[1] McMaster Univ, Michael G DeGroote Sch Med, Hamilton, ON, Canada
[2] Univ Toronto, Univ Hlth Network, Toronto Western Hosp, Dept Anesthesia & Pain Management, Toronto, ON, Canada
[3] Univ Toronto, Inst Med Sci, Temerty Fac Med, Toronto, ON, Canada
[4] Univ Hlth Network, Lib & Informat Serv, Toronto, ON, Canada
[5] Univ Texas MD Anderson Canc Ctr, Div Anesthesiol & Perioperat Med, Crit Care & Pain Med, Houston, TX USA
[6] Univ Texas Southwestern Med Ctr, Dept Anesthesiol & Pain Management, Dallas, TX USA
[7] Univ Toronto, Univ Hlth Network, Toronto Western Hosp, Dept Anesthesia & Pain Med, 399 Bathurst St,MCL 2-405, Toronto, ON M5T 2S8, Canada