1 Neurosciences Critical Care, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, and Neurosciences Critical Care, Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, and Neurosciences Critical Care, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD Division of Cardiac Surgery, Cardiovascular Surgical Intensive Care, Department of Surgery, Johns Hopkins University of Medicine, Baltimore, MD Department of Neurological Sciences, Rush Medical College, Chicago, IL, and Department of Neurosurgery, Rush Medical College, Chicago, IL, and Department of Internal Medicine, Rush Medical College, Chicago, IL, and Department of Anesthesiology, Rush Medical College, Chicago, IL Neurosciences Critical Care, Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, and Neurosciences Critical Care, Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, and Neurosciences Critical Care, Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD.