Frequency of previous anaesthesia in an anaesthetic patient population

Ten thousand patients presenting for anaesthesia were questioned about their anaesthetic history; 6672 had received an anaesthetic previously, 19.2% in the preceding 4 weeks. Of 2780 in whom the agents were known, 80.4% had received thiopentone, 18.1% Althesin and 57.4% halothane. Thirty-seven per cent of the total survey population had received two or more anaesthetics.