Topical nitroglycerin and lidocaine locally vasodilate the radial artery without affecting systemic blood pressure: A dose-finding phase I study

Abstract Purpose Small radial artery diameter (RAD) and vasospasm are barriers to radial artery cannulation. We performed this study to determine if topical nitroglycerin and/or nitroglycerin plus topical lidocaine increases RAD without affecting systemic blood pressure. Materials and Methods This was a randomized, double-blind, placebo-controlled study. In the first visit, to determine the optimal dose of nitroglycerin, subjects were randomized to either 15 or 30 mg nitroglycerin on one wrist and placebo on the other. In visit 2, to assess for any effect of lidocaine on the vasodilator function of nitroglycerin, the same subjects were randomized to 20 mg lidocaine + 30 mg nitroglycerin vs 20 mg lidocaine + placebo, or 40 mg lidocaine + 30 mg nitroglycerin vs 40 mg lidocaine + placebo. In both visits, blood pressure and RAD using ultrasonography were measured for 2 hours. Results In visit 1, both nitroglycerin groups significantly increased RAD, with greater increases with 30 mg nitroglycerin ( P P P Conclusions Topical nitroglycerin and lidocaine significantly increase RAD within 30 to 60 minutes with no effect on contralateral radial artery or blood pressure, indicating a direct, local effect on the radial artery. ( Clinicaltrials.gov number NCT00686231 )