local tissue oxygenation and the wound’s response to supplemental or hyperbaric oxygen. Measurements can help clinicians understand whether the surrounding tissue is severely hypoxic and whether oxygen delivery improves under test conditions.

No single oxygen measurement should be interpreted in isolation. Results must be considered alongside vascular anatomy, wound characteristics, infection status, edema, temperature, technical quality, and the overall clinical picture. A favorable oxygen response does not correct inadequate offloading or untreated infection, while a poor result may prompt further vascular evaluation before an HBOT course is started.

What a Course of HBOT May Involve

Treatment protocols are prescribed by a hyperbaric physician according to the wound, patient risk factors, chamber system, and clinical response.

Many chronic-wound protocols use pressures between approximately 2.0 and 2.5 atmospheres absolute, with 60 to 90 minutes of oxygen breathing at treatment pressure. Treatments are often scheduled five days per week over several weeks, although the pressure, duration, air breaks, and total number of sessions vary. (UHMS)

A typical visit includes:

1. Pre-treatment assessment, including review of symptoms, medications, glucose status, and ear-clearing ability.
2. Removal of prohibited items and preparation according to hyperbaric fire-safety requirements.
3. Gradual chamber compression.
4. Oxygen exposure at the prescribed treatment pressure.
5. Air breaks when included in the protocol.
6. Controlled decompression and post-treatment assessment.

Patients with diabetes commonly require blood glucose testing before treatment. Depending on their medication regimen and clinical risk, glucose may also be checked after treatment. Meal timing, insulin administration, glucose trends, and symptoms of hypoglycemia should be reviewed throughout the course.

The wound should continue to be measured regularly. HBOT should not continue automatically because a predetermined number of sessions was ordered. The team should reassess perfusion, infection, offloading adherence, wound area, tissue quality, and overall progress.

What the Evidence Shows About Healing and Amputation

The evidence for HBOT in diabetic foot ulcers remains clinically promising but methodologically mixed. Trials have used different ulcer classifications, levels of ischemia, treatment protocols, definitions of healing, follow-up periods, and amputation outcomes. Some studies have been small or at high risk of bias.

The 2023 IWGDF review found conflicting results. The studies with the lowest risk of bias suggested possible improvement in complete wound healing and ulcer-area reduction, but the guideline found insufficient evidence to establish a reliable reduction in amputation. It therefore issued a conditional recommendation based on low-certainty evidence. (IWGDF Guidelines)

A 2024 systematic review and meta-analysis reported improved complete healing with HBOT but did not find a statistically significant effect on major or minor amputation rates. These findings illustrate why outcomes should not be presented as guaranteed and why careful patient selection remains essential. (PubMed)

Differences in the evidence do not mean HBOT has no clinical role. They indicate that benefit is unlikely to be uniform across all diabetic foot ulcers. A deeply infected or ischemic wound that remains hypoxic despite optimized care is clinically different from a superficial neuropathic ulcer that has not been adequately offloaded.

Risks and Practical Barriers to Treatment

HBOT is generally well tolerated in appropriately screened patients, but it is not risk free. Potential adverse effects include:

• Middle-ear or sinus barotrauma
• Temporary myopic vision changes
• Blood glucose instability
• Claustrophobia or anxiety
• Pulmonary oxygen effects
• Rare oxygen-induced seizure

An untreated pneumothorax is generally considered an absolute contraindication. Pulmonary disease, inability to equalize ear pressure, seizure risk, heart failure, implanted devices, medication interactions, and severe confinement anxiety require individual assessment.

The treatment course may also be demanding. Patients may need transportation to a hyperbaric center five days per week while simultaneously attending wound-care, vascular, infectious-disease, surgical, endocrinology, or rehabilitation appointments. Mobility limitations, caregiver responsibilities, work schedules, and financial strain can affect completion.

These barriers should be discussed honestly before treatment. A compassionate care plan considers not only whether a patient is medically eligible, but whether the complete wound-healing strategy is practical and sustainable.

Measuring Whether HBOT Is Helping

The purpose of HBOT is not simply to complete a series of chamber sessions. It is to contribute to measurable clinical progress.

Indicators of improvement may include:

• Reduction in wound area, depth, or volume
• Improved granulation tissue
• Reduced devitalized tissue
• Stabilization of wound margins
• Improved control of edema or local inflammation
• Progress toward reconstructive closure
• Preservation of viable tissue after surgery
• Avoidance of further tissue loss

A wound that is not progressing requires renewed assessment. Persistent failure may reflect inadequate perfusion, continued pressure, residual infection, unrecognized osteomyelitis, poor glucose control, malnutrition, tobacco exposure, edema, or an incorrect diagnosis.

HBOT should remain one component of a coordinated limb-preservation strategy. The best candidate is not simply a person with diabetes and a difficult wound. It is a patient with an appropriately classified, viable, hypoxic or ischemic ulcer for whom standard care has been optimized, correctable vascular problems have been addressed, and adjunctive oxygen therapy offers a clinically reasonable opportunity to support healing.

A Clinical Guide to Patient Selection, Pressure-Related Injury, Oxygen Toxicity, Medication Considerations, and Risk Reduction

Hyperbaric oxygen therapy is generally well tolerated when it is prescribed appropriately and delivered by trained personnel in a medically supervised setting. Most adverse effects are mild, temporary, and manageable. However, HBOT exposes the body to increased ambient pressure and elevated oxygen partial pressure, creating risks that require careful screening and monitoring.

A contraindication does not always mean that treatment can never be performed. In many cases, it identifies a condition that must be stabilized, investigated, or managed before the patient enters the chamber. The decision should consider the urgency of the indication, the expected clinical benefit, the available chamber system, and the facility’s ability to manage the patient safely.

The Absolute Contraindication to Hyperbaric Oxygen Therapy

An untreated pneumothorax is generally recognized as the primary absolute contraindication to HBOT.

