Paramedic perception of elapsed field time.

An independent observer was placed with city paramedic teams to: a) record exactly how long emergency field procedures take; and b) determine the paramedic's perception of elapsed field time. One hundred eighteen runs were monitored; 33% required advanced life support skills, and 36% were for trauma. The response time (mean +/- S.E.M.) averaged 5.4 +/- 0.26 min, scene time 11.2 +/- 0.54 min, and transport time 9.5 +/- 0.86 min. The average time required to perform scene procedures ranged from 1.5 +/- 0.5 min for defibrillation to 5.0 +/- 0.47 min to start an IV. Paramedic perception of elapsed time for the entire run varied from the actual time by an average absolute value of 20%, with the greatest errors occurring in scene time estimates. Paramedics tended to overestimate elapsed time during short runs, and underestimate time on long runs. This report provides realistic field procedure times for urban paramedics. Distortion of time perception in the field environment emphasizes the need for strict medical control.