Study the influence of changes of the blood removal pressure on the actual blood flow rate in blood purification systems

Comparison of the relative flow rate error of changes of the blood removal pressure among 3 systems

Abstract

In recent years, use of blood purification systems with monitoring of the blood removal status based on changes of the blood removal pressure has become popular. However, there are no reports on the influence of differences of the blood removal pressure on the actual blood flow rate among 3 blood purification systems manufactured by Asahi Kasei Medical Co., LTD., ACH-Σ^® (hereafter referred to as Σ), Plasauto iQ21^® (iQ), and Plasauto LC^® (LC). Therefore, we studied the influence of changes of the blood removal pressure on the actual blood flow rate for these systems.［Methods］The blood pump flow rate was set at 50, 80, 150 and 200mL/min, and the blood removal pressure at －70, －100, －150, and －250mmHg. The weight of a mimic blood discharged for one minute was measured 3 times each with an electronic balance. The actual blood flow rate was calculated from the mimic blood weight and the relative flow rate error was obtained using the formula, {(actual flow rate−blood pump setting flow rate)/blood pump setting flow rate}×100. [Results] Regression equations revealed the following relationships between the relative flow rate error (y) and blood removal pressure (x): Σ: y＝0.0249x－3.694, iQ: y＝0.0384x＋4.544, LC: y＝0.0417x＋0.666. [Conclusion] The slope of the regression equation for Σ was smaller than the slope values for iQ and LC, therefore, Σ may be said to not be influenced by the blood removal pressure. These findings have implications for the understanding of each device characteristic because of each device affect the different actual flow rate on the blood removal pressure.