Physician Referral Guide: Hyperbaric Oxygen for Necrotizing Soft Tissue Infections

Assessing the patient before referral

While arranging surgery and hyperbaric assessment, the receiving emergency department should:

• Achieve source control first: emergent surgical consultation for debridement is the priority, with hyperbaric referral layered on afterward rather than before.
• Start broad-spectrum intravenous antibiotics covering Gram-positive, Gram-negative, and anaerobic organisms without waiting for culture results.
• Provide aggressive fluid resuscitation and haemodynamic support, because many patients present in or near septic shock.
• Document the exposure and progression history: onset, rate of spread, pain out of proportion to examination findings, crepitus, and any imaging showing gas in soft tissue.
• Note any factors affecting chamber suitability, including pneumothorax, the degree of vasopressor dependence, and relevant comorbidities, so the hyperbaric team can plan safely around an unstable patient.

What the evidence supports

The rationale for hyperbaric oxygen in necrotizing infection is mechanistic and supported by observational data, not by randomised trials, which are ethically infeasible in this rapidly fatal condition. Untreated mortality is high: roughly 20 to 40 percent even with optimal modern care, rising to 50 percent or higher when surgical debridement is delayed beyond 24 hours. This underscores that surgery, not hyperbaric oxygen, drives survival.

The mechanistic basis for adjunctive hyperbaric oxygen is well established. Bactericidal neutrophil activity requires a tissue oxygen tension above about 30 mmHg, whereas necrotic tissue is profoundly hypoxic, often below 5 mmHg; raising dissolved plasma oxygen restores oxygen-dependent killing. Hyperbaric oxygen also inhibits Clostridium perfringens alpha-toxin and Group A streptococcal exotoxin production, enhances the tissue penetration of aminoglycosides, fluoroquinolones, and beta-lactams, and helps demarcate viable from non-viable tissue across successive debridements.

Necrotizing infection is recognised as UHMS indication number 9, with a Level B (moderate) evidence rating from controlled studies and clinical data. Observational cohort studies and meta-analyses, including work by Wilkinson and Doolette (2004), Soh (2012), Hedetoft (2021), and Huang (2023), report an association between adjunctive hyperbaric oxygen and reduced mortality and fewer debridement procedures. The observational evidence is not uniform: some cohorts report lower mortality with adjunctive hyperbaric oxygen while others report no difference. Because these are observational data, they show association rather than proof of causation, and they consistently position hyperbaric oxygen as an adjunct to, never a replacement for, prompt surgery and antibiotics.

The Canadian referral pathway

Necrotizing soft tissue infection is treated as an emergency adjunct at Canadian hospital-based hyperbaric programmes and is covered by provincial insurance, with all 11 hospital-based programmes across seven provinces (Ontario, Quebec, British Columbia, Alberta, Nova Scotia, Newfoundland and Labrador, and Saskatchewan) accepting these referrals. Because source control cannot wait, the pathway is physician-to-physician and runs in parallel with the surgical plan.

• Ontario: call CritiCall Ontario at 1-800-668-4357, the 24/7 physician-to-physician coordination line that connects emergency departments and surgical teams to the Toronto General (UHN), Hamilton General, and The Ottawa Hospital programmes and arranges Ornge transport when needed.
• British Columbia: route to Vancouver General Hospital (Leon Judah Blackmore Pavilion), the hospital chamber in the province; covered under MSP.
• Alberta: route to Misericordia Community Hospital (Edmonton) or Foothills Medical Centre (Calgary); covered by Alberta Health.
• Quebec: RAMQ covers the hospital-based programmes, including Hopital du Sacre-Coeur de Montreal and Hotel-Dieu de Levis.
• Provinces and territories without a chamber: the patient is debrided and stabilised locally, and hyperbaric referral, where appropriate, routes to the nearest receiving programme by inter-provincial air-ambulance transfer.

For any necrotizing infection, the surgeon and intensivist lead; the hyperbaric team is engaged once the patient is in the operating theatre or recovering from the first debridement, never as a reason to delay it. You can read more background on the necrotizing soft tissue infections condition page.

How to use the research list below

The list contains every necrotizing soft tissue infection study in the Canada Hyperbarics database that was published in 2020 or later and has a freely available full-text version, each linked directly to that full text. Paywalled and abstract-only studies are excluded, and retracted studies are removed. This is a reference list, not a set of summaries. Counts and the open-access set refresh each quarter.