Assessment of the value and pattern of use of a target controlled propofol infusion system

Thirty one anaesthetists were supplied with a pharmacokinetic based target controlled propofol infusion system for evaluation. Twenty seven of 30 replies to a questionnaire sent to them indicated that the system had changed their use of propofol for maintenance of anaesthesia. The main reasons were greater ease of use and more confidence regarding the predictability of anaesthetic effects compared with manually controlled infusion. Data obtained from 770 patients anaesthetised with the system were analysed. The median maximum target concentration selected was 6.6 micrograms/ml. Younger patients (18-35 yr) required significantly greater target concentrations than older patients (65-80 yr). The mean time during which the system was in maintenance mode, when the predicted blood concentration of propofol was held constant for at least one minute, was 26.1 minutes. The median number of alterations in propofol concentration was 6. The target controlled infusion system provided an inexpensive and acceptable method of delivering intravenous anaesthesia.