AUTOMATED PERITONEAL DIALYSIS CYCLER AND METHODS OF USE

• US 20110160649A1
• Filed: 12/20/2010
• Published: 06/30/2011
• Est. Priority Date: 12/24/2009
• Status: Active Grant

• Current Assignee: VR Medical, Inc.
• Original Assignee: VR Medical, Inc.
• Inventors: Pan, Li
• Granted Patent: US 8,597,229 B2
• Time in Patent Office: Days
• US Class Current: 604/28
• CPC Class Codes: A61M 1/153 the cassette being adapted for heating or cooling the treating fluid, e.g. the dialysate or the treating gas
• CPC Class Codes: A61M 1/1562 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/159 specially adapted for peritoneal dialysis
• CPC Class Codes: A61M 1/1643 with weighing of fresh and used dialysis fluid
• CPC Class Codes: A61M 1/166 Heating for sterilisation A61M1/1686
• CPC Class Codes: A61M 1/28 Peritoneal dialysis ; Other peritoneal treatment, e.g. oxygenation
• CPC Class Codes: A61M 1/281 Instillation other than by gravity
• CPC Class Codes: A61M 1/282 Operational modes
• CPC Class Codes: A61M 2205/3393 by weighing the reservoir
• CPC Class Codes: G01B 13/00 Measuring arrangements characterised by the use of fluids
• CPC Class Codes: G01F 22/02 involving measurement of pressure

Abstract

Automated peritoneal dialysis (APD) cycler systems and methods are disclosed. The APD cycler can include a heater tray with load cells configured to measure the weight of fluid contained within a heater bad and/or a drain bag. The load cells can be toggleable between enabled and disabled configurations. The APD cycler can include a pressure-based volume measurement system, which can be used to confirm measurements made by the load cells. In some embodiments, the APD cycler can have algorithms for tracking an estimated patient volume to prevent overfilling the patient.

Claims

1. A dialysis system comprising:

a containment chamber containing a first volume of gas and configured to receive a heater bag and a drain bag therein;

a first pressure sensor configured to measure the pressure in the containment chamber;

a reference chamber containing a second volume of gas;

a second pressure sensor configured to measure the pressure in the reference chamber;

a valve configured to selectively open and close a pathway between the containment chamber and the reference chamber;

one or more pumps configured to apply pressure to the containment chamber and to the reference chamber; and

a controller configured to apply a first pressure to the containment chamber using the one or more pumps, to apply a second pressure to the reference chamber using the one or more pumps, to open the pathway between the containment chamber and the reference chamber with the valve, and to measure an equalized pressure in at least one of the containment chamber and the reference chamber after the pressures of the containment chamber and the reference chamber have substantially equalized.

2. The dialysis system of claim 1, wherein the controller is configured to calculate the first volume of gas inside the containment chamber based at least in part on the measured equalized pressure.

3. The dialysis system of claim 2, wherein the controller is configured to determine a volume of an amount of fluid in at least one of the heater bag and the drain bag based at least in part on the calculated first volume of gas inside the containment chamber.

4. The dialysis system of claim 3, further comprising a weigh scale configured to measure the weight of an amount of fluid in at least one of the heater bag and the drain bag.

5. The dialysis system of claim 4, wherein the controller is configured to compare the measurement of the weigh scale to the calculated volume of the amount of fluid in at least one of the heater bag and the drain bag, and to post an alarm if the calculated volume differs from the measurement of the weigh scale by more than a threshold amount.

6. The dialysis system of claim 4, wherein the controller is configured to calculate the volume of the fluid in at least one of the heater bag and the drain bag based at least in part on the measured weight, to compare the volume calculated from the measured weight to the volume calculated from the equalized pressure, and to post an alarm if the volume calculated from the measured weight differs from the volume calculated from the equalized pressure by more than a threshold amount.

7. The dialysis system of claim 1, wherein the first pressure applied to the containment chamber is a negative pressure, and wherein the second pressure applied to the reference chamber is a negative pressure.

8. The dialysis system of claim 7, wherein the second pressure applied to the reference chamber is a higher negative pressure than the first pressure applied to the containment chamber.

9. A method of determining a volume, comprising:

providing a containment chamber containing a first volume of gas and configured to receive a heater bag and a drain bag therein;

providing a reference chamber containing a second volume of gas;

applying a first pressure to the containment chamber using one or more pumps;

applying a second pressure to the reference chamber using the one or more pumps;

opening a pathway between the containment chamber and the reference chamber;

allowing the pressures of the containment chamber and the reference chamber to substantially equalize;

measuring an equalized pressure in at least one of the containment chamber and the reference chamber; and

calculating, using one or more computing devices, the first volume of gas inside the containment chamber based at least in part on the measured equalized pressure.

10. The method of claim 9, further comprising determining a volume of an amount of fluid in at least one of the heater bag and the drain bag based at least in part on the calculated first volume of gas inside the containment chamber.

11. The method of claim 10, further comprising measuring the weight of an amount of fluid in at least one of the heater bag and the drain bag using a weigh scale.

12. The method of claim 11, further comprising:

comparing the measured weight to the calculated volume of the amount of fluid in at least one of the heater bag and the drain bag; and

posting an alarm if the calculated volume differs from the measurement of the weigh scale by more than a threshold amount.

13. The method of claim 11, further comprising:

calculating the volume of the fluid in at least one of the heater bag and the drain bag based at least in part on the measured weight;

comparing the volume calculated from the measured weight to the volume calculated from the equalized pressure; and

posting an alarm if the volume calculated from the measured weight differs from the volume calculated from the equalized pressure by more than a threshold amount.

