Adopting the pre-hospital index for interfacility helicopter transport: a proposal.

Background: Interfacility helicopter transport is expensive without proven outcome benefit in trauma patients. Our objectives were to determine the fastest method of rural to urban interfacility transport, and develop a triage tool to identify patients most in need of rapid transport.

Methods: Retrospective cohort study. Adults ISS > or = 12 transported from January 1996 to December 1998. Transport time variables were compared between geographical zones. A pre-transport index (PTI) identified two patient cohorts in which outcome was assessed.

Results: Air ambulance was faster than ground transport, with helicopter overall superior to fixed-wing (< 225 km range). Seventy-two percent of patients with PTI < 4 (n = 196) had no outcome indicating severe injury versus 29% of the PTI > or = 4 cohort (n=151). Mortality for PTI<4 was 1.4% versus 22% for PTI > or = 4.

Conclusion: Interfacility helicopter transport of severely injured rural trauma patients was the overall fastest method within a 225 km range. PTI > 4 identifies patients most in need of this fast but expensive method of transport.