Abstract
The objective of this study was to compare clinical efficacy of two opioid analgesics postoperatively using Patient Controlled Analgesia (PCA). It was a randomized, double-blind study involving 43 women undergoing elective abdominal hysterectomy. Each patient received a loading dose of 0.04 mL/kg (0.04 mg/kg morphine or 0.1 □g/kg sufentanil) which was administered up to a maximum of three doses. Analgesic efficacy was assessed using a visual analog scale of pain (VAS). The PCA pump was set to administer a maintenance dose of 0.02 mL/kg (0.02 mg/kg morphine or 0.05 □g/kg sufentanil) with a lockout interval of 8 minutes in all patients. Drug use was recorded and the VAS for pain was recorded at first request for analgesia, at 10, 20, 30, and 60 minutes, and at 4, 20 and 24 hours thereafter. Patients required 9.2, □ 4.4 □g of sufentanil and 7.28 □ 3.7 mg morphine as loading dose for adequate analgesia (p < 0.05). During the first hour, 7.13 □ 3 mL (17.8 □ 7.5 □g) of sufentanil and 13.4 □ 5.68 mL (13.4 □ 5.68 mg) of morphine were used (p < 0.05). At 24 hours, the opioid doses were 223 □ 87 □g of sufentanil and 58.8 □ 24.3 mg of morphine were used (p <0.05). Sufentanil provided significantly better analgesia at 10, 20, 30 and 60 minutes than morphine (p < 0.05). The ratio of sufentanil to morphine necessary for adequate analgesia changed from 1:791 at one hour to 1:267 at 24 hours. All the above differences significantly different. Sufentanil provides more rapid onset of analgesia and a lower demand to delivery ratio than morphine. The ratio of the dose requirements of sufentanil to morphine changed over time being higher initially and decreasing over the next 24 hours.