Helicopter emergency medical service for time critical interfacility transfers of patients with cardiovascular emergencies

BACKGROUND
The goal of improving quality through centralisation of specialised medical services must be balanced against potential harm caused by delayed access to emergency treatments in rural areas. This study aims to assess the duration of transfers of critically ill patients with cardiovascular emergencies from smaller hospitals to major medical centres by a helicopter emergency medical service (HEMS) in Switzerland.

METHODS
This retrospective observational cohort study includes all consecutive emergency interfacility transfers (IFTs) conducted by Switzerland's largest HEMS provider between July 3rd, 2019, and March 31st, 2021. All patients with acute myocardial infarction, non-traumatic strokes, ruptured aortic aneurysms, and other acute vascular emergencies were included. The duration and distance of each HEMS IFT were compared to calculated distances and duration of travel for the same missions using ground-based transportation (GEMS). The ground-based mission distance beyond which the total mission duration of HEMS is expected to be faster than GEMS was calculated.

FINDINGS
A total of 645 patients were transferred for stroke (n = 364), myocardial infarction (n = 252) and other acute vascular emergencies (n = 29). The median total mission duration from emergency call to landing at the destination was 59.9 (IQR 51.5 to 70.5) minutes. The median road distance for the same missions was 60 (IQR 43 to 72) km. Regression analysis revealed that HEMS is expected to be faster if the road distance is more than 51.3 km.