Conscious Sedation Using a Patient-Controlled Sedation Technique

Kim, Dong Hee

Abstract

BACKGROUND: Patient-controlled sedation (PCS) involves the patient self administering the sedative agent to the point at which he or she is satisfied with the level of sedation with the advantage to overcome the pharmacodynamic differences between individual patients. We compared three different bolus dosages of propofol for providing effective and safe sedation during PCS.
METHODS
Sixty patients underwent spinal anesthesia with 0.5% hyperbaric bupivacaine 12-18 mg or a brachial plexus block with 1% mepivacaine 40 ml. These patients were allowed to self-administer a propofol bolus dose of either 4 mg (P4 group), 10 mg (P10 group), or 20 mg (P20 group) at a time to the point of the patient's satisfaction with the level of sedation. Infusion rate, BIS (bispectral index), SpO2, duration of induction and recovery, recall of operative procedure and patient's satisfaction were checked.
RESULTS
The mean (range) infusion rate (ug/kg/min) was not significantly different among the groups: P4 group, 24.2 (14.3 - 69.7); P10 group, 26.4 (19.4 - 72.1); and P20 group, 30.4 (21.4 - 89.1). Duration of induction was significantly extended in the P4 (14.1 min) and P10 group (12.9 min) as compared with the P20 group (6.0 min). The mean value of the OAA/S (observer's assessment of alertness/sedation) scale and BIS and the numbers of recall were significantly lower in the P20 group than the other groups (p < 0.05). Inadequate sedation and involuntary movement occurred more frequently in the P4 and P10 group than the P20 group, and the numbers of satisfaction were higher in the P20 group than the other groups.
CONCLUSIONS
20 mg of propofol as a PCS bolus dose provided more effective sedation than 4 mg or 10 mg. When we use 4 mg or 10 mg of propofol as a bolus dose, we may want to consider combining if with other sedatives or analgesics (midazolam, ketamine, fentanyl).