OXYGENATION AND BLOOD-VOLUME CHANGES IN FLAPS ACCORDING TO NEAR-INFRARED SPECTROPHOTOMETRY

Objective: To test the ability of near-infrared spectrophotometry (NIR S) to predict vascular compromise in flaps postoperatively. Design: Pi lot study. Subjects: Eleven denervated latissimus dorsi flaps were ass essed in 8 pigs. Interventions: Flaps were isolated on their vascular pedicle. We used NIRS to demonstrate tissue oxygen saturation and quan tities of deoxygenated hemoglobin and oxygenated hemoglobin when flaps underwent venous or arterial occlusions. Oxygen saturation (percentag e of oxygenated hemoglobin) was calculated as the difference between t he 2 light intensities (860-750 nm) with the use of 2 time periods: pr eoperative (80%) oxygen saturation and during arterial occlusion (0%) oxygen saturation with NIRS, Blood volume changes within the flap were also measured. Results: Arterial occlusion resulted in significant de creases in oxygen saturation and in blood volume with immediate recove ry. Venous occlusion resulted in an initial rapid increase in blood vo lume with no appreciable early deoxygenation. Conclusions: Near-infrar ed spectrophotometry appears promising as a noninvasive, low-cost, por table bedside monitor that can demonstrate in real time changes in blo od volume and oxygen saturation within a flap at a variety of tissue d epths.