1 Department of Anesthesiology and Critical Care Medicine, The University of Chicago, Chicago, Illinois, [email protected] Department of Anesthesiology, University of Colorado-Anschutz Medical Campus, Children's Hospital Colorado, Aurora, Colorado Departments of Anesthesiology & Pediatrics, Washington University School of Medicine, St Louis Children's Hospital, St Louis, Missouri United States National Aeronautics and Space Administration, Ames Research Center, Moffett Field, California.