ABSTRACT
Presurgical epidural analgesia can effectively attenuate peripheral and central sensitization to pain. In a blinded randomized study, we investigated the effects of presurgical administration of single-shot epidural morphine alone or with co-administration of bupivacaine or ropivacaine. The outcome measures were postoperative analgesia, side effects and surgical stress. Ninety patients undergoing open kidney surgery were randomly allocated to receive presurgical epidwal analgesia with morphine 3 mg in normal saline [Group MS], morphine 3 mg plus bupivacaine 50 mg [Group MB] or morphine 3 mg plus ropivacaine 75 mg [Group MR]. All epidural solutions were prepared in equal; 20 ml sealed aliquots. Patients were observed during operative period for hemodynamics and the need for deepening anesthesia. During postoperative period, analgesia was assessed with the visual analog scale; VAS. Venous blood samples were withdrawn at the morning of operation and the morning of first postoperative day for measuring serum corttsol level. Patients in MS group needed higher inspired isoflurane concentration than patients in the other two groups. During positioning for surgery, more patients in MB [90%] and MR [93%] groups were treated with ephedrine to treat hypotension compared to MS [20%]. No differences in pain scores were observed among the patients at rest but during cough or mobilization, more patients in MS group reported significantly higher pain scores at 8, 12, 24h postoperatively. Analgesic drug consumption was higher in MS group than the other two groups; P <0.05. Nausea and pruritus showed no significant differences among the three groups. Serum cortisol levels were comparable in all patients and showed no significant differences among the patients before and after operation. Presurgical administration of epidural morphine-alone or with -bupivacaine or -ropivacaine provide effective analgesia during rest and attenuate the stress response to surgery. The addition of either bupivacaine or ropivacaine to epidural morphine improves analgesia during mobilization