A pneumothorax occurs when gas enters the pleural space between the lung and chest wall. During decompression, trapped pleural gas can expand as ambient pressure falls. If the gas cannot escape, it may compress the affected lung, shift mediastinal structures, impair venous return, and develop into a life-threatening tension pneumothorax.

A patient with a known pneumothorax generally requires appropriate chest drainage before hyperbaric exposure. In an emergency where HBOT is urgently indicated, such as severe arterial gas embolism or carbon monoxide poisoning, the clinical team must address the pneumothorax while coordinating treatment with specialists experienced in critical care and hyperbaric medicine. (NCBI)

A remote history of pneumothorax is not automatically an absolute contraindication. It does warrant evaluation of the underlying cause, recurrence risk, previous treatment, current pulmonary status, and available imaging.

Relative Contraindications Require Individual Assessment

Most other HBOT contraindications are relative rather than absolute. A relative contraindication means that treatment may carry an increased risk, but the risk may be reduced through additional testing, treatment modification, consultation, or closer monitoring.

Common relative contraindications and precautions include:

• Pulmonary blebs, bullae, or significant air trapping
• Chronic obstructive pulmonary disease with carbon dioxide retention
• Active upper respiratory or sinus infection
• Inability to equalize middle-ear pressure
• Uncontrolled fever
• Poorly controlled seizure disorder
• Severe claustrophobia or confinement anxiety
• Unstable cardiovascular disease
• Decompensated heart failure
• Uncontrolled blood glucose
• Pregnancy, depending on the indication
• Certain current or previous medications
• Implanted medical devices without a verified pressure rating

These conditions should not be treated as a universal list of automatic exclusions. Their importance depends on the individual patient and the reason HBOT is being considered.

For example, pregnancy may lead clinicians to avoid elective or nonurgent HBOT when maternal and fetal benefit is uncertain. In severe carbon monoxide poisoning, however, hyperbaric treatment may be considered because carbon monoxide presents a significant risk to both the pregnant patient and fetus. (NCBI)

Middle-Ear Barotrauma

Middle-ear barotrauma is the most frequently reported adverse effect of HBOT. It occurs when pressure in the middle ear does not equalize with the rising chamber pressure during compression. (PubMed Central (PMC))

Patients may experience:

• Ear fullness or pressure
• Increasing ear pain
• Reduced hearing
• Tinnitus
• Dizziness
• Fluid or bleeding behind the tympanic membrane
• Tympanic membrane injury in more severe cases

The risk is greater in patients with eustachian tube dysfunction, congestion, previous ear surgery, radiation-related tissue changes, altered mental status, or an inability to understand and perform equalization techniques.

Before treatment, patients should be taught how to equalize pressure by swallowing, yawning, moving the jaw, or performing an appropriate pressure-equalization maneuver. Compression should be slowed or paused when discomfort develops. Continuing compression through significant pain increases the likelihood of injury.

Patients who repeatedly cannot equalize may require evaluation by an otolaryngologist. Tympanostomy tubes may be considered when a prolonged HBOT course is necessary and conservative strategies are unsuccessful.

Children, sedated patients, intubated patients, and individuals with cognitive impairment may be unable to report symptoms promptly. These patients require a plan that accounts for their limited ability to participate in equalization.

Sinus and Dental Barotrauma

The paranasal sinuses are also vulnerable to pressure-related injury. Swelling, infection, polyps, mucosal inflammation, or structural obstruction can prevent gas from moving freely between a sinus cavity and the surrounding environment.

Sinus barotrauma may cause facial pressure, localized pain, headache, dental discomfort, or nasal bleeding. Symptoms often occur during compression, but reverse-block symptoms can develop during decompression if gas becomes trapped within a sinus.

Patients should report new congestion or respiratory illness before each treatment. Delaying a nonurgent session may be safer than attempting treatment when pressure equalization is likely to be impaired.

Dental barotrauma is less common. It may occur when gas becomes trapped beneath a restoration, within a damaged tooth, or near recent dental work. Significant unexplained dental pain should be evaluated rather than attributed automatically to normal chamber pressure.

Pulmonary Barotrauma and Air Trapping

Pulmonary barotrauma is rare during routine clinical HBOT, but it can be serious. The greatest concern occurs when gas becomes trapped in a region of the lung and expands during decompression.

Potential complications include:

• Pneumothorax
• Pneumomediastinum
• Subcutaneous emphysema
• Pulmonary tissue injury
• Arterial gas embolism

Patients with severe obstructive lung disease, active bronchospasm, bullous lung disease, pulmonary cysts, previous spontaneous pneumothorax, or recent thoracic surgery may require pulmonary assessment and imaging before treatment.

Mechanical ventilation adds further complexity. Ventilator settings, endotracheal tube cuffs, airway pressures, breathing circuits, and device performance can be affected by changes in ambient pressure. Critically ill patients should be treated only in facilities equipped and staffed for hyperbaric critical care.

Patients should never hold their breath during decompression. Conscious patients are generally instructed to breathe normally so expanding gas can leave the lungs.

Central Nervous System Oxygen Toxicity

Breathing oxygen at elevated partial pressure can produce central nervous system oxygen toxicity. The most recognized manifestation is a generalized tonic-clonic seizure.

Oxygen-induced seizures are uncommon during standard clinical treatments and are typically self-limited after oxygen exposure is discontinued. They remain important because a seizure inside a chamber creates risks related to patient positioning, airway protection, aspiration, and the controlled management of chamber pressure. (UHMS)

Possible warning symptoms may include:

• Facial or lip twitching
• Nausea
• Visual changes
• Auditory changes
• Dizziness
• Irritability or unusual behavior
• Tingling sensations
• Confusion

These symptoms are not always present before a seizure.

Factors that may increase susceptibility include fever, hypoglycemia, carbon dioxide retention, certain medications, stimulant use, withdrawal states, a history of seizures, acute brain injury, and prolonged or higher-pressure oxygen exposure.

