Preoperative infiltration of the surgical area enhances postoperative analgesia of a combined low–dose epidural bupivacaine and morphine regimen after upper abdominal surgery

In a randomized, blinded trial we assessed the value of adding preoperative infiltration of the surgical area with bupivacaine to a low dose epidural regimen for postoperative pain treatment. Forty–nine patients scheduled for major upper abdominal surgery during combined thoracic epidural (bupivacaine + morphine) and general anaesthesia were studied. Postoperative analgesia was epidural bupivacaine 10 mg hr^-1 + morphine 0.2 mg hr^-1 for 72 h. The patients randomly received preoperative infiltration of the surgical area with bupivacaine 0.25%, 40 ml (group I); or no infiltration (group II). Pain was evaluated at rest, during cough and during mobilization six and eight h after start of surgery, and at 8 a.m. and 4 p.m. on the following days until 72 h after start of surgery. The sensory level of analgesia was evaluated by pin prick. We found no difference between the two groups during rest and cough. However, during mobilization group I had lower pain scores compared to group II ( P < 0.05). There was a significant reduction in the need for supplemental intramuscular morphine in the treatment group compared to the control group ( P <0.05). Thus an enhanced analgesic effect was demonstrated by adding preoperative infiltration of the surgical area with local anaesthetic to a low dose epidural bupivacaine/morphine regimen after upper abdominal surgery.