1 Department of Nursing and Health Promotion, Faculty of Health Sciences, Oslo Metropolitan University, St.Olavs plass, Oslo 0130, Norway.
2 Centre for Patient Centered Heart and Lung Research, Department of Cardiothoracic Surgery, Oslo University Hospital, Kirkeveien 166, Oslo 0450, Norway.
3 Department of Health Sciences in Gjøvik, Norwegian University of Science and Technology, Gjøvik, Norway.