The effect of nitroglycerin as an adjuvant to lidocaine in intravenous regional anesthesia.

PURPOSE The disadvantages of intravenous regional anesthesia (IVRA) include slow onset, poor muscle relaxation, tourniquet pain, and rapid onset of pain after tourniquet deflation. In this randomized, double-blind study, we evaluated the effect of nitroglycerin (NTG) in quality improvement when added to lidocaine in IVRA. METHODS Forty-six patients (20-50 yrs), were randomly allocated in two equal groups. Under identical condition, the control group received a total dose of 3 mg/kg of lidocaine 1% diluted with saline, and the study group received an additional 200 microg NTG. Vital signs and tourniquet pain, based on visual analog scale (VAS) score were measured and recorded before and 5, 10, 15, 20, and 30 min after anesthetic solution administration. The onset times of sensory and motor block were measured and recorded in all patients. After the tourniquet deflation, at 30 min and 2, 4, 6, 12 and 24 h, VAS score, time to first analgesic requirement, total analgesic consumption in the first 24 h after operation, and side effects were noted. RESULTS The sensory and motor block onset time were shortened in study group (2.61 vs. 5.09 and 4.22 vs. 7.04 min, respectively) (p < 0.05). The recovery time of sensory and motor block and onset of tourniquet pain were also prolonged (7.26 vs. 3.43, 9.70 vs. 3.74 and 25 vs. 16.65 min., respectively) (p < 0.05). Analgesia time after tourniquet deflation was prolonged and tourniquet pain intensity was lowered in study group (p < 0.05). Intraoperative fentanyl and meperedine requirement during first postoperative day and pain intensity at 4, 6, 12 and 24 hr postoperatively were lower in the study group (p < 0.05). There were no significant side effects. CONCLUSION The NTG adding to lidocaine in intravenous regional anesthesia shortens onset times of sensory and motor block and decreases the tourniquet and postoperative pain, without any side effect.