title: The efficacy and safety of prehospital therapeutic hypothermia in patients with out-of-hospital cardiac arrest: A systematic review and meta-analysis.
abstract: BACKGROUND
  The benefit of therapeutic hypothermia (TH) to patients suffering out-of-hospital cardiac arrest (OHCA) has been well established. However, the effect of prehospital cooling remains unclear. We aimed to investigate the efficacy and safety of prehospital TH for OHCA patients by conducting a systematic review of randomised controlled trials (RCTs).
  
  
  METHODS
  The MEDLINE, EMbase and CENTRAL databases were searched for publications from inception to April 2015. RCTs that compared cooling with no cooling in a prehospital setting among adults with OHCA were eligible for inclusion. Random- and fixed-effect models were used depending on inter-study heterogeneity.
  
  
  RESULTS
  Eight trials that recruited 2379 participants met the inclusion criteria. Prehospital TH was significantly associated with a lower temperature at admission (mean difference (MD) -0.94; 95% confidence interval (CI) -1.06 to -0.82). However, survival upon admission (Risk ratio (RR) 1.01, 95%CI 0.98-1.04), survival at discharge (RR 1.02, 95%CI 0.91-1.14), in-hospital survival (RR 1.05, 95%CI 0.92-1.19) and good neurological function recovery (RR 1.06, 95% CI 0.91-1.23) did not differ between the TH-treated and non-treated groups. Prehospital cooling increased the incidence of recurrent arrest (RR 1.23, 95%CI 1.02-1.48) and decreased the PH at admission (MD -0.04, 95%CI -0.07 to -0.02). Pulmonary oedema did not differ between the arms (RR 1.02, 95%CI 0.67-1.57). None of the potentially controversial issues (cooling methods, time of inducing TH, the proportion of continuing cooling in hospital, actual prehospital infusion volume and primary cardiac rhythms) affected the efficacy.
  
  
  CONCLUSIONS
  Evidence does not support the administration of prehospital TH to patients with OHCA.
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Fang-Yang
authors: FY
authors: Huang
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Bao-Tao
authors: BT
authors: Huang
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Peng-Ju
authors: PJ
authors: Wang
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Zhi-Liang
authors: ZL
authors: Zuo
authors: Department of Family Medicine, West China Hospital, Sichuan University, Chengdu, China.
authors: Yue
authors: Y
authors: Heng
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Tian-Li
authors: TL
authors: Xia
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Yi-Yue
authors: YY
authors: Gui
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Wen-Yu
authors: WY
authors: Lv
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Chen
authors: C
authors: Zhang
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Yan-Biao
authors: YB
authors: Liao
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China.
authors: Wei
authors: W
authors: Liu
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China. Electronic address: hmaochen@vip.sina.com.
authors: Mao
authors: M
authors: Chen
authors: Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China. Electronic address: zhuye1974@163.com.
authors: Ye
authors: Y
authors: Zhu
mesh_terms: D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D004632:Emergency Medical Services / Q000379:methods*; D007036:Hypothermia, Induced / Q000379:methods*; D058687:Out-of-Hospital Cardiac Arrest / Q000628:therapy*; D012449:Safety / Q000592:standards*
keywords: Out-of-hospital cardiac arrest; Prehospital; Therapeutic hypothermia