Topically Confined Enhancement of Cutaneous Microcirculation by Cold Plasma

Introduction: We aim to explore potentials and modalities of cold atmospheric pressure plasma (CAP) for the subsequent development of therapies targeting an increased perfusion of the lower leg skin tissue. In this study, we addressed the question whether the microcirculation enhancement is restricted to the tissue in direct contact with plasma or if adjacent tissue might also benefit. Methods: A dielectric barrier discharge (DBD)-generated CAP device exhibiting an electrode area of 27.5 cm² was used to treat the anterior lower leg of ten healthy subjects for 4.5 minutes. Subsequently, hyperspectral imaging (HIS) was performed to measure tempo-spatially resolved characteristics of microcirculation parameters in superficial (up to 1 mm) and deeper (up to 5 mm) skin layers. Results: In the tissue area covered by the plasma electrode, DBD-CAP treatment enhances most of the perfusion parameters. The maximum oxygen saturation (StO2) increase reached 8 %, the near infrared perfusion index (NIR) increases by a maximum of 4 %, and the maximum tissue hemoglobin (THI) increase equaled 14 %. Tissue water index (TWI) was lower in both the control and the plasma group thus not affected by the DBD-CAP treatment. Yet, our study reveals that adjacent tissue is hardly affected by the enhancements in the electrode area and the effects are locally confined. Conclusion: Application of DBD-CAP to the lower leg resulted in enhancement of cutaneous microcirculation that extended 1 h beyond the treatment period with localization to the tissue area in direct contact with the cold plasma. This suggests the possibility of tailoring application schemes for topically confined enhancement of skin microcirculation, e.g. in the treatment of chronic wounds.