Retrospective analysis of characteristics and transfer times of helicopter interhospital transfer of stroke patients: balancing air and ground transport efficiency

BACKGROUND: Ongoing changes in the hospital landscape, combined with evolving patient transfer modalities, are reshaping acute care pathways. This study analyzed the medical needs of transferred stroke patients and assessed the potential time advantage of helicopter transport in this shifting context. METHODS: A retrospective analysis of all interhospital helicopter transfers for patients with suspected or confirmed stroke conducted by one HEMS service between 2012 and 2020 was performed. Patient characteristics, medical interventions, and transfer times were extracted from the operational database. Helicopter transfer times were compared to calculated ambulance driving times, which were estimated using Google Maps data adjusted by a correction factor accounting for driving with lights and sirens. RESULTS: Out of 179,000 total missions, 7,528 were interhospital stroke transfers. Among these, 6,273 patients (83.3%) were classified as NACA 3 or 4, and 1,154 (13.3%) required mechanical ventilation. 2,227 patients (29.6%) received no medical intervention during transport. Complete transfer times and distances were available for 5,243 missions. The median total flight time-from alert to landing at the receiving hospital-was 49 min (IQR 37-63), compared to a median calculated driving time of 54 min (IQR 44-67). In 1,873 cases (62.8%), the total flight time was shorter than the estimated driving time, with a median time difference of - 3.4 min (IQR - 14.1 to + 7.3). CONCLUSIONS: Since many stroke patients required no interventions during transport, careful patient selection could help reserve specialized transfer resources for the most critical cases. While air transport provided a time advantage for patients in many cases, it was not always the fastest mode of transfer. Future design of emergency medical resources and dispatch strategies should be guided by the estimated time of patient arrival at the accepting hospitals.