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UHMS Indication #9 Level B - Moderate Evidence

Necrotizing Soft Tissue Infections and HBOT

Hyperbaric oxygen therapy is an adjunct to emergency surgical debridement and broad-spectrum intravenous antibiotics for necrotizing fasciitis and other necrotizing soft-tissue infections. It enhances neutrophil bactericidal activity in hypoxic tissue, inhibits anaerobic toxin production, and improves antibiotic penetration. Necrotizing soft-tissue infection is on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme.

· · Canada Hyperbarics Editorial Team · Sources

Quick Answer

Does HBOT help necrotizing soft tissue infections? Hyperbaric oxygen therapy is an adjunct to emergency surgical debridement and broad-spectrum intravenous antibiotics for necrotizing fasciitis and other necrotizing soft-tissue infections. It enhances neutrophil bactericidal activity in hypoxic tissue, inhibits anaerobic toxin production, and improves antibiotic penetration. Necrotizing soft-tissue infection is on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026); in other provinces, check with the provincial hospital programme.

Authoritative references: Health Canada on hyperbaric oxygen therapy · UHMS clinical practice guidelines · Canadian regulatory framework

What Is Necrotizing Soft Tissue Infections?

Necrotizing soft-tissue infections (NSTIs) are rapidly progressive bacterial infections that destroy skin, subcutaneous tissue, fascia, and sometimes muscle. The category includes necrotizing fasciitis (Type I polymicrobial, Type II monomicrobial Group A Streptococcus, Type III marine Vibrio, Type IV fungal), Fournier's gangrene (perineal/genital), Ludwig's angina (cervical), and craniofacial necrotizing infection. Reported 30-day mortality is around 20 percent even with optimal modern care, rising to roughly 30 percent at one year, and higher when surgical debridement is delayed.

Classic presentation includes pain out of proportion to visible findings, rapidly spreading erythema with poorly demarcated borders, skin discoloration progressing to purple or black, bullae, crepitus from gas-producing organisms, and systemic toxicity (fever, tachycardia, hypotension, leukocytosis, lactic acidosis). The LRINEC score (Laboratory Risk Indicator for Necrotizing Fasciitis) using CRP, white-cell count, haemoglobin, sodium, creatinine, and glucose can support clinical suspicion but does not replace it; a score below 6 does not exclude the diagnosis.

NSTIs follow trauma (penetrating, blunt, or surgical), insect bites, intravenous drug use injection sites, pressure ulcers, and post-operative wounds. Risk factors include diabetes mellitus, immunosuppression, chronic alcohol use, peripheral vascular disease, age over 60, and obesity. The single most important determinant of survival is time from presentation to first surgical debridement; HBOT is added when feasible without delaying surgery.

How HBOT Helps

HBOT addresses NSTIs through four convergent mechanisms.

First, neutrophil bactericidal restoration. The oxygen-dependent oxidative burst that neutrophils use to kill bacteria is markedly impaired at the low oxygen tensions found in infected tissue and improves as tissue pO2 rises, but necrotic tissue is profoundly hypoxic (pO2 often below 5 mmHg). HBOT at 2.4 ATA can raise tissue pO2 to several hundred mmHg, restoring full neutrophil killing capacity at the wound margin.

Second, anaerobic toxin suppression. Clostridium perfringens alpha-toxin and Group A Streptococcus exotoxin production are inhibited at the elevated oxygen tensions achieved with HBOT. Toxin suppression helps halt the rapid tissue spread that defines NSTIs.

Third, antibiotic synergy. HBOT enhances the activity of aminoglycosides, fluoroquinolones, and certain beta-lactam antibiotics by improving their tissue penetration and oxygen-dependent intracellular accumulation. This is particularly relevant in the hypoxic, edematous wound bed where standard antibiotic delivery is impaired.

Fourth, demarcation and wound preparation. Repeated HBOT helps the surgical team distinguish viable from non-viable tissue at successive debridement procedures, reduces post-debridement oedema, and promotes granulation in the wound bed before reconstructive surgery.

