The Effect of Nitroglycerine Infusion on Postoperative Pain in Lower Limb Surgery: A Clinical Double-Blind Study

Background: Acute postoperative pain causes severe discomfort in patients accompanied by hemodynamic and metabolic instability. Objectives: The aim of this study was to evaluate the effects of nitroglycerin addition on the infusion of intravenous analgesia pump in patients with lower limb orthopedic surgery. Methods: This study was a double-blind clinical trial conducted on 75 patients with lower limb fracture. Patients were randomly assigned to receive three regimens for postoperative pain control via intravenous analgesia pump, including group A (fentanyl 10mc/kg + 10 mL distilled water), B (fentanyl 10 mc/kg + nitroglycerin 500 mc), and C (fentanyl 10 mc/kg + nitroglycerin 1000 mc). The patients at the beginning of recovery and prior to putting the pain pump at the time of 4, 8, 12, 24, and 48 hours, were assessed with visual analogue scale (VAS) to measure pain and Ramsay scale to measure sedation. Results: The results showed that weight, height, and gender distribution were not significantly different in the three groups. The HR, MAP, and VAS mean scores showed a significant difference for intragroup and intergroup differences in the three groups at many times. Conclusions: Low dose nitroglycerine, as an adjuvant drug, can be added to intravenous patient-controlled analgesia pump in patients undergoing surgery for better analgesic purposes in patients without underlining disease.