A previous seizure disorder is not necessarily an absolute contraindication. Clinicians should assess seizure control, medication adherence, recent events, fever, metabolic abnormalities, and other factors that may lower the seizure threshold. Treatment pressure, oxygen duration, and air-break scheduling may be adjusted when clinically appropriate. (NCBI)

If a seizure occurs, staff typically discontinue oxygen exposure when possible, protect the patient from injury, maintain airway safety, and follow the facility’s emergency protocol. Immediate uncontrolled decompression is generally avoided because rapid pressure reduction can introduce additional risk.

Pulmonary Oxygen Toxicity

Pulmonary oxygen toxicity is associated with excessive cumulative oxygen exposure. It is more relevant during prolonged treatment tables, repeated high-dose exposures, or unusually intensive treatment schedules than during many routine outpatient protocols.

Symptoms may include:

• Dry cough
• Substernal discomfort
• Chest tightness
• Shortness of breath
• Airway irritation
• Reduced pulmonary function

Routine clinical HBOT protocols are designed to limit this risk through controlled pressure, defined oxygen-breathing periods, air breaks when indicated, and limits on treatment duration. Pulmonary symptoms should still be evaluated, particularly in patients with underlying lung disease or previous exposure to pulmonary-toxic therapies. (PubMed Central (PMC))

Temporary Vision Changes and Ocular Risks

Repeated HBOT sessions can produce a temporary myopic shift. Patients may notice that distance vision becomes blurred while near vision remains stable or improves.

This change is believed to result primarily from oxygen-related alterations within the lens. It often develops gradually during a multiweek treatment course and commonly improves after treatment ends, although recovery may take several weeks or months. (UHMS)

Patients should be informed about this possibility before beginning a prolonged course. Purchasing new prescription lenses during treatment is often discouraged unless the visual change creates a significant functional or safety problem.

Cataract progression has also been reported, particularly with extensive cumulative oxygen exposure. Patients with significant preexisting ocular disease may require individualized assessment. The presence of an intraocular lens after cataract surgery does not create the same lens-related myopic response as a natural crystalline lens, but other ocular considerations may still apply.

New eye pain, visual field loss, flashes, floaters, or sudden major visual deterioration should not be assumed to be a routine HBOT effect. These symptoms require prompt ophthalmic evaluation.

Cardiovascular Risks and Heart Failure

Hyperbaric oxygen causes systemic vasoconstriction and can increase systemic vascular resistance. Heart rate and cardiac output may decrease during exposure. Many patients tolerate these changes without difficulty, but individuals with limited cardiac reserve require additional caution.

Patients with decompensated heart failure may be at increased risk of pulmonary congestion or pulmonary edema. HBOT may still be considered in selected patients after optimization of volume status, cardiac medications, and monitoring, particularly when the treatment indication is urgent or strongly supported.

The pre-treatment assessment should consider:

• Current dyspnea or orthopnea
• Recent weight gain or edema
• Left ventricular function
• Arrhythmias
• Blood pressure control
• Recent acute coronary syndrome
• Valvular disease
• Diuretic use
• Baseline oxygen and ventilation requirements

Chest pain, acute respiratory distress, new hypoxemia, or signs of pulmonary edema require immediate clinical assessment. Cardiovascular disease is not a single yes-or-no contraindication. Risk depends on stability, severity, treatment urgency, and the resources available within the hyperbaric facility.

Blood Glucose Changes During HBOT

Patients with diabetes may experience changes in blood glucose during the treatment period. Reduced food intake, insulin timing, oral medications, infection, treatment duration, and individual metabolic response can contribute to hypoglycemia.

Symptoms such as sweating, confusion, tremor, visual disturbance, or behavioral change may be difficult to distinguish from anxiety or oxygen-related neurologic symptoms inside the chamber.

Hyperbaric programs commonly establish protocols for:

• Pre-treatment glucose testing
• Meal and medication timing
• Minimum glucose thresholds
• Approved in-chamber glucose treatment
• Post-treatment reassessment
• Management of insulin pumps and continuous glucose monitors

A universal glucose cutoff is not appropriate for every patient. Decisions should account for the patient’s usual control, current trend, medication regimen, treatment length, chamber type, and ability to communicate symptoms. Blood glucose concerns should be addressed before compression whenever possible. (UHMS)

Medication and Chemotherapy Considerations

A complete medication history is essential before HBOT. The review should include current prescriptions, recently discontinued medications, chemotherapy history, over-the-counter products, supplements, substance use, and medication withdrawal.

Several medications have historically raised concern because of potential interactions with hyperoxia or pressure. Frequently discussed agents include:

• Doxorubicin
• Bleomycin
• Cisplatin
• Disulfiram
• Mafenide acetate

These medications should not be treated as a simple permanent exclusion list. The evidence, proposed mechanism, timing, dose, treatment indication, and patient condition differ for each agent.

Concurrent doxorubicin exposure has raised concern about enhanced cardiotoxicity. Previous bleomycin exposure requires assessment of pulmonary toxicity, cumulative dose, time since treatment, symptoms, and lung function. Cisplatin may raise concerns related to wound healing when HBOT is being used for a chronic wound. (PubMed)

In urgent situations, the risk of delaying HBOT may exceed the theoretical or known interaction risk. The decision should be made jointly by the hyperbaric physician and relevant specialists, such as oncology, pulmonology, cardiology, infectious disease, or clinical pharmacy.

Medication should not be stopped solely because a patient sees it on a general contraindication list. Unsupervised discontinuation can create greater harm than the potential interaction.

Claustrophobia, Anxiety, and Behavioral Considerations

Some patients experience significant anxiety in an enclosed chamber. Symptoms may include panic, rapid breathing, agitation, a sense of entrapment, or an urgent desire to end treatment.

