Aim: To describe the results of three years of attempted resuscitation from prehospital cardiac arrest by the Auckland Ambulance Service.
Methods: Observational cohort study in a largely urban New Zealand population of 935,000. All cases of attempted resuscitation from out of hospital cardiac arrests occurring between 1 January 1991 and 31 December 1993. Main outcome measures were the number and outcome of patients receiving resuscitation from primary cardiac arrest. Core data conformed to Utstein recommendations.
Results: Of 1176 cases of consecutive cardiac arrest, 1069 (91%) were deemed primary cardiac arrest (978 unmonitored and 91 monitored). Four hundred and sixty (43%) of the 1069 cases were transported to hospital. 240 (22%) were admitted and 135 (13%) were discharged. By initial rhythm, 693 (65%) of cases were in ventricular fibrillation (VF) and 96 (14%) were discharged. One hundred and forty three cases (13%) were in asystole, 113 (11%) were in electromechanical dissociation (EMD), 29 (3%) were in an idioventricular rhythm. Of these 285 cases, only one survived to discharge (a 25 year old woman in EMD). There were 91 monitored arrests (cardiac arrest in front of ambulance officers). Fifty seven cases went into VF and 36 (63%) were discharged. Two cases in ventricular tachycardia became pulseless; each received a single DC shock and both were discharged. The remaining 32 cases of monitored arrest developed rhythms not amenable to DC shocks. None survived to hospital discharge. Eighteen (4%) of the 437 cases not receiving bystander cardiopulmonary resuscitation were discharged from hospital. Thirteen (7%) of the 197 cases receiving ineffective bystander CPR were discharged, and 64 (19%) of 330 cases receiving effective bystander CPR were discharged.
Conclusion: Only those patients with prehospital cardiac arrest who were in ventricular fibrillation or ventricular tachyardia had a reasonable prospect of survival. Effective bystander CPR showed a substantial effect on patient survival to hospital discharge.