[1] Univ British Columbia, Dept Anesthesiol, Vancouver, BC V5Z 4E3, Canada
[2] Univ British Columbia, Ctr Anesthesia & Analgesia, Dept Anaesthesia, Vancouver, BC V5Z 4E3, Canada
[3] Univ British Columbia, Ctr Anesthesia & Analgesia, Dept Pharmacol, Vancouver, BC V5Z 4E3, Canada
[4] Univ British Columbia, Ctr Anesthesia & Analgesia, Dept Therapeut, Vancouver, BC V5Z 4E3, Canada