1 From the Department of Anesthesiology and Intensive Care Medicine, University Duisburg-Essen, Faculty of Medicine, University Hospital Essen, Essen, Germany.
2 Department of Anesthesiology, University of Maryland School of Medicine, R Adams Cowley Shock Trauma Center, Baltimore, Maryland.
3 Department of Anesthesiology, University of Texas, Health Science Center, McGovern Medical School, Houston, Texas.