The efficacy of mild hypothermia for the treatment of patients successfully resuscitated from cardiac arrest: a meta-analysis

Objective To study the effectiveness and safety of therapeutic mild hypothermia in patients successfully resuscitated from cardiac arrest using a meta-analysis.Methods We searched the MEDLINE (1966-April 2012),OVID (1980 to April 2012),EMBASE (1980 to April 2012),Chinese bio-medical literature & retrieval system (CBM) (1978 to April 2012),Chinese medical current contents (CMCC) (1995 to April 2012),and Chinese medical academic conference (CMAC) (1994 to April 2012).Studies were included (1) the study design was a randomized controlled trial (RCT); (2) the study population included patients successfully resuscitated from cardiac arrest,and received either conventional post-resuscitation care with normothermia or mild hypothermia; (3) the study provided data about good neurologic outcome and survival till hospital discharge.Relative risk (RR) and 95％ corfidence interval (CI) were used to pool the effect.Results The study included four RCTs with a collected total of 417 patients successfully resuscitated from cardiac arrest.Compared to conventional post-resuscitation care with normothermia,patients in the hypothermia group were more likely to have good neurologic outcome (RR =1.43,95％ CI 1.14 ～ 1.80,P =0.002) and were more likely to survive till hospital discharge (RR =1.32,95％ CI 1.08 ～ 1.63,P =0.008).From all over the studies there was no significant difference in reported adverse events between the normothermia and hypothermia group (P ＞ 0.05).There did not exist heterogeneity and publication bias.Conclusions Therapeutic mild hypothermia improves neurologic outcome and survival in patients successfully resuscitated from cardiac arrest. Key words: Cardiac arrest;  Cardiopulmonary resuscitation;  Return of spontaneous circulation;  Mild hypothermia ;  Neurologic function ;  Survival to hospital discharge ;  Meta-analysis ;  Randomised controlled trial