EPIDURAL BUPIVACAINE SUFENTANIL THERAPY FOR POSTOPERATIVE PAIN CONTROL IN PATIENTS TOLERANT TO OPIOID AND UNRESPONSIVE TO EPIDURAL BUPIVACAINE/MORPHINE/

Background: Opioids are thought to have equal analgesic effects when e quivalent doses are used. However, sufentanil may achieve maximum effe ct while occupying fewer spinal opioid receptors (higher intrinsic eff icacy). Therefore, sufentanil may be more effective than morphine when administered intraspinally in opioid-tolerant patients. Methods: This study evaluated 20 chronic cancer pain patients who underwent abdomin al surgery for tumor resection. All patients used large doses of morph ine (> 250 mg/day(-1)) preoperatively for 3 months or longer. Intraope ratively, patients received combined general-epidural anesthesia with 0.5% bupivacaine and 0.02% morphine at 8 ml/h(-1). Postoperative conti nuous epidural analgesia with 0.1% bupivacaine and 0.02% morphine at 5 ml/h(-1) plus intravenous patient-controlled analgesia morphine (3 mg every 6 min) was given. Epidural infusions were Increased every 30 mi n by 1 ml/h(-1) to achieve a dynamic (during coughing) visual analog p ain score (VAPS) of less than 5/10. If the desired VAPS was not achiev ed after 6 h or the epidural morphine infusion was increased to 2 mg/h (-1), 50 mu g of sufentanil in 10 ml of normal saline was given as an epidural bolus dose. The epidural infusion then was switched to 0.0002 % sufentanil (2 mu g/ml(-1)) and 0.1% bupivacaine (1 mg/ml(-1)) at 7 m l/h(-1). Further titration to maintain a dynamic VAPS of less than 5/1 0 occurred every 4 h. Results: Mean preoperative daily oral morphine u se was 380 +/- 97 mg (range 290-490) for 4 +/- I months. Before the sw itch to sufentanil, patients had received a mean maximum morphine dose of 8.8 +/- 0.2 mg intraoperatively plus 9.0 +/- 1.2 mg during 4.2 +/- 0.3 h postoperatively (1.8 +/- 0.4 mg/h(-1)), at which point VAPS ran ged between 7-10/10. All patients experienced adequate analgesia withi n 1 h of starting sufentanil therapy. The mean sufentanil dose during the first 4 h of treatment was 17 +/- 0.2 mu g/h(-1). At this time, VA PS ranged from 0-3/10. Satisfactory analgesia was achieved with sufent anil at a lower than a calculated equally potent dose of morphine (23 mu g/h(-1) vs. 17 mu g/h(-1) P < 0.01). Intravenous patient-controlled analgesia morphine requirements were also lower (7.8 mg/h(-1) vs. 2.0 mg/h(-1), P < 0.01). Length of morphine and sufentanil therapies were 5 +/- 3 h and 10 +/- 2 days, respectively. No patient experienced sig ns or symptoms of opioid withdrawal. Conclusions: These results sugges t that sufentanil can be used successfully in opioid-tolerant patients who do not experience adequate pain control in the early postoperativ e period despite a large dose of epidural morphine. Moreover, sufentan il should be considered an effective alternative therapy for postopera tive pain control in chronic opioid users using high doses of oral opi oids before surgical intervention.