Patient‐maintained propofol sedation

We have developed a system which allows patients to operate a target‐controlled infusion of propofol to provide sedation and we have studied its use in 36 unpremedicated patients undergoing local and regional anaesthetic procedures lasting 10–280 min. An intravenous propofol infusion was started at a target plasma level of 1 μg.ml−1. The patient was able to increase the target propofol concentration in 0.2‐μg.ml−1 increments by pressing a demand button. There was a lockout interval of 2 min and a maximum permissible target concentration of 3 μg.ml−1. There was considerable interindividual variability in propofol consumption (mean 39.3 μg.kg−1.min−1, range 3–131 μg.kg−1.min−1), no cardiovascular instability and little oversedation. Eight patients required supplementary oxygen. Optimal sedation was provided at median target concentrations of 0.8–0.9 μg.ml−1. The target‐controlled infusion system bias was − 47% and the inaccuracy was 48%. Patient satisfaction was high and 89% said that they would definitely use the technique again. This technique combines the benefits of target‐controlled infusion with patient‐controlled feedback and produces safe intra‐operative sedation.