Hyperbaric oxygen therapy is an emergency adjunct to surgical debridement and broad-spectrum intravenous antibiotics for clostridial myositis and myonecrosis (gas gangrene). Recompression to 3.0 ATA on 100 percent oxygen achieves the tissue oxygen tension required to halt clostridial alpha-toxin production, the biological mechanism that drives the rapid tissue destruction. Gas gangrene is recognised by Health Canada as one of the 14 conditions for which provincial health insurance covers HBOT at hospital-based programmes.
Quick Answer
Does HBOT help gas gangrene (clostridial myositis and myonecrosis)? Hyperbaric oxygen therapy is an emergency adjunct to surgical debridement and broad-spectrum intravenous antibiotics for clostridial myositis and myonecrosis (gas gangrene). Recompression to 3.0 ATA on 100 percent oxygen achieves the tissue oxygen tension required to halt clostridial alpha-toxin production, the biological mechanism that drives the rapid tissue destruction. Gas gangrene is recognised by Health Canada as one of the 14 conditions for which provincial health insurance covers HBOT at hospital-based programmes.
Gas gangrene, formally clostridial myositis and myonecrosis, is a fulminant infection of skeletal muscle caused primarily by Clostridium perfringens (Type A) and less commonly by other Clostridium species. The defining clinical feature is rapid spread of necrosis through muscle, with palpable or radiographic gas in the soft tissues, severe pain disproportionate to visible findings, characteristic bronze or copper skin discoloration, hemorrhagic bullae, and systemic toxicity progressing to circulatory collapse and multi-organ failure within hours of onset. Mortality remains 25 to 50 percent even with optimal modern care, rising sharply when surgical debridement is delayed beyond 12 to 24 hours of presentation.
Gas gangrene follows penetrating trauma (especially crush injuries with soil contamination, agricultural injuries, blast injuries from improvised explosive devices), surgery (particularly bowel, biliary tract, and orthopaedic procedures with hardware), illicit injection drug use ("black tar" heroin contaminated with Clostridium spores), septic abortion, and (rarely) spontaneous origin from C. septicum bacteremia in patients with occult colonic malignancy or neutropenia. The Clostridium organisms are anaerobic spore-formers that proliferate in hypoxic devitalised tissue; once established, they produce a battery of exotoxins (alpha-toxin, theta-toxin, perfringolysin O, others) that rapidly digest muscle and connective tissue and trigger systemic vascular collapse.
Clinical recognition is the single most important determinant of survival. Severe pain at a recent wound or surgical site, beyond what the local examination would predict, in a patient with tachycardia and apparent toxicity, should prompt immediate operating-room mobilisation. Imaging (plain radiograph or CT showing soft-tissue gas) supports but does not delay the surgical decision; absence of gas does not exclude the diagnosis. Time from presentation to first surgical debridement is the strongest predictor of survival; HBOT is added when feasible without delaying surgery.
Hyperbaric oxygen therapy treats clostridial myonecrosis through three convergent mechanisms.
First, alpha-toxin suppression. C. perfringens alpha-toxin (a phospholipase C) and the related toxins drive the rapid muscle destruction and vascular injury that define the disease. Alpha-toxin production is inhibited at tissue pO2 above approximately 250 mmHg, a threshold reached only at hyperbaric pressures of 2.8 to 3.0 ATA on 100 percent oxygen. At standard normobaric oxygen, even 100 percent FiO2 by mask, tissue pO2 in the necrotic bed remains far below this threshold and toxin production continues. Halting toxin production gives the surgical and antibiotic teams the time they need to control the infection.
Second, oxygen-dependent neutrophil bactericidal activity. The oxidative burst that neutrophils use to kill ingested clostridia requires tissue pO2 above 30 mmHg. The necrotic muscle bed is profoundly hypoxic, with measured pO2 below 5 mmHg, and neutrophil killing is essentially zero in this environment. HBOT at 2.8 to 3.0 ATA restores neutrophil function at the wound margin.
Third, demarcation and surgical-decision support. Repeated HBOT sessions help the surgical team distinguish viable from non-viable muscle at successive debridement procedures, supporting tissue-sparing decisions and reducing the extent of definitive amputation when limb-salvage is possible.
