Method and device for regulating fluid pump pressures

• US 20050118038A1
• Filed: 10/25/2004
• Published: 06/02/2005
• Est. Priority Date: 07/10/2000
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Gray, Larry, Bryant, Robert
• Granted Patent: US 7,421,316 B2
• Time in Patent Office: Days
• US Class Current: 417/313
• CPC Class Codes: A61M 1/152 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/1565 Details of valves
• CPC Class Codes: A61M 1/159 specially adapted for peritoneal dialysis
• CPC Class Codes: A61M 1/282 Operational modes
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 5/16809 by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• CPC Class Codes: F04B 43/06 Pumps having fluid drive
• CPC Class Codes: G05D 16/2073 with a plurality of pressure sources
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 137/0318 Processes

Abstract

A method is provided for regulating fluid pump pressures by detecting an elevation differential between a fluid flow control device and the distal end of a fluid line in communication with the fluid flow control device. A fluid flow control device, for instance a peritoneal dialysis device, is at a first height, a distal end of a fluid line is at a second height, and a valved outlet, when open, affords communication between the fluid flow control device and the distal end of the fluid line. The elevation differential is correlatable with a pressure measurable during a calibration procedure provided as a part of the methodology.

Claims

1. A method for estimating the relative elevation between a first location and a second location, the method comprising:

placing a fluid flow control device at the first location, the fluid flow control device having a membrane pump in valved communication with the second location, the membrane pump having a pressure transducer;

isolating the membrane pump from the second location;

calibrating the pressure transducer;

establishing communication between the membrane pump and the second location;

measuring the pressure in the membrane pump with the pressure transducer; and

estimating the relative elevation based on the pressure.

2. A method according to claim 1, wherein calibrating the pressure transducer comprises:

filling the membrane pump with fluid in pressure equilibrium with the pressure at the first location;

measuring a first calibration pressure in the membrane pump;

filling the membrane pump with fluid in pressure equilibrium with a known calibration pressure;

measuring a second calibration pressure in the membrane pump; and

estimating the relative elevation by constructing a linear fit between pressure and relative elevation based on the known calibration pressure, the first calibration pressure, and the second calibration pressure.

3. A method according to claim 2, wherein the relative elevation is determined by a processor.

4. A computer program product for use on a processor for determining an elevation differential between a first location and a second location, wherein a fluid flow control device is located at the first location, the fluid flow control device including at least one liquid volume in valved communication with a second location via a distal end of a fluid line, the computer program product comprising a computer usable medium having computer readable program code thereon, the computer readable program code including:

program code for reading and storing pressure values within the pumps;

program code for computing and identifying correlations between stored pressure values;

program code for calculating pressure values based on the identified correlations; and

program code for estimating the elevation differential based upon the calculated pressures.

5. The computer program product according to claim 4, further comprising:

program code for calculating a desired pumping pressure based upon the elevation differential; and

program code for adjusting the pumping pressured within the fluid flow control device in accordance with the desired pumping pressure.

6. A computer program product for use on a processor for regulating fluid pump pressures, wherein a fluid flow control device is located at the first location, the fluid flow control device including at least one liquid volume in valved communication with a second location via a distal end of a fluid line, the computer program product comprising a computer usable medium having computer readable program code thereon, the computer readable program code including:

program code for reading and storing pressure values within the pumps;

program code for computing and identifying correlations between stored pressure values;

program code for calculating pressure values based on the identified correlations; and

program code for calculating a desired pumping pressure based on the identified correlations.

7. A fluid flow control device for detecting an elevation differential between a first location and a second location, wherein the device is located at the first location, the fluid flow control device comprising:

at least one liquid volume;

a fluid line in valved pressure communication with the liquid volume, the fluid line having a distal end located at the second location;

at least one transducer for measuring pressure associated with the liquid volume; and

a processor for;

reading and storing pressure values;

computing and identifying a correlation between the pressure values;

calculating pressure values based on the identified correlations; and

estimating the elevation differential based upon the calculated pressures.

8. A device according to claim 7, wherein the correlation computed and identified is a linear fit.

9. A device according to claim 7, wherein the liquid volume includes a flexible membrane that separates the liquid volume from a control volume, and wherein the pressure measurements are taken from the control volume.

10. A device according to claim 7, wherein the liquid volume is disposed within a cassette.

11. A device according to claim 7, further comprising at least one pump.

12. A device according to claim 7, further comprising at least one piston.