Prognosis of patients with ventricular fibrillation in out-of-hospital cardiac arrest in Hong Kong: prospective study.

OBJECTIVE To determine the prognosis of patients with ventricular fibrillation in out-of-hospital cardiac arrest in Hong Kong and examine its relationship with the other links in the chain of survival. DESIGN Prospective descriptive study. SETTING Three accident and emergency departments, Hong Kong. PARTICIPANTS Patients older than 18 years with non-traumatic out-of-hospital cardiac arrest who were transported to the hospitals by ambulance between 15 March 1999 and 15 October 1999. MAIN OUTCOME MEASURES Demographic data, characteristics of the cardiac arrest and the response times of the emergency medical service according to the Utstein style, and survival to hospital discharge rate. RESULTS Three hundred and twenty patients were included. The incidence of ventricular fibrillation in this group of patients was 14.1%. The chance of survival to hospital discharge was significantly higher for patients with ventricular fibrillation than those with other rhythms of cardiac arrest (4.4% versus 0.7%). Approximately 40.0% of all cardiac arrests were witnessed. The bystander cardiopulmonary resuscitation rate was low at 15.6%. The median intervals for recognition to activation of the emergency medical service, time to cardiopulmonary resuscitation, time to defibrillation, and time to advanced life support were 1, 8, 9, and 27 minutes, respectively. CONCLUSION Patients with ventricular fibrillation in out-of-hospital cardiac arrest have a better chance of survival than those with other cardiac rhythms. Further improvement requires simultaneous strengthening of all four links in the chain of survival.