EFFECT OF IV KETAMINE IN COMBINATION WITH EPIDURAL BUPIVACAINE OR EPIDURAL MORPHINE ON POSTOPERATIVE PAIN AND WOUND TENDERNESS AFTER RENAL SURGERY

We studied 60 patients undergoing operation on the kidney with combine d general and epidural anaesthesia, in a double-blind, randomized, con trolled study. Patients were allocated to receive a preoperative bolus dose of ketamine 10 mg i.v., followed by an i.v. infusion of ketamine 10 mg h(-1) for 48 h after operation, or placebo. During the first 24 h after surgery, all patients received 4 ml h(-1) of epidural bupivac aine 2.5 mg ml(-1). From 24 to 48 h after operation, patients received epidural morphine 0.2 mg h(-1) preceded by a bolus dose of 2 mg. In a ddition, patient-controlled analgesia (PCA) with i.v. morphine (2.5 mg , lockout time 15 min) was offered from 0 to 48 h after operation. Pat ients who received keta mine felt significantly more sedated at 0-24 h , but not at 24-48 h after operation, compared with patients who recei ved placebo (P=0.002 and P=0.127, respectively). There were no signifi cant differences in pain (VAS) at rest, during mobilization or cough, PCA morphine consumption, sensory block to pinprick, pressure pain det ection threshold assessed with an algometer, touch and pain detection thresholds assessed with von Frey hairs, peak flow or side effects oth er than sedation. The power of detecting a reduction in VAS scores of 20 mm in our study was 80% at the 5% significance level. We conclude t hat we were unable to demonstrate an (additive) analgesic or opioid sp aring effect of ketamine 10 mg h(-1) i.v. combined with epidural bupiv acaine at 0-24 h, or epidural morphine at 24-48 h after renal surgery.