Mild confinement anxiety can often be managed through education, chamber orientation, clear communication, visual contact, relaxation techniques, and gradual exposure. In some cases, medication may be considered after evaluating its effects on respiratory status, mental status, and seizure threshold.

Severe claustrophobia may prevent safe treatment if the patient cannot remain still, follow instructions, or communicate reliably. Chamber type can influence tolerance. A patient who cannot tolerate a monoplace chamber may feel more comfortable in a larger multiplace system, although the oxygen hood or mask used in a multiplace chamber can create a different form of confinement discomfort.

Anxiety should not be dismissed as a lack of cooperation. A patient who understands what will happen and trusts that the team will respond to distress is more likely to complete treatment safely.

Implanted and External Medical Devices

Pacemakers, implantable cardioverter-defibrillators, infusion pumps, neurostimulators, glucose-management devices, ventilators, and other medical equipment must be evaluated for use under pressure.

The exact manufacturer and model matter. A device approved for one pressure range may not be appropriate at another. Pressure can affect gas-filled components, seals, flow rates, alarms, battery performance, displays, and mechanical operation.

The facility should verify:

• The manufacturer’s pressure limit
• Compatibility with the prescribed treatment pressure
• Whether the device can remain active
• Whether programming changes are required
• Whether external equipment can remain outside the chamber
• The consequences of device failure
• The emergency plan if the device malfunctions

A device should not be cleared based solely on prior uneventful use in another patient. Evaluation and documentation must be specific to the device and treatment profile.

Fire and Chamber-Environment Risks

The oxygen-rich hyperbaric environment increases the ease and intensity of combustion. Oxygen is not itself flammable, but it supports rapid burning when fuel and an ignition source are present.

Potential hazards include unapproved electronics, batteries, synthetic clothing, petroleum-based products, hand warmers, lighters, aerosols, skin products, dressings, and medical equipment that has not been assessed for hyperbaric use.

In August 2025, the FDA emphasized proper grounding, fire prevention, staff training, equipment maintenance, and adherence to manufacturer instructions following reports of serious injuries and deaths involving HBOT devices. (U.S. Food and Drug Administration)

These environmental hazards are not patient contraindications in the traditional medical sense, but they can make treatment unsafe until the prohibited material is removed or replaced. Every item entering the chamber should be approved under the facility’s safety program.

Balancing HBOT Risks Against Clinical Benefit

HBOT risk assessment should be tied to the clinical indication. The acceptable level of risk may be different for an elective course treating delayed radiation injury than for an emergency involving arterial gas embolism, decompression sickness, or severe carbon monoxide poisoning.

A careful evaluation asks:

• Is HBOT supported for this diagnosis?
• How urgent is treatment?
• What is the expected benefit?
• Can the identified risks be corrected or reduced?
• Is additional imaging or specialist consultation needed?
• Does the patient require monoplace or multiplace capability?
• Can the facility provide the necessary monitoring?
• What are the risks of not treating?

Most HBOT complications can be reduced through appropriate patient selection, pressure-equalization coaching, controlled oxygen dosing, glucose management, medication review, equipment verification, and continuous observation.

The presence of a relative contraindication should prompt clinical reasoning, not automatic rejection. The goal is to determine whether HBOT can be delivered with a favorable risk-benefit balance and a safety plan tailored to the patient.

Clinical Systems for Patient Screening, Fire Prevention, Chamber Operations, Monitoring, and Emergency Response

Hyperbaric oxygen therapy places patients, personnel, medical equipment, and combustible materials in an environment where pressure and oxygen behave differently than they do under ordinary clinical conditions. These differences make hyperbaric medicine highly protocol driven.

Safe treatment requires more than operating a chamber correctly. It depends on coordinated clinical screening, fire prevention, equipment control, staff competency, continuous observation, preventive maintenance, and rehearsed emergency procedures.

In the United States, hyperbaric chambers are regulated as Class II medical devices. Facilities must operate each system according to its cleared intended use and the manufacturer’s instructions. Hyperbaric programs may also be subject to NFPA 99, healthcare accreditation requirements, building and fire codes, state regulations, and institutional policies. NFPA 99’s hyperbaric chapter addresses electrical, fire, pressure, and medical gas hazards associated with hyperbaric facilities. (NFPA LiNK)

Patient Screening Before Hyperbaric Oxygen Therapy

A comprehensive medical assessment should be completed before treatment begins. Screening identifies conditions that may increase the risks of pressure exposure, oxygen toxicity, barotrauma, glucose instability, or clinical deterioration inside the chamber.

The evaluation should consider:

• The clinical indication for HBOT
• Relevant pulmonary and cardiovascular history
• Previous pneumothorax or thoracic surgery
• Difficulty equalizing middle-ear or sinus pressure
• Seizure history and factors that may lower seizure threshold
• Diabetes and glucose-lowering medications
• Current respiratory infection, fever, or congestion
• Pregnancy status when clinically relevant
• Claustrophobia, anxiety, or cognitive impairment
• Implanted medical devices
• Medication interactions
• The patient’s ability to communicate during treatment
• The need for monitoring, ventilation, or other advanced support

An untreated pneumothorax presents a serious hazard because trapped pleural gas can expand during decompression. A history of spontaneous pneumothorax, significant pulmonary air trapping, bullous disease, or recent thoracic procedures also requires careful risk assessment. In emergency diving and hyperbaric situations, pneumothorax management may require specialized drainage and decompression strategies directed by experienced physicians. (UHMS)

Medication review is particularly important. Certain stimulants, psychiatric medications, antineoplastic agents, analgesics, antibiotics, withdrawal states, fever, and carbon dioxide retention may influence seizure risk or alter the patient’s response to hyperoxia. The hyperbaric physician should determine whether the medication can be continued, temporarily held, or accommodated through a modified treatment protocol. (UHMS)

Screening is not a one-time event. The clinical team should reassess the patient before every treatment because respiratory symptoms, medication use, glucose levels, wounds, dressings, and overall medical status can change during a treatment course.

