Out-of-hospital cardiac arrest caused by acute intoxication.

We experienced 20 cases of out-of-hospital cardiac arrest (OHCA) caused by acute intoxication between April 1999 and March 2008. The causative agents were organophosphates in 8 cases, carbon monoxide in 5 cases, and barbiturates in 3 cases. Other agents were paraquat, tricyclic anti-depressants, lime sulfur, and amphetamine. Cardiac arrest was witnessed by bystanders while waiting for the ambulance arrival in 3 cases, and by emergency medical personnel during transfer to our hospital in 4 cases. In these 7 witnessed cases, prehospital resuscitation was provided in 6 cases. No case demonstrated ventricular arrhythmia at the prehospital scene. The restoration of spontaneous circulation was achieved in 8 cases, and 4 cases were discharged alive with overall performance category 1. All the survivors were victims of organophosphate or barbiturate intoxication. It is assumed that these agents caused myocardial depression or respiratory insufficiency following cardiac arrest. From the review of the OHCA caused by organophosphate or barbiturate intoxication, cardiopulmonary resuscitation alone seemed to be effective for restoration of spontaneous circulation and should be emphasized in the prehospital care setting as well as in cardiogenic OHCA.