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

Journal of Critical Care, 06/15/2012

Topical nitroglycerin and lidocaine significantly increase radial artery diameter (RAD) within 30 to 60minutes with no effect on contralateral radial artery or blood pressure, indicating a direct, local effect on the radial artery.

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 30mg 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 20mg lidocaine+30mg nitroglycerin vs 20mg lidocaine+placebo, or 40mg lidocaine+30mg nitroglycerin vs 40mg lidocaine+placebo.
  • In both visits, blood pressure and RAD using ultrasonography were measured for 2hours.

Results

  • In visit 1, both nitroglycerin groups significantly increased RAD, with greater increases with 30mg nitroglycerin (P<.01) and no significant increase in RAD in placebo wrists.
  • In visit 2, increase in RAD was significantly greater with 20mg lidocaine+30mg nitroglycerin vs 20mg lidocaine+placebo (P<.001), and 40mg lidocaine+30mg nitroglycerin vs 40mg lidocaine+placebo (P<.001), indicating that lidocaine does not alter the effect of nitroglycerin.
  • There were significant increases in RAD seen as early as 30minutes.
  • There were no significant change in RAD in lidocaine+placebo–treated wrists and no change in blood pressure in any group.

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