Fewer
patients with evidence of persistent neurological manifestations at 3 months
following carbon monoxide intoxication following a single hyperbaric oxygen
treatment.
Clinical Bottom Line:
1.
Treatment with HBO resulted in fewer patients with persistent neurological
manifestations at 3 months after exposure, but not 1 or 6 months.
Appraised
by: Mike Bennett Dept. of Diving and
Hyperbaric Medicine
Prince of Wales Hospital,
Sydney; Thursday, 19 November, 1998
Clinical
Scenario: Non-comatose patient with
carbon monoxide intoxication.
Three-part
Question: In non-comatose patients with
CO poisoning, does the application of hyperbaric oxygen as compared to
normobaric oxygen result in fewer patients with neurological manifestations?
Search
Terms: Hyperbaric oxygenation, carbon
monoxide
The
Study:
Non-blinded randomised
controlled trial with intention-to-treat.
Adult, non-comatose patients
presenting within 12 hours and with a measured HbCO of greater than 10%.
Excluded if there was mixed poisoning, pregnancy or specific contraindication.
Control group (N = 276; 276
analysed): 100% oxygen for 12 hours at 1ATA.
Experimental group (N = 299; 299
analysed): Hyperbaric oxygen at 2.5ATA for 90 minutes.
The
Evidence:
|
Outcome |
Time
to Outcome |
NBO |
HBO |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Persistent
neurological manifestations |
1
month |
0.26 |
0.23 |
12% |
0.030 |
33 |
|
95%
CI |
|
|
|
-16%
to 39% |
-0.04
to 0.10 |
NNT=10
to INF NNH=25 to
INF |
|
PNM |
3
months |
0.15 |
0.095 |
37% |
0.055 |
18 |
|
95%
CI |
|
|
|
1%
to 72% |
0.001
to 0.11 |
9
to 746 |
|
PNM |
12
months |
0.05 |
0.043 |
16% |
0.007 |
-143 |
|
95%
CI |
|
|
|
-64%
to 96% |
-0.03
to 0.04 |
NNT=37
to INF NNH=24 to
INF |
Comments:
1. Interim report only with
insufficient detail of outcome measures, randomisation, blinding or numbers of
patients who reached final follow-up.
3. There does not appear to have
been any sham treatment.
4. The effect shown is probably
unreliable given nature of report.
Expiry
date: September 2004
References:
1. Mathieu D, Wattel F, Mathieu-Nolf M,
Durak C, Tempe JP, Bouachour G, Sainty JM. Randomized prospective study
comparing the effect of HBO versus 12 hours NBO in non-comatose CO poisoned
patients: results of the interim analysis. In: Proceedings of the International
Joint Meeting on Hyperbaric and Underwater Medicine, Marroni A, Oriani G, Wattel
F eds. Grafica Victoria, Bolognia 1996; 331.
