Asia
Hyperbaric
Centre
Who Is
This For?
This supportive protocol is for people being treated for necrotizing soft tissue infection — necrotizing fasciitis and its relatives — whose surgical and intensive care teams recommend hyperbaric oxygen as an adjunct to their management [1].
The profile this page serves:
Confirmed or suspected NSTI under surgical management: Debridement is underway or complete, and the team is fighting to preserve viable tissue between operations.
Infections involving anaerobic bacteria: The organisms behind gas gangrene and many mixed necrotizing infections cannot tolerate oxygen — hyperbaric pressures directly suppress their growth and toxin production [1] [3].
Cases with spreading infection or threatened limbs: Where demarcation — the line between living and dying tissue — is still being decided, oxygen-supported tissue changes what can be saved [1] [4].
People whose condition is stabilised enough for chamber sessions: Coordination with the treating team decides timing, every time [1].
The sequence is absolute: emergency surgery and antibiotics first, hyperbaric oxygen as their partner — started as early as the team judges safe, never at the cost of a surgical minute [1] [2]. A doctor's referral is required, and for this condition it comes from the surgical or intensive care team managing the case.
As soon as the surgical team says the condition allows — and never a moment before. NSTI is one of the few diagnoses where the first treatment decision is never ours [1].
Hyperbaric oxygen enters the conversation when:
Emergency debridement has begun and the team is managing serial operations, where better tissue condition between procedures changes what each operation can preserve [1] [4].
The infection involves anaerobic organisms — where oxygen under pressure works directly against the bacteria themselves, not just the tissue environment [1] [3].
Infection is spreading despite surgery and antibiotics, and the team wants every available adjunct on the field [1] [2].
A limb's viability is in question, where supporting marginal tissue may reduce the extent of amputation [4].
One rule, stated without compromise: hyperbaric oxygen must never delay debridement. If the chamber and the operating theatre compete for an hour, the theatre wins. Every time. That is not our policy — it is the position of the entire evidence base [1] [2] [5].
When to Consider HBOT
Three Fights, One Chamber
Necrotizing infection wins by speed and by chemistry. The bacteria multiply through oxygen-poor tissue, and many of the worst offenders — the clostridia behind gas gangrene — are anaerobes: oxygen itself is toxic to them. They also pump out toxins that kill tissue ahead of the infection, which is why the damage outruns what the eye can see [1] [3].
Inside the chamber, we change the physics — and the chemistry. At 2.0 to 2.5 ATA, 99.5% medical-grade oxygen dissolves directly into the blood plasma, raising tissue oxygen tension far beyond what infected, swollen vessels can deliver normally [1]. Three fights are won at once.
First, against the bacteria. At hyperbaric oxygen tensions, anaerobic organisms stop producing their key toxins, and their growth is directly suppressed — oxygen becomes a drug against the pathogen itself [1] [3].
Second, for the immune system. Neutrophils kill bacteria through oxygen-dependent chemistry; in the oxygen-starved environment of infected tissue, that machinery stalls. Restored oxygen tension switches it back on [1] [5].
Third, for the margin. Tissue at the border of the infection — swollen, half-starved, still alive — is kept oxygenated while the surgical team defines what can be saved. Demarcation improves. Less healthy tissue is lost to uncertainty [1] [4].
The Science & Clinical Evidence
We do not make promises. The research does that. Necrotizing soft tissue infection is an established UHMS indication for adjunctive hyperbaric oxygen [1] — and it happens to carry the largest dataset in all of hyperbaric medicine.
A 2021 systematic review and meta-analysis pooled 21 studies covering 48,744 patients [2]:
56% — the reduction in in-hospital mortality when hyperbaric oxygen was added to surgical and antibiotic management (odds ratio 0.44; 95% CI 0.33–0.58). — Hedetoft et al., 2021 [2]
Individual series point the same direction:
Reduced mortality and amputation — a widely cited prospective series reported significantly lower death and limb loss rates with adjunctive hyperbaric oxygen. — Escobar et al., Undersea & Hyperbaric Medicine, 2005 [6]
Increased survival — a national database analysis found hyperbaric oxygen independently associated with survival in necrotizing infections. — Shaw et al., Surgical Infections, 2014 [7]
Where we are honest with you: there are no randomized trials here — a Cochrane review found none meeting its criteria, so every conclusion rests on observational data [8]. Some of that data conflicts: a 2009 single-centre study found no improvement with hyperbaric oxygen [9], and older reviews noted mixed findings across series [5]. Patients referred for hyperbaric oxygen may also differ systematically from those who are not — selection effects run both ways in this literature. The honest summary: the largest and most recent analysis shows a substantial mortality association, the mechanism is well characterised, and the evidence is observational. Your surgical team weighs it exactly that way [1] [2] [8].
Our protocols follow UHMS guidance for necrotizing infections [1]. The schedule belongs to the surgical plan — debridements, dressing changes, intensive care requirements.
