Conscious sedation allows patients to undergo procedures which they would otherwise be unable to tolerate. The sedation must not contribute any morbidity or mortality to the procedure and ideally should be safe when used by surgeons and physicians as well as anaesthetists. Satisfactory sedation has been reported with TCI propofol in patients undergoing upper gastrointestinal endoscopy and surgery under regional blockade.
Patient-maintained sedation (PMS) allows the patient to control the target concentration of propofol using a button push. Studies suggest that this provides rapid, safe and effective relief of anxiety. The requirement was to develop a system which cannot allow the patient to overdose. Recent studies demonstrated the feasibility of using degradation in patient reaction time as a control function. The use of reaction time to control the target concentration of propofol may increase the margin of safety during sedation.
With more procedures being undertaken using minimally invasive surgical techniques, there will be increased requirements for conscious sedation. The techniques employed must be safe and efficacious and may be directed towards allowing the patient to participate more in the drug delivery. PMS propofol may fulfil this requirement.