Patient sedation: technical problems and developments.

Target-controlled infusion (TCI) systems have dramatically simplified the technique of total intravenous infusion. Systems have been used successfully to provide patient sedation during a variety of surgical procedures. Initial studies indicate that sedation for surgery is achieved rapidly without undue oversedation, and is easily maintained at a constant level. TCI systems have also been used successfully for patient-controlled analgesia (PCA). Using the analgesic alfentanil, good quality post-operative analgesia can be achieved without under- or overdosing. The recent development of using effector-site drug concentrations as a guide to the extent of sedation should allow fine control of patient sedation with TCI systems.