(Lopez-Gil, Cebrian) Consultant Anesthesiologist, Department of Anaesthesia and Reanimation, Maranon University Hospital, Madrid, Spain.(Brimacombe) Clinical Associate Professor, University of Queensland; Department of Anaesthesia and Intensive Care, Cairns Base Hospital, Cairns, Australia.(Arranz) Resident Anesthesiologist, Maranon University Hospital, Madrid, Spain.Received from the Department of Anaesthesia and Reanimation, Maranon University Hospital, Madrid, Spain, and Department of Anaesthesia and Intensive Care, Cairns Base Hospital, Cairns, Australia. Submitted for publication June 16, 1995. Accepted for publication December 12, 1995.Address reprint requests to Dr. Brimacombe: Department of Anaesthesia and Intensive Care, Cairns Base Hospital, The Esplanade, Cairns 4870, Australia.