Remifentanil for postoperative patient-controlled analgesia after laparoscopic-assisted vaginal hysterectomy: dose-finding study

Background: This randomized, double-blinded clinical study was designed to compare the efficacy and safety of three regimens of intravenous (IV) patient-controlled analgesia (PCA) with remifentanil for postoperative analgesia after laparoscopic-assisted vaginal hysterectomy during the first 24 postoperative hours. Methods: Thirty-four patients were randomly allocated into three groups. The first group received IV remifentanil PCA at a basal rate of 0.02 μg/kg/min, a bolus of 0.3 μg/kg, and a lockout time of 15 min. The second group received IV-PCA at a basal rate of 0.025 μg/kg/min, a bolus of 0.375 μg/kg, and a lockout time of 15 min. The third group received IV-PCA at a basal rate of 0.03 μg/kg/min, a bolus of 0.45 μg/kg, and a lockout time of 15 min. Age, weight, height, and duration of surgery and anesthesia were recorded. Heart rate, systolic and diastolic blood pressure (BP) and oxygen saturation by pulse oxymetry were recorded in the recovery room as a base line after the operation. Heart rate, systolic and diastolic BP, sedation score, visual analogue scale (VAS), and postoperative nausea and vomiting (PONV) scores were recorded at 1 h, 3 h, 6 h, 12 h, and 24 h after the initiation of IV-PCA. Results: Thirty two patients were evaluated. The VAS in group 1 at 1, 3 and 6 hours after surgery was significantly higher than in other groups (P < 0.05). There were no clinically relevant differences between the groups in PONV, sedation scores, or hemodynamic parameters. Conclusions: This study suggests that IV remifentanil PCA with at a basal rate of 0.025 μg/kg/min (group 2) provided efficacious analgesia after laparoscopic-assisted vaginal hysterectomy. Special attention must be given to respiratory depression during establishment of PCA with remifentanil. (Korean J Anesthesiol 2009; 56: 54~9)