ローラーポンプの圧閉度の電気的測定

摘要

For prompt and precise control of an extracorporeal circulation system, we developed an apparatus which continuously measures the occlusion degree of a roller pump-driven circuit electrically. The principle of our measurement is that the degree of the occlusion of a tube fulfilled with electrically conductive fluid correlates with the electrical resistance between two electrodes set both at inflow and outflow side of the tube occluding site. Our preliminary study using this apparatus elucidated that the correlation between the measured electrical resistance and the degree of the tube occlusion was almost linear. It was also revealed that the electrical resistance at the proper occlusion degree determined by Japan Industrial Standards (JIS) was approximately ten times that at the open, not occluded, state. With our apparatus, more simple and precise application of proper tube occlusion degree was feasible than with the previous method checking the fluid reflux in the occluded tube. Moreover, the continuous measurement of the tube pressure during the roller pump works might detect the deviation of the rotation axis of the roller pump so that early detection of the pump trouble would be possible. In the future, our equipment will enable not only the automated detection of the proper tube occlusion degree but also the automated regulatory system for the extra-corporeal circulation.