Kjetil G Ringdal1,2
, Timothy J Coats3
, Rolf Lefering4
, Stefano Di Bartolomeo5
, Petter Andreas Steen2
, Olav Røise6
, Lauri Handolin7
, Hans Morten Lossius1
and Utstein TCD expert panel 
1
Department of Research, Norwegian Air Ambulance Foundation, Drøbak, Norway
2
Faculty of Medicine, Faculty Division Ullevål University Hospital, University of Oslo, Norway
3
Academic Unit of Emergency Medicine, Leicester University, UK
4
Institute for Research in Operative Medicine, University of Witten/Herdecke, Cologne-Merheim Medical Centre, Cologne, Germany
5
Unit of Hygiene and Epidemiology, DPMSC, School of Medicine, University of Udine, Italy
6
Orthopaedic Centre, Ullevål University Hospital, Oslo, Norway
7
Department of Orthopaedics and Traumatology, Helsinki University Central Hospital, Finland