Differences in air ambulance patient mix demonstrated by physiologic scoring.

Severity of illness or injury should be the primary justification for aeromedical transport. To determine whether differences in patient severity were detectable in air transport programs, helicopter-transported patients were examined by three established physiologic scores: the Trauma Score, the Acute Physiology and Chronic Health Evaluation Score, and the Rapid Acute Physiology Score. These scores were obtained prospectively on 1,868 consecutive patient transfer requests from six air medical services for periods ranging from two to six months. A patient meeting strict physiologic criteria was considered critically ill. Overall, 42.6% of the patients (range, 34.8% to 53.3%) were considered critically ill. Patients transported from inpatient hospital units and patients with cardiac disease were less likely to be critically ill than those transported emergently from scenes of accident or from emergency departments. There were also significant differences between programs with regard to the percentage of critically ill patients transported. This study suggests that physiologic scoring may be useful in comparing air ambulance programs and that a majority of patients transported by these services may not be critically ill.