Typical Treatment Protocol
The standard adjunctive protocol is recompression to 3.0 ATA on 100 percent oxygen for 90 minutes per session, with the high pressure required to achieve the approximately 250 mmHg tissue pO2 needed to halt clostridial alpha-toxin production. Three sessions are delivered in the first 24 hours, then twice daily for the next 24 to 48 hours, then once daily until clinical and microbiologic control is achieved. Total course is typically 7 to 10 sessions over four to seven days, paralleled with serial surgical debridement and broad-spectrum IV antibiotics (penicillin G plus clindamycin remains the canonical regimen, with addition of metronidazole, vancomycin, or piperacillin-tazobactam depending on the suspected polymicrobial component and local resistance patterns). HBOT is delivered between surgical procedures, NEVER as a substitute for or as a delay to debridement. The sequence is debride first, antibiotics second, HBOT third. If transfer to a hyperbaric programme would push the first debridement beyond 12 hours of presentation, the local team should debride first and consider HBOT as a secondary stage after the patient is stabilised.
Level B - Moderate Evidence
Supported by controlled studies and clinical evidence
C. perfringens alpha-toxin production is inhibited at tissue pO2 above approximately 250 mmHg, a threshold reached only at hyperbaric pressures of 2.8 to 3.0 ATA on 100 percent oxygen. This is the central mechanistic rationale for the high-pressure protocol used in clostridial myonecrosis.
Retrospective cohort and case-control studies (Hart 1983, Brown 1994, Wilkinson and Doolette 2004 and others) suggest adjunctive HBOT is associated with reduced mortality and reduced extent of definitive amputation compared to standard surgery and antibiotics alone. Randomised controlled trials are not feasible for ethical reasons in this rapidly fatal condition.
Time to surgical debridement is the strongest single predictor of survival. Mortality rises sharply when debridement is delayed beyond 12 to 24 hours of presentation. HBOT is added without delaying surgery.
Standard adjunctive protocol is recompression to 3.0 ATA on 100 percent oxygen for 90 minutes per session, three times in the first 24 hours, then twice daily for the next 24 to 48 hours, then once daily, for a total course of 7 to 10 sessions.
HBOT supports surgical decision-making by helping the surgical team distinguish viable from non-viable muscle at serial debridement, contributing to tissue-sparing decisions where limb-salvage is feasible.
In Ontario, urgent inter-facility transfer for adjunctive HBOT is coordinated through CritiCall Ontario (1-800-668-4357), which provides 24/7 physician-to-physician triage between the surgical team and the receiving hyperbaric programme.
Highest-evidence-tier studies tagged to this condition in the Canada Hyperbarics research database, ranked by evidence tier (1 = meta-analysis or RCT, 2 = cohort, 3 = case series), most recent first.
Eur J Surg Suppl · 1993 · Clinical Study
Unfallchirurgie (Heidelb) · 2025 · Case Report
Microorganisms · 2024 · Review
Cureus · 2019 · Case Report
Suspected gas gangrene is a surgical emergency, and the patient's first stop is the operating theatre. The local surgical team performs the index debridement of all visibly necrotic muscle, often returning to theatre two or three times in the first 24 to 48 hours for serial debridement as the infection's full extent declares itself. Broad-spectrum IV antibiotics (typically penicillin G plus clindamycin, with metronidazole and an anti-MRSA agent added) start before surgery and continue through the post-operative period.
The surgical team contacts the hospital hyperbaric programme as soon as gas gangrene is recognised; in Ontario, this is most efficiently done through CritiCall Ontario (1-800-668-4357). The first hyperbaric session typically begins within hours of the index debridement, with the patient often still requiring vasopressor support, ventilation, and continuous critical-care monitoring. Multiplace chambers accommodate this level of support; a hyperbaric-trained nurse and physician are inside the chamber alongside other patients.
