Does Exsanguination Enhance Skin Microcirculation in Remote Ischemic Conditioning Using a Tourniquet? A Randomized Controlled Trial on 50 Healthy Subjects

Remote Ischemic Conditioning (RIC) improves cutaneous microcirculation in free flap surgery. As no universal RIC protocol exists, refinements have mainly focused on cycle duration and number. We aimed to assess whether ischemic stimulus intensity, using a tourniquet with additional exsanguination, affects cutaneous microcirculation. In this randomized controlled trial, 50 healthy volunteers were randomized into two groups (25 each). Both underwent an RIC protocol of three cycles of 10-minute ischemia followed by 10-minute reperfusion. In the control group (Tourniquet, T), ischemia was induced with a surgical tourniquet inflated to 250 mm Hg on the right upper arm. In the experimental group (Tourniquet with exsanguination, Te), the arm was additionally exsanguinated using an Esmarch bandage. Cutaneous microcirculation parameters (oxygen saturation [SO2], blood flow [BF], and relative amount of hemoglobin [rHb]) were assessed non-invasively with the oxygen to see (O2C) device. Both groups showed significant changes in all microcirculatory parameters compared with baseline. Although SO2 and BF values tended to be higher during reperfusion in the experimental group (Te), overall differences were not statistically significant (except at the end of the first reperfusion phase in BF [Tmean 1.33 ± 0.54 vs. Te mean 1.93 ± 0.91; p = 0.017] and at the beginning of the second reperfusion phase in SO2 [Tmean 1.05 ± 0.18 vs. Te mean 1.13 ± 0.17; p = 0.045], respectively). Exsanguination, in addition to tourniquet application, does not enhance cutaneous microcirculation in RIC protocols. The relatively small sample size remains a limitation and restricts generalizability. Future studies should confirm these findings in larger and more diverse cohorts and explore potential clinical applications.