1 Air Ambulance Kent, Surrey and Sussex, Redhill Airfield, Redhill, Surrey, RH1 5YP, UK. ewoudteravest@aakss.org.uk.
2 University Medical Center Groningen, University of Groningen, Groningen, Netherlands. ewoudteravest@aakss.org.uk.
3 Emergency Medical Services, Centre for Prehospital Emergency Care, Department of Emergency, Anaesthesia and Pain Medicine, Tampere University, FinnHEMS 30 & 40, Tampere, Finland. maria.kratz@helsinki.fi.
4 Department of Anaesthesiology and Pain Medicine, University Hospital Bern, Inselspital, Bern, Switzerland.
5 Emergency Medical Transfer Retrieval Service- Wales Air Ambulance, Ty Elusen, Ffordd Angel, Llanelli Gate, Dafen, Llanelli, UK.