The effect of a mobile coronary care unit on mortality in patients with acute myocardial infarction or cardiac arrest outside hospital.

Abstract

Patients requesting an ambulance for symptoms suggestive of acute myocardial infarction (AMI) were randomized by the ambulance controllers to the hospital-based mobile coronary care unit (MCCU) or to a standard ambulance (STA) in the proportions 60% and 40%, respectively. The MCCU was operated by two ambulance drivers and two CCU nurses. Eight hundred and twenty-one patients under 75 years of age were included in the study, of whom 56 patients were found to have cardiac arrest. Two of the 36 in the MCCU group were successfully resuscitated and discharged from hospital. No patient in the STA group of 20 survived. Among 765 patients who were alive when the ambulance arrived, 163 had a definite hospital diagnosis of AMI, 99 in the MCCU and 64 in the STA group. Median delay time from the start of the symptoms to the call for an ambulance was 2 h. During transport, two patients in the MCCU developed ventricular fibrillation and were successfully resuscitated. Two patients in the STA died suddenly and could not be resuscitated. No significant difference in mortality in the prehospital and hospital phase was found for any of the randomized patients. For AMI patients, alive when the ambulance arrived, mortality was 17% for MCCU patients and 33% for STA patients ( P =0.036). The difference in mortality remained for up to five years. It is concluded that a MCCU caused a moderate reduction in mortality in patients with cardiac arrest outside hospital and a significant reduction of mortality in AMI patients alive at the arrival of the ambulance.