TL;DR Hyperbaric oxygen therapy (HBOT) is a treatment in which a patient breathes near-100% oxygen inside a chamber pressurised above one atmosphere. Its “dose” is the combination of pressure (ATA), session duration, session count and total course. In the 2025 to 2026 systematic reviews in our library, the authors repeatedly report heterogeneous protocols and no established optimal dose. Quantitative safety limits for oxygen toxicity and barotrauma are largely absent from the abstracts we reviewed.

Hyperbaric oxygen dose, pressure and protocol optimization is a question referring physicians meet every time they write a referral: what pressure, for how long, and for how many sessions? This evidence review, published by Canada Hyperbarics, looks at how recent systematic reviews answer that question. It also draws on older primary sources where they state a protocol.

A caution up front. The evidence base here is the studies in the Canada Hyperbarics research library that matched this topic, not an exhaustive search. Most of the recent systematic reviews describe protocols as variable rather than prescribing one. That finding is itself the main result.

What does “dose” mean in HBOT?

HBOT involves inhaling 100% oxygen at pressures exceeding one atmosphere within a chamber, as one 2026 review puts it. A prescription therefore has at least four parts: the pressure in atmospheres absolute (ATA), the minutes at pressure, the number of sessions, and the schedule.

A 2025 narrative review states that oxygen is typically given at pressures between 1.5 and 3.0 ATA for 60 to 120 minutes, depending on the clinical presentation (Oxy-inflammation review, PubMed | Our Assessment). It is a narrative review, so it describes practice rather than testing which setting works best.

What do 2025 to 2026 systematic reviews say about HBOT protocols?

Across conditions, the recent systematic reviews describe heterogeneity and call for standardisation. Here is what each one reports as its principal finding on protocols.

Burn care

A 2026 systematic review followed PRISMA guidelines and included 13 studies of 566 burn patients: 5 randomised controlled trials, 7 cohort studies and 1 case-control study (Burn care review, PubMed | Our Assessment). The authors reported that burn severity, HBOT protocols and outcomes varied substantially. That heterogeneity limited meta-analysis.

The review described evidence for efficacy as inconsistent, with no clear consensus in practice. Several studies reported less need for surgery and shorter hospital stays, while mortality benefits were inconsistent. The authors called for well-designed randomised trials to establish standardised protocols.

Sleep breathing disorders

A 2026 systematic review of HBOT in obstructive sleep apnea, central sleep apnea and altitude-related breathing disorders described the evidence as promising but preliminary (Sleep breathing review, PubMed | Our Assessment). The authors cited heterogeneity in protocols, small sample sizes and limited long-term follow-up as constraints.

They stated that future multicentre trials should focus on optimizing treatment pressure, duration and patient selection, while ensuring safety across vulnerable populations. In other words, pressure and duration are named as unresolved variables.

Radiation enteritis

A 2025 systematic review and meta-analysis covered 22 clinical studies with 1,318 subjects, including six randomised controlled trials in the meta-analysis (Radiation enteritis review, PubMed | Our Assessment). The abstract notes that no standardised clinical protocols have been established, and that clinical application protocols were analyzed.

Moderate-quality evidence suggested HBOT could reduce the incidence of radiation enteritis (OR 0.32, 95% CI 0.14 to 0.72). The authors concluded that optimized treatment protocols and individualized adjustments are essential, and that caution is still warranted in clinical practice. The abstract text available to us does not give the pressures or session counts.

Diabetic foot ulcers

A 2025 systematic review and meta-analysis of 10 randomised controlled trials compared advanced modalities for diabetic foot ulcers (DFU meta-analysis, PubMed | Our Assessment). Negative pressure wound therapy was reported as superior for ulcer closure and healing time. HBOT was reported to reduce amputation rates, though the abstract’s printed confidence interval for that estimate is wide. The authors said more effort is required to refine the protocols of these therapies.

A 2025 network meta-analysis of 99 randomised controlled trials (7,356 patients) found HBOT associated with a lower amputation risk than standard of care (OR 0.35, 95% CI 0.16 to 0.78) (DFU network meta-analysis, PubMed | Our Assessment). Its abstract does not state an HBOT pressure or session count, so it cannot inform dosing.

What pressures, durations and session counts do the primary sources report?

Where a pressure is stated, it usually comes from older reviews or primary reports rather than from the recent systematic reviews. Treat these as descriptions of practice, not validated optima.

  • Diabetic foot ulcers: a 2012 review states treatment is usually given as daily 90 to 120 minute sessions at 2.0 to 2.5 ATA, aiming for 30 to 40 sessions (PubMed | Our Assessment). The same abstract says developing robust criteria to improve protocols, and deciding when to start and stop, remain open issues.
  • Tissue injury session counts: a retrospective chart review of 1,506 cases using an open protocol found acute injuries required 11 to 18 sessions depending on severity, while chronic injuries required about 30 per patient (PubMed | Our Assessment). The authors said prospective studies may better determine session numbers. The abstract does not state the pressure used.
  • Altitude decompression sickness: a prospective series of 12 patients tested USAF Treatment Table 8, which delivers 100% oxygen at 2 ATA in four 30 minute periods with 10 minute air breaks (total oxygen dose of 2 hours) (PubMed | Our Assessment). Treatment succeeded in 91% of Type I cases and 50% of Type II cases, and the authors suggested a more extensive clinical trial.
  • Sudden sensorineural hearing loss: a retrospective comparison of 52 patients given 2.5 ATA for 60 minutes (plus two 5 minute air breaks), once daily five days a week, with 81 patients treated pharmacologically only (PubMed | Our Assessment). The HBOT group was a combined-therapy group with higher-dose corticosteroids, so the effect of HBOT alone cannot be separated.
  • Opioid withdrawal symptoms: a pilot randomised controlled trial of eight adults compared a 90 minute session at 2.0 ATA with a sham at 1.3 ATA or less, after two consecutive days (PubMed | Our Assessment). It was a feasibility study; the authors described trends toward improvement and supported a fully powered trial.
  • Radiation hemorrhagic cystitis: a single case report of a 95-year-old patient described 196 sessions with a personal protocol of 1.4 to 1.6 ATA (PubMed | Our Assessment). A case report cannot establish that this pressure is effective or optimal.

