Weaver 2002 NEJM RCT + 6-year follow-up establish mortality/morbidity benefit. Weaver protocol is standard of care.
Overview
HBOT is UHMS-approved for severe carbon monoxide poisoning, defined by loss of consciousness, cardiovascular compromise, severe metabolic acidosis, or CO level >25%. The Weaver et al. 2002 NEJM trial demonstrated significant reduction in cognitive sequelae at 6 weeks and 12 months versus normobaric oxygen.
How HBOT Works
HBOT accelerates CO displacement from haemoglobin by elevating dissolved plasma oxygen and competing CO off haemoglobin binding sites. The CO half-life drops from ~5 hours on room air to ~20 minutes at 3.0 ATA with 100% oxygen. Beyond COHb clearance, HBOT reduces leukocyte-mediated reperfusion injury implicated in delayed neurological sequelae.
Clinical Protocol
Typical protocol
1–3 sessions at 2.5–3.0 ATA, 90 minutes each (Weaver protocol)
Evidence level
Strong (RCT) — UHMS approved
FDA / regulatory status
FDA-approved indication
Weaver protocol: first session at 3.0 ATA for 60 minutes with air breaks, two subsequent sessions at 2.0 ATA for 60 minutes with air breaks, all within the first 24 hours. Pregnant patients and specific severe presentations may require additional sessions.
Cautions & Considerations
Time-critical — initiate within hours of exposure for maximum benefit.
Requires 24/7 hyperbaric facility access.
Severe CO poisoning is often polyvictim (building fires, suicide attempts) — require coordinated emergency response.
Pregnancy is a specific indication (CO poisoning in pregnancy threatens fetus disproportionately).