Component selection to optimize blood flow for continuous arteriovenous hemofiltration and dialysis.

Abstract

Blood flow with an arteriovenous access is limited by the resistance of the catheters and hemofilters or dialyzers in the extracorporeal system. Resistance data from manufacturers are varied as to the test conditions used, however, making it difficult to select optimum components. Furthermore, the same size catheters may have varying inner diameters, resulting in large differences in flow resistance. The pressure at various flow rates was determined using a water manometer. The pressure/flow relationship for catheters gave a curve, whereas the logarithmic function resulted in a straight line with a slope of 1.48. The pressure/flow relationship for hemofilters and dialyzers was a straight line with an intercept close to the origin. The data in the tables for flow resistance at 50 and 100 ml/min can be used to compare the various components, and to estimate flow in a given extracorporeal system.