Reduced mortality in injured adults transported by helicopter emergency medical services

Some studies have shown improved outcomes with helicopter emergency medical services (HEMS) transport, while others have not. Safety concerns and cost have prompted reevaluation of the widespread use of HEMS.

To determine whether the mode of transport of trauma patients affects mortality.

Data for 56,744 injured adults aged ≥ 18 years transported to 62 U.S. trauma centers by helicopter or ground ambulance were obtained from the National Sample Program of the 2007 National Trauma Data Bank. In-hospital mortality was calculated for different demographic and injury severity groups. Adjusted odds ratios (AOR) were produced by utilizing a logistic regression model measuring the association of mortality and type of transport, controlling for age, gender, and injury severity (Injury Severity Score [ISS] and Revised Trauma Score [RTS]).

The odds of death were 39% lower in those transported by HEMS compared with those transported by ground ambulance (AOR = 0.61, 95% confidence interval [CI] = 0.54-0.69). Among those aged ≥ 55 years, the odds of death were not significantly different (AOR = 0.92, 95% CI = 0.74-1.13). Among all transports, male patients had a higher odds of death (AOR = 1.23, 95% CI = 1.10-1.38) than female patients. The odds of death increased with each year of age (AOR = 1.040, 95% CI = 1.037-1.043) and each unit of ISS (AOR = 1.080, 95% CI = 1.075-1.084), and decreased with each unit of RTS (AOR = 0.46, 95% CI = 0.45-0.48).

The use of HEMS for the transport of adult trauma patients was associated with reduced mortality for patients aged 18-54 years. In this study, HEMS did not improve mortality in adults aged ≥ 55 years. Identification of additional variables in the selection of those patients who will benefit from HEMS transport is expected to enhance this reduction in mortality.