Effect of location on out-of-hospital cardiac arrests involving older adults in Hong Kong: secondary analysis of a territory-wide cohort.

INTRODUCTION

Most out-of-hospital cardiac arrests in Hong Kong involve older adults. The likelihood of survival varies among locations. This study investigated patient and bystander characteristics, as well as the timing of interventions, that affect the prevalences of shockable rhythm and survival outcomes among cardiac arrests involving older adults in homes, on streets, and in other public places.

METHODS

This secondary analysis of a territory-wide historical cohort used data collected by the Fire Services Department of Hong Kong from 1 August 2012 to 31 July 2013.

RESULTS

Bystander cardiopulmonary resuscitation was primarily performed by relatives in homes but not in non-residential locations. The intervals in terms of receipt of emergency medical services (EMS) call, initiation of bystander cardiopulmonary resuscitation, and receipt of defibrillation were longer for cardiac arrests that occurred in homes. The median interval for EMS to reach patients was 3 minutes longer in homes than on streets (P<0.001). Forty-seven percent of patients who developed cardiac arrest on streets had a shockable rhythm within the first 5 minutes after receipt of EMS call. Defibrillation within 15 minutes after receipt of EMS call was an independent predictor of 30-day survival (odds ratio=4.07; P=0.02). Fifty percent of patients who received defibrillation within 5 minutes in non-residential locations survived.

CONCLUSION

There were significant location-related differences in patient and bystander characteristics, interventions, and outcomes among cardiac arrests involving older adults. A large proportion of patients had a shockable rhythm in the early period after cardiac arrest. Good survival outcomes in out-of-hospital cardiac arrests involving older adults can be achieved through early bystander defibrillation and intervention.