Reduced postoperative analgesic demand after inhaled anesthesia in comparison to combined epidural-inhaled anesthesia in patients undergoing abdominal surgery

We studied the effect of epidural/general combination anesthesia, in comparison to inhaled anesthesia, on postoperative pain and analgesic consumption in patients undergoing upper abdominal surgery. Anesthesia was induced with propofol and maintained with enflurane in 70% N2O as necessary to maintain arterial blood pressure within 20% of baseline. Group I received bupivacaine 0.25% 0.2 mL/kg and sufentanil 1 mu g/kg 65 +/- 3 min before dermal incision and 0.1 mL/kg bupivacaine 0.25% + sufentanil 2 mu g/mL (BS) every hour thereafter. Group II received 0.2 mL/kg of BS 316 +/- 15 min after dermal incision in the recovery room. Postoperative patient-controlled epidural analgesia (PCEA) with BS was provided. Pain intensities and consumption of PCEA BS were recorded on postoperative days (PODs) 1 to 5. Inspiratory fraction of enflurane was lower (0.5% +/- 0.01% vs 1.6% +/- 0.04%; P < 0.001) in Group I compared with Group II, Cumulative postoperative consumption of PCEA BS was higher in Group I compared with Group II from the evening of POD 2 until the end of the study (301 +/- 19 mt vs 249 +/- 17 mt; P < 0.001), while pain intensities were comparable at all times. The intraoperative effects of combined BS and enflurane/N2O (inspiratory fraction [F-i] similar to 1 minimum alveolar anesthetic concentration [MAC]) did not preempt postoperative pain in contrast to enflurane/N2O anesthesia (F-i similar to 2.8 MAC).