Preventing Middle-Ear and Sinus Barotrauma

Pressure-related ear injury is among the most common complications of HBOT. During compression, the patient must actively equalize pressure between the middle ear and the chamber environment.

Before the first treatment, patients should be taught techniques such as swallowing, yawning, jaw movement, the Toynbee maneuver, or a gentle Valsalva maneuver when medically appropriate. Demonstration and coaching are more effective than simply instructing the patient to “clear the ears.”

Compression should be slowed or stopped when a patient reports pain, pressure, or an inability to equalize. Continuing compression against significant discomfort can produce tympanic membrane injury, middle-ear bleeding, or more severe barotrauma.

Patients with severe congestion, upper respiratory illness, sinus obstruction, previous ear surgery, or persistent equalization difficulty may require additional assessment. In selected cases, an otolaryngology evaluation or tympanostomy tube placement may be appropriate before continuing treatment. Patient preparation, staff vigilance, and early response to discomfort can substantially influence the frequency and severity of ear injuries. (UHMS)

Compassionate communication is also a safety intervention. Patients should know that reporting ear pain will not be viewed as noncompliance. Prompt reporting allows the operator to adjust compression before discomfort becomes an injury.

Fire Prevention in Hyperbaric Chambers

Fire is one of the most serious hazards in hyperbaric medicine. Oxygen does not ignite by itself, but increased oxygen concentration can lower ignition thresholds and cause combustible materials to burn more rapidly and intensely.

In August 2025, the FDA reminded healthcare providers to follow chamber manufacturers’ instructions, maintain staff training, use appropriate grounding, avoid prohibited or static-generating items, control clothing and linens, perform equipment maintenance, and maintain fire-prevention procedures. The communication followed reports of serious hyperbaric chamber fires that resulted in injuries and deaths. (U.S. Food and Drug Administration)

Every potential fuel and ignition source should be controlled. Items commonly restricted or prohibited unless specifically evaluated include:

• Cell phones, tablets, headphones, and personal electronics
• Battery-powered devices
• Lighters, matches, and heating elements
• Synthetic, wool, or silk clothing
• Petroleum-based products
• Alcohol-containing products that have not fully evaporated
• Aerosols
• Cosmetics, hair products, and certain skin preparations
• Unapproved blankets, pillows, or linens
• Hand warmers and chemical heat packs
• Medical equipment not evaluated for hyperbaric use

A product that is acceptable elsewhere in a hospital is not automatically safe inside a hyperbaric chamber. The hyperbaric safety program should require a documented risk assessment for every dressing, device, medication container, monitoring accessory, and patient-care item introduced into the chamber environment. The assessment should consider flammability, static generation, electrical energy, heat production, vapor release, battery chemistry, chamber atmosphere, and total fuel load. (UHMS)

Patients should change into facility-approved attire and remove personal belongings before treatment. In oxygen-filled monoplace chambers, proper grounding of the patient and chamber helps reduce static electricity risk. Grounding systems must be checked and maintained according to the chamber manufacturer’s instructions and applicable safety standards. (UHMS)

The Pre-Treatment Hyperbaric Safety Check

A standardized safety pause should occur before every chamber cycle. It provides a final opportunity to identify errors before the patient is exposed to increased pressure and oxygen.

The Undersea and Hyperbaric Medical Society recommends a documented process confirming the right patient, right treatment, and right safety conditions. (UHMS)

A pre-treatment check commonly verifies:

• Two patient identifiers
• The prescribed diagnosis and treatment profile
• Current vital signs and clinical stability
• Blood glucose when indicated
• Ear-equalization ability
• Removal of prohibited items
• Approved clothing, linens, and dressings
• Patient grounding for applicable monoplace systems
• Oxygen-delivery system fit and function
• Chamber communication
• Monitoring equipment operation
• Appropriate positioning of lines and tubes
• Emergency equipment availability
• Staff assignments and supervision
• Documentation of any protocol modification

The checklist should be specific enough to prevent omissions but brief enough to be performed consistently. Simply checking boxes without visually confirming the patient, chamber, and equipment can create a false sense of security.

Interruptions and unrelated activity should be limited during patient preparation and chamber operation. Hyperbaric safety guidance identifies distraction and complacency as factors that can contribute to mistakes. (UHMS)

Blood Glucose Management During HBOT

Patients with diabetes require a defined glucose-management protocol. Changes in meal timing, insulin administration, glucose-lowering medication, infection, physical stress, and the treatment schedule may contribute to glucose instability.

Facilities commonly check glucose before treatment and repeat testing afterward according to institutional policy and the patient’s clinical risk. The patient should also be assessed for recent hypoglycemia, reduced oral intake, changes in medication, and symptoms that could become difficult to interpret at pressure.

A low or rapidly falling glucose level should be corrected before treatment. Staff should know how glucose will be treated if symptoms develop inside the chamber and which carbohydrate products are approved for the specific chamber environment.

Numeric treatment thresholds should be established by the facility’s medical director rather than applied universally. Safe decisions depend on the patient’s baseline glucose, medication profile, recent trends, chamber type, treatment length, and access to the patient during the session. UHMS-associated nursing guidance emphasizes pre-treatment assessment, coordination with medication timing, and prevention of in-chamber hypoglycemia. (UHMS)

Monitoring Patients Under Pressure

Patients must remain under continuous observation throughout compression, oxygen exposure, air breaks, and decompression.

Monitoring should be appropriate to the patient’s acuity and may include:

• Visual observation
• Two-way voice communication
• Heart rate and blood pressure
• Cardiac rhythm
• Respiratory status
• Oxygen-delivery system performance
• Neurologic status
• Blood glucose
• Ventilator parameters
• Infusion status
• Pain, anxiety, or ear symptoms

Pulse oximetry has limited value for confirming the hyperbaric oxygen dose because hemoglobin is usually already highly saturated. It may still be useful for detecting equipment problems or changes during air breathing, depending on the clinical context.

