In this study, we developed a tourniquet based on the EHD pump. A tourniquet is a medical device that pneumatically stops bleeding in limbs during orthopedic surgery, thereby securing the surgical site. Generally, the hemostatic pressure from a tourniquet is determined based on a rule of thumb, and there is no clear standard for this. As a result, the limbs are compressed at a constant high pressure, resulting in residual damage. In a previous study using rat models, we confirmed that the higher the pressure, the greater the damage to the body and the lower the tissue oxygen saturation (rSO2) in the vicinity of the compression point. Additionally, we highlighted the possibility of reducing damage to living tissue by fine-tuning the stopping pressure based on rSO2. However, fine adjustment of the pressure with a conventional pneumatic tourniquet is difficult to achieve because of the complexity of the system. Therefore, we considered using the EHD pump, which can adjust the pressure only by voltage. We developed a tourniquet equipped with an rSO2 measurement unit that can fine-tune the pressure using the EHD pump as a driving source. We evaluated the time response and accuracy of pressure adjustment and conducted experiments to adjust the hemostatic pressure using rSO2 as an index. The results confirmed that the proposed EHD tourniquet has superior controllability that enables more detailed pressure setting and adjustment. In addition, by incorporating a function that automatically adjusts the compression pressure according to changes in rSO2 using in data from an on-board rSO2 measurement device, we confirmed that the compression pressure is automatically adjusted according to the rSO2 through actual clinical tests on humans.
