1 "Guglielmo da Saliceto" Hospital, Department of Anesthesiology and Intensive Care, Piacenza, Italy.
2 University of Bologna, G.B. Morgagni Hospital, Pulmonology Unit, Forlì, Italy.
3 St George's University Hospitals, Department of Anaesthesia, London, UK.
4 Military Medical Academy, Department of Anesthesiology and Intensive Care, Belgrade, Serbia; University of Defence, Medical Faculty of the Military Medical Academy, Belgrade, Serbia. Electronic address: dusicastamenkovic@yahoo.com.