Objective: Compare the efficacy of sedation of propofol infusion during spinal anesthesia between effective-site target controlled infusion and manually controlled infusion during spinal anesthesia.

Material and Method: Sixty inpatients scheduled for elective surgery undergoing spinal anesthesia were studied. The patients were allocated to one of two groups. Each group has 30 patients. The TCI group (n = 30) received propofol infusion using effective-site target controlled infusion. The initial target concentration of the effective site of propofol was 1.5 μg/ml. The MCI group (n = 30) received initial bolus 0.5 mg/kg and initial infusion rate 1.5 mg/kg/hr. The anesthesiologist adjusted to increase or decrease the infusion rate in both groups every minute in order to maintain the desired level of sedation (OAA/S score of 3 or 4). Hemodynamic, OAA/S score, the induction time, propofol dose, complications were recorded.

Results: The TCI group achieved the desired level of sedation (OAA/S score 3 or 4) faster than MCI group. The patients in TCI group had sedation score < 3 more than MCI group during surgery. Mean arterial pressure of TCI group were significantly lower than the MCI group at 15, 30, 45 min. Four patients in the TCI group was experienced airway obstruction. Two patients in the TCI group aspirated saliva and choked when they were sleeping. Eight patients in the TCI group and one patient in the MCI group were restless and there were intermittent patient movements.

Conclusion: The clinical benefit when used for sedation during spinal anesthesia of MCI was not different from TCI. There were complications in the TCI group more than the MCI group.

Keywords: OAA/S score, Effective-site target controlled infusion, Manually controlled infusion