Abstract
Background
Guidelines recommend mild induced hypothermia (MIH) to reduce mortality and neurological
impairment after out-of-hospital cardiac arrest. Our objective was to systematically
evaluate the evidence for MIH taking into consideration the risks of systematic and
random error and to GRADE the evidence.
Methods
Systematic review with meta-analysis and trial sequential analysis of randomised trials
evaluating MIH after cardiac arrest in adults. We searched CENTRAL, MEDLINE, and EMBASE
databases until May 2009. Retrieved trials were evaluated with Cochrane methodology.
Meta-analytic estimates were calculated with random- and fixed-effects models and
random errors were evaluated with trial sequential analysis (TSA).
Results
Five randomised trials (478 patients) were included. All trials had substantial risk
of bias. The relative risk (RR) for death was 0.84 (95% confidence interval (CI) 0.70
to 1.01) and for poor neurological outcome 0.78 (95% CI 0.64 to 0.95). For the two
trials with least risk of bias the RR for death was 0.92 (95% CI 0.56 to 1.51) and
for poor neurological outcome 0.92 (95% confidence interval 0.56 to 1.50). TSA indicated
lack of firm evidence for a beneficial effect. The substantial risk of bias and concerns
with directness rated down the quality of the evidence to low.
Conclusions
Evidence regarding MIH after out-of-hospital cardiac arrest is still inconclusive
and associated with non-negligible risks of systematic and random errors. Using GRADE-methodology,
we conclude that the quality of evidence is low. Our findings demonstrate that clinical
equipoise exists and that large well-designed randomised trials with low risk of bias
are needed.
Keywords
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Article info
Publication history
Published online: July 01, 2010
Accepted:
June 4,
2010
Received:
March 29,
2010
Identification
Copyright
© 2010 Elsevier Ireland Ltd. Published by Elsevier Inc. All rights reserved.
