Mechanical cardiopulmonary resuscitation and hospital survival among adult patients with nontraumatic out-of-hospital cardiac arrest attending the emergency department: A prospective, multicenter, observational study in Japan (SOS-KANTO [Survey of Survivors after Out-of-Hospital Cardiac Arrest in Kanto Area] 2012 study)

Background--Mechanical cardiopulmonary resuscitation (mCPR) for patients with out-of-hospital cardiac arrest attending the emergency department has become more widespread in Japan. The objective of this study is to determine the association between the mCPR in the emergency department and clinical outcomes. Methods and Results--In a prospective, multicenter, observational study, adult patients with out-of-hospital cardiac arrest with sustained circulatory arrest on hospital arrival were identified. The primary outcome was survival to hospital discharge. The secondary outcomes included a return of spontaneous circulation and successful hospital admission. Multivariate analyses adjusted for potential confounders and within-institution clustering effects using a generalized estimation equation were used to analyze the association of the mCPR with outcomes. Between January 1, 2012 and March 31, 2013, 6537 patients with out-of-hospital cardiac arrest were eligible; this included 5619 patients (86.0%) in the manual CPR group and 918 patients (14.0%) in the mCPR group. Of those patients, 28.1% (1801/ 6419) showed return of spontaneous circulation in the emergency department, 20.4% (1175/5754) had hospital admission, 2.6% (168/ 6504) survived to hospital discharge, and 1.2% (75/6419) showed a favorable neurological outcome at 1 month after admission. Multivariate analyses revealed that mCPR was associated with a decreased likelihood of survival to hospital discharge (adjusted odds ratio, 0.40; 95% confidence interval, 0.20-0.78; P=0.005), return of spontaneous circulation (adjusted odds ratio, 0.71; 95% confidence interval, 0.53-0.94; P=0.018), and hospital admission (adjusted odds ratio, 0.57; 95% confidence interval, 0.40-0.80; P=0.001). Conclusions--After accounting for potential confounders, the mCPR in the emergency department was associated with decreased likelihoods of good clinical outcomes after adult nontraumatic out-of-hospital cardiac arrest. Further studies are needed to clarify circumstances in which mCPR may benefit these patients.