Ducasse

Hyperbaric oxygenation was associated with more rapid clinical recovery in non-comatose patients with carbon monoxide poisoning.

Clinical Bottom Line:

1. Early hyperbaric oxygen treatment results in a significant reduction in those with clinical impairment at 2 and 12 hours.

Appraised by: Mike Bennett, Dept. of Diving and Hyperbaric Medicine, Prince of Wales Hospital Sydney; Tuesday, 24 November, 1998

Clinical Scenario: Non-comatose patient with carbon monoxide intoxication and presenting to hospital within 2 hours.

Three-part Question: In non-comatose patients suffering with carbon monoxide intoxication, does the application of hyperbaric oxygen, compared to a normobaric oxygen regime, result in any improvement in neurological outcome?

Search Terms: Hyperbaric oxygenation, carbon monoxide poisoning.

The Study: Single-blinded randomised controlled trial with intention-to-treat. Presenting within 2 hours of exposure, less than 12 hours exposure, Glasgow Coma Score of 12 or more and not pregnant. Control group (N = 13; 13 analysed): Oxygen at 1ATA for 6 hours, then 0.5ATA for 6 hours in the ICU. Experimental group (N = 13; 13 analysed): Oxygen at 2.5ATA for 2 hours in a hyperbaric chamber, then at 1ATA for 4 hours and 0.5ATA for 6 hours.

The Evidence:

Outcome	Time to Outcome	NBO group	HBO group	Relative risk reduction	Absolute risk reduction	Number needed to treat
Clinical abnormalities	2 hours	0.692	0.154	78%	0.54	2
95% CI				32% to 100%	0.22 to 0.86	1 to 5
Clinical abnormalities	12 hours	0.385	0	100%	0.39	3
95% CI					0.12 to 0.65	2 to 8

Comments:1. Patients and staff not blinded to treatment.2. No information on longer-term outcomes. No apparent neurological differences.3. Clinical abnormalities included headache, reflex impairment, asthenia and pulmonary

Expiry date: August 2022

References: 1. Ducasse JL, Cesis P, Marc-Vergnes JP. Non-comatose patients with acute carbon monoxide poisoning: hyperbaric or normobaric oxygenation? Undersea Hyperbaric Medicine 1995;22:9-15.

2. Ducasse JL, Izard PH, Celcis P, Leclercq Ch et al. Moderate carbon monoxide poisoning: hyperbaric or normobaric oxygenation? In: Bakker DJ, Schmutz J eds. Hyperbaric Medicine Proceedings, 2nd Swiss Symposium on Hyperbaric Medicine. Basel, Switzerland: Foundation for Hyperbaric Medicine 1990:289-297.