CARBON MONOXIDE POISONING DOESN’T BENEFIT FROM HYPERBARIC O2 (HBO)
|
Clinical Bottom Lines:
1. Patients without loss of consciousness do not benefit from 2 hrs of hyperbaric O2 (HBO) at 2 ATA (+4 hrs of 100% normobaric O2 (NBO)) when compared to 6 hrs 100% NBO.
2. In patients with loss of consciousness (including coma) at site of rescue, no benefit of 2 sessions of HBO as compared to one session only, both receiving concurrent NBO.
3. No controlled trials of HBO vs only NBO, in patients with loss of consciousness |
File listing: cohybarc.doc Appraiser: S. Sauvé
CAT: therapy Date Appraised: November 11th 1992
The Evidence: [1] Randomized unbllinded trial. If no LOC: compared 2 hrs HBO (2 ATA) + 4 hrs 100% NBO to 6 hrs 100% NBO. If LOC: compared 2*2 hrs of HBO + NBO to 1*2 hrs HBO + NBO.
|
Trial, strata, outcome |
"control" |
"Tx" |
ARR |
|
[1] without LOC (n=343) resumption of former activity |
97% |
97% |
0 |
|
persistent symptoms at 1 mth |
34% |
32% |
1.7% |
|
persistent neuro sign at 1 mt |
0 |
0 |
0 |
|
death |
0 |
0 |
0 |
|
[1] with LOC (n=286) resumption of former activity |
91% |
91% |
0 |
|
persistent symptoms at 1 mth |
42% |
43% |
-0.6% |
|
persistent neuro sign at 1 mt |
2.4% |
3.2% |
-0.8% |
|
death |
1.6% |
1.6% |
0 |
Comments:
1. unblinded, but since no seen treatment advantage, likely unimportant
2. 11% loss to follow-up in all 4 groups
3. COHb level not a predictor of outcome, but coma is.
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REFERENCES:
[1] Raphael JC, Elkharrat D, Jars-Guincestre MC, et al. Trial of normobaric and hyperbaric oxygen for acyte carbon monoxide intoxication. Lancet 1989;Aug 19th:414-419