1 Department of Anaesthesiology and Intensive Care Medicine, St. Olav's University Hospital, Trondheim, Norway; Institute of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Norwegian Air Ambulance Foundation, Department of Research and Development, Oslo, Norway. Electronic address: bjorn.hoftun.farbu@stolav.no.
2 Department of Anaesthesiology and Intensive Care Medicine, St. Olav's University Hospital, Trondheim, Norway; Institute of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway.
3 Central Norway Regional Health Authority, Stjørdal, Norway.