IMPACT OF 1ST-RESPONDER DEFIBRILLATION IN AN URBAN EMERGENCY MEDICAL-SERVICES SYSTEM

Objective.-To evaluate the impact of adding first-responder defibrilla tion by fire-fighters to an existing advanced life-support emergency m edical services system. Design.-Nonrandomized, controlled clinical tri al with periodic crossover. Setting.-Memphis, Tenn, a city of 610337 p eople, which is served by a fire department-based emergency medical se rvices system. All city ambulances provide advanced life support. Pati ents.-Adult victims of out-of-hospital cardiac arrest due to heart dis ease. Intervention.-Twenty of 40 participating engine companies were e quipped with an automated external defibrillator and ordered to apply it immediately in all cases of cardiac arrest. The other 20 companies were ordered to start cardiopulmonary resuscitation (CPR) immediately and wait for paramedics to arrive. Every 75 days, group roles were rev ersed. Care otherwise proceeded according to 1986 American Heart Assoc iation guidelines. Main Outcome Measures.-Return of spontaneous circul ation in the field, survival to hospital admission, survival to hospit al discharge, and neurological status at discharge. Results.-During th e 39-month study interval, 879 patients were treated by a project engi ne company. Four hundred thirty-one (49%) of these were found in ventr icular fibrillation. Bystander CPR was started in only 12% of cases. O verall, firefighters reached the scene a mean of 2.5 minutes faster th an simultaneously dispatched paramedics. Although our automated extern al defibrillators proved to be reliable and efficacious for terminatin g ventricular fibrillation and pulseless ventricular tachycardia, pati ents treated by an automated external defibrillator-equipped engine co mpany were no more likely than CPR-treated controls to be resuscitated (32% vs 34%, respectively), to survive to hospital admission (31% vs 29%), or to survive to hospital discharge (14% vs 10%). Neurological o utcomes were also, similar in the two treatment groups. Conclusions.-I n a fast-response, urban emergency medical services system served by p aramedics, the impact of adding first-responder defibrillation appears to be small. Early defibrillation alone cannot overcome low community rates of by-stander CPR. Careful attention to every link in the ''cha in of survival'' is needed to achieve optimal rates of survival after cardiac arrest.