A comparison of prehospital estimated time of arrival and actual time of arrival to an emergency department.

The accuracy of the paramedic's estimated time until arrival (ETA) to an emergency department has never been studied. Two hundred and eighty paramedic runs were prospectively studied in a suburban, residency-affiliated emergency department. The average ETA was 7.39 +/- 3.72 minutes. The average actual time until arrival, as clocked by the directing emergency physician was 10.29 +/- 3.95 minutes. Two hundred and twenty-seven (81%) patients arrived later than their ETA. There were 24 (8.5%) cases where the physician's prehospital management would have been different had the ETA been more accurate.