1 From the School of Medicine, University of Auckland, and the Department of Anaesthesia, Auckland City Hospital - both in Auckland, New Zealand (S.J.M.); Prince of Wales Clinical School, University of New South Wales, and Wales Anaesthesia, Prince of Wales Hospital - both in Sydney (M.H.B.); and the Departments of Anesthesiology and Medicine, Duke University Medical Center, and the Center for Hyperbaric Medicine and Environmental Physiology, Duke University - both in Durham, North Carolina (R.E.M.).