Typical Treatment Protocol

There is no single standard adjunctive protocol: published series report treatment at 2.5 ATA (a University of Turku series of perineal necrotizing fasciitis, in which survivors received 2 to 12 sessions) and at 2.8 ATA on 100 percent oxygen for 90 minutes (one department standard protocol for necrotizing fasciitis). The session schedule between the surgical debridements is set by the treating team. Course length is set by the treating team, guided by clinical response, serial debridement findings, and wound bed status. Therapy is paused or stopped when the wound is clean and granulating, or when reconstructive surgery is scheduled. HBOT is delivered between surgical procedures, NEVER as a substitute for or as a delay to debridement. The sequence is debride first, antibiotics second (broad-spectrum IV with anti-MRSA, anti-anaerobic, and anti-Streptococcus coverage pending culture), HBOT third. If the receiving hyperbaric facility is more than 60 to 90 minutes away from the surgical theatre, transfer for HBOT is considered only after the initial debridement is complete and the patient is hemodynamically stable.

Evidence Summary

B

Level B - Moderate Evidence

Supported by controlled studies and clinical evidence

Key Research Findings

  • Time-to-first-debridement is the strongest predictor of survival in NSTIs. Delay to surgical debridement is consistently associated with worse outcomes. HBOT is added without delaying surgery.

  • Evidence basis: retrospective cohort studies and meta-analyses (Wilkinson and Doolette 2004, Soh 2012, Hedetoft 2021, Huang 2023) suggest adjunctive HBOT is associated with reduced mortality and fewer debridement procedures. Randomised controlled trials are not feasible for ethical reasons in this life-threatening condition, so the Level B rating reflects consistent observational evidence supporting established adjunctive-care practice at hospital programmes, not RCT-level proof.

  • HBOT raises tissue oxygen tension, and neutrophil oxygen-dependent killing improves in a graded way as oxygen tension rises, with no single threshold (in an animal bone-infection model, killing was markedly reduced at 23 mm Hg and most effective at 150 mm Hg).

  • Anaerobic toxin production by Clostridium perfringens and Group A Streptococcus is inhibited at the elevated oxygen tensions HBOT delivers, helping halt tissue spread.

  • There is no single standard adjunctive protocol: published series report 2.5 ATA (University of Turku) and 2.8 ATA for 90 minutes (one department, necrotizing fasciitis), with the schedule and course length set by the treating team and guided by wound response.

  • 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.

  • Key supporting studies in the Canada Hyperbarics research database: PMID 33761539, PMID 36966323, PMID 38507909.

Top studies in our database

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.

Registered trials (ClinicalTrials.gov)

Studies in our database that include a ClinicalTrials.gov registration. Trial registration is a marker of methodological rigour because the protocol, primary outcome, and analysis plan are deposited before enrolment begins.

See all necrotizing soft tissue infections studies in our research database

What to Expect from Treatment

Necrotizing soft-tissue infection is a surgical emergency, and the patient's first stop is the operating theatre, not the hyperbaric chamber. After the initial debridement, broad-spectrum IV antibiotics, and stabilisation, the surgical team contacts the hospital hyperbaric programme to coordinate adjunctive HBOT. In Ontario, this is most efficiently done through CritiCall Ontario (1-800-668-4357), which provides 24/7 physician-to-physician triage. In other provinces the call goes directly to the receiving hospital chamber.

The first HBOT session typically begins within hours of the index debridement, often while the patient is still being stabilised in the surgical ICU. In a multiplace chamber, you remain on full critical-care support (ventilator, infusions, monitoring) with a hyperbaric-trained nurse and physician inside the chamber alongside other patients. In a monoplace chamber, the support is delivered through purpose-designed pass-throughs. Pressurisation takes five to ten minutes, the treatment phase is on 100 percent oxygen at the pressure the team sets (published NSTI series report 2.5 to 2.8 ATA), and decompression takes another five to ten minutes.

Subsequent sessions alternate with serial surgical debridements over the first several days. Most patients require two to four debridements before the wound bed is clean. HBOT continues on a schedule the treating team sets until the wound is granulating or reconstructive surgery is scheduled. Course length is set by the treating team. The hyperbaric medicine team, the surgical team, infectious diseases, critical care, and (later) plastic surgery all participate in the multi-disciplinary management. Recovery from severe NSTIs is typically prolonged, with significant rehabilitation needs after the acute treatment phase.

Accessing HBOT for Necrotizing Soft Tissue Infections in Canada

Necrotizing soft-tissue infection is on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026). Treatment is delivered on an emergency-priority basis at hospital-based hyperbaric programmes. In Ontario, OHIP funds HBOT for necrotizing soft tissue infections (Ontario Schedule of Benefits, as of April 1, 2026); in another province, check with your provincial hospital programme.

CUHMA's directory lists no unit in Manitoba, New Brunswick, Prince Edward Island, Yukon, the Northwest Territories or Nunavut. In Ontario, hospital-based physicians can reach CritiCall Ontario at 1-800-668-4357.

The receiving emergency department must coordinate three things in parallel: immediate surgical debridement at the local hospital, broad-spectrum IV antibiotics, and arrangement of transfer to the nearest hyperbaric programme. HBOT is delivered between debridement procedures; the patient continues to require the surgical team's care throughout. CritiCall Ontario specifically provides 24/7 physician-to-physician triage to coordinate this multi-team handover.

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Provincial Access for Necrotizing Soft Tissue Infections

Health Canada has licensed hyperbaric chambers to treat 14 conditions (the list the UHMS recognised in 2011); this condition falls under one of them: necrotizing soft tissue infections. In Ontario, OHIP insures hyperbaric oxygen therapy for necrotizing soft tissue infections (subcutaneous tissue, muscle, fascia), an indication on its funded list (Ontario Schedule of Benefits for Physician Services, as of April 1, 2026). Other provinces set their own lists; check with your provincial hospital programme. Use the links below for province-specific coverage, referral pathway, and emergency routing details.

ON Ontario

Hospital + Private

OHIP (Ontario Health Insurance Plan)
BC British Columbia

Hospital-Based

MSP (Medical Services Plan)
AB Alberta

Hospital + Private

Alberta Health / AHCIP
QC Quebec

Hospital-Based

RAMQ
SK Saskatchewan

Open for Outpatient Care

Saskatchewan Health Authority
MB Manitoba

CUHMA Lists No Unit

Manitoba Health
NS Nova Scotia

Hospital-Based

MSI (Medical Services Insurance)
NB New Brunswick

CUHMA Lists No Unit

Medicare NB
NL Newfoundland and Labrador

Hospital-Based

MCP (Medical Care Plan)
PE Prince Edward Island

CUHMA Lists No Unit

PEI Medicare
YT Yukon

CUHMA Lists No Unit

Yukon Health and Social Services
NT Northwest Territories

CUHMA Lists No Unit

NWT Health and Social Services
NU Nunavut

CUHMA Lists No Unit

Nunavut Department of Health

For acute or emergency presentations of Necrotizing Soft Tissue Infections, call 911 first (in Nunavut, which has no 9-1-1 service, dial the first three digits of your local RCMP phone line followed by 1111, or 1-867-979-1111). In Ontario, hospital-based physicians can reach CritiCall Ontario at 1-800-668-4357. For a dive accident or injury, call 911 first (in Nunavut, which has no 9-1-1 service, your community RCMP line), then the Divers Alert Network (DAN) at +1 (919) 684-9111.

