1. Department of Anesthesiology and Pain Medicine, University of Washington, Seattle
2. Department of Anesthesiology and Pain Medicine, University of Washington, Seattle2Department of Epidemiology, University of Washington, Seattle
3. Department of Biostatistics, University of Washington, Seattle
4. Veterans Affairs Puget Sound Health Care System, Seattle, Washington5Department of Health Services, University of Washington, Seattle
5. Veterans Affairs Puget Sound Health Care System, Seattle, Washington6Department of Otolaryngology–Head and Neck Surgery, University of Washington, Seattle
6. Li Ka Shing Knowledge Institute of St Michael’s Hospital, Toronto, Ontario, Canada8Department of Anesthesia and Pain Management, Toronto General Hospital, Toronto, Ontario, Canada9Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada10