Affiliation: | M.A. Skues, BMedSci, BM, BS, FRCA, Senior Registrar, Department of Anaesthesia, Northern General Hospital, Herries Road, Sheffield S5 7AU.;E.A. Welchew, MB, ChB, FRCA, Consultant, Department of Anaesthesia, Northern General Hospital, Herries Road, Sheffield S5 7AU. |