Method and apparatus for controlling medical fluid pressure

• US 20030220608A1
• Filed: 05/24/2002
• Published: 11/27/2003
• Est. Priority Date: 05/24/2002
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Kienman, Rick, Hopping, Peter, Huitt, Bruce
• Granted Patent: US 6,939,111 B2
• Time in Patent Office: Days
• US Class Current: 604/29
• 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 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/1561 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/1565 Details of valves
• CPC Class Codes: A61M 1/159 specially adapted for peritoneal dialysis
• 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 1/288 Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/122 using evacuated interfaces to enhance contact
• CPC Class Codes: A61M 2205/127 with provisions for heating or cooling
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3337 Controlling, regulating pressure or flow by means of a valve by-passing a pump
• CPC Class Codes: A61M 2205/3344 Measuring or controlling pressure at the body treatment site
• CPC Class Codes: A61M 2205/35 Communication
• CPC Class Codes: A61M 2205/3653 by Joule effect, i.e. electric resistance
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 5/445 the media being heated in the reservoir, e.g. warming bloodbags
• CPC Class Codes: F04B 43/02 : having plate-like flexible members, e.g. diaphragms F04B43/14 takes precedence
• CPC Class Codes: F04B 45/04 : having plate-like flexible members, e.g. diaphragms F04B45/10 takes precedence
• CPC Class Codes: H05B 1/025 : For medical applications
• CPC Class Codes: Y10S 706/90 : Fuzzy logic
• CPC Class Codes: Y10T 137/87161 : With common valve operator

Abstract

A method, system and apparatus for performing peritoneal dialysis are provided. To this end, in part, a method of controlling pressure in a medical fluid pump is provided. The method includes the steps of controlling a pump member acceleration during a first portion of a pump stroke and adaptively changing the pump member velocity during a second portion of the pump stroke.

Claims

1. A method of controlling pressure in a medical fluid pump comprising the steps of:

controlling a pump member acceleration during a first portion of a pump stroke; and

adaptively changing the pump member velocity during a second portion of the pump stroke.

2. The method of claim 1, which further includes the step of controlling a pump member deceleration during the first portion of the stroke.

3. The method of claim 1, wherein the pump stroke is a patient fill stroke.

4. The method of claim 1, wherein controlling the pump member acceleration includes moving the member at a rate of acceleration until a predefined velocity is reached.

5. The method of claim 1, which includes the step of beginning the pump stroke at an initial, non-zero velocity.

6. The method of claim 1, which includes the step of dividing the second portion into at least two sub-portions and adaptively changing the pump member velocity differently for the different sub-portions.

7. The method of claim 1, which includes the step of adaptively changing the pump member velocity to correct for overshooting a pressure set point.

8. The method of claim 1, which includes the step of adaptively changing the pump member velocity to achieve a pressure set point.

9. The method of claim 1, which includes the step of adaptively changing the pump member velocity to achieve a desired end of stroke velocity.

10. The method of claim 1, wherein adaptively changing the pump member velocity includes determining an error between a desired pressure and an actual pressure and performing an error compensating for the determined error.

11. The method of claim 10, which includes the step of storing the error compensation for use in a subsequent pump stroke.

12. The method of claim 10, which includes the step of adjusting the error compensation during a subsequent stroke.

13. The method of claim 10, which includes the step of adjusting the error compensation during a subsequent stroke based on an error determination made during the subsequent stroke.

14. The method of claim 1, wherein adaptively changing the pump member velocity includes changing the velocity based on at least one parameter selected from the group consisting of:

a beginning pump member acceleration, a pressure proximity threshold, a rate of pressure change, a maximum pump member velocity, a pump member deceleration, a proportional coefficient, a derivative coefficient and an integral coefficient.

15. The method of claim 14, which includes changing the velocity based on different ones of the parameters during different sub-portions of the second portion of the stroke.

16. A method of controlling pressure in a medical fluid pump comprising the steps of:

effecting a pump member acceleration and deceleration during a first portion of a pump stroke, the acceleration and deceleration determined before the first portion;

using a first set of factors determined during a second portion of the pump stroke to change the pump member velocity during the second portion; and

using a second set of factors determined during a third portion of the pump stroke to change the pump member velocity during the third portion.

17. The method of claim 16, wherein the first set of parameters corrects an overshoot or undershoot in actual pressure with respect to a desired pressure caused during the first portion of the pump stroke.

18. The method of claim 16, wherein the second set of parameters causes an actual pressure to oscillate about a desired pressure.

19. The method of claim 16, wherein the pump stroke is a first pump stroke and which includes bypassing the acceleration/deceleration of the first portion of the first stroke, and using only the adaptive control of the second and third portions of the first stroke, during all of a second pump stroke.

20. The method of claim 16, which includes adapting at least one of the first and second sets of parameters to compensate for a system variable selected from the group consisting of:

patient physiology, fluid supply elevation, fluid supply level and fluid drain level.

21. A method of controlling pressure in a medical fluid pump comprising the steps of:

adaptively controlling fluid pressure in a first patient fill stroke;

remembering at least one parameter setting used for changing the pressure in the first patient fill stroke; and

adaptively controlling fluid pressure in a second patient fill stroke using the parameter setting used during the first patient fill stroke.

22. The method of claim 21, which includes the step of adjusting the parameter setting for use during the second patient fill stroke.

23. The method of claim 22, which includes the step of deciding whether to adjust the parameter setting based upon whether an error between actual pressure and a desired pressure has increased or decreased.

24. The method of claim 21, wherein adaptively controlling the first and second patient fill strokes includes controlling the velocity of a motor.

25. The method of claim 21, which includes adaptively controlling a plurality of patient fill strokes, storing the parameter setting in a data table and modifying the setting over the plurality of strokes.

26. A method of controlling pressure in a medical fluid pump comprising the steps of:

controlling fluid pressure in a fluid pump fill stroke using pure adaptive control; and

controlling fluid pressure in a patient fill stroke using a preset motion control and adaptive motion control.

27. The method of claim 26, which further includes the step of:

controlling fluid pressure in a patient drain stroke using pure adaptive control; and

controlling fluid pressure in a drain stroke using a preset motion control and adaptive motion control.

28. An automated medical fluid system comprising:

a medical fluid pump; and

a controller that operates with the medical fluid pump to;

effect a pump member acceleration during a first portion of a pump stroke, the acceleration determined before the first portion;

use a first set of factors determined during a second portion of the pump stroke to change the pump member velocity during the second portion; and

use a second set of factors determined during a third portion of the pump stroke to change the pump member velocity during the third portion.