Survivors of Prehospital Cardiac Arrest

BEFORE the early 1970s, the uniform fatality of prehospital cardiac arrest led research efforts almost exclusively to the fields of pathology and epidemiology. Then, with the development of community-based emergency medical systems (EMSs), clinical investigators developed an interest in the prognosis and management of survivors of prehospital cardiac arrest. The outcome of these efforts is summarized in this article. Mechanisms of Prehospital Cardiac Arrest The majority of prehospital cardiac arrests occur by the mechanism of ventricular fibrillation (VF), but other mechanisms, primarily ventricular tachycardia (VT) and various forms of bradyarrhythmias or asystole,1also may cause sudden and unexpected cardiovascular collapse. Of 352 consecutive events observed between 1975 and 1978, in which (1) the onset of cardiac arrest was witnessed, (2) the EMS personnel were summoned without delay, and (3) arrival on the scene was documented to have occurred within four minutes of summons (Fig 1), the initial rhythm recorded