Helicopter-based Emergency Medical Service: dispatches, decisions and patient outcome
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Introduction: Although Norway has one of the most developed air ambulance services in the world, its helicopter emergency medical service (HEMS) capacity is limited. Few studies have assessed the medical decisions involved with Norway’s HEMS, and little is known about the selection of missions and medical priorities on-scene. The aim of this work was to increase knowledge about HEMS use, HEMS physicians’ medical priorities among patients, and factors influencing on-scene time.
Method: Extensive mission data from 42,500 dispatches of HEMS in Førde, Bergen, and Stavanger during 2004–2013 were analysed to assess mission profiles, identify variations in on-scene time and compare patient survival after transport by either ground ambulances or HEMS.
Results: The annual number of dispatches to primary missions was stable during the 10-year period. Summer, weekends, and daytime were the busiest times. More than one third of all dispatches were cancelled, with lower proportions cancelled in summer and during daytime. In 95% of the completed emergency missions, patients were reached within 45 minutes, and response and on-scene times in helicopter missions were short (24 and 11 min, respectively). There was a 2-minute decrease in on-scene time during the last five years of the study period. However, if HEMS performed endotracheal intubation of the patient, this increased on-scene time by almost 10 minutes. Basic treatment prior to HEMS arrival reduced on-scene time in patients suffering from acute myocardial infarction by almost 2 minutes. Trauma was the most common condition among the patients encountered in primary missions, followed by cardiac arrest and chest pain. One third of the HEMS patients were severely ill or injured and more than two thirds of this group received advanced interventions. When concurrent HEMS missions occurred, more of the patients prioritized by HEMS seemed to be critically ill compared with patients transported by ground ambulance, although survival was similar.
Conclusion: HEMS cancellation rates were rather low, and response and on-scene times in primary missions were short. One third of the patients were seriously ill or injured, and more than two thirds of this group received advanced interventions. When concurrent missions occurred, HEMS seemed to select the missions that may have the most impact. Prehospital data should be automatically registered to improve future research quality in the provision of both HEMS and ground ambulance services.