Ingrid Wåhlin1, Peter Samuelsson2, Susanna Ågren3. 1. Intensive Care Department, Kalmar Hospital, Kalmar, Sweden; School of Health and Caring Sciences, Linnaeus University, Växjö, Kalmar, Sweden. Electronic address: ingrid.wahlin@ltkalmar.se. 2. Intensive Care Department, Kalmar Hospital, Kalmar, Sweden. 3. Department of Cardiothoracic Surgery, Linköping Hospital, Sweden; Department of Medical and Health Sciences, Linköping University, Sweden.