Malfunction Detection Via Pressure Pulsation

• US 20070093753A1
• Filed: 09/18/2006
• Published: 04/26/2007
• Est. Priority Date: 09/19/2005
• Status: Abandoned Application

• Current Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Original Assignee: Lifescan Incorporated (Duv Holding Corporation)
• Inventors: Bohm, Sebastian, Krulevitch, Peter, Anex, Deon, Zhao, Mingqi
• Application Number:
  US11/532,726
• Publication Number:
  US 20070093753A1
• Time in Patent Office: Days
• US Class Current: 604/131
• CPC Class Codes: A61M 2005/14513 with secondary fluid driving or regulating the infusion
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 5/14244 adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence

Abstract

Systems and methods of detecting occlusions and fluid-loss conditions (e.g., disconnects and/or leakages) in an infusion pump are discussed. For example, electrokinetic infusion pumps may develop an occlusion in the fluid flow path, which can disrupt control of fluid dispersed from the pump. As well, an infusion set disconnect can also result in a fluid-loss that can be disruptive. Such disruptions can be troublesome to systems that control the infusion pump, such as closed loop controllers. Accordingly, systems and methods described herein can be used to detect such occlusions and fluid-loss conditions during infusion pump operation. For example, a position sensor can be used to monitor fluid flow from the infusion pump, with the measurement being compared with an expected value to detect an occlusion or fluid-loss condition. Other algorithms for utilizing the position sensor are also described.

Claims

1. A method for detecting a malfunction in an infusion pump having a non-mechanically driven movable partition, comprising:

determining a first position of the movable partition of the infusion pump using a position sensor disposed on the pump;

activating the infusion pump for a first pre-determined amount of time to induce movement of the movable partition;

de-activating the infusion pump for a second pre-determined amount of time;

determining a second position of the movable partition using the position sensor;

calculating a measured displacement based on the first and second positions of the movable partition; and

comparing the measured displacement to a pre-determined threshold value to determine whether the infusion pump is malfunctioning.

2. The method of claim 1, wherein the pre-determined threshold value is a minimum acceptable value for the measured displacement of the movable partition.

3. The method of claim 2, wherein comparing the measured displacement to the pre-determined threshold value further comprises indicating the presence of an occlusion in the infusion pump if the measured displacement is less than the pre-determined threshold value.

4. The method of claim 3, further comprising:

generating an alarm if the presence of the occlusion is detected.

5. The method of claim 2, further comprising:

repeating the steps of the method as the movable partition proceeds through the infusion pump.

6. The method of claim 5, wherein the steps of determining the first position of the movable partition include equating the first position of the movable partition with a previously measured position of the movable partition.

7. The method of claim 1, wherein the pre-determined threshold value is a maximum acceptable value for the measured displacement of the movable partition.

8. The method of claim 7, wherein comparing the measured displacement to the pre-determined threshold value further comprises indicating the presence of a fluid-loss condition in the infusion pump if the measured displacement is greater than the pre-determined threshold value.

9. The method of claim 8, further comprising:

generating an alarm if the presence of the fluid-loss condition is detected.

10. The method of claim 7, further comprising:

repeating the steps of the method as the movable partition proceeds through the infusion pump.

11. The method of claim 10, wherein the steps of determining the first position of the movable partition include equating the first position of the movable partition with a previously measured position of the movable partition.

12. The method of claim 1, wherein determining the position of the movable partition further comprises using a magnetic sensor.

13. The method of claim 1, wherein activating the infusion pump for the first pre-determined amount of time is effective to cause a pressure build up in the pump.

14. The method of claim 13, wherein de-activating the infusion pump includes increasing the second pre-determined amount of time to cause a larger drop in pressure in the pump.

15. The method of claim 13, wherein de-activating the infusion pump includes decreasing the second pre-determined amount of time to cause a smaller drop in pressure in the pump.

16. The method of claim 1, wherein calculating a measured displacement comprises calculating a measured volume based on the first and second positions of the movable partition.

17. The method of claim 1, wherein the infusion pump is an electrokinetic infusion pump.

18. A system for detecting a malfunction in an infusion pump, comprising:

an infusion pump having a non-mechanically driven movable partition disposed therein;

a position sensor disposed on the pump, wherein the position sensor comprises at least one of a magnetic sensor, an optical sensor, and a linear variable differential transformer;

a controller associated with the infusion pump and adapted to operate the infusion pump in an activate/de-activate cycle, the cycle comprising activating the pump for a first pre-determined amount of time to induce movement of the movable partition and de-activating the pump for a second pre-determined amount of time; and

a processor associated with the position sensor, the processor adapted to calculate a measured displacement based on the first and second positions of the movable partition, and to compare the measured displacement with a pre-determined threshold value to determine whether the infusion pump is malfunctioning.

19. The system of claim 18, wherein the controller is adapted cause a pressure build up in the infusion pump, the pressure build up being associated with the activation of the pump for the first pre-determined amount of time.

20. The system of claim 18, wherein the pre-determined threshold value is a minimum acceptable value for the measured displacement.

21. The system of claim 20, wherein the processor is adapted to indicate a presence of an occlusion in the infusion pump if the measured displacement is less than the pre-determined threshold value.

22. The system of claim 18, wherein the pre-determined threshold value is a maximum acceptable value for the measured displacement.

23. The system of claim 22, wherein the processor is adapted to indicate a presence of a fluid-loss condition in the infusion pump if the measured displacement is greater than the pre-determined threshold value.

24. The system of claim 18, wherein the controller is further adapted to repeat the activate/de-activate cycle while fluid is being delivered by the infusion pump.

25. The system of claim 18, further comprising an alarm signal generator coupled to the processor and configured to produce an alarm signal if the processor determines that the infusion pump is malfunctioning.

26. The system of claim 18, wherein the infusion pump is an electrokinetic infusion pump.