Influence of ketamine and pentobarbital on microvascular perfusion in normal skin and skin flaps.

The influence of two anesthetics, ketamine and sodium pentobarbital, on the microvascular perfusion of normal skin and skin flaps was evaluated by the use of a laser Doppler perfusion imager which allows the rapid scanning of tissue perfusion. Arterial skin flaps with a distal random random portion were created on the ears of hairless mice (n = 20), and perfusion was measured in the proximal, central, and distal parts of the flap. No differences in microvascular perfusion throughout the whole experiment were found between the ketamine and the pentobarbital group. In normal skin microvascular perfusion decreased to 83-73% of baseline values after induction of anesthesia. After flap creation, the perfusion was further reduced in the distal and central parts of the flap to 48-43% of baseline values, whereas no significant change was found in the proximal part. Six hours after flap creation, with the animal awake, perfusion had increased again in all parts of the flap, remaining at a constant level during the rest of the experiment. Anesthesia had less effects on microvascular perfusion in skin flaps as observed 1 day after flap creation. Perfusion of the central and distal parts of the flap decreased by 10-16%, whereas, in contrast to normal skin, the proximal part remained unaffected. Our study shows that baseline measurements are required in skin flap models when the microvascular perfusion in skin flaps is analyzed under general anesthesia.