Introduction: Helicopter transport is often considered in an effort to minimize time to critical interventions, such as cardiac catheterization or arterial thrombolysis in stroke patients. However, for interfacility transports, the extra time considerations for helicopter preparation, takeoff, and time to get to the transferring hospital may not offset the slower transport times for local ground ambulances. The purpose of this study was to compare transport times for helicopter with traditional ground ambulance for interfacility transfers within a regional referral system.
Methods: All patients transported from an outside hospital to the intensive care unit of the University of Wisconsin were eligible for this study. Equal numbers of patients transferred by ground and by helicopter from each facility were sequentially selected. The following intervals were compared: time from call to dispatch, time from dispatch to arrival at the referring hospital, time at the referring hospital, transport time to the receiving hospital, and total transport time.
Results: One hundred forty-five patients were included in this study, transferred from 20 hospitals within the UW referral system. Dispatch times and time at the referring hospital were location independent, and each was shorter for ground transport. Ground dispatch times were 5+/-6 minutes, whereas for helicopter transport dispatch times were 17+/-8 (P<.001). Times at the referral hospital were on average longer for helicopter transport (31+/-11 minutes for air ambulance, 25+/-13 for ground; P=.008). Other intervals were location dependent. Arrivals were much more variable for ground transport, reflecting the fact that private ambulance services may have to travel some distance to reach the referring hospital (helicopter 18+/-8 minutes, ground 19+/-18 minutes). As expected, transport time from the referring hospital was shorter for helicopter transport. From each of the hospitals, average helicopter transport was as fast as the best ground transport.
Conclusion: Helicopter transport was faster than ground transport for interfacility transfer of patients from all hospitals studied in our referral system. Under optimal dispatch and transport conditions, the time difference from several hospitals was minimal. For stable patients for whom the only issue is time to critical procedure, it may be reasonable for those hospitals to try ground transport first if timely service is available to transport in that way. Even for those hospitals, helicopter transport should be considered for these patients if ground transport is not optimally available, as well as for patients in whom minimizing time outside of the hospital is a significant consideration, or when transport of such patients impacts emergency medical services availability to the community for a significant time.