J.H. Vranken1, M.G.W. Dijkgraaf2, M.R. Kruis1, M.H. van der Vegt1, M.W. Hollmann1, M. Heesen3
1Department of Anesthesiology, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
2Department of Clinical Epidemiology, Biostatistics & Bio-informatics, Academic Medical Center, University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands
3Department of Anesthesiology, Bamberg Hospital, Bamberg, Germany