[1] Univ Oxford, Nuffield Dept Primary Care Hlth Sci, Oxford, England
[2] Queen Mary Univ London, Sch Med & Dent, London, England
[3] Queen Mary Univ London, Barts & London Sch Med & Dent, London, England
[4] City Univ London, Sch Law, London, England
[5] St Georges Univ Hosp Fdn Trust, Dept Anaesthesia, London, England
[6] John Radcliffe Hosp, Dept Anaesthesia, Oxford, England
[7] Royal Alexandra Hosp, Dept Anaesthesia, Paisley, Renfrew, Scotland
[8] Patient Representat, Leeds, W Yorkshire, England