Flap monitoring and salvage are crucial aspects of free-flap surgery. Although this surgery has a high success rate, flap failure can occur for various reasons, including thrombosis, external pressure, kinking, or hematoma. Prompt detection and correction of flap compromise are essential, as even brief periods of ischemia can lead to irreversible tissue damage. The primary objective of flap monitoring is to detect circulatory compromise rapidly, since approximately 70%–80% of flaps with poor perfusion can be salvaged by prompt intervention.