Pressurisation takes five to ten minutes, the treatment phase is on 100 percent oxygen at 3.0 ATA for 90 minutes (with brief air breaks to limit oxygen toxicity), and decompression takes another ten to fifteen minutes. Three sessions are delivered in the first 24 hours, then twice daily, then once daily. Total course is typically 7 to 10 sessions over four to seven days, with serial debridement continuing in parallel. Recovery from severe gas gangrene is prolonged, often requiring weeks of inpatient care, extensive rehabilitation, and (in many cases) reconstructive surgery for the soft-tissue and muscle defects left by the necessary debridement.
Gas gangrene is recognised by Health Canada as one of the 14 conditions for which hyperbaric oxygen is the established adjunctive treatment. It is uncommon in absolute numbers (typically a handful of cases per Canadian hyperbaric programme per year), but the clinical urgency and the high mortality of untreated disease make it one of the highest-priority emergency indications. Treatment is delivered at the 11 hospital-based hyperbaric programmes across seven provinces under provincial health insurance.
In Ontario, OHIP covers treatment at the three hospital programmes (Toronto General / UHN, Hamilton General Hospital, The Ottawa Hospital). CritiCall Ontario at 1-800-668-4357 is the standard line for inter-facility transfer coordination, providing 24/7 physician-to-physician triage between the surgical team and the receiving hyperbaric programme. In British Columbia, treatment is at Vancouver General Hospital with BC Ambulance critical-care transport for cases originating outside the Lower Mainland. In Alberta, both Misericordia Edmonton (Covenant Health) and the Foothills Medical Centre / AJECCC Calgary (Alberta Health Services) accept gas-gangrene referrals. RAMQ covers treatment at Hôpital du Sacré-Cœur de Montréal and Hôtel-Dieu de Lévis in Quebec. MSI (Nova Scotia), MCP (Newfoundland and Labrador), and Saskatchewan also cover their respective hospital programmes.
For patients in provinces or territories without an in-province hospital programme (Manitoba, New Brunswick, Prince Edward Island, Yukon, Northwest Territories, Nunavut), urgent inter-facility transfer is arranged through the receiving province's transfer service, but only after the index debridement has been completed at the local hospital. The Divers Alert Network 24/7 emergency consultation line at 1-919-684-9111 can also assist Canadian emergency departments and surgical teams in locating accepting chambers when local pathways are unclear.
Hyperbaric oxygen therapy for the 14 Health Canada-recognised conditions, including Gas Gangrene (Clostridial Myositis and Myonecrosis), is delivered at the 11 hospital hyperbaric programmes located in seven provinces (Ontario, Quebec, British Columbia, Alberta, Nova Scotia, Newfoundland and Labrador, and Saskatchewan). The six provinces and territories without an in-province hospital programme (Manitoba, New Brunswick, Prince Edward Island, Yukon, Northwest Territories, and Nunavut) route patients to the nearest receiving hospital programme. Use the links below for province-specific coverage, referral pathway, and emergency routing details.
Hospital + Private
OHIP (Ontario Health Insurance Plan)
Hospital Only
MSP (Medical Services Plan)
Hospital + Private
Alberta Health / AHCIP
Hospital Only
RAMQ
Disrupted
Saskatchewan Health Authority
No Hospital Chamber
Manitoba Health
Hospital Only
MSI (Medical Services Insurance)
No Hospital Chamber
Medicare NB
Hospital Only
MCP (Medical Care Plan)
Out-of-Province Referral
Health PEI
Out-of-Province Referral
Yukon Health and Social Services
Out-of-Province Referral
NWT Health and Social Services
Out-of-Province Referral
Nunavut Department of Health
For acute or emergency presentations of Gas Gangrene (Clostridial Myositis and Myonecrosis), call 911 first. The receiving emergency department coordinates urgent transfer to the nearest hospital hyperbaric programme through the relevant provincial transfer network (CritiCall Ontario at 1-800-668-4357, BC Patient Transfer Network, EHS Nova Scotia, or equivalent). For diving-related emergencies, the Divers Alert Network (DAN) emergency hotline is 1-919-684-9111.
