EMT-defibrillation: the Wisconsin experience.

The survival rate for patients with prehospital cardiac arrest has improved in some communities with early defibrillation by emergency medical technician-defibrillators (EMT-Ds). In rural areas, previous studies on survival with defibrillation by EMT-Ds have been variable. We conducted an EMT-D study to determine effectiveness in various prehospital settings. Sixty-four ambulance services from communities ranging in size from rural areas to city suburbs participated in our prospective study. EMTs were trained in rhythm recognition and the use of a manual defibrillator during a standardized 20-hour course. Over 18 months, data were collected locally for central analysis. Five hundred sixty-six patients with primary cardiac arrest were included in our study: 36 (6.4%) survived. Retrospective review revealed survival before EMT-D implementation to be 3.6% (P less than .02). Three hundred four patients (54%) had an initial rhythm of ventricular fibrillation, with 33 (11%) surviving. The survival rate for EMT-D-witnessed arrest with an initial rhythm of ventricular fibrillation was 42%. Patients with asystole were countershocked in our study; however, there were no survivors from this group. The neurologic status of survivors at time of hospital discharge was normal in 72%. The average response time, defined as time of emergency medical services activation to the time of EMT-D arrival, was 7.3 +/- 5.8 and 3.7 +/- 2.0 minutes for nonsurvivors and survivors, respectively (P less than .002). There were no survivors when the response time was more than eight minutes.(ABSTRACT TRUNCATED AT 250 WORDS)