PATIENT-MAINTAINED PROPOFOL SEDATION - ASSESSMENT OF A TARGET-CONTROLLED INFUSION SYSTEM

We have developed a system which allows patients to operate a target-c ontrolled infusion of propofol to provide sedation and we have studied its use in 36 unpremedicated patients undergoing local and regional a naesthetic procedures lasting 10-280 min. An intravenous propofol infu sion was started at a target plasma level of 1 mu g.ml(-1). The patien t was able to increase the propofol concentration in 0.2-mu g.ml(-1) i ncrements by pressing a demand button. There was a lockout interval of 2 min and a maximum permissible target concentration of 3 mu g.ml(-1) . There was considerable interindividual variability in propofol consu mption (mean 39.3 mu g.kg(-1).min(-1), range 3-131 mu g.kg(-1).min(-1) ), no cardiovascular instability and little oversedation. Eight patien ts required supplementary oxygen. Optimal sedation was provided at med ian target concentrations of 0.8-0.9 mu g.ml(-1). The target-controlle d infusion system bias was - 47% and the inaccuracy was 48%. Patient s atisfaction was high and 89% said that they would definitely use the t echnique again. This technique combines the benefits of target-control led infusion with patient-controlled feedback and produces safe intra- operative sedation.