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 oedema.
Expiry date: September 2004
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.
