1 Divisions of Cardiothoracic Anesthesiology and Critical Care Medicine, Department of Anesthesiology, Duke University Medical Center, Box 3094, Durham, NC, 27710, USA. sharon.mccartney@duke.edu.
2 Johns Hopkins, Baltimore, MD, USA.
3 Division of Cardiothoracic Anesthesiology and Critical Care Medicine, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA.