Outcome predictors of patients in out-of-hospital cardiac arrests with pre-hospital defibrillation in Hong Kong

Abstract

Objective: To report the epidemiology, outcomes and the predictors of survival in patients with out-of-hospital cardiac arrest (OHCA) with pre-hospital shockable cardiac rhythms in Hong Kong. Methods: It was a prospective study based on data from the cardiac arrest registry of emergency departments (ED) in two regional hospitals in Hong Kong from 1st August 2010 to 31st January 2012. All non-traumatic patients aged 18 years or above presented with OHCA with shockable pre-hospital cardiac rhythm and received pre-hospital defibrillation were included. The characteristics of patients, pre-hospital data, management and outcomes were recorded in a standardised form compatible with Utstein template at the time of patient consultation. Binominal logistic regression was applied to evaluate the relationship between survival to admission (STA) and patients' variables. Results: A total of 135 patients fulfilled the inclusion criteria. The mean age was 67.0 years old. The STA rate was 34.8% and the survival to discharge (STD) rate was 6.7%. Factors independently associated with better prognosis in terms of STA were presence of bystander cardiopulmonary resuscitation (CPR) (OR 5.76, 95% CI=1.08-30.5), restoration of spontaneous circulation (ROSC) before arrival to ED (OR 43.94, 95% CI= 4.19-460.43) and short time from calling emergency medical services (EMS) to first defibrillation (OR 0.82, 95% CI=0.70-0.96). Conclusion: STA rate for adults presenting with shockable OHCA in our study was 34.8%. Patients with shockable OHCA with bystander CPR, short call-to-shock time and achieved ROSC before arrival to ED are significantly associated with higher STA rate.