Aksys Gmbh

Eric Bell

Frederick H Peter, Jr

Thomas M Feldsein

Rodney S Kenley

Dawn Matthews

A hemodialysis machine is described that has an extracorporeal circuit that is primed automatically prior to connection of the patient to the machine. The priming is accomplished by filling the extracorporeal circuit with a priming fluid, such as a saline or dialysate solution or blood. The blood pump and clamps in the arterial and venous lines are operated by a control system in a fashion to create multiple brief pressure pulses in the priming fluid. The pressure pulses shear air bubbles present on the blood side of the dialyzer membrane off the membrane. The blood pump is then operated to clear the bubbles from the dialyzer compartment where they are removed from the priming fluid by conventional bubble trap apparatus.

Hemodialysis machine with automatic priming by induced pressure pulses

A method is described for determining the sodium clearance of a dialyzer. Dialysate containing sodium ions is circulated through the dialysate side of the dialyzer. Water is continuously circulated through the blood side of the dialyzer, the water being single passed through the blood side of the dialyzer. Measurements of the conductivity of the dialysate are made prior to the dialysate entering the dialyzer, and measurements of the conductivity of the dialysate are made after the dialysate has passed through the dialyzer. The clearance of the sodium ions by the dialyzer is calculated from the measurements of conductivity. The measurements of conductivity of the dialysate after passing through the dialyzer becomes substantially constant as the dialysate and water are circulated through the dialyzer. The sodium clearance corresponds to urea clearance of the dialyzer, since the two molecules are approximately the same size.

Method for determining sodium clearance of dialyzer

A method is described for priming a dialyzer placed in an extracorporeal circuit of a hemodialysis machine in situ. The method comprises the steps of substantially filling the extracorporeal circuit and the blood side of the dialyzer with fluid (such as dialysate, RO water, saline, etc.), and inducing pressure pulses in the fluid. The pressure pulses cause air bubbles from the blood side of the dialyzer to be sheared off the dialyzer membrane. The air bubbles are then conducted from the dialyzer and removed from the extracorporeal circuit. Backfiltering of fluid across the dialyzer from the dialysate circuit into the extracorporeal circuit is performed in synchrony with the pressure pulses to assist in the shearing off of air bubbles from the blood side of the dialyzer membrane.

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Wheeling, IL, United States of America

Eric Bell