Epidemiology and outcome of out-of-hospital cardiac arrest in Zhejiang province

Abstract

Objective To investigate the epidemiological features of out-of-hospital cardiac arrest (OHCA) in Zhejiang and to analysis factors associated with outcomes for providing evidence on improving the success rate of cardiopulmonary resuscitation (CPR). Methods Clinical data of 493 patients with OHCA collected from the emergency department (ED) of Zhejiang Provincial People's Hospital, Ningbo Emergency Medical Service Center and Shaoxing Emergency Medical Service Center from January 2012 to August 2016 were analyzed retrospectively. All the data were recorded following the Utstein style included causes of arrest, location of arrest, first arrest rhythm, witnessed by bystanders, bystander CPR, pre-hospital defibrillation, pre-hospital intubation, pre-hospital epinephrine administration, emergency medical services (EMS) response time, return of spontaneous circulation (ROSC) at scene/enroute, ROSC at ED, admission to hospital, survival to hospital discharge and neurological outcomes at discharge. Factors associated with 30 days survival rate of patients with OHCA were analyzed. Results 493 patients were enrolled, of whom 342 were male and 151 were female. The average age was (58.8±21.4) years. The causes of arrests consisted of cardiac etiology (219 cases), trauma (155 cases), respiratory disease (22 cases), drowning (19 cases), electrocution (8 cases) and others (70 cases). Most of the events occurred at home (65.1%) and public places (22.7%). 55.2% patients were witnessed by bystanders while bystander CPR was performed in only 2.6% cases. Asystole was the predominant rhythm (78.7%) observed by the ambulance crew at the arrest site while only 5.5% first arrest rhythms were ventricular fibrillation/ventricular tachycardia (VF/VT). Only 6.9% patients underwent pre-hospital defibrillation. Pre-hospital intubations were attempted in 16.4% patients. Epinephrine was administered in 56.4% patients at scene or in ambulances. EMS response time was (13.6±8.0) minutes. 4.5% patients had ROSC at scene/enroute and 7.7% had ROSC at ED. Only 9.7% patients were admitted to hospital and 1.2% discharged alive. 0.8% patients were still in hospital on 30th day. The 30-day survival rate was 2.0% (10/493) and only 0.8% patients had neurologically favorable survivals [with the cerebral performance category (CPC) score of 1 or 2]. Witnessed by bystanders (3.31% vs. 0.45%), VF/VT as the first arrest rhythm (7.41% vs. 1.72%), bystander CPR (15.38% vs. 1.67%), pre-hospital defibrillation (8.82% vs. 1.53%) and EMS response time < 10 minutes (3.57% vs. 0.74%) could improve 30-day survival rate of OHCA significantly (all P < 0.05). Conclusion Resuscitation survival of OHCA in Zhejiang province was unsatisfactory. Improvements are required in series aspects of OHCA survival chain. Key words: Out-of-hospital cardiac arrest; Cardiopulmonary resuscitation; Epidemiology; Outcome; Emergency medical services response time