The analgesic effect of nitroglycerin added to lidocaine on intravenous regional anesthesia.

We evaluated the analgesic effect of nitroglycerine (NTG) when added to lidocaine in IV regional anesthesia. Thirty patients undergoing hand surgery were randomly assigned to two groups. The control group (group C, n = 15) received a total dose of 40 mL with 3 mg/kg of lidocaine diluted with saline, and the NTG group (group NTG, n = 15) received an additional 200 mug NTG. Hemodynamic variables, tourniquet pain measured before and 1, 5, 10, 20, and 30 min after tourniquet inflation, and analgesic requirements were recorded during the operation. After the tourniquet deflation, at 1 and 30 min and 2 and 4 h, visual analog scale (VAS) score, time to first analgesic requirement, total analgesic consumption in the first 24 h after operation, and side effects were noted. Shortened sensory and motor block onset time (3.2 +/- 1.1 versus 4.5 +/- 1.2 min; P = 0.01 and 3.3 +/- 1.6 versus 5.2 +/- 1.8; P = 0.009 in group NTG and group C, respectively), prolonged sensory and motor block recovery times (6.8 +/- 1.6 versus 3.1 +/- 1.2 min P < 0.0001 and 7.3 +/- 1.3 versus 3.6 +/- 0.8 P < 0.0001 in group NTG and group C, respectively), shortened VAS scores of tourniquet pain (P = 0.023), and improved quality of anesthesia were found in group NTG (P < 0.05). VAS scores were lower in group NTG after tourniquet release and in the postoperative period (P = 0.001). First analgesic requirement time was longer in group NTG (225 +/- 74 min versus 39 +/- 33 min) than in group C (P < 0.0001). Postoperative analgesic requirements were significantly smaller in group NTG (P < 0.0001) but the side effects were similar in both groups. We conclude that the addition of NTG to lidocaine for IV regional anesthesia improves sensory and motor block, tourniquet pain, and postoperative analgesia without side effects.