Table: reported dosing ranges by condition

Condition or setting Pressure reported Duration reported Sessions reported Source type
General practice range 1.5 to 3.0 ATA 60 to 120 min Not stated Narrative review, 2025
Diabetic foot ulcers 2.0 to 2.5 ATA 90 to 120 min daily 30 to 40 aimed for Review, 2012
Acute tissue injuries Not stated Not stated 11 to 18 Retrospective, 1,506 cases
Chronic tissue injuries Not stated Not stated About 30 Retrospective, 1,506 cases
Altitude decompression sickness 2 ATA Four 30 min periods, 2 h oxygen Single treatment table Prospective series, n=12
Sudden hearing loss 2.5 ATA 60 min plus air breaks Daily, five days a week Retrospective comparison
Opioid withdrawal symptoms 2.0 ATA (sham 1.3 ATA or less) 90 min Two consecutive days Pilot RCT, n=8
Radiation hemorrhagic cystitis 1.4 to 1.6 ATA Not stated 196 Case report
Burns, sleep breathing, radiation enteritis Not stated in abstracts Not stated Not stated 2025 to 2026 systematic reviews: protocols varied or non-standardised

Where is no optimal dose established?

For most conditions in this pool, no optimal pressure, duration or session count has been established. The systematic reviews above say so for burns, sleep breathing disorders and radiation enteritis. Other reviews say the same for further conditions.

  • A 2016 review of stroke stated that there are no uniform criteria for the dose and session duration of HBOT in different strokes, and that the evidence is not yet sufficiently strong because of too few randomised double-blind trials (PubMed | Our Assessment).
  • A 2025 review of cardiovascular applications cited the lack of standardised treatment protocols and called for further optimization of therapeutic parameters (PubMed | Our Assessment).
  • A 2025 review of skull base osteoradionecrosis said HBOT shows promise but lacks robust evidence for standardised use (PubMed | Our Assessment).

Because protocols differ so widely, pooled estimates average across different pressures and session counts. A pooled odds ratio cannot tell a clinician which setting produced the effect.

What safety limits do the reviews report for oxygen toxicity and barotrauma?

The abstracts in this pool do not report quantitative safety limits. None of them gives a pressure-duration threshold for oxygen toxicity, and none reports barotrauma rates. We therefore cannot state a safe ceiling from this evidence.

What the abstracts do say is limited. The radiation enteritis review evaluated safety as one of its aims and advised caution in clinical practice, but the abstract does not list adverse event rates. The sleep breathing review asked that future trials ensure safety across vulnerable populations. The altitude decompression sickness study framed its short table as a way to reduce oxygen and pressure-producing resources without sacrificing efficacy.

For researchers, this is a reporting gap. Dose-finding needs adverse events recorded against specific pressure, duration and cumulative session exposure. Clinicians should rely on their own hyperbaric service’s contraindication screening and protocols, not on these summaries.

How should referring physicians read this evidence?

  1. Do not infer a dose from a pooled effect. Meta-analyses that mix protocols do not identify the effective setting.
  2. Check design. Several dosing figures above come from case reports, retrospective reviews or a pilot of eight participants.
  3. Ask the treating service for its protocol. Pressure, duration, air breaks and planned session count should be explicit.
  4. Treat session counts as provisional. The 1,506-case series used an open protocol and was retrospective.

Frequently Asked Questions

What pressure is used in hyperbaric oxygen therapy?

A 2025 narrative review states pressures typically range from 1.5 to 3.0 ATA. Primary reports in this pool used 2 ATA to 2.5 ATA for specific conditions, and one case report used 1.4 to 1.6 ATA. No single pressure is established as optimal across conditions.

How many HBOT sessions are typical?

It depends on the condition. A 2012 review cites 30 to 40 sessions for diabetic foot ulcers, and a retrospective series found about 11 to 18 for acute injuries and about 30 for chronic injuries. These are descriptive figures, not tested prescriptions.

Do systematic reviews agree on an optimal HBOT dose?

No. The 2025 to 2026 systematic reviews on burns, sleep breathing disorders and radiation enteritis each report variable or non-standardised protocols and call for further research.

What are the reported safety limits for oxygen toxicity and barotrauma?

The studies in this pool do not report numerical limits or event rates for either. This is a gap in the abstracts we reviewed, not evidence that the risks are absent.

Why does heterogeneity matter?

When pressure, duration and session count differ between trials, a combined result cannot show which regimen worked. The burn care review stated that treatment-regimen heterogeneity limited meta-analysis.

Is there a dose-response relationship for HBOT?

The pool does not establish one. A pilot trial compared a 2.0 ATA session with a low-pressure sham, which tests presence of treatment rather than dose levels.

Next step

The Canada Hyperbarics research library holds over 14,000 studies, and this review draws on only a small slice of them. Anyone considering HBOT should talk to their physician about whether it is appropriate for them.

This content is for informational purposes only and is not medical advice.