AUTOMATED DIALYSIS PUMPING SYSTEM USING STEPPER MOTOR

• US 20070213651A1
• Filed: 12/21/2006
• Published: 09/13/2007
• Est. Priority Date: 05/24/2002
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Din, Shahid, Busby, Don, Lauman, Brian, Shang, Sherwin, Kienman, Rick, Richardson, Ian, Hopping, Peter, Childers, Robert, Bowman, Joseph, Alvaro, Jose, Lundtveil, Loren, Eu, Bruce
• Granted Patent: US 7,789,849 B2
• Time in Patent Office: Days
• US Class Current: 604/5.40
• CPC Class Codes: A61M 1/1522 the interface being evacuated interfaces to enhance contact
• CPC Class Codes: A61M 1/1524 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• 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 1/156 Constructional details of the cassette, e.g. specific details on material or shape
• 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 1/267 used for pumping
• 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 1/288 Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 2205/127 with provisions for heating or cooling
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback

Abstract

A peritoneal dialysis system includes: (i) an enclosure; (ii) a stepper motor housed by the enclosure; (iii) a pump head in operable communication with the stepper motor; and (iv) a disposable unit including at least one flexible membrane attached to a rigid piece, the enclosure configured to receive the disposable unit such that the stepper motor can move the pump head towards and away from the flexible membrane to cause, (a) the flexible membrane to move outwardly with respect to the rigid piece as the pump head is moved away from the disposable unit, and (b) the flexible membrane to move inwardly with respect to the rigid piece as the pump head is moved away from the disposable unit.

Claims

1. A peritoneal dialysis system comprising:

an enclosure;

a stepper motor housed by the enclosure;

a pump head in operable communication with the stepper motor; and

a disposable unit including at least one flexible membrane attached to a rigid piece, the enclosure configured to receive the disposable unit such that the stepper motor can move the pump head towards and away from the flexible membrane to cause,

the flexible membrane to move outwardly with respect to the rigid piece as the pump head is moved away from the disposable unit, and

the flexible membrane to move inwardly with respect to the rigid piece as the pump head is moved towards the disposable unit.

2. The peritoneal dialysis system of claim 1, which includes a ball screw in operable communication with the stepper motor and the pump head, the ball screw operable to convert a rotational output of the stepper motor to a translational motion of the pump head.

3. The peritoneal dialysis system of claim 2, which includes a pump piston coupled to the pump head and operable with the ball screw.

4. The peritoneal dialysis system of claim 1, wherein the stepper motor is a linear stepper motor.

5. The peritoneal dialysis system of claim 1, which includes an encoder positioned to sense a position of the pump head.

6. The peritoneal dialysis system of claim 1, which includes a home position and a sensor that indicates how far from the home position the pump head has traveled.

7. The peritoneal dialysis system of claim 6, wherein the home position is a fully opened or fully closed position for the membrane with respect to the rigid piece of the disposable unit.

8. The peritoneal dialysis system of claim 6, which is configured to move the stepper motor automatically upon power-up until the home position is sensed.

9. A peritoneal dialysis system comprising:

an enclosure;

a stepper motor housed by the enclosure;

a rotational to translational conversion mechanism in operable communication with the stepper motor;

a pump head in operable communication with the rotational to translational conversion mechanism; and

the enclosure configured to receive the disposable a disposable unit, the disposable unit having a moveable membrane operable with the pump head, the stepper motor and the rotational to translational conversion mechanism in operable communication to move the pump head towards and away from the disposable unit, and wherein the moveable membrane of the disposable unit is positioned to follow the pump head as the head is moved towards the disposable unit.

10. The peritoneal dialysis system of claim 9, wherein the moveable membrane of the disposable unit is in contact with the pump head as the head is moved towards the disposable unit.

11. The peritoneal dialysis system of claim 9, the enclosure and the disposable unit configured to allow a negative pressure to exist between the pump head and the moveable membrane, the negative pressure causing the moveable membrane to follow the pump head as the head is moved away from the disposable unit.

12. The peritoneal dialysis system of claim 11, wherein the negative pressure is supplied by a pneumatic source separate from the pump head.

13. The peritoneal dialysis system of claim 9, wherein the rotational to translational conversion mechanism includes a ball screw.

14. A peritoneal dialysis system comprising:

an enclosure;

a stepper motor housed by the enclosure;

a pump head in operable communication with the stepper motor;

a disposable unit operable with the enclosure, the disposable unit including a moveable membrane operable with the pump head, the stepper motor configured to move the pump head towards and away from the disposable unit; and

a position detection apparatus located to detect a position of the pump head relative to a reference position.

15. The peritoneal dialysis system of claim 14, which is configured such that the moveable membrane of the disposable unit moves with the pump head as the pump head is moved towards or away from the disposable unit.

16. The peritoneal dialysis system of claim 14, which is operable with the position detection apparatus such that the position of the pumping head is known upon power-up of the system.

17. The peritoneal dialysis system of claim 14, wherein the position detection apparatus is of a type selected from the group consisting of:

(i) a rotary encoder;

(ii) a linear encoder;

(iii) a proximity sensor and (iv) a magnetic pick-up.

18. The peritoneal dialysis system of claim 14, wherein the position detection apparatus is operable with a battery back-up.

19. The peritoneal dialysis system of claim 14, wherein the reference position is a fully opened or fully closed position for the moveable membrane of the disposable unit.

20. The peritoneal dialysis system of claim 14, which is configured to move the pump head automatically upon power-up until the reference position is sensed.