Hemodynamics after microsurgical anastomosis: the effects of topical lidocaine

The hemodynamics in the femoral arteries of 30 rats were measured with a 20-MHz pulsed Doppler velocity meter (PUDVM) in an attempt to define the changes resulting from anastomosis and to assess the effects of 1% lidocaine on those changes. Control values were obtained, the arteries were severed and anastomosed, and either physiologic saline or 1% lidocaine was applied topically to the vessels in a randomized blind study. Velocity measurements, derivations of vessel lumen diameters, and calculations of blood flow then were made with the velocity meter at intervals of 1,2,3,5, and 10 minutes after the addition of the experimental fluid. The measurements obtained indicated that calculated blood flow through the anastomoses was reduced 36% at the 10-minute interval in the group treated with physiologic saline but only 5% in the group treated with 1% lidocaine. These results demonstrate that microsurgical anastomosis adversely effects normal hemodynamic variables, but these effects are minimized by the application of a bolus of 1% lidocaine, a topical vasodilator. These results also suggest that the 20-MHz PUDVM has sufficient resolution and sensitivity to provide the measurements of blood velocity necessary for reproducible calculations of blood flow distal to a microsurgical anastomosis in small vessels.