There are no absolute contraindications to adjunctive HBOT in suspected gas gangrene given the high mortality of untreated disease. The single condition that must be addressed before chamber entry is untreated pneumothorax, which will tension under compression and decompression; emergency tube thoracostomy is performed first. HBOT must NOT delay surgical debridement. If transfer to a hyperbaric programme would push the first debridement beyond 12 hours of presentation, the local team should debride first and consider HBOT as a secondary stage. Severe haemodynamic instability requiring continuous high-dose vasopressor titration is a relative contraindication because chamber-side pump titration is more difficult; modern multiplace chambers accommodate this level of support but the threshold for proceeding requires individual judgement.
No. HBOT is always used as an adjunct to aggressive surgical debridement and broad-spectrum IV antibiotics. Surgical debridement of all visibly necrotic muscle remains the primary treatment and is the strongest predictor of survival. HBOT helps by halting clostridial alpha-toxin production, restoring neutrophil bactericidal function, and supporting surgical decisions at serial debridement.
As soon as possible after the initial surgical debridement, ideally within 6 to 12 hours of presentation. Three sessions in the first 24 hours at 3.0 ATA on 100 percent oxygen are typically recommended, followed by twice-daily sessions until clinical improvement, then once-daily sessions for the remainder of the course.
Because clostridial alpha-toxin production, the biological driver of the rapid tissue destruction, is only inhibited at tissue pO2 above approximately 250 mmHg. Reaching this tissue oxygen tension requires recompression to 2.8 to 3.0 ATA on 100 percent oxygen. The standard 2.0 to 2.4 ATA pressures used for chronic wounds and many other indications do not achieve this threshold.
Retrospective cohort and case-control studies suggest adjunctive HBOT is associated with reduced mortality and reduced extent of definitive amputation when added to standard surgical and antibiotic treatment. The evidence base is observational because randomised trials are not ethically feasible in this rapidly fatal condition; the totality of evidence supports adjunctive use whenever it can be arranged without delaying surgery.
Yes. Gas gangrene (clostridial myositis and myonecrosis) is recognised by Health Canada and covered as an emergency indication at all 11 hospital-based hyperbaric programmes under OHIP, RAMQ, MSP, AHCIP, MSI, MCP, and Saskatchewan Health. For patients in provinces without an in-province hospital programme, urgent inter-facility transfer is arranged through provincial transfer services such as CritiCall Ontario (1-800-668-4357).
Gas gangrene is a specific form of necrotizing soft-tissue infection caused by Clostridium species (most commonly C. perfringens) and characterised by primary muscle involvement (myositis and myonecrosis) and toxin-mediated rapid spread. Necrotizing fasciitis is a broader category covering Type I (polymicrobial) and Type II (monomicrobial Group A Streptococcus) infections that involve fascia and subcutaneous tissue. The two overlap clinically and microbiologically, and the surgical and HBOT principles are similar; gas gangrene is treated at higher pressure (3.0 ATA) because of the alpha-toxin threshold.
The canonical regimen is high-dose IV penicillin G plus clindamycin (clindamycin both for its broad anti-anaerobic activity and for its ability to suppress toxin production by inhibiting bacterial protein synthesis). Metronidazole, vancomycin, or piperacillin-tazobactam are commonly added depending on the suspected polymicrobial component and local resistance patterns. Antibiotic choice is finalised by infectious-disease consultation based on Gram stain, culture, and clinical course.
For ventilated and vasopressor-supported patients, the chamber session feels like routine ICU care with the addition of pressurisation. Multiplace chambers accommodate stretchers, ventilators, infusion pumps, and a hyperbaric-trained nurse and physician inside the chamber. Pressurisation takes five to ten minutes and feels like an aircraft descent. The treatment phase at 3.0 ATA on 100 percent oxygen lasts 90 minutes with brief air-breaks to limit oxygen toxicity. Decompression takes another ten to fifteen minutes. The patient is continuously monitored throughout.
All 11 Canadian hospital hyperbaric programmes treat gas gangrene as an emergency indication. The Canada Hyperbarics verified directory at canadahyperbarics.ca/facilities/ lists all programmes with phone numbers, addresses, and current operational status. In an emergency, the local emergency department or surgical team will arrange the referral; in Ontario, this is coordinated through CritiCall Ontario at 1-800-668-4357.