1 Departments of General Anesthesiology and Outcomes Research, Anesthesiology Institute, Cleveland Clinic, Cleveland, Ohio, USA elsharh@ccf.org.
2 Department of Anesthesiology, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio, USA.
3 Guy's & St Thomas' NHS Foundation Trust, Department of Anaesthesia, St Thomas' Hospital; Westminster Bridge Road, London, UK.
4 VA Palo Alto Health Care System; and Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Palo Alto, California, USA.