[1] Karolinska Inst, Dept Clin Sci, Danderyds Hosp, S-11691 Stockholm, Sweden
[2] Ersta Hosp, Dept Surg, S-11691 Stockholm, Sweden
[3] Univ Auckland, Dept Surg, Auckland, New Zealand
[4] Counties Manukau Hlth, Dept Surg, Auckland, New Zealand
[5] Royal Derby Hosp, Derby Teaching Hosp NHS Fdn Trust, East Midlands Bariatr & Metab Inst, Derby DE22 3NE, England
[6] Univ Nottingham, Sch Clin Sci, Nottingham NG7 2UH, England
[7] Univ Hosp CHUV, Dept Visceral Surg, Lausanne, Switzerland
[8] CHU Estaing 1, Serv Chirurg Digest, Dept Anesthesie Reanimat, Pl Lucie & Raymond Aubrac, Clermont Ferrand, France
[9] Univ Buenos Aires, Hosp Italiano Buenos Aires, Dept Anesthesia, RA-1179 Buenos Aires, DF, Argentina
[10] All India Inst Med Sci, Dept Anesthesia, New Delhi 110029, India
[11] Univ Nottingham Hosp, Nottingham Digest Dis Biomed Res Unit, Natl Inst Hlth Res, Gastrointestinal Surg, Nottingham NG7 2UH, England
[12] Univ Nottingham, Queens Med Ctr, Nottingham NG7 2UH, England