Abstract: A dialysis apparatus includes a series blood circuit that extends from a single needle through a hemodialyzer and back to the needle. Extending from this circuit is a single ended arm that includes a pump and a blood accumulation chamber. The pump is cyclically operated in opposite directions (in cooperation with associated valves) to alternately withdraw blood from the patient to the chamber and to expel blood from the chamber back to the patient. During one of these operations, blood flows through the dialyzer. By hydraulically isolating the pump and expansion chamber from the series blood circuit, the apparatus avoids large pressure swings and the attendant ultrafiltration that can occur with other single needle systems.

Abstract: A method and apparatus for monitoring operation of a valve is disclosed in which a signal, such as an alternating current electrical signal, is propagated through a fluid path defined by the valve. The occlusion of the fluid path is indicated by monitoring the propagation of the signal. The system is highly immune to electrical noise and to variations in fluid conductivity. The system is also well adapted for monitoring operation of valves having a plurality of ports. In installations employing a plurality of valves, as plurality of valve monitors can be used without mutual interference.

Abstract: An apparatus for preparing dialysate solution directly from a dry chemical mix for continuous supply to a dialysis machine is disclosed. The preferred embodiment includes a drum for containing the dry chemical mix, a conveyor belt, a mixing vessel and monitoring equipment. The drum includes internal baffles that cause the dry chemical to be deposited onto the end of the conveyor belt as the drum rotates. The conveyor belt passes the chemical through a profile-determining gate and into the top of a funnel-shaped mixing vessel. The rate at which the conveyor belt delivers the chemical to the mixing vessel is governed by an electronic circuit that measures the conductivity of the dissolved solution and adjusts the belt speed as necessary to maintain the conductivity at a set value. The dissolved solution flows out the side of the mixing vessel and into a flow controller which regulates the rate at which dialysate can be withdrawn.

Abstract: A method of hemodialytic ultrafiltration in a device utilizing a dialysate flow path, a hemodialyzer, a first receptacle and a second receptacle comprises supplying fresh dialysate to the first receptacle. Spent dialysate is withdrawn from the second receptacle at substantially the same rate fresh dialysate is supplied to the first receptacle. This method includes variably withdrawing fresh dialysate from the first receptacle and supplying same to the hemodialyzer, and variable withdrawing spent dialysate from the hemodialyzer and delivering same to the second receptacle. The dialysate levels in the receptacles are maintained at relatively constant, pre-determined levels. Further, this method includes withdrawing a controlled amount of dialysate from the dialysate flow path between and including the receptacles to thereby effect a withdrawal of ultrafiltrate from the patient's blood into the flow path to substantially balance the amount of dialysate withdrawn therefrom.

Abstract: Hemodialysis ultrafiltration apparatus comprises a hemodialyzer, a supply line for supplying fresh dialysate to the hemodialyzer. A drain line is provided for removing spent dialysate from the hemodialyzer. The dialyzer is adapted to be connected to a patient so that the patient's blood may be supplied to and removed from the hemodialyzer. A weighing mechanism allows a fixed amount of fresh dialysate, by weight, to flow through the hemodialyzer. Spent dialysate emerging from the hemodialyzer is then weighed by the weighing device to determine the weight differential therebetween to monitor and control the amount and rate of ultrafiltrate removed from blood in the hemodialyzer.A method of hemodialytic ultrafiltration is carried out substantially in accordance with the above-described apparatus.

Abstract: Hemodialysis ultrafiltration apparatus comprises a dialyzer. A closed circuit is provided for supplying fresh dialysate to and for removing spent dialysate from the dialyzer. Blood is supplied to and removed from the dialyzer. The closed circuit for supplying fresh dialysate and removing spent dialysate is apportioned into below mean dialyzer blood pressure and above atmospheric pressure sections, with the dialyzer being positioned in the below mean dialyzer blood pressure section. A mechanism is provided for controlling the pressure of fresh dialysate introduced into the below mean dialyzer blood pressure section to substantially match the pressure on the dialysate side of the dialyzer. A mechanism is provided for controlling the above atmospheric pressure portion of the spent dialysate circuit.

Abstract: Improved cellulose semipermeable hollow fibers useful in detoxifying blood during hemodialysis or hemofiltration treatments. The cellulose fibers are fine, capillary fibers that are made by melt extrusion of certain cellulose ester polyol melt spin compositions into self-supporting gelled fibers. The cellulose ester gelled fibers are subsequently chemically converted into cellulose fibers by deacetylation, in aqueous alkali solution. The product fibers exhibit improved wet intrinsic tensile strength and higher water permeability characteristics than heretofore known cellulose fibers made from cellulose ester spin compositions.The invention includes the method of making the improved fibers and separatory cells such as hemodialyzers or hemofilters which contain the improved fibers in a gamma ray sterilized condition.