Effects of EMS transportation on time to diagnosis and treatment of acute myocardial infarction in the emergency department.

Abstract

Recent studies have documented decreased time to emergency department (ED) thrombolytic therapy with the use of prehospital electrocardiography. Is the time to ED diagnosis and treatment of acute myocardial infarction (AMI) patients with thrombolytic agents decreased by emergency medical services (EMS) transport when compared with those transported by other means (non-EMS)? Retrospective, case-control study. The AMI patients treated with thrombolytic agents at a 34,000-visit, community hospital ED during 1992. Review of records of patients who received thrombolytic therapy for AMI. Statistical analysis was performed using "Student's" t-test and Yates corrected Chi-square (chi 2). Eighty-seven patients received thrombolytic agents for AMI during 1992; 33 arrived by ambulance, 54 arrived by other methods. There were no differences in age, gender, or time of ED arrival among these groups. Ambulance patients received standard advanced life support (ALS) care, but not a 12-lead electrocardiogram (ECG) or thrombolytic agents. Ambulance patients experienced a significantly shorter time to first ECG (12.9 +/- 9.1 min. versus 20.8 +/- 25.3 min.; p = .028) and received thrombolytic therapy sooner than did controls (56.0 +/- 31.5 min. versus 78.0 +/- 63.4 min.; p = .018). There was no difference in time from diagnosis to treatment between these groups. Emergency medical services transport of AMI patients in this study decreased time to diagnosis and treatment and may be a confounder in studies that assess the value of field EMS interventions. Non-EMS AMI patients did not receive as rapid diagnosis and treatment, and emergency physicians should evaluate and address this issue in their departments.