The chamber operator should watch for early signs of oxygen intolerance, including facial twitching, visual changes, nausea, dizziness, unusual behavior, anxiety, or neurologic symptoms. Oxygen-induced seizures are uncommon but remain a recognized risk. If a seizure occurs, the immediate priorities are to protect the patient from injury, discontinue oxygen exposure when operationally possible, maintain the airway, and follow the facility’s emergency protocol. Decompression should be controlled because an uncontrolled pressure change can create additional risk.

The attending physician is responsible for selecting the treatment profile, managing complications, documenting the procedure, and ensuring that specialized nursing or respiratory support is available when required. (UHMS)

Medical Equipment and Implanted Devices

Medical devices must be evaluated before exposure to increased pressure or an oxygen-enriched environment. Pressure can affect gas-filled components, seals, displays, batteries, alarms, flow delivery, sensor accuracy, and mechanical performance.

The clinical team should confirm:

• The device manufacturer’s pressure rating
• Compatibility with the planned chamber atmosphere
• Whether the device contains a battery or ignition source
• Whether external components can remain outside the chamber
• How tubing and cables will pass through approved penetrators
• Whether pressure changes alter flow or dose delivery
• Whether emergency removal or disconnection is possible
• Whether testing or manufacturer consultation is required

Implanted devices require similar review. Pacemakers, defibrillators, infusion systems, pumps, neurostimulators, and other implants should not be cleared based only on the general device category. The exact manufacturer, model, programmed mode, and pressure limit should be verified.

The final decision should be documented by the hyperbaric physician and safety director using device labeling, manufacturer information, clinical necessity, and a formal risk assessment.

Chamber Operation and Preventive Maintenance

Hyperbaric chambers should be operated only by personnel trained for the specific system. Training must include normal operation, pressure control, oxygen delivery, patient communication, emergency decompression, fire response, equipment failure, and post-event reporting.

Preventive maintenance should follow the manufacturer’s schedule and applicable regulatory or accreditation requirements. Maintenance commonly includes inspection and testing of:

• Chamber doors and seals
• Pressure-control systems
• Relief valves
• Oxygen and air supplies
• Grounding systems
• Communications
• Fire-suppression equipment
• Oxygen-monitoring systems
• Electrical components
• Viewports
• Piping, valves, and penetrators
• Emergency controls

Maintenance records should identify the work performed, date, responsible technician, findings, corrective actions, and return-to-service authorization.

A chamber should not remain in operation simply because a defect appears minor. Changes in pressure performance, unusual sounds, oxygen leakage, failed communications, damaged seals, alarms, or inconsistent control behavior require evaluation before further patient use. The FDA specifically advises facilities to perform regular maintenance and follow each device’s instructions for use. (U.S. Food and Drug Administration)

Emergency Preparedness and Staff Drills

Hyperbaric emergencies are uncommon, which can make regular drills even more important. Staff must be able to respond without relying on improvisation during a high-pressure event.

Emergency procedures should address:

• Fire inside or near the chamber
• Loss of oxygen or compressed-air supply
• Power failure
• Communication failure
• Patient seizure
• Cardiac or respiratory arrest
• Acute chest pain or respiratory distress
• Suspected pneumothorax
• Severe hypoglycemia
• Oxygen-delivery system failure
• Unplanned decompression
• Entrapment or door malfunction
• Facility evacuation

Each protocol should define who stops oxygen flow, who initiates decompression, who contacts emergency services, who retrieves emergency equipment, and who maintains observation of other patients.

Multiplace programs also require clear inside-attendant staffing and decompression policies. Staff exposed to pressure must be medically fit, appropriately trained, and managed to limit occupational pressure and oxygen exposure. UHMS emphasizes that safe multiplace operations depend on appropriate patient-to-staff ratios and trained personnel both inside and outside the chamber. (UHMS)

Drills should be documented and evaluated. The purpose is not merely to prove that a drill occurred. It is to identify communication gaps, delayed actions, unclear responsibilities, inaccessible equipment, and steps that do not function as intended.

Documentation, Event Review, and Safety Culture

Every treatment record should document the prescribed protocol, pressure, oxygen periods, air breaks, treatment duration, patient response, monitoring, complications, and any deviation from the original plan.

Near misses should be reviewed with the same seriousness as events that cause harm. A prohibited item discovered before compression, a communication failure detected during setup, or an incorrect treatment profile caught during the safety pause provides valuable information about weaknesses in the system.

A strong hyperbaric safety culture gives all team members the authority to stop a treatment when a concern has not been resolved. This includes chamber operators, nurses, technicians, respiratory therapists, safety personnel, and physicians.

Patients also play an important role. They should be encouraged to report new medications, congestion, ear discomfort, low glucose symptoms, anxiety, and any personal item that may have been brought into the treatment area. Clear explanations help patients understand that chamber restrictions are not arbitrary. They are safeguards designed for an environment in which a seemingly ordinary object can create an unusual hazard.

Safe hyperbaric medicine depends on consistent execution. Patient screening, equipment review, fire prevention, staff training, treatment monitoring, and emergency preparedness must function as one integrated system. When safety becomes part of every clinical decision rather than a separate administrative exercise, the chamber environment can be managed with the discipline required for reliable, compassionate care.

A Clinical Comparison of Chamber Design, Oxygen Delivery, Patient Access, Safety, and Treatment Workflow

Hyperbaric oxygen therapy can be delivered in either a monoplace or multiplace chamber. Both systems expose the entire patient to increased atmospheric pressure while providing oxygen at a prescribed treatment dose. The principal differences involve how the chamber is pressurized, how oxygen is delivered, how many patients can be treated, and whether clinical personnel can remain inside during treatment.