Risks and Contraindications

Untreated pneumothorax is the one absolute contraindication to HBOT; a pneumothorax is treated before chamber entry. Other contraindications are relative and are weighed case by case against the high mortality of untreated or under-treated disease. HBOT must NOT delay surgical debridement under any circumstance. If transfer to a hyperbaric programme would delay the first debridement (a 2024 review advises debridement ideally within 6 hours of presentation), the local team should debride first and consider HBOT as a secondary stage. Severe haemodynamic instability requiring continuous vasopressor titration is a relative contraindication because chamber-side pump titration is more difficult; most modern multiplace chambers accommodate ventilator-dependent and vasopressor-dependent patients with appropriate critical-care support.

Frequently Asked Questions

Yes, as an adjunct to emergency surgical debridement and broad-spectrum intravenous antibiotics. HBOT enhances neutrophil bactericidal activity in hypoxic tissue, inhibits anaerobic toxin production, and improves antibiotic penetration. It is not a substitute for surgery; the standard sequence is debride first, antibiotics second, HBOT third, with HBOT delivered between debridement procedures.

No. Surgical debridement remains the primary and most critical treatment. Current guidelines recommend debridement ideally within 6 hours of presentation, and delays are associated with worse outcomes. HBOT is added when it can be arranged without delaying surgery.

Retrospective cohort studies and meta-analyses suggest adjunctive HBOT is associated with reduced mortality and fewer surgical debridements when added to standard surgical and antibiotic treatment. Randomised controlled trials are not ethically feasible in this life-threatening condition, so the evidence base is observational.

As soon as the patient is hemodynamically stable after the first surgical debridement. The session schedule after that is set by the treating team: there is no single standard adjunctive protocol.

Course length is set by the treating team. There is no single standard adjunctive protocol: published series report 2.5 to 2.8 ATA, and in a University of Turku series of perineal necrotizing fasciitis (Fournier gangrene) survivors received 2 to 12 sessions. Total course is guided by clinical response, serial debridement findings, and wound bed status.

In Ontario, OHIP funds HBOT for necrotizing soft tissue infections (Ontario Schedule of Benefits, as of April 1, 2026); in another province, check with your provincial hospital programme. For patients in provinces without an in-province hospital programme, urgent inter-facility transfer is coordinated through provincial transfer services such as CritiCall Ontario (1-800-668-4357).

No. Surgical debridement comes first. If transfer to a hyperbaric programme would delay the first debridement (a 2024 review advises debridement ideally within 6 hours of presentation), the local team should debride first and consider HBOT as a secondary stage after the patient is stabilised.

Fournier gangrene is necrotizing fasciitis of the perineum and external genitalia, more common in men with diabetes or immunosuppression. It is treated the same way: emergency surgical debridement, broad-spectrum IV antibiotics, and adjunctive HBOT, with the protocol set by the treating team (a University of Turku series of perineal necrotizing fasciitis treated at 2.5 ATA).

Necrotising soft tissue infections is on Ontario's OHIP-funded list for HBOT (Ontario Schedule of Benefits, as of April 1, 2026); for coverage and referral in Ontario or another province, check with the hospital hyperbaric programme. The only absolute contraindication to HBOT is untreated pneumothorax (trapped intrathoracic air expands on decompression); concurrent bleomycin chemotherapy (oxygen-induced pulmonary fibrosis risk) and concurrent disulfiram (interferes with superoxide dismutase, the enzyme that neutralises hyperbaric-oxygen-generated free radicals) are relative contraindications, weighed case by case. Other relative contraindications include severe haemodynamic instability requiring continuous high-dose vasopressor titration, uncontrolled seizure disorder, severe COPD with bullous lung disease, and uncontrolled claustrophobia. In pregnancy, HBOT is indicated for carbon monoxide poisoning; for other conditions the evidence is limited (a 2023 review suggests stabilising the mother may take priority in a life-threatening emergency), and elective treatment during pregnancy has no established indication or safety data.

Last reviewed: April 28, 2026 | Reviewed by: Canada Hyperbarics Editorial Team | Editorial process | Research sources | Counts & methodology

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