1 From the Department of Anaesthesiology and Resuscitation, Emergency Center, Clinical Center of Serbia, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
2 Institute of Social Medicine, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
3 Department of Anesthesiology, University Children's Hospital, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
4 Department of Anaesthesiology, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.