Received: 14 May 2020
Accepted: 24 June 2020
First Online: 25 July 2020
Ethics approval and consent to participate
: The institutional review board of the Bern cantonal ethics committee (KEK) reviewed the study design and granted permission for use of patient data without individual consent, according to the federal act on research involving human beings, and the ordinance on human research with the exception of clinical trials. The permission covered the use of patient data collected during the HEMS operation and related hospital stays (KEK Bern, September 13, 2016, reference number 2016–01473).
: Not applicable.
: The authors declare that they have no competing interest.