1 Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, Geert Grooteplein Zuid 10, P.O. Box 9101, Nijmegen 6500 HB, The Netherlands.
2 Department of Intensive Care Medicine, Radboud University Medical Center, Nijmegen, Geert Grooteplein Zuid 10, P.O. Box 9101, Nijmegen 6500 HB, The Netherlands. Electronic address: peter.pickkers@radboudumc.nl.