Air versus ground transport of major trauma patients to a tertiary trauma centre: a province-wide comparison using TRISS analysis.

OBJECTIVE The purpose of this study was to compare the outcomes of adult (aged > 15 yr) blunt trauma patients with an Injury Severity Score (ISS) = 12 who were transported to a single tertiary trauma centre (TTC) by helicopter emergency medical service (HEMS) versus those transported by ground ambulance. METHODS We retrospectively analyzed all adult (aged > 15 yr) trauma patients between March 27, 1998 and March 28, 2002 with an ISS score = 12, as identified through the provincial trauma registry. We used the Trauma and Injury Severity Score (TRISS) methodology to determine a difference in outcomes between the 2 groups. RESULTS We identified 823 patients; of these, we excluded 32 (3.9%) penetrating trauma patients. Of the blunt trauma cases (n = 791) 237 (30%) patients were transported by air and 554 were transported by ground (70%). A total of 770 (97.3%) patients were eligible for TRISS analysis. Using the TRISS methodology, the air group had a Z statistic of 2.77, yielding a W score of 6.40. This compared with the ground transport group, whose Z statistic was 1.97 and W score was 2.39. CONCLUSION The transport of trauma patients with an ISS = 12 by a provincially dedicated rotor wing air medical service was associated with statistically significantly better outcomes than those transported by standard ground ambulance. This is the first large Canadian study to specifically compare the outcome of patients transported by ground with those transported by air.