Research on Hollow Fiber Dialyzer Units

摘要

During the contract year covered by this report, extensive clinical experience with the Dow Hollow Fiber Artificial Kidney (HFAK) has been gained. At the date of writing this report, the total clinical experience with the Dow HFAK comprises nearly 3,500 dialyses on approximately 80 patients plus approximately 275 dialyses on 40 different patients in the independent clinical evaluations. The in vivo ultrafiltration rate of the dialyses has been established to be 1 ml per hour per mm Hg transmembrane pressure. The dialyzer withstands transmembrane pressures up to 500 mm Hg safely. Fiber occlusion from thrombus formation proved to be the only limitation on the otherwise outstanding clinical performance of the dialyzer and continues to be intensively studied. In 20 patients, fiber occlusion was not judged to be a significant problem. In 10 patients, fiber occlusion was estimated to average 20% or more of the fiber bundle per dialysis, but rarely required termination of a dialysis because of complete clotting of the dialyzer. In attempts to eliminate flow compression in the HFAK tube sheets, on fabrication process change has been the introduction of mechanical reinforcement of the tube sheets. Highly swollen cellulose ester gel membranes, in the form of flat membranes, have shown remarkably good ultrafiltration coefficients and diffusivities. Basic research studies, related to interaction of platelets and of coagulation factors with regenerated cellulose with and without the PEI-heparin surface treatment, are presented. A model system for studying the behavior of blood flowing through hollow fibers, particularly with respect to platelet aggregation, has been developed.