Target-controlled anaesthesia: Concepts and first clinical experiences

Propofol has a favourable pharmacokinetic profile for total intravenous anaesthesia and several manual infusion schemes have been proposed to maintain a constant blood concentration during anaesthesia. However, such schemes cannot respond predictably to changing surgical and anaesthetic requirements. A pharmacokinetic model for propofol has been incorporated into a target-controlled infusion system. This allows the desired target blood concentration appropriate for any individual patient and level of surgical stimulation to be achieved and maintained at any time. There is no single blood concentration of an anaesthetic agent which will result in satisfactory anaesthesia for all patients and all surgical conditions. It is necessary to titrate the target concentration against each patient's clinical response. Target-controlled systems provide the best estimate of the blood concentration at any time and permit the required target concentration to be achieved as accurately and as rapidly as possible.