(A151) Non-Traumatic Out-of-Hospital Arrests: Initial Cardiac Arrhythmia, Circadian Differences and Cause of Death

Abstract

Background

Out-of-hospital cardiopulmonary arrest (OHA) is an international health issue. There is an urgent need to better understand the key factors that affect OHA survival. Epidemiological surveillance is the first step towards scientific understanding of the problem. This study looks at the profiles of patients who suffered an OHA.

Methodology

In this retrospective study, the medical records of all patients who died upon arrival at Tan Tock Seng Hospital, Emergency Department (TTSH ED) between 1^st January 2009 and 31^st December 2009 were reviewed. The outcomes include patient demographics, pre-hospital management and the cause of death.

Results

Within the study period, there were a total of 275 OHA, 5 (1.8%) traumatic and 270 (98.2%) non-traumatic cases. Emergency Medical Service (EMS) conveyed 247 (91.5%) of OHA and 23 (8.5%) arrived by self-transport. The incidence of non-traumatic OHA was 14 per 10,000 ED attendees, predominantly male (72.2%). Male were significantly younger than female (63 vs 70 years, p = 0.002). The commonest initial cardiac arrhythmia recorded on scene by paramedics was asystole (54.1%), pulseless electrical activity (34.8%) and ventricular fibrillation (11.1%). One hundred sixty-one (59.6%) patients collapsed during the day (0600 – 1759 hours). Patients found in ventricular fibrillation on scene peaked in the morning (1020hours). All OHA were started on cardiopulmonary resuscitation, intubated with laryngeal airway mask, given intravenous adrenaline, and all ventricular fibrillation was electrically defibrillated en-route by the paramedics. Despite continued resuscitative efforts in the ED, all remained in asystole. The State Coroner reviewed 266 (96.7%) OHAs, of which, 96 (36%) were subjected to post mortem. Among patients with asystole at scene, acute coronary syndrome (55.2%), hypertensive heart disease (13%) and bronchopneumonia (5.2%) were the three commonest cause of death. The commonest cause of death for ventricular fibrillation at scene was acute coronary syndrome (76.7%), of which 10 (43.5%) had no pre-existing medical conditions.

Conclusion

In our study population, majority of patients had asystole as their presenting arrhythmia at scene. OHA with ventricular fibrillation demonstrated significant circadian differences and the underlying cause of death was acute coronary syndrome. This knowledge will allow EMS to devise future strategies that have the greatest potential to improve survival outcomes.