14. The method of claim 9, wherein the first pressure applied to the containment chamber is a negative pressure, and wherein the second pressure applied to the reference chamber is a negative pressure.

15. The method of claim 14, wherein the second pressure applied to the reference chamber is a higher negative pressure than the first pressure applied to the containment chamber.

16. A load cell comprising:

a main body;

a sensor configured to generate a signal representative of force applied to the main body;

a tray coupled to the main body; and

an isolation member moveable between an enabled position and a disabled position;

wherein, when the isolation member is in the enabled position, weight applied to the tray is transferred to the main body to generate a signal using the sensor that is representative of the weight applied to the tray;

wherein, when the isolation member is in the disabled position, the weight applied to the tray is transferred through the isolation member such that the weight is not applied to the main body.

17. The load cell of claim 16, further comprising a support bar, wherein the isolation member is configured to engage the support bar when in the disabled position such that the weight from the tray is transferred through the isolation member to the support bar.

18. The load cell of claim 16, wherein the tray is secured to the main body using a screw that comprises a head and a shaft, wherein the isolation member comprises a head and a shaft, and wherein the head of the isolation member abuts against the head of the screw when the isolation member is loosened.

19. The load cell of claim 16, further comprising one or more additional load cells, wherein the plurality of load cells are configured to operate in parallel such that the measurements of the plurality of load cells are combined to produce a value representative of the weight applied to the tray.

20. A dialysis system comprising:

a sealed containment chamber;

a drain bag positioned inside the containment chamber;

a patient line in fluid communication with the drain bag, wherein the patient line is configured for attachment to a patient catheter;

a controller configured to apply a negative pressure to the containment chamber, using one of more pumps, such that fluid is drawn through the patient line into the drain bag, monitor the flow rate of fluid into the drain bag, and reduce the negative pressure in the containment chamber in response to a measured reduction in the flow rate of fluid into the drain bag.

21. The dialysis system of claim 20, wherein the controller is configured to gradually reduce the negative pressure in the containment chamber as the flow rate of fluid into the drain bag reduces.

22. The dialysis system of claim 20, wherein the controller is configured to maintain the negative pressure in the containment chamber at a substantially constant level until the flow rate drops below a first threshold rate, and to reduce the negative pressure in response to the flow rate dropping below the first threshold level.

23. The dialysis system of claim 22, wherein the controller is configured to stop the drain of fluid into the drain bag in response to the flow rate dropping below a second threshold level.

24. A method of performing a dialysis treatment comprising:

infusing an infusion volume of dialysis solution into a patient;

draining fluid from a patient;

identifying an indicator that the drain is complete;

measuring the volume of fluid in the drain bag;

calculating a minimum drain volume, wherein the minimum drain volume is a predetermined percentage of the expected drain volume, wherein the expected drain volume comprises the infusion volume and an estimated residual patient volume; and

determining, using one or more computing devices, if the measured volume of fluid is less than the minimum drain volume.

25. The method of claim 24, further comprising posting an alarm if the measured volume of fluid is less than the minimum drain volume.

26. The method of claim 24, further comprising continuing the dialysis treatment if the measured volume of fluid is not less than the minimum drain volume.

27. The method of claim 26, further comprising updating the estimated residual patient volume to be the difference between the expected drain volume and the measured volume.

28. The method of claim 27, further comprising repeating the method of claim 24 and using the updated estimated residual patient volume to calculate the minimum drain volume.

29. The method of claim 26, further comprising reducing the volume of a subsequent infusion stage if the measured volume is less than the expected drain volume.

30. The method of claim 29, further comprising:

adding an additional infusion cycle to a treatment session schedule;

determining an amount of infusion fluid remaining to be infused during the dialysis treatment;

calculating an adjusted infusion volume by dividing the amount of infusion fluid remaining by the number of scheduled infusion cycles; and

infusion the adjusted infusion volume of dialysis solution to the patient;

31. The method of claim 24, wherein the expected drain volume further comprises an expected ultrafiltration volume.

32. A connector comprising:

a port configured to attach to a container for containing fluid, the port having a septum configured to seal the container;

a tube connector configured to attach to a tubing element;

a spike attached to the tube connector and configured such that the spike pierces the septum of the port when the tube connector is advanced toward the port such that a fluid connection if formed from the container through the port, through a fluid pathway in the spike, through the tube connector, and into the tube element; and

a seal member attached at a first end to the port and attached at a second end to the tube connector, wherein the seal member provides a seal between the port and the tube connector such that the spike can be advanced to pierce the septum without exposing the spike or septum to the outside environment.

33. The connector of claim 32, wherein the seal member is a bellows member.

34. The connector of claim 32, further comprising one or more protective cover pieces configured to maintain the tube connector at distance from the port at which the spike does not pierce the septum.

35. The connector of claim 34, wherein the one or more protective cover pieces are removable to allow the spike to be advanced to pierce the septum.

36. The connector of claim 32, further comprising a container, wherein the port is coupled to the interior surface of the bag.

37. The connector of claim 36, further comprising an adapter port bonded to the interior surface of the container, wherein the port is attached to the adapter port.

38. The connector of claim 36, further comprising an automated peritoneal dialysis cycler wherein the container is a heater bag configured to use in infusing fluid into a patient as part of a peritoneal dialysis treatment.

39. The connector of claim 32, further comprising one or more guide members configured to guide the spike toward the septum as the spike is advanced.