1. P.A. Stone,* FRCSEd, FCAnaes, Department of Anaesthesia, Queen Mother's Hospital, Yorkhill, Glasgow.
2. A.W.A. Kilpatrick, FCAnaes, Registrars, Department of Anaesthesia, Queen Mother's Hospital, Yorkhill, Glasgow.
3. J. Thorburn, FCAnaes, Consultant, Department of Anaesthesia, Queen Mother's Hospital, Yorkhill, Glasgow.