Postoperative Remote Ischemic Conditioning (RIC) significantly improves entire flap microcirculation beyond 4 hours

Abstract

Objective: Free flap transfer is a safe and reliable technique for soft tissue reconstruction. However, impaired flap perfusion with consecutive microcirculatory failure leading to partial or total flap failure remains a clinically relevant problem. Remote ischemic conditioning (RIC) has been shown to improve microcirculation in adipo-cutaneous tissues in healthy humans as well as in free flaps. Yet, little is known about its effects on different perfusion zones in free flaps and the duration of these effects.

Methods: Twenty-five patients with free perforator-based adipo-cutaneous flap transfer were included in the study. RIC (3 cycles: 10/10 min ischemia/reperfusion) was applied via an inflatable tourniquet placed on the upper arm. Continuous measurement of flaps' microcirculation on postoperative day (POD) 1, 3, and 5 was performed by utilizing an O2C device ("Oxygen-to-see" ©LEA Medizintechnik Germany) during RIC and for the following 4 h. Probes were located both in the flaps' center and on its distal edge.

Results: Twenty patients were included in the final analysis. RIC significantly improved flaps' blood flow (BF) by a max. of + 19.6% and oxygen saturation of + 15.7%. Changes affected the entire flap, without significant difference between zones. The increase in flap perfusion could be observed for at least 4 h after the completion of RIC.

Conclusion: Postoperative application of RIC might serve as an additional treatment to enhance whole flap perfusion and prevent microcirculatory disorders, therefore reducing the risk for potential tissue necrosis, especially in the distal parts of the flaps.

Keywords: Free Flap; Microcirculation; Reconstructive Surgery; Remote Ischemic Conditioning (RIC).