摘要： Purpose: The differentiation of arterial versus venous occlusion in free tissue transfers has rarely been described. This study investigated changes in blood flow caused by arterial and venous occlusion and the potential for laser Doppler flowmetry to distinguish between these 2 conditions for better clinical assessment and management of free tissue transfer. Methods: Six patients with a mean age of 43.5 years underwent microsurgical free tissue transfer. The venous and arterial blood flow of the vessels and skin flap were monitored using laser Doppler flowmetry with high-frequency pulsed Doppler transducers for vessels and skin before, during, and after clamping the vessels for 10 minutes. Results: The average decreases in blood flow in the artery and vein caused by clamping were 94.4% and 93.8%, respectively. On average, arterial occlusion demonstrated a sudden drop of 67.7% and venous occlusion caused a decrease of 26.6% on laser Doppler flowmetry in free tissue skin. Conclusion: Using a vessel-holding probe, laser Doppler flowmetry could be used to differentiate between arterial and venous occlusion in free tissue transfer, thereby aiding decision-making for better clinical management.