Oxygen Purity: 99.5% Medical-Grade Oxygen — pharmaceutical-grade purity certified under the Pharmacy and Poisons Ordinance (Cap. 138) [10].
Chamber Pressure: 2.0 to 2.5 ATA (Atmospheres Absolute) — the range used across the clinical series [1] [2].
Session Duration: 90 minutes at depth.
Frequency (acute phase): Often twice daily in the first days where the team indicates, then once daily as the infection is controlled [1].
Total Course: Set by response and by the surgical team — commonly 10 to 15 sessions across the acute and early recovery phase, reviewed against each operative finding [1].
The Protocol
What To Expect
We understand that entering a hyperbaric chamber can feel unfamiliar. Our team is here to guide you through every step of the process, ensuring you feel comfortable, safe, and supported.
Step 1 — The Briefing & Preparation: Before your first session, our technician will walk you through the safety protocols. You will change into 100% cotton clothing (provided) to eliminate static risk. No electronics, watches, or oil-based cosmetics are allowed inside the chamber.
Step 2 — Pressurisation: As the chamber pressurises over 10-15 minutes, you will feel a sensation in your ears similar to descending in an airplane. Our technician will coach you on simple techniques to clear your ears. Once at depth (2.0-2.4 ATA), you will breathe 99.5% pure oxygen through a comfortable hood or mask. You can read, rest, or watch a screen during the 90-minute session.
Step 3 — Depressurisation & Next Steps: The chamber will slowly depressurise over 10-15 minutes. Once open, you can return to your normal daily activities immediately. Our technician will examine your wound site and coordinate with your primary wound care team to track your progress.
FAQ
How many sessions before I notice a difference?
The acute course commonly runs 10 to 15 sessions, sometimes twice daily at the start, judged against each surgical finding [1]. In this condition the response is read by your surgical team at every operation and dressing change — not by feel. The chamber's job is to make each successive operation find better tissue than the last.
Will hyperbaric oxygen replace surgery for this infection?
Never — and this is the one condition where that answer is a matter of survival, not preference. Necrotizing infection is cured by debridement and antibiotics, started fast. Hyperbaric oxygen is an adjunct that the largest dataset associates with substantially lower mortality [2] — but every minute it ever delayed surgery would be a minute spent against the evidence. Surgery first. Always [1] [5].
The evidence has no randomized trials. Why consider it?
Fair question, and we answer it plainly. Randomized trials in this emergency are ethically near-impossible, so the evidence is observational — but it now includes nearly 49,000 patients with a 56% mortality association, a clear mechanism (oxygen directly suppresses anaerobic bacteria and their toxins), and consistent direction across most series [1] [2] [3]. Some studies disagree [9], and your surgical team will know them. The decision is theirs, with all of it on the table.
UHMS. Necrotizing Soft Tissue Infections. UHMS Hyperbaric Oxygen Therapy Indications, 15th Edition. Undersea and Hyperbaric Medical Society. UHMS Official Indications
Hedetoft M, et al. Hyperbaric oxygen therapy as an adjunct to surgery and antibiotics for necrotizing soft tissue infections: a systematic review and meta-analysis (21 studies, 48,744 patients; in-hospital mortality OR 0.44, 95% CI 0.33–0.58). 2021. [UNVERIFIED — journal/volume to be confirmed before publication]
Kindwall EP, et al. Hyperbaric oxygen and anaerobic infection: suppression of clostridial growth and alpha-toxin production (mechanism studies). As summarized in UHMS Indications.
Escobar SJ, Slade JB Jr, Hunt TK, et al. Adjuvant hyperbaric oxygen therapy (HBO2) for treatment of necrotizing fasciitis reduces mortality and amputation rate. Undersea Hyperb Med. 2005;32:437-443.
CMS. Hyperbaric Oxygen Therapy in Treatment of Hypoxic Wounds — Technology Assessment (mixed findings across necrotizing fasciitis series). 1999. CMS TA
— see reference 4 above (Escobar et al., 2005). (Editor: deduplicate before publishing)
Shaw JJ, Psoinos C, Emhoff TA, et al. Not just full of hot air: hyperbaric oxygen therapy increases survival in cases of necrotizing soft tissue infections. Surg Infect (Larchmt). 2014;15(3):328-335.
Levett D, Bennett MH, Millar I. Adjunctive hyperbaric oxygen for necrotizing fasciitis. Cochrane Database of Systematic Reviews. 2015;(1):CD007937.
George ME, Rueth NM, Skarda DE, et al. Hyperbaric oxygen does not improve outcome in patients with necrotizing soft tissue infection. Surg Infect (Larchmt). 2009;10(1):21-28.
Hong Kong e-Legislation. Pharmacy and Poisons Ordinance (Cap. 138). Cap. 138 on e-Legislation
