Transdermal nitroglycerine potentiates the analgesic effect of patient controlled epidural analgesia after lower abdominal surgery

Background: This study was designed to evaluate the effect of pre-emptive use of transdermal nitroglycerine (NTG) patch as an adjuvant to combined general epidural anesthesia (CGEA) in patients undergoing lower abdominal surgery. Method: Forty patients (ASA I or II) were randomly allocated to two equal groups; control group (group C) and nitroglycerine group (group NG). Nitroderm patch, 5 mg, was applied to patients in group NG, 2 h before surgery. All patients received epidural bolus of 18 ml of 0.25% bupivacaine with fentanyl 2 mu g/ml followed by continuous infusion at the rate of 5 ml/h combined with general anesthesia. Patients used patient controlled analgesia (PCA) device to receive bolus dose of 5 ml of patient controlled epidural analgesia (PCEA) solution containing bupivacaine 0.125% and fentanyl 2 lg/ml after surgery. Perioperative mean arterial blood pressure (MAP) and heart rate (HR), time to first rescue analgesic, postoperative bupivacaine and fentanyl consumption, and VAS pain scores were measured for 24 h postoperatively. Patient satisfaction score was also recorded. Results: Postoperative MAP and HR increased significantly to both baseline and the other group at 2 h in group C and at 4 h in group NG (p < 0.05). The time to first rescue analgesic was significantly longer in group NG (238.62 +/- 54.3 min) than in group C (126.75 +/- 35.1 min) (p < 0.05). Pain scores were significantly higher compared to the other group at 2 h in group C and at 4 h in group NG (p < 0.05). Postoperative bupivacaine and fentanyl consumption were significantly lower in group NG (74.91 +/- 26.34 mg and 121.83 +/- 32.5 lg, respectively) than in group C (118.68 +/- 29.4 mg and 194.21 +/- 45.31 lg, respectively). Patient satisfaction was significantly better in group NG than in group C (p < 0.05). Conclusion: Pre-emptive application of 5 mg transdermal nitroglycerine patch as adjuvant to CGEA provided significant prolongation of the postoperative analgesia and reduction of the postoperative bupivacaine and fentanyl consumption. (C) 2011 Egyptian Society of Anesthesiologists. Production and hosting by Elsevier B.V.