System and method for detecting abnormal medicament pump fluid pressure

• US 6,423,029 B1
• Filed: 04/29/1999
• Issued: 07/23/2002
• Est. Priority Date: 04/29/1999
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Elsberry, Dennis D.
• Primary Examiner(s): Casler, Brian L.
• Assistant Examiner(s): Lam, Ann Y.
• Application Number:
  US09/301,935
• Time in Patent Office: 1,181 Days
• Field of Search: 604/131, 604/65, 604/66, 604/67, 604/151, 604/153, 604/246, 604/132, 604/133
• US Class Current: 604/65
• CPC Class Codes: A61M 2005/16868 Downstream occlusion sensors
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31794 Of cross-linked polyester

Abstract

A system is disclosed for providing an indication of abnormal upstream fluid pressure, abnormal downstream fluid pressure, and/or abnormal differential upstream versus downstream fluid pressures for a medicament pump that is implantable within a person'"'"'s body and has a pressurized source of fluid. The system includes upstream and downstream fluid pressure sensors, which could be commercially available strain gauges attached to, or incorporated into, the wall of the inlet tubing and the wall of the outlet tubing, respectively, for sensing the amount of deformation of the tubing walls as a result of fluid pressure changes. Fluid source overpressurization could be indicated, via activation of an alarm, based upon detection of either: abnormally high upstream fluid pressure; or the difference between the upstream fluid pressure and the downstream fluid pressure exceeding a predetermined range of acceptable values. Pump outlet tube occlusion could be indicated, via activation of an alarm, based upon detection of either: abnormally high downstream fluid pressure; or the difference between the upstream fluid pressure and the downstream fluid pressure being less than a predetermined range of acceptable values. Even when the differential pressure is within an acceptable range of values, the inlet and outlet pressure values can be used to distinguish between (1) normal conditions at both the inlet and outlet; and (2) abnormal conditions at both the inlet and outlet that can not be detected differentially, such as simultaneous overpressurization at both the inlet and outlet.

Claims

1. A system for providing an indication of an abnormal fluid pressure upstream or downstream or both upstream and downstream of a human-implantable medicament pump having a pressurized source of fluid operatively coupled to an inlet of the medicament pump, the system comprising:

a pump inlet pressure sensor for sensing fluid pressure upstream from the pump;

a pump outlet pressure sensor for sensing fluid pressure downstream from the pump; and

a processor for calculating a difference between the pressure upstream of the pump and the pressure downstream of the pump and for providing an indication that the pressure upstream of the pump minus the pressure downstream of the pump is greater than a maximum-difference threshold.

2. The system as in claim 1 wherein the pump inlet pressure sensor comprises a strain gauge operatively attached to a wall of a pump inlet tube for monitoring fluid pressure in the pump inlet tube.

3. The system as in claim 1 wherein the pump inlet pressure sensor comprises a strain gauge incorporated into a wall of a pump inlet tube for monitoring fluid pressure in the pump inlet tube.

4. The system as in claim 1 wherein:

the pump outlet pressure sensor comprises a strain gauge operatively attached to a wall of a pump outlet tube for detecting changes in fluid pressure downstream from the pump.

5. The system as in claim 1 wherein:

the pump outlet pressure sensor comprises a strain gauge incorporated into a wall of a pump outlet tube for detecting changes in fluid pressure downstream from the pump.

12. The system as in claim 1, the system further comprising:

an abnormal inlet pressure alarm operatively coupled and responsive to the pump inlet pressure sensor for indicating abnormal fluid pressure upstream of the pump when the sensed fluid pressure upstream from the pump is greater than a maximum-upstream-fluid-pressure threshold.

13. The system as in claim 12, wherein the abnormal inlet pressure alarm indicates abnormal fluid pressure upstream of the pump when the sensed fluid pressure upstream from the pump is less than a minimum-upstream-fluid-pressure threshold.

14. The system as in claim 1, the system further comprising:

an abnormal inlet pressure alarm operatively coupled and responsive to the pump inlet pressure sensor for indicating abnormal fluid pressure upstream of the pump when the sensed fluid pressure upstream from the pump is less than a minimum-upstream-fluid-pressure threshold.

15. The system as in claim 1, the system further comprising:

an abnormal outlet pressure alarm operatively coupled and responsive to the pump outlet pressure sensor for indicating abnormal fluid pressure downstream from the pump when the sensed fluid pressure downstream from the pump is greater than a maximum-downstream-fluid-pressure threshold.

16. The system as in claim 15, wherein the abnormal outlet pressure alarm indicates abnormal fluid pressure downstream from the pump when the sensed fluid pressure downstream from the pump is less than a minimum-downstream-fluid-pressure threshold.

17. The system as in claim 1, the system further comprising:

an abnormal outlet pressure alarm operatively coupled and responsive to the pump outlet pressure sensor for indicating abnormal fluid pressure downstream from the pump when the sensed fluid pressure downstream from the pump is less than a minimum-downstream-fluid-pressure threshold.

18. The system as in claim 1, wherein the processor provides an indication that the calculated difference is outside a predetermined range of acceptable difference pressure values when the pressure upstream of the pump minus the pressure downstream of the pump is less than a minimum-difference threshold.

6. A method of indicating abnormal fluid pressure upstream and/or downstream of a human-implantable medicament pump, the method comprising the steps of:

monitoring the fluid pressure upstream of the pump;

monitoring the fluid pressure downstream from the pump;

calculating a difference between the upstream pressure and the downstream pressure; and

activating an abnormal difference pressure alarm when the calculated difference pressure is greater than a maximum-difference threshold.

7. The method as in claim 6 further comprising the step of:

activating an abnormal inlet pressure alarm when the monitored upstream fluid pressure is greater than a maximum-upstream-fluid-pressure threshold.

8. The method as in claim 7 further comprising the step of:

activating an abnormal inlet pressure alarm when the monitored upstream fluid pressure is less than a minimum-upstream-fluid-pressure threshold.

9. A human-implantable medicament pump having a computer-readable medium, the computer-readable medium having computer-executable instructions for performing the steps recited in claim 6.

10. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 7.

11. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 8.

19. The method as in claim 6 further comprising the step of:

activating an abnormal inlet pressure alarm when the monitored upstream fluid pressure is less than a minimum-upstream-fluid-pressure threshold.

20. The method as in claim 6 further comprising the step of:

activating an abnormal outlet pressure alarm when the monitored downstream fluid pressure is greater than a maximum-downstream-fluid-pressure threshold.

21. The method as in claim 20 further comprising the step of:

activating the abnormal outlet pressure alarm when the monitored downstream fluid pressure is less than a minimum-downstream-fluid-pressure threshold.

22. The method as in claim 6 further comprising the step of:

activating an abnormal outlet pressure alarm when the monitored downstream fluid pressure is less than a minimum-downstream-fluid-pressure threshold.

23. The method as in claim 6 further comprising the step of:

activating the abnormal difference pressure alarm when the calculated difference pressure is less than a minimum-difference threshold.

24. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 19.

25. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 20.

26. The medicament pump computer-readable medium as in claim 25 having computer-executable instructions for performing the steps recited in claim 21.

27. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 22.

28. The medicament pump computer-readable medium as in claim 9 having computer-executable instructions for performing the steps recited in claim 23.