Evaluation of Blood Cell Destruction by Measuring Occlusion Distance

Abstract

Roller pumps are commonly used for electric motor-driven blood purification. Even the optimal occlusion for a roller pump is stimulated in JIS (Japanese Industrial Standard) -T1603, the blood cells can be destroyed if an applied pressure is too strong on the tube. On the other hand, the perfused blood volume might decrease if the pressure becomes weaker. Therefore, skilled operation is required. However, as there are no techniques to automatically measure occlusion, a highly reproducible method is urgently required to obtain an optimal setting. In this study, we classified the occlusion specified in JIS-T1603 into five categories (3, 6, 9, 12, and 15 drops/min) and measured those using a laser sensor. The distance between each occlusion was only a few microns. Based on the microscopic observation of the blood cell morphology at each occlusion, the blood cells with normal outlines were classified as normal blood cells, while those with protrusions were labeled as acanthocytes. Further, we calculated the normalized milligram index of hemolysis (mgNIH) to confirm hemolysis for each occlusion. By classifying occlusion into five categories and converting them into distances, we derived a safe, easy, and highly reproducible method.