EMT DEFIBRILLATION DOES NOT INCREASE SURVIVAL FROM SUDDEN CARDIAC DEATH IN A 2-TIERED URBAN-SUBURBAN EMS SYSTEM

Objective: The use of automatic external defibrillators (AEDs) by EMS initial responders is widely advocated. Evidence supporting the use of AEDs is based largely on the experience of one metropolitan area, wit h effect on survival in many systems not yet proved. We conducted this study to determine whether the addition of AEDs to an EMS system with a response time of 4 minutes for first-responder emergency medical te chnicians (FREMTs) and 10 minutes for paramedics would affect survival from cardiac arrest. Methods: This prospective, controlled, crossover study (AED versus no AED) of consecutive cardiac arrests managed by 2 4 FREMT fire companies took place from 1992 to 1995 in Charlotte, Nort h Carolina, a city of 455,000. Patients were stratified using the Utst ein criteria. The primary endpoint was survival to hospital discharge among patients with bystander-witnessed arrests of cardiac origin. Res ults: Of the 627 patients, 243 were bystander-witnessed arrests of car diac origin. Survival to hospital discharge was accomplished in 5 of 1 10 patients (4.6%; 95% confidence interval [CI] 0.6% to 8.4%) with AED compared with 7 of 133 (5.3%, 95% CI 1.5% to 9.1%) without AED (P=.8) . Both groups were comparable with regard to age, gender, history of m yocardial infarction, congestive heart failure or diabetes, arrest at home, bystander CPR, and whether or not ventricular fibrillation (Vf) was the initial rhythm. For arrests of any cause, witnessed by bystand ers or EMS personnel, with an initial rhythm of VF or Ventricular tach ycardia (VT), 5 of 77 (6.5%, 95% CI 1.0% to 12.0%) with AED survived c ompared with 8 of 105 patients (7.6%, 95% CI 2.5% to 12.7%) without AE D (P=.8). Statistically significant differences were noted in race and EMS response times between the two groups, which did not affect survi val. Conclusion: Addition of AEDs to this EMS system did not improve s urvival from sudden cardiac death. The data do not support routinely e quipping initial responders with AEDs as an isolated enhancement, and raise further doubt about such expenditures in similar EMS systems wit hout first optimizing bystander CFR and EMS dispatching.