Open AccessArticle by Dariusz Gajniak 1, Konrad Mendrala 2,*, Tomasz Cyzowski 2, Michał Polak 1, Danuta Gierek 1 and Łukasz J. Krzych 2 1 Department of Anaesthesiology and Intensive Care, Upper Silesian Medical Centre, Medical University of Silesia, 40-752 Katowice, Poland 2 Department of Anaesthesiology and Intensive Care, Faculty of Medical Sciences in Katowice, Medical University of Silesia, 40-752 Katowice, Poland * Author to whom correspondence should be addressed. J. Clin. Med.