1 Department of Emergency Surgery and Trauma, Department of Clinical Science, Intervention and Technology (CLINTEC), Unit of Surgery, Karolinska University Hospital Stockholm, Karolinska Institute, Stockholm, Sweden. folke.hammarqvist@ki.se.
2 Department of Emergency Surgery and Trauma, Department of Clinical Science, Intervention and Technology (CLINTEC), Unit of Surgery, Karolinska University Hospital Stockholm, Karolinska Institute, Stockholm, Sweden.