Neither chamber type is inherently more therapeutic. When the same treatment pressure and oxygen exposure are delivered appropriately, the fundamental physiologic effects of HBOT remain the same. Chamber selection is usually based on patient acuity, staffing, facility design, treatment volume, equipment needs, safety requirements, and operational priorities.

What Is a Monoplace Hyperbaric Chamber?

A monoplace chamber is designed to treat one patient at a time. Most clinical monoplace systems consist of a horizontal pressure vessel with a clear acrylic section that allows staff to observe the patient throughout treatment.

The patient typically lies on a chamber stretcher that slides into the vessel. The chamber is then sealed and pressurized, commonly using medical-grade oxygen. Because the oxygen serves as both the breathing gas and the chamber atmosphere, the patient does not usually need to wear an oxygen mask or hood during the primary treatment periods. FDA-cleared monoplace chamber models are generally designed to administer oxygen at pressures greater than ambient pressure, with the precise operating range determined by the chamber’s specifications. (FDA Access Data)

The patient remains physically separated from the clinical team by the chamber wall. Staff communicate through an intercommunication system and monitor the patient visually, often with additional physiologic monitoring when medically appropriate.

The single-patient configuration can provide privacy and individualized scheduling. It also allows treatment profiles to be adjusted for one patient without affecting others.

What Is a Multiplace Hyperbaric Chamber?

A multiplace chamber is designed to accommodate more than one person. Depending on the system, patients may sit in reclining seats, remain on stretchers, or receive treatment in a configuration that supports more complex medical care.

Unlike a typical monoplace chamber, a multiplace chamber is generally pressurized with compressed air. Patients receive oxygen through an individually fitted delivery system, such as:

• An oronasal mask
• A transparent oxygen hood
• An endotracheal or tracheostomy connection
• Another chamber-compatible breathing circuit

Clinical personnel can enter the chamber with the patients when the staffing model and treatment circumstances require it. This permits direct assessment, assistance with oxygen-delivery equipment, management of anxiety or ear-pressure difficulties, and hands-on care for patients who require closer supervision. CMS describes multiplace treatment as exposure to increased pressure in an air-filled chamber while oxygen is supplied through a mask, hood, or airway device. (Centers for Medicare & Medicaid Services)

Although multiple patients can be treated during the same session, each patient must still receive an individually prescribed treatment. Oxygen fit, breathing periods, air breaks, monitoring needs, and contraindications remain patient specific.

Oxygen Delivery in Monoplace and Multiplace Chambers

The most visible difference between the two chamber types is the treatment atmosphere.

In a conventional monoplace chamber, the chamber itself is commonly filled with oxygen. The patient breathes directly from the surrounding atmosphere. Air breaks, when included in the protocol, require a separate breathing system that supplies air while the chamber remains pressurized.

In a multiplace chamber, the surrounding atmosphere is compressed air. Oxygen is delivered directly to the patient through a mask, hood, or airway circuit. During an air break, the patient removes or switches from the oxygen-delivery device and breathes the chamber atmosphere according to the facility’s protocol.

Both approaches can produce the increased arterial and tissue oxygen tensions required for HBOT. The clinical oxygen dose is determined by several variables, including:

• Treatment pressure
• Oxygen concentration at the patient interface
• Duration of oxygen breathing
• Number and duration of air breaks
• Total treatment time
• Treatment frequency

The chamber type does not replace careful dose selection. A patient does not receive a more effective treatment simply because the chamber is larger or because the chamber atmosphere contains oxygen. The prescribed pressure and verified oxygen exposure are the clinically important factors.

Patient Access During Hyperbaric Treatment

Physical access to the patient is one of the most important operational differences.

In a monoplace chamber, clinical personnel remain outside. Staff can observe and communicate with the patient, but they cannot immediately touch the patient or adjust equipment without ending or interrupting the treatment and decompressing the chamber.

This configuration is well suited to many stable patients who can communicate, follow instructions, equalize middle-ear pressure, and remain safely positioned during treatment. Monoplace systems can also be used for medically complex patients when the facility has appropriate protocols, compatible equipment, experienced personnel, and a treatment plan that accounts for the absence of an inside attendant.

In a multiplace chamber, a trained attendant may remain inside and provide direct care. This can be valuable for:

• Critically ill or mechanically ventilated patients
• Young children who require a parent or clinical attendant
• Patients with significant mobility limitations
• Patients who cannot reliably manage an oxygen mask or hood
• Individuals with cognitive impairment, severe anxiety, or communication barriers
• Patients requiring repeated assessment or intervention during treatment

UHMS materials describe the treatment of critically ill and mechanically ventilated pediatric patients in multiplace environments when appropriate personnel and precautions are available. (UHMS)

Direct access does not eliminate risk. Personnel inside a multiplace chamber are also exposed to increased ambient pressure. Their cumulative pressure exposure, decompression profile, oxygen exposure, medical fitness, and staffing rotation must be managed carefully.

Monitoring and Critical Care Capabilities

Both monoplace and multiplace chambers can support patient monitoring, but the equipment configuration differs.

In a monoplace system, monitors, ventilators, infusion pumps, and other devices may remain outside the chamber with approved tubing, cables, or interfaces passing through designated penetrators. Some equipment may be specifically designed or cleared for operation in a hyperbaric environment. Device compatibility must be evaluated for the chamber pressure, oxygen concentration, electrical characteristics, and intended clinical use.

A multiplace chamber may permit more equipment and personnel to remain near the patient, but every item introduced into the chamber must still meet facility safety requirements. Standard hospital equipment cannot be assumed to function safely or accurately under pressure. Increased pressure can affect gas-filled components, flow delivery, calibration, heat production, battery behavior, and device performance.

