Research Leading to an Improved Artificial Kidney. I. Further Development of Cellulose Acetate Dialysis Membranes. II. Laser Doppler Flowmeter

摘要

Dialysis and hemodialysis membranes were cast from cellulose diacetate under controlled solvent partial pressure in a dry-box. Their transport properties were related to the casting conditions and to membrane morphology. The time-dependent transport behavior of some membranes was investigated in detail. An experiment is described for determining the dialysis and osmotic coefficients simultaneously in a stirred dialyzer. The thin membranes has high permeabilities to water, urea and other metabolites, and were shown to have good retention for bovine serum albumin and also fair tensile strength. Methods were developed for reinforcing these membranes with open fabrics, giving high resistance to tear propogation. Results from transport studies and from electron micrographs imply that the membrane consists of a microporous top layer supported by a much thicker and more open structure. The laser doppler flowmeter is now in complete operation, and has been used to measure the growth of the steady state laminar velocity profile in a rectangular channel. The diameter of the sensing spot is estimated to be 39 microns. Measurements have been made well inside the laminar sublayer, showing significant velocity fluctuations are close as 10 microns from the wall.