Continuous infusion of two doses of remifentanil immediately after laparoscopic-assisted vaginal hysterectomy

BACKGROUND: We evaluated the effect and safety of the immediate postoperative continuous infusion of remifentanil at two doses in patients undergoing laparoscopic-assisted vaginal hysterectomy (LAVH) with alfentanil-based patient-controlled analgesia (PCA). METHODS: The study enrolled 50 ASA physical status 1 or 2 patients scheduled to undergo LAVH. Anesthesia was maintained with sevoflurane-remifentanil-air. At the last skin suture, the sevoflurane was discontinued, and patients were randomized to receive remifentanil 0.05 µg/kg/min (group I) or 0.1 µg/kg/min (group II). PCA was started at the time of eye opening and response to a verbal command. In the recovery room, we monitored the mean arterial blood pressure (MAP), heart rate (HR), respiratory rate (RR), SpO(2), and bispectral index (BIS) at 5-minute intervals. Thirty minutes after starting PCA, the remifentanil was discontinued. Pain was assessed using a visual analog scale (0 = no pain; 100 = the worst possible pain) at 0, 5, 10, and 30 minutes after stopping the remifentanil infusion. RESULTS: The eye opening time, BIS, MAP, and HR did not differ significantly between the two groups, and pain scores were similar between the two groups. Respiratory depression (SpO(2) < 90% or RR < 8/min) did not occur in group I but did occur in three patients in group II. CONCLUSIONS: Continuous remifentanil infusion (0.05 µg/kg/min) immediately postoperatively with alfentanil-based PCA had a similar effect as a 0.1 µg/kg/min infusion with respect to pain control without side effects. However, special attention must be given to respiratory depression.