Feasibility of prehospital r-TPA therapy in chest pain patients

Abstract

Study objective: The purpose of this study was to determine the number of eligible prehospital thrombolytic candidates and to estimate the potential time saved if field thrombolysis had been initiated in a series of prehospital chest pain patients. Design and setting: Prehospital 12-lead ECGs were obtained by paramedics during initial evaluation of chest pain patients and stored in the computerized ECG. Prehospital 12-lead ECGs, prehospital charts, and hospital charts then were reviewed retrospectively for final hospital diagnosis, prehospital and emergency department times, and historical exclusion criteria for prehospital treatment with recombinant tissue-type plasminogen activator (r-TPA). Type of participants: One hundred fifty-seven stable adult prehospital patients with a chief complaint of nontraumatic chest pain were enrolled. Six patients were excluded. Two had unretrievable 12-lead ECGs, and four refused paramedic transport and thus provided no further data. There were complete data on 151 patients making up the final study population. Interventions: Prehospital care was unaltered except for acquisition of 12-lead ECGs. No prehospital thrombolytic therapy was administratered during this study. Measurements and main results: The incidence of r-TPA exclusion criteria was as follows: 45 patients (29%) were 75 years of age or older, 57 (38%) had chest pain for more than six hours, 24 (16%) had hypertension with blood pressure of more than 180/110 mm Hg, and six (4%) had a history of a cerebrovascular accident. The time from paramedic scene arrival to prehospital ECG (8.4±5.1 minutes) was significantly shorter than the time from ED arrival to ED ECG (24.2+21.6 minutes, P<.001). Prehospital ECGs increased paramedic scene time over a retrospective control by 5.2 minutes. Mean time from prehospital ECG to ED ECG (potential time saved) was 50.2+22.4 minutes in all patients and 43.4±7.7 minutes in patients with a final diagnosis of acute myocardial infarction ( P=NS). Thirteen of 151 patients (8.6%) had prehospital ECGs diagnostic for acute myocardial infarction; eight of these (5.3% overall) met criteria for prehospital r-TPA therapy. Conclusion: Prehospital 12-lead ECGs provide an ECG diagnosis 40 to 50 minutes earlier than ED ECGs. However, with current exclusion criteria, the number of prehospital r-TPA candidates is limited.