Method for calibrating a pump segment used in a peristaltic pump and a medical machine adapted for carrying out the method

• US 5,733,257 A
• Filed: 02/22/1996
• Issued: 03/31/1998
• Est. Priority Date: 10/11/1993
• Status: Expired due to Term

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: Gambro AB (Baxter International Inc.)
• Inventors: Sternby, Jan
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): MENDEZ, MANUEL A
• Application Number:
  US08/602,749
• Time in Patent Office: 768 Days
• Field of Search: 604/30-34, 604/49, 604/65-67, 604/151, 604/246, 128/DIG. 13, 128/12
• US Class Current: 604/27
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 Mode of operation
• CPC Class Codes: A61M 1/3663 Flow rate transducers; Flow integrators
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/70 with testing or calibration facilities
• CPC Class Codes: A61M 60/113 in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/279 Peristaltic pumps, e.g. roller pumps
• CPC Class Codes: A61M 60/38 Blood oxygenation
• CPC Class Codes: A61M 60/523 using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/546 of blood flow, e.g. by adapting rotor speed
• CPC Class Codes: A61M 60/585 User interfaces
• CPC Class Codes: A61M 60/851 Valves
• CPC Class Codes: A61M 60/892 Active valves, i.e. actuated by an external force
• CPC Class Codes: A61M 60/894 Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: F04B 43/1253 by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing

Abstract

A method and medical machine for calibrating a peristaltic pump (36, 39) intended to be used in connection with the medical machine, such as a dialysis machine. The machine comprises an internal fluid flow meter (18, 19). Fluid is introduced into the pump segment (36) and is pumped by the peristaltic pump at a substantially constant rotation rate. Three different inlet pressures are obtained and measured by a pressure meter (16) and the corresponding fluid flow is measured by the internal fluid flow meter (18, 19) for obtaining calibration pair values. A calibration curve is calculated from said pair values by a computer (23) inside the medical machine. The actual fluid flow rate is determined by said computer (23) from said calibration curve based on the actual inlet pressure and the actual revolution rate of the propelling means.

Claims

1. A method for calibrating a peristaltic pump including a replaceable tube segment having an inlet and an outlet and propelling means for propelling a fluid through said replaceable tube segment, said method comprising introducing a fluid into said inlet of said replaceable tube segment, pumping said fluid through said replaceable tube segment by operating said propelling means at a substantially constant propelling rate, measuring at least one adjusted inlet pressure for said fluid at said inlet to said replaceable tube segment, and measuring the fluid flow rate through said replaceable tube segment corresponding to said at least one adjusted inlet pressure in order to thereby obtain at least one calibration pair value for said peristaltic pump.

2. The method of claim 1 wherein said peristaltic pump is adapted for use with medical treatment apparatus including an internal fluid flow meter, and wherein said measuring of said fluid flow rate is carried out utilizing said internal fluid flow meter.

3. The method of claim 2 wherein said measuring of said fluid flow rate comprises flowing said fluid from said outlet of said replaceable tube segment to said internal fluid flow meter of said medical treatment apparatus.

4. The method of claim 3 including providing said adjusted inlet pressure by adjustably throttling said fluid flow to said inlet of said replaceable tube segment.

5. The method of claim 2 wherein said medical treatment apparatus includes at least one fluid outlet, and including measuring said fluid flow rate by passing a fluid from said at least one fluid outlet to said inlet of said replaceable tube segment and measuring said fluid flow rate utilizing said internal fluid flow meter of said medical treatment apparatus.

6. The method of claim 5 wherein said medical treatment apparatus includes at least one internal pump, and including supplying said fluid to said inlet of said replaceable tube segment by means of said at least one internal pump.

7. The method of claim 2 wherein said medical treatment apparatus comprises a dialysis machine.

8. The method of claim 1 wherein said measuring of said fluid flow rate comprises measuring at least two of said fluid flow rates through said replaceable tube segment corresponding to at least two of said adjusted inlet pressures in order to obtain at least two calibration pair values for said peristaltic pump, and calculating a calibration curve for said calibration pair values representing the relationship between said fluid flow rate and said inlet pressure at said substantially constant propelling rate.

9. The method of claim 8 including obtaining at least a third calibration pair value for said peristaltic pump comprising a standard pair value corresponding to said peristaltic pump.

10. The method of claim 8 including selecting an actual inlet pressure and an actual constant propelling rate and determining the actual fluid flow rate from said calibration curve for said selected actual inlet pressure and said selected actual constant propelling rate.

11. The method of claim 1 including adjusting said at least one calibration pair value by compensating for the time dependency of said fluid flow rate.

12. The method of claim 11 including compensating for said time dependency by means of a standard value compensation for said peristaltic pump.

13. The method of claim 11 including compensating for said time dependency by permitting a predetermined time period to elapse for said pumping of said fluid through said replaceable tube segment before calibrating said peristaltic pump.

14. The method of claim 13 wherein said predetermined time period comprises at least about 15 minutes.

15. The method of claim 13 wherein said predetermined time period comprises at least about 30 minutes.

16. A medical treatment apparatus including an internal fluid flow meter and a peristaltic pump comprising a replaceable tube segment including an inlet and an outlet and propelling means for propelling a fluid through said replaceable tube segment at a substantially constant propelling rate, said apparatus including peristaltic pulp calibration means comprising a first hose for connecting a source of a solution to said inlet of said replaceable tube segment, a second hose for connecting said outlet of said replaceable tube segment to disposal means, providing means for providing said fluid to said inlet of said replaceable tube segment, pressure measuring means for measuring an adjusted inlet pressure for said fluid at said inlet to said replaceable tube segment, flow measuring means for measuring the fluid flow rate of said fluid through said replacement tube segment during maintenance of said adjusted inlet pressure in order to thereby obtain at least one calibration pair value for said peristaltic pump, and calculation means for calculating a calibration curve from said at least one calibration pair value representing the relationship between said fluid flow rate and said inlet pressure at said substantially constant propelling rate.

17. The apparatus of claim 16 wherein said flow measuring means comprises said internal flow meter.

18. The apparatus of claim 17 including at least one fluid inlet member, and wherein said second hose connects said outlet of said replaceable tube segment to said at least one fluid inlet member upstream of said disposal means, whereby said fluid flow rate can be measured by said internal fluid flow meter.

19. The apparatus of claim 17 including at least one fluid outlet member, and wherein said first hose is connected to said at least one fluid outlet member as said source of said solution, whereby said fluid flow rate can be measured by said internal flow meter.

20. The apparatus of claim 19 including pressure adjusting means for adjusting the pressure at said at least one fluid outlet member thereby adjusting the pressure of said inlet to said adjustable pump segment.

21. The apparatus of claim 16, including determining means for determining the actual fluid flow rate for an actual inlet pressure and an actual constant propelling rate utilizing said calibration curve.

22. The apparatus of claim 16 including an adjustable throttle valve associated with said inlet of said adjustable pump segment for adjusting the inlet pressure of said adjustable pump segment to said adjusted inlet pressure.

23. The apparatus of claim 16 wherein said medical treatment apparatus comprises a dialysis machine.