While large cities typically staff ambulances with two emergency medical services (EMS) professionals, some EMS agencies use three people for ambulance crews. The Greenville, North Carolina, EMS agency converted from three-person to two-person EMS crews in July 1993. There are no published reports investigating the best crew size for out-of-hospital emergency care.

Two-person EMS crews perform the same number and types of interventions as three-person EMS crews. Two-person EMS crews do not have longer on-scene times than do three-person EMS crews.

Data for the two most common advanced life support calls in this system—seizures and chest pains—were collected for the months of June and August 1993. Three-person EMS crews responded to both types of calls in June. In August, two-person EMS crews responded to seizure calls; two-person EMS crews accompanied by a fire department engine (pumper) with additional manpower responded to chest pain calk. The frequency of specific interventions, number of total interventions, and scene times for the August calls were compared to their historical control groups, the June calls.

One hundred twenty-six patient contacts were included in the study. There were no significant differences in total number or types of procedures performed for the two patient groups. Mean on-scene time for patients with seizures was 11.0±4.2 minutes for three-person crews and 19.4±8.3 minutes for two-person crews (p <0.001). Mean on-scene time for patients with chest pain was 13.6±4.9 minutes for three-person crews, and 15.4±3.2 minutes for two-person crews assisted by fire department personnel (p >0.05).

Two-person EMS crews perform the same number of procedures as do three-person EMS crews. However, without the assistance of additional responders, two-person EMS crews may have statistically significantly longer onscene times than three-person EMS crews.