Frequency of Hyperbaric Oxygen Therapy Sessions
For carbon monoxide poisoning, administer three hyperbaric oxygen treatments within 24 hours at 3.0 atmospheres absolute, which is the protocol that demonstrated a 50% reduction in cognitive sequelae at 6 and 12 months. 1
Carbon Monoxide Poisoning Protocol
The optimal treatment regimen consists of:
- Three HBOT sessions within the first 24 hours of presentation for acute CO poisoning 1
- Treatment pressure of 3.0 atmospheres absolute (atm abs) for the first session, which is used in 69% of U.S. facilities 1
- Each session typically lasts 60-90 minutes 1
- Persistently symptomatic patients may receive up to three total treatments, though the exact protocol is left to the managing hyperbaric physician's discretion 1
This regimen is based on the Weaver study, which showed patients receiving three HBOT treatments had approximately half the rate of cognitive sequelae (25% vs 46%) at 6 weeks compared to normobaric oxygen, with benefits persisting at 12 months 1. The American Journal of Respiratory and Critical Care Medicine guidelines emphasize that while the optimal dose and frequency remain technically "unknown," the three-treatment protocol within 24 hours represents the best available evidence 1.
Sudden Sensorineural Hearing Loss Protocol
For sudden hearing loss, treatment frequency varies by timing:
- Initial therapy (within 2 weeks): Daily HBOT sessions combined with steroids 1
- Salvage therapy (within 1 month): Daily sessions as adjunctive treatment when initial therapy fails 1
- Treatment typically involves daily sessions until clinical response or completion of protocol 1
The American Academy of Otolaryngology-Head and Neck Surgery recommends HBOT be initiated within 14 days of symptom onset for optimal results, with better outcomes observed when treatment begins within 2 weeks 1.
General Treatment Considerations
Treatment frequency depends heavily on the specific indication:
- Acute conditions (CO poisoning, air embolism): Multiple treatments within 24 hours or daily sessions 1, 2
- Chronic wound healing: Typically daily sessions for 1-2 hours at 2.0-2.8 atm abs 3
- Sports injuries: Usually 3-10 sessions total, administered daily 3
- Interstitial cystitis: 30 treatment sessions of 90 minutes each at 2.4 atm abs 4
Important Caveats
The effects of each HBOT session do not persist until the next treatment, which supports the rationale for frequent dosing in acute conditions 5. Research on severely brain-injured patients demonstrated that shorter, more frequent exposures may optimize treatment outcomes 5.
For CO poisoning specifically, do not withhold HBOT because a patient appears clinically stable—the goal is preventing long-term neurocognitive dysfunction, not just short-term survival 1, 2. Only 3% of CO-poisoned patients die, but cognitive sequelae affect a much larger proportion 1.
Timing is critical: The American Heart Association emphasizes that HBOT should be administered as soon as possible after diagnosis, particularly within the first 24 hours for CO poisoning 2. For sudden hearing loss, efficacy decreases significantly after 2 weeks 1.