Hypothermia for neuroprotection after cardiac arrest: systematic review and individual patient data meta-analysis.
OBJECTIVE
Only a few patients survive cardiac arrest with favorable neurologic recovery. Our objective was to assess whether induced hypothermia improves neurologic recovery in survivors of primary cardiac arrest.


METHODS
Studies were identified by a computerized search of MEDLINE, EMBASE, CINAHL, PASCAL, the Cochrane Controlled Trial Register, and BIOSIS.


METHODS
We included randomized and quasi-randomized, controlled trials of adults who were successfully resuscitated, where therapeutic hypothermia was applied within 6 hrs after arrival at the emergency department and where the neurologic outcome was compared. We excluded studies without a control group and studies with historical controls.


METHODS
All authors of the identified trials supplied individual patient data with a predefined set of variables.


RESULTS
We identified three randomized trials. The analyses were conducted according to the intention-to-treat principle. Summary odds ratios were calculated using a random effects model and translated into risk ratios. More patients in the hypothermia group were discharged with favorable neurologic recovery (risk ratio, 1.68; 95% confidence interval, 1.29-2.07). The 95% confidence interval of the number-needed-to-treat to allow one additional patient to leave the hospital with favorable neurologic recovery was 4-13. One study followed patients to 6 months or death. Being alive at 6 months with favorable functional neurologic recovery was more likely in the hypothermia group (risk ratio, 1.44; 95% confidence interval, 1.11-1.76).


CONCLUSIONS
Mild therapeutic hypothermia improves short-term neurologic recovery and survival in patients resuscitated from cardiac arrest of presumed cardiac origin. Its long-term effectiveness and feasibility at an organizational level need further research.
Holzer
Michael
M
Department of Emergency Medicine, General Hospital Vienna, Medical University of Vienna, Vienna, Austria.
Bernard
Stephen A
SA
Hachimi-Idrissi
Said
S
Roine
Risto O
RO
Sterz
Fritz
F
Müllner
Marcus
M
D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced; D016032:Randomized Controlled Trials as Topic; D012151:Resuscitation; D016896:Treatment Outcome