Baxter Travenol Laboratories, Inc.

Baxter Laboratories, Inc.

Wendell V Ebling

Herbert Goldsmith

Rene G Lamadrid

Richard L Afflerbaugh

Rodolfo R Rodriquez

Jan Soderstrom

David Allan Witsoe

Earl G Phillips

There is disclosed herein a dialysis machine for use with a negative-pressure-type dialyzer. The machine includes a flow system for drawing fresh dialysis solution, under a negative pressure, through the dialyzer and a system for determining, setting and controlling ultrafiltration rates in the dialyzer. The ultrafiltration system includes a branch for communication with the dialyzer when flow to and from the dialyzer is terminated. In the branch there is provided a pump for applying negative pressure to the dialyzer and drawing liquid therethrough, and a meter for measuring the flow rates. Means are also provided for measuring negative pressure and transmembrane pressure during operation of the ultrafiltration branch. Pressure controls are also provided so as to assure maintenance of the ultrafiltration rates. There is also disclosed herein a method for determining, setting and controlling the ultrafiltration rate. The method includes terminating flow of dialysis solution to and from the dialyzer, drawing liquid from the dialyzer in order to establish a desired ultrafiltration rate and maintenance of that ultrafiltration rate during actual dialysis by appropriate pressure controls and adjustment of negative pressure and transmembrane pressure.

Ultrafiltration control system

A device, which may be used in a dialysis system, is disclosed for separating low density material such as gas bubbles from a liquid by swirling the liquid, to cause the bubbles to migrate toward the center of the swirling liquid. A liquid storage chamber having side walls of generally circular cross-section of the longitudinal axis is provided. A port is provided for removing the bubbles or the like, positioned adjacent the longitudinal axis of the chamber. A liqud inlet passes into the chamber in such a position as to pass liquid into the chamber circumferentially about the side walls, to provide swirling of liquid passing into the chamber. In accordance with this invention, outlet means and pump means are provided for removing bubble-free liquid from the chamber at a point spaced from the inlet but adjacent the side wall. A first conduit conveys a portion of the bubble-free liquid so removed to a desired site of use, while a second conduit conveys the balance of the bubble-free liquid so removed back to the liquid inlet for reentry into the chamber, to enhance the swirling action of fluid in the chamber.

Device for separating low density material such as gas bubbles from a

There is disclosed herein a blood pressure alarm system for use in a dialysis machine whereby alarms may be activated, and a blood pump deactivated if the actual blood pressure increases above or decreases below predetermined levels. The levels are determined by setting a particular blood pressure point and setting the amount by which the pressure can vary above and below the set point. A memory is provided for storing the set point and preventing variation of the set point with time. The dialysis machine and alarm system can malfunction under certain conditions and protection circuitry operates the alarms if a malfunction occurs.

Digital memory with power outage and memory overload logic in a dialysis

A conductivity monitoring system including a temperature sensing means for sensing the temperature of a fluid and also providing a temperature compensated conductivity signal. Electronic circuitry is provided for detecting and indicating the inoperability of the temperature sensor.

Conductivity monitoring system

A conductivity monitoring system which includes at least three electrodes disposed within a housing of a conductivity cell, into and through which a fluid to be monitored is caused to flow. One of the electrodes is a common electrode and is positioned closer to one of the other two electrodes. The conductivity is measured between the wide spaced pair of electrodes and between the closer spaced pair of electrodes, with the difference being taken as the actual conductivity. With this arrangement, changes in the conductivity as a result of foreign matter collecting on the electrodes and the housing over a period of time are compensated for, since the difference in the conductivity between the two pairs of electrodes remain the same, even though the conductivity between each respective pair may change.

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Libertyville, IL, United States of America

Wendell V Ebling