Microcirculatory changes following different temperature washouts in a free flap model

In spite of the extensive experimental work on vascular washout in free fla p surgery, an optimal temperature for the washout solution has not been est ablished. This study was designed to determine the effect of the washout so lution temperature on the degree to which the microcirculation is cleared o f blood. The cremaster muscle flap in the rat was used, in which the microc irculation can be directly viewed and the presence of blood and perfusion p arameters within various vessels can be measured during and after washout. Washout was started with a single, high-pressure infusion and continued at 130 mmHg for 15 minutes. The temperature of the washout solution was either 2-2, 20-22, or 35 degrees C. In all three groups, washout cleared the micr ocirculation almost completely within the first minute. However, we observe d that a cold or room temperature washout cleared the microcirculation more completely than a warm washout did. The temperature of the washout solutio n did not effect post washout capillary perfusion and/or arterial diameters . (C) 1999 Wiley-Liss, Inc.