Detecting Empty Medical Pump Reservoir

• US 20110264006A1
• Filed: 04/27/2010
• Published: 10/27/2011
• Est. Priority Date: 04/27/2010
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Miesel, Keith A., Sarkinen, Scott A., Kalpin, Scott L., Ali, Irfan Z.
• Granted Patent: US 8,246,573 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• CPC Class Codes: A61B 5/1116 Determining posture transitions
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 5/14212 Pumping with an aspiration and an expulsion action
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence

Abstract

A medical device system comprises a reservoir configured to store a therapeutic fluid and a medical pump configured to deliver the therapeutic fluid from the reservoir to a patient. The system also comprises a sensor that can detect a characteristic associated with the pump and a processor to determine if the characteristic detected indicates the reservoir is empty or near empty. The characteristic may comprise a property associated with the energization of an actuation mechanism configured to be energized to provide a pump stroke. The characteristic may also comprise a characteristic of a noise made by an actuator within the pump at the end of a pump stroke.

Claims

1. A medical device system comprising:

a reservoir configured to store a therapeutic fluid;

a medical pump configured to deliver the therapeutic fluid from the reservoir to a patient, the medical pump comprising an actuation mechanism configured to be energized to provide a pump stroke;

a sensor configured to detect a property associated with the energy required to energize the actuation mechanism; and

a processor configured to determine when the property associated with the energy required to energize the actuation mechanism indicates the reservoir is empty or near empty.

2. The system of claim 1, wherein the actuation mechanism comprises a coil configured to be energized to provide a pump stroke and an actuator that is movable in response to the energization of the coil.

3. The system of claim 1, wherein an implantable device comprises the reservoir and the medical pump.

4. The system of claim 1, wherein the processor is configured to determine the reservoir is empty or near empty when the property associated with the energy required to energize the actuation mechanism of each of a predetermined number of a set of prior pump strokes indicates the reservoir is empty or near empty, or when the property associated with the energy required to energize the actuation mechanism of each of a predetermined number of consecutive pump strokes indicates the reservoir is empty or near empty.

5. The system of claim 1, wherein the property associated with the energy required to energize the actuation mechanism comprises at least one of a shape of a current waveform through the actuation mechanism when providing for a pump stroke, an energy supplied to the actuation mechanism in order to produce a pump stroke, and a voltage change across the actuation mechanism during a pump stroke.

6. The system of claim 1, wherein a baseline shape that indicates the reservoir is empty or near empty is stored on a memory, wherein the processor is configured to compare the baseline shape to a shape of a current waveform through the actuation mechanism when providing for a pump stroke to determine if the reservoir is empty or near empty.

7. The system of claim 1, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the coil during a pump stroke, wherein a starting voltage across the actuation mechanism is fixed, and wherein the processor determines the voltage change by measuring the ending voltage across the actuation mechanism after the pump stroke.

8. The system of claim 1, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the actuation mechanism during a pump stroke, wherein the processor determines the voltage change by measuring a starting voltage across the actuation mechanism before the pump stroke and by measuring an ending voltage across the actuation mechanism after a pump stroke.

9. The system of claim 1, further comprising a power source to selectively energize the actuation mechanism.

10. The system of claim 9, wherein the property associated with the energy required to energize the actuation mechanism comprises an energy supplied by the power source to the actuation mechanism in order to produce the pump stroke when the reservoir is empty or near empty.

11. The system of claim 9, wherein the power source comprises a capacitor, wherein the property associated with the energy required to energize the actuation mechanism comprises at least one of a time required to recharge the capacitor after a selective energization of the actuation mechanism by the capacitor in order to produce a pump stroke, an energy required to recharge the capacitor after a selective energization of the actuation mechanism by the capacitor in order to produce the pump stroke, and a voltage change across the capacitor during recharging of the capacitor.

12. The system of claim 11, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the capacitor during recharging of the capacitor, wherein an ending voltage across the capacitor is fixed, and wherein the processor determines the voltage change by measuring the starting voltage across the capacitor before the pump stroke.

13. The system of claim 11, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the capacitor during recharging of the capacitor, wherein the processor determines the voltage change by measuring a starting voltage across the capacitor before the pump stroke and by measuring an ending voltage across the capacitor after a pump stroke.

14. A method comprising:

removing therapeutic fluid from a reservoir using a medical pump comprising an actuation mechanism configured to be energized to provide a pump stroke;

detecting a property associated with the energy required to energize the actuation mechanism; and

determining that the property associated with the energy required to energize the actuation mechanism indicates the reservoir is empty or near empty.

15. The method of claim 14, wherein the actuation mechanism comprises a coil configured to be energized to provide a pump stroke and an actuator that is movable in response to the energization of the coil.

16. The method of claim 14, wherein an implantable device comprises the reservoir and the medical pump.

17. The method of claim 14, further comprising determining that the reservoir is empty or near empty when the property associated with the energy required to energize the actuation mechanism of each of a predetermined number of a set of prior pump strokes indicates the reservoir is empty or near empty or when the property associated with the energy required to energize the actuation mechanism of each of a predetermined number of consecutive pump strokes indicates the reservoir is empty or near empty.

18. The method of claim 14, wherein the property associated with the energy required to energize the actuation mechanism comprises at least one of a shape of a current waveform through the actuation mechanism when the actuation mechanism is energized to provide a pump stroke;

a total energy supplied to the actuation mechanism in order to produce a pump stroke; and

a voltage change across the actuation mechanism after a pump stroke.

19. The method of claim 14, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the actuation mechanism during a pump stroke, wherein a starting voltage across the actuation mechanism is fixed, further comprising determining the voltage change by measuring the ending voltage across the actuation mechanism after the pump stroke.

