The effect of topical vasodilating agents on microvascular vessel diameter in the rat model.

Topical vasodilating agents maximize blood flow and prevent vasospasm in microvascular tissue-transfer procedures. Two commonly used agents are papaverine and lidocaine. Although these drugs have vasodilating properties, no studies have directly compared their vasodilating abilities in a controlled, in vivo model. We used videomicroscopy and direct microscopic measurements to compare the vasodilating capacity of papaverine, 1% lidocaine, and saline solution in the femoral artery of Sprague-Dawley rats. Degree of maximum dilation, ability to sustain dilation, average dilation over a 10-minute period, and time to achieve maximum dilation were considered. Both papaverine and lidocaine were found to be superior to saline solution as vasodilating agents. Papaverine was found to sustain vasodilation longer than lidocaine, suggesting that it is a superior vasodilating agent in microvascular anastomoses.