Aksys Gmbh

Baxter Healthcare Sa

Tom L Brose

Rodney S Kenley

Dennis M Treu

Douglas L Wilkerson

Frederick H Peter, Jr

Dawn Matthews

Joel DeJesus

Andrew Gebhardt

Dilip H Shah

Shawn O Barrett

Thomas M Feldsein

Michael Edward Wiklund

Lori A Plummer

Derek Wiebenson

John A Blasko

Shincy Maliekkal

Kenneth E Pawlak

Russell L Sage

William R Dolan

Russel L Sage

Richard J Faehnrich

A method of calibrating a dialysis machine to determine the volume of a dialysate flow path of the machine including a dialysate preparation tank includes the steps of introducing a known quantity of electrically conductive chemicals into the dialysate preparation tank, filling the dialysate solution flow path with water, mixing the chemicals with water to form a solution, measuring the conductivity of the solution, calculating the system volume (V,) according to the relation: V,&equals;M/(a,r&plus;b,) where M is the mass in grams of the chemicals, a,and b,are a coefficient of linearity and a constant of linearity, respectively, for the chemicals and r is the measured conductivity of the solution.

Method of determining system volume of a dialysis machine

A user interface for a medical instrument such as a dialysis machine is described which uses both a touch screen and at least one hard key off of the touch screen to effectuate a change in a parameter associated with the operation of the machine or the treatment session. The user interface is connected to a central computer control system having a host microprocessor and a backup safety microprocessor. The hard key is directly wired to the safety microprocessor. After the user selects a new parametric value on the touch screen, the user presses a hard key. The host and safety microprocessors implement a verification routine to insure that the entered parameter is appropriate for the patient's treatment and the display on the touch screen. If the verification procedure ends in a positive result, the user is prompted to presses a second hard key to confirm the change, causing an additional verification check to be preformed. If the additional verification check is successful, the parametric value is entered into a memory (such as a hard disk) storing instructions for operation of the medical instrument.

User interface and method for control of medical instruments, such as

A batch of dialysate solution is made from a mixture of bicarbonate formulation and a liquid acid formulation. The liquid acid formulation is introduced into a dialysate tank and then removed from the tank and stored elsewhere, such as in an ultrafiltration tank, where it is diluted with a few litres of water. The dialysate tank is then filled with water and the bicarbonate formulation is added to the dialysate tank. The bicarbonate formulation is mixed and dissolved by circulation in a closed loop, with the liquid acid formulation kept separate. When the bicarbonate solution has been prepared, the liquid acid solution and the bicarbonate solution are mixed together and stored in the dialysate preparation tank. An additional quantity of dilution water is introduced into the dialysate system to bring the final conductivity down to the desired range. The excess dialysate solution can be used for several purposes, such as an endotoxin flush of the blood tubing set or a dialyzer clearance test.

Method of preparation of batch of physiologic solution

A method for raising or lowering the fluid level in a chamber in an extracorporeal circuit of a dialysis machine, such as an air trap or compliance chamber, is provided which uses a touch screen. The user of the machine is prompted to indicate on the touch screen the current or actual level of fluid (e.g., blood) in the drip chamber. The user then touches the touch screen to indicate the level, such as by touching an illustration of the chamber at a level corresponding to the actual level. The control system for the machine determines from the level indicated on the touch screen whether the level in the chamber needs to be raised or lowered, and by how much, and responsively operates chamber level adjustment apparatus (such as pressure adjustment apparatus in air communication with the chamber) to raise or lower the level closer to the proper level.

Methods and apparatus for adjustment of blood drip chamber of dialysis

A user interface for a medical instrument such as a dialysis machine is described which uses both a touch screen and at least one hard key off of the touch screen to effectuate a change in a parameter associated with the operation of the machine or the treatment session. The user interface is connected to a central computer control system having a host microprocessor and a backup safety microprocessor. The hard key is directly wired to the safety microprocessor. After the user selects a new parametric value on the touch screen, the user presses a hard key. The host and safety microprocessors implement a verification routine to insure that the entered parameter is appropriate for the patient's treatment and the display on the touch screen. If the verification procedure ends in a positive result, the user is prompted to presses a second hard key to confirm the change, causing an additional verification check to be performed. If the additional verification check is successful, the parametric value is entered into a memory (such as a hard disk) storing instructions for operation of the medical instrument.

Methods and apparatus for increasing the accuracy of ultrafiltration in a dialysis machine and decreasing the time required for dialysis. The machine inclused a substantially non-compliant tank for mixing and storing a batch of dialsyate. In a preferred form, the tank is a hollow vessel made from a lightweight and chemically inert material, such as polypropylene, reinforced on its exterior. The machine further includes an ultrafiltration pump for pumping fluid from an extracorporeal circuit to an ultrafiltration tank commensurate with the removal of water from the patient. The pump is calibrated with the volume of fluid in the tank. The reduction in the time to conduct hemodialysis of the patient is achieved by introducing the patient's blood into the arterial line and conducting the blood to the blood pump, measuring the pressure of the blood in the arterial line, increasing the pump rate of the blood pump, and in the event that the pressure measured in the arterial line drops below a predetermined threshold value, slowing the pump rate of the blood pump.

Methods for ultrafiltration control in hemodialysis

A method is described for automatically testing the integrity of a dialyzer filter within a dialysis machine. The method consists of substantially removing fluids which may be present from the blood side of the dialyzer filter, pumping air into the blood side of the dialyzer filter with a blood pump to pressurize the dialyzer filter, and measuring the pressurization of the dialyzer filter. If the dialyzer filter pressurizes, the rate of decay of pressurization is measured. The pressurization and rate of decay are indicative of the integrity of the membrane of the dialyzer filter.

Filter integrity test method for dialysis machines

A method for detecting the presence of blood in a dialysate solution is disclosed. The method provides for certain measurement of light intensity passing through solutions both before and during the dialysis session. Before dialysis is commenced, measurements are made of the intensity of light passing through a chamber containing a control dialysate solution that is free of blood. The light source is a first condition. The light source's state is changed from a first condition to a second condition different from the first condition. Next, a second measurement of the intensity of light is made. The first and second measurements are stored. During dialysis, the method continues with the following steps: conducting a third measurement of the intensity of light of the light source that passes though the chamber, the chamber containing dialysate solution that may contain the patient's blood, with the light source in the first condition. Next, the state of the light source is changed from the first condition to the second condition. A fourth measurement of the intensity of light passing through the solution is made. A suitable processor calculates an attenuation coefficient indicative of the presence of blood in the dialysate solution during dialysis from the first, second, third and fourth measurements.

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Gurnee, IL, United States of America

Tom L Brose