The ability to place an attendant beside the patient may make multiplace care more practical for certain unstable or intervention-dependent patients. However, critical care capability depends on much more than chamber size. It requires:

• Hyperbaric-trained physicians and clinical personnel
• Chamber-compatible monitoring and life-support equipment
• Tested emergency procedures
• Appropriate staffing ratios
• Reliable communication systems
• A plan for rapid treatment termination and patient removal
• Coordination with intensive care, respiratory therapy, surgery, and other services

FDA clearances demonstrate that certain infusion and support systems have been evaluated for use under hyperbaric conditions, but facilities must follow the specific device labeling and chamber compatibility requirements. (FDA Access Data)

Fire Safety and Oxygen Management

Fire prevention is a central safety concern in every hyperbaric facility. Increased pressure and elevated oxygen concentrations can cause materials to ignite more easily and burn more rapidly.

In a monoplace chamber filled with oxygen, the entire internal environment is oxygen rich. Clothing, linens, dressings, skin products, medical devices, and any item entering the chamber must be carefully controlled. Staff must follow established procedures for patient preparation, electrical grounding, static control, chamber cleaning, equipment approval, and prohibited materials.

A multiplace chamber is typically pressurized with air, which reduces the extent of the oxygen-enriched chamber atmosphere. However, oxygen can accumulate around leaking or poorly fitted masks, hoods, breathing circuits, or exhaust systems. The use of electrical and medical equipment inside the chamber also introduces safety considerations that require rigorous equipment review.

The different chamber atmospheres change the fire-risk profile, but they do not make either design free from fire hazards. Both monoplace and multiplace chambers require trained operators, controlled materials, documented maintenance, emergency procedures, and compliance with applicable hyperbaric safety standards. UHMS guidance emphasizes that patients in either chamber type depend on trained personnel for safe operation and emergency egress. (UHMS)

Treatment Scheduling and Facility Workflow

Monoplace chambers treat one patient per chamber cycle. Facilities may operate several chambers simultaneously, allowing each patient to begin treatment on a separate schedule and receive an individualized pressure profile.

This arrangement can provide operational flexibility. A delayed patient, shortened treatment, or protocol adjustment may affect only one chamber. Individual treatment can also reduce distractions for patients who prefer a quieter environment.

Multiplace chambers can treat several patients during one pressure cycle. This may offer efficient capacity when multiple patients require compatible treatment profiles. However, group treatment also requires coordinated scheduling. Patients generally compress and decompress together unless the chamber includes locks or other design features that permit personnel or supplies to enter and leave while the main compartment remains under pressure.

A clinical issue affecting one multiplace patient may alter the session for others. The facility must have protocols for managing oxygen intolerance, ear pain, anxiety, medical deterioration, equipment failure, or the need for an unscheduled decompression.

Throughput therefore depends on more than the number of available seats. It is influenced by chamber cycle time, staffing, patient preparation, oxygen-delivery setup, cleaning, emergency capacity, and the degree to which patient protocols can be grouped safely.

Patient Comfort and Treatment Experience

Patient comfort varies according to individual preference and clinical circumstances.

A monoplace chamber may feel more private and less medically busy. The transparent acrylic structure allows the patient to see outside, and many facilities provide audio or visual entertainment. Some patients appreciate being able to lie down throughout treatment.

Others may feel isolated or confined. Because the patient cannot remove themselves from the chamber independently, communication and reassurance from the outside team are important. Patients should understand how to report ear discomfort, anxiety, nausea, respiratory symptoms, visual changes, or other concerns.

A multiplace chamber provides a larger internal space and may allow patients to sit upright. The presence of other patients and an inside attendant can be reassuring. It may also make the experience feel more social and less confined.

However, patients must tolerate the oxygen-delivery interface. Masks and hoods can cause discomfort, pressure points, warmth, noise, or a sense of enclosure. Proper fitting is essential because oxygen leakage can reduce treatment efficiency and contribute to local oxygen enrichment.

Compassionate preparation matters in either setting. Explaining the sounds, pressure changes, communication system, oxygen equipment, and expected duration can substantially improve the patient’s ability to participate safely in treatment.

Are Clinical Outcomes Different Between Chamber Types?

The therapeutic goal of HBOT is to deliver a defined exposure to oxygen at increased pressure. A correctly administered treatment can be delivered in either a monoplace or multiplace chamber.

Clinical outcomes are more likely to be influenced by factors such as:

• Whether HBOT is appropriate for the diagnosis
• Timing of treatment
• Treatment pressure and oxygen duration
• Adherence to the prescribed course
• Quality of wound, surgical, antimicrobial, or critical care
• Patient selection and risk management
• Staff training and emergency readiness

The chamber type may indirectly affect outcomes when one design is better suited to a patient’s monitoring, mobility, ventilation, or staffing needs. For example, a patient requiring continuous bedside intervention may be more practically managed in a multiplace unit. A stable outpatient receiving a routine treatment series may be managed efficiently in a monoplace system.

The choice should be based on the level of care the facility can deliver safely, not on the assumption that one chamber design provides stronger oxygen.

Choosing the Appropriate Hyperbaric Chamber

For an individual patient, the most appropriate chamber is the one that can safely deliver the prescribed treatment while meeting that patient’s medical and psychological needs.

For a healthcare organization, chamber selection requires a broader assessment of:

• Expected inpatient and outpatient volume
• Types of clinical indications treated
• Need for ventilator or intensive-care support
• Availability of trained inside attendants
• Physical space and construction requirements
• Oxygen and compressed-air infrastructure
• Capital, maintenance, and staffing resources
• Emergency access and hospital support
• Anticipated scheduling model

Some programs operate only monoplace chambers. Others are built around a multiplace system. Larger centers may use both, allowing the clinical team to assign patients according to acuity, treatment protocol, scheduling needs, and available resources.

Regardless of design, a hyperbaric chamber is a regulated medical device intended to increase environmental pressure and promote oxygen movement into the body. Safe treatment depends on appropriate equipment, qualified personnel, patient screening, maintenance, and adherence to recognized clinical and technical standards. (eCFR)