The effect of differences in L/D (length/diameter) of hemofilter on product lifetime due to membrane surface area

Abstract

Continuous Renal Replacement Therapy (CRRT) has become indispensable in the field of intensive care and hemofilters used in CRRT are required to be usable over a long period of time. In this study, hemofilter lifetime was examined in a crossover comparative study between AEF 0.7（Excelflo^®, membrane surface area 0.7m²）and AEF 1.0（Excelflo^®, membrane surface area 1.0m2）. In addition, the internal flow of the hemofilters was observed under fluoroscopic X-ray in an experimental setup. Lifetime with AEF 0.7 was 1,908±210 minutes-significantly longer than lifetime with AEF 1.0 (1,305±213 minutes). In addition, the experimental results suggested that the larger the membrane surface area, the more uneven the internal hemofilter blood flow distribution. AEF is designed so that the larger the membrane surface area, the smaller the L/D and the larger the header diameter. In this study, the decrease of linear velocity as a result of the increased header diameter and the effects of uneven blood flow distribution are thought to be the reasons why lifetime was shortened with AEF with a large membrane surface area. Accordingly, a proper L/D is important for extending hemofilter lifetime.