Hyperbaric
oxygen and thrombolysis in the treatment of acute myocardial infarction improved
symptom resolution and may limit myocardial damage.
Clinical
Bottom Line:
1.Administration
of HBO and thrombolysis together is feasible and is not associated with poor
outcomes.
2.Myocardial
damage, as estimated by enzyme rise, may be less in the HBO group.
3.There
is earlier resolution of pain associated with HBO administration.
Appraised
by:
Mike Bennett, Dept.of Diving and Hyperbaric Medicine, Prince of Wales Hospital,
Sydney Monday, 14 December, 1998
Clinical
Scenario:
A 55-year-old man with suspected myocardial infarction presenting to the
Emergency Department.
Three-part
Question:
In evolving myocardial infarction where thrombolysis is considered appropriate,
does the addition of hyperbaric oxygenation compared to thrombolysis alone,
result in any improvement in outcome?
Search
Terms:
Hyperbaric oxygenation, myocardial infarction.
The
Study:
Non-blinded
concealed randomised controlled trial without intention-to-treat.
Presentation
with suspected MI, pain duration less than six hours and considered suitable for
rTPA administration.
Control
group (N = 41; 34 analysed): Usual cardiac care including rTPA, total dose
100mg.
Experimental
group (N = 41; 32 analysed): As above, but transferred immediately to hyperbaric
chamber for a single session at 2ATA for 60 minutes on 100%oxygen.
The
Evidence:
|
Outcome |
Time
to Outcome |
RTPA
rate |
HBO
rate |
Relative
risk reduction |
Absolute
risk reduction |
NNT |
|
Death |
Discharge |
0.06 |
0 |
100% |
0.059 |
17 |
|
95%
CI: |
|
|
|
|
-0.02
to 0.14 |
NNT=7
to INF NNH=49 to
INF |
|
Revascularization |
Discharge |
0.56 |
0.59 |
-6% |
-0.035 |
-29 |
|
95%
CI: |
|
|
|
-49%
to 36% |
-0.27
to 0.20 |
NNT=5
to INF NNH=4 to
INF |
|
Balloon
pump |
Discharge |
0.12 |
0.03 |
74% |
0.087 |
11 |
|
95%
CI: |
|
|
|
-31%
to 100% |
-0.04
to 0.21 |
NNT=5
to INF NNH=27 to
INF |
Non-Event
Time to
rTPA group
rTPA and HBO group
P-value
Outcomes
outcome
CPK
12
hours
2385
1552
0.03
Pain
relief (mins) 664
275
<0.001
ST
resolution (mins)
285
185
>0.05
LOS(days)
9.2
7.4
>0.05
Comments:
1.
Small, pilot study without intention to treat. About 50% recruitment rate of
eligible patients due to physician refusal. No attempt to blind.
2.
Larger, multi-centre study with similar protocol is under way.
Expiry date: October 2004
References:
1.Shandling AH, Ellestad MH, Hart GB, Crump R, Marlow D, Van Natta B, Messenger
JC, Strauss M, Stavitsky Y. Hyperbaric oxygen and thrombolysis in myocardial
infarction: The "HOT MI" pilot study. American Heart Journal 1997;
134:544-550.
