^aDepartment of Anesthesiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA

^bDepartment of Anaesthetics, Pain Medicine and Intensive Care, Faculty of Medicine, Imperial College London, London, UK

^cDepartments of Anesthesiology and Neurology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box 604, Rochester, NY 14642, USA

^*Corresponding author. Tel.: +1 585 275 3524; fax: +1 585 473 5007.

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