Induction and maintenance of intravenous anaesthesia using target-controlled infusion systems

Total intravenous anaesthesia (TIVA) has several potential advantages: (i) each component of anaesthesia can be regulated independently and adapted to changes in the stimulus during surgery, (ii) lack of pollution, (iii) ease of use in ‘remote locations’, (iv) quality of recovery. The main drawback of TIVA is that it is difficult to use. Target-controlled infusion (TCI) is a new technique for the administration of intravenous agents based on real-time pharmacokinetic and pharmacodynamics simulations. Its aim is to control and maintain a steady therapeutic level of drugs with a narrow margin of safety. TCI is intended to be similar to the vaporizer of volatile anaesthetics. TCI has been used for more than 15 years for research purposes but the recent availability of a marketed system dedicated to propofol (Diprifusor) is a landmark in the dissemination of the technique. TCI can be used with other hypnotic drugs (midazolam, ketamine, etomidate) and also with opioids. Sedation and post-operative analgesia are also indications for TCI administration. TCI makes it possible to apply more easily certain tedious pharmacokinetic and pharmacodynamic concepts at the bedside at a low cost with potential clinical benefits for the patient. Clinical studies have demonstrated that TCI is as safe as manual infusion techniques but is preferred by anaesthesiologists because it reduces the workload. The main limit of this method at the present time is the large interindividual pharmacokinetic and pharmacodynamic variability and the lack of marketed systems for opioids. Population pharmacokinetics, effect compartment control and even closed-loop systems or Bayesian forecasting are possible directions for future improvements