Evaluation of the use of automatic external defibrillation in out-of-hospital cardiac arrest in Hong Kong.

A retrospective 6-month audit of out-of-hospital cardiac arrests in Hong Kong following the introduction of automatic external defibrillators is presented. During the 6-month period from 1 July 1995 to 31 December 1995, resuscitation was attempted on 754 patients. Of the 744 patients with cardiac arrest whose records were available, 53.6% had a witnessed arrest. Few cardiac arrest patients (8.9%) received bystander cardiopulmonary resuscitation (CPR) and the majority (80%) of arrests occurred at home. Six hundred and forty-three (86.4%) patients were declared dead on arrival at hospital or in the Accident and Emergency department; 89 (12%) died in hospital and only 12 (1.6%) were discharged alive. The average ambulance response interval (call receipt to arrival of ambulance at scene) was 6.42 min. The average arrest-to-first-shock interval was 23.77 min. Factors predicting survival included initial rhythm and arrest-to-first-shock interval. The survival rate of 1.6% is low by world standards. To improve the survival rates of people with out-of-hospital cardiac arrest, the arrest-to-call interval must be reduced and the frequency of bystander CPR assistance increased. Once these changes are in place, a beneficial effect from the use of pre-hospital defibrillation might be seen.