20. The method of claim 14, wherein the property associated with the energy required to energize the actuation mechanism comprises a voltage change across the actuation mechanism during a pump stroke, further comprising determining the voltage change by measuring a starting voltage across the actuation mechanism before the pump stroke and by measuring an ending voltage across the actuation mechanism after a pump stroke.

21. The method of claim 14, further comprising storing a baseline shape that indicates the reservoir is empty or near empty on a memory, determining a shape of a current waveform through the actuation mechanism when the actuation mechanism is energized to provide a pump stroke, and comparing the baseline shape to the shape of the current waveform through the actuation mechanism to provide the pump stroke to determine if the reservoir is empty or near empty.

22. The method of claim 14, wherein removing the therapeutic fluid from the reservoir comprises energizing the actuation mechanism with a capacitor, and wherein the property associated with the energy required to energize the actuation mechanism comprises at least one of a time to recharge the capacitor after a selective energization of the actuation mechanism by the capacitor in order to produce a pump stroke, an energy required to recharge the capacitor after a selective energization of the actuation mechanism by the capacitor in order to produce a pump stroke, or a voltage change across the capacitor during recharging of the capacitor.

23. The method of claim 14, further comprising initiating an alarm when it is determined that the property associated with the energy required to energize the actuation mechanism indicates the reservoir is empty or near empty.

24. A medical device system comprising:

means for storing therapeutic fluid;

means for removing therapeutic fluid from the means for storing the therapeutic fluid, the means for removing the therapeutic fluid comprising means for actuating the fluid and means for energizing the means for actuating the fluid to provide a pump stroke;

means for detecting a property associated with the energy required to energize the means for actuating the fluid; and

means for determining that the property associated with the energy required to energize the means for actuating the fluid indicates the means for storing the therapeutic fluid is empty or near empty.

25. The system of claim 24, wherein the property associated with the energy required to energize the means for actuating the fluid comprises at least one of a shape of a current waveform through the means for actuating the fluid when providing for a pump stroke, an energy supplied to the means for actuating the fluid in order to produce a pump stroke, a voltage change across the means for actuating the fluid during a pump stroke, a time required to recharge the means for energizing the means for actuating the fluid after a selective energization of the means for actuating the fluid in order to produce a pump stroke, an energy required to recharge the means for energizing the means for actuating the fluid after a selective energization of the means for actuating the fluid in order to produce the pump stroke, and a voltage change across the means for energizing the means for actuating the fluid during recharging of the means for energizing the means for actuating the fluid.

26. A medical device system comprising:

a reservoir configured to store a therapeutic fluid;

a medical pump configured to deliver the therapeutic fluid from the reservoir to a patient, the pump comprising an actuator that is movable through a pump stroke, wherein the actuator makes a noise at an end of the pump stroke;

a sensor configured to detect a characteristic of the noise; and

a processor configured to determine when the characteristic of the noise indicates the reservoir is empty or near empty.

27. The system of claim 26, wherein the processor is configured to determine the reservoir is empty or near empty when the characteristic of the noise of each of a predetermined number of a set of prior pump strokes indicates the reservoir is empty or near empty or when the characteristic of the noise of each of a predetermined number of consecutive pump strokes indicates the reservoir is empty or near empty.

28. The system of claim 26, wherein an implantable device comprises the reservoir and the medical pump.

29. The system of claim 26, wherein the characteristic of the noise comprises at least one of a type or a volume of the noise.

30. The system of claim 26, wherein the sensor comprises a piezoelectric crystal configured to detect vibrations associated with the noise.

31. The system of claim 26, wherein the sensor is a machine health monitor configured to detect mechanical faults within the pump, the machine health monitor being further configured to detect vibrations associated with the noise.

32. The system of claim 26, wherein the sensor is a posture sensor configured to detect the posture of the patient, the posture sensor being further configured to detect vibrations associated with the noise.

33. A method comprising:

removing therapeutic fluid from a reservoir using a medical pump comprising an actuator that is movable through a pump stroke, wherein the actuator makes a noise at an end of the pump stroke;

detecting a characteristic of the noise; and

determining that the characteristic of the noise indicates the reservoir is empty or near empty.

34. The method of claim 33, further comprising determining that the reservoir is empty or near empty when the characteristic of the noise of each of a predetermined number of a set of prior pump strokes indicates the reservoir is empty or near empty or when the characteristic of the noise of each of a predetermined number of consecutive pump strokes indicates the reservoir is empty or near empty.

35. The method of claim 33, wherein an implantable device comprises the reservoir and the medical pump.

36. The method of claim 33, wherein the characteristic of the noise comprises at least one of a type or a volume of the noise.

37. The method of claim 33, wherein the characteristic of the noise is detected by a piezoelectric crystal configured to detect vibrations associated with the noise.

38. The method of claim 33, wherein the characteristic of the noise is detected by a machine health monitor configured to detect mechanical faults within the pump, the machine health monitor being further configured to detect vibrations associated with the noise.

39. The method of claim 33, wherein the characteristic of the noise is detected by a posture sensor configured to detect the posture of the patient, the posture sensor being further configured to detect vibrations associated with the noise.

40. The method of claim 33, further comprising initiating an alarm when it is determined that the characteristic of the noise indicates the reservoir is empty or near empty.

41. A medical device system comprising:

means for storing therapeutic fluid;

means for removing therapeutic fluid from the means for storing the therapeutic fluid, the means for removing the therapeutic fluid comprising means for actuating the fluid and to provide a pump stroke, wherein the means for actuating the fluid makes a noise at an end of the pump stroke;

means for detecting a characteristic of the noise; and

means for determining that the characteristic of the noise indicates the means for storing the therapeutic fluid is empty or near empty.