BACKGROUND: Propofol is a drug which has both sedative and anxiolytic properties which when given in IV form can provide a rapid onset of effects. However inter-individual dose requirement can vary widely, making titiration to effect essential. Patient-controlled sedation (PCA), which administers bolus doses of the sedative agent to the point at which the patient is satisfied have been found to be both effective and popular for patients undergoing surgery under loco-regional anethesia. The aim of this study was to compare the effectiveness and quality of target-controlled infusion (TCI) of propofol by the anesthesiologist (anesthesiologist-controlled sedation: ACS) versus PCS to achieve conscious sedation. METHODS: Sixty patients scheduled to undergo spinal anesthesia with 0.5% hyperbaric bupivacaine 12-18 mg or brachial plexus block with 1% lidocaine 40 ml were divided into 2 groups. In the ACS group (n = 30), the initial target concentration of propofol was 1.0 microgram/ml and the target concentration was adjusted in steps of 0.2 microgram/ml to maintain an Observer's Assesment of Alertness/Sedation (OAA/S) score of 3 with a TCI pump. In the PCS group (n = 30), a 20 mg bolus of propofol was delivered at each button without a lockout interval to the point at which a patient was satisfied with the level of sedation. Infusion rate, total dosage, duration of induction and recovery and recall of operative procedure were checked. BIS, EKG, heart rate, noninvasive anterial blood pressure, respiratory rate and SpO2 were recorded during the operation. RESULTS: The mean (range) infusion rate and total infusion dose were not significantly different with each group: ACS 38.5 (13.1-101.0) microgram/ml, 132 (80-241) mg/h and PCS 25.4 (21.3-80.1) microgram/ml, 118 (69-220) mg/h. Duration of induction was significantly extended in the PCS group (5.8 min) as compared with the ACS group (2.9 min)(P < 0.05). The intensity of amnesia related to blood propofol concentration was more improved in the ACS group and inadequate sedation and involuntary movement were occurred more frequently in the PCS group. CONCLUSIONS: PCS with propofol provided more effective sedation, but had more frequent delayedinduction time, inadequate sedation and incomplete amnesia than ACS.
Amnesia ; Anesthesia, Conduction* ; Anesthesia, Spinal ; Blood Pressure ; Brachial Plexus ; Bupivacaine ; Conscious Sedation ; Dyskinesias ; Electrocardiography ; Equidae ; Heart Rate ; Humans ; Lidocaine ; Propofol* ; Respiratory Rate ; Surgical Procedures, Operative