Non-constant pressure infusion pump

• US 20020156464A1
• Filed: 03/01/2001
• Published: 10/24/2002
• Est. Priority Date: 03/01/2001
• Status: Active Grant

• Current Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories)
• Original Assignee: Advanced Neuromodulation Systems Incorporated (Abbott Laboratories)
• Inventors: Erickson, John H., Blischak, Brian, Daglow, Terry, Hooper, Sandra Marie, Wigness, Bruce David
• Granted Patent: US 6,620,151 B2
• Time in Patent Office: Days
• US Class Current: 604/892.1
• CPC Class Codes: A61M 2005/14264 with means for compensating influence from the environment
• CPC Class Codes: A61M 2005/14506 mechanically driven, e.g. spring or clockwork
• CPC Class Codes: A61M 2205/33 Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3372 Temperature compensation
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/16881 Regulating valves on-off valves, e.g. clamps A61M39/28

Abstract

The present invention relates to an implantable infusion pump having a refillable infusate reservoir in fluid communication with a delivery site via a flow path. This flow path includes a flow resistance. The infusion pump includes a sensing device(s), positioned relative to the flow path, to provide data regarding a flow rate along the flow path. The infusion pump effects a division of a total flow period into at least a plurality of unit dose periods, each unit dose period effecting delivery of a unit dose of infusate. The cumulative effect of delivering the total number of unit dose periods is the delivery of a desired dose over the total flow period. The present invention permits a reservoir pressure to vary over any portion of total flow period but effects a constant-pressure state over each unit dose cycle.

Claims

1. An infusion device for implantation in a living body, the device comprising:

at least one variable-volume chamber to receive and transiently store a fluid infusate;

at least one inlet conduit, wherein each variable-volume chamber is in fluid communication with an inlet conduit;

an energy source to effect an expulsion of stored infusate from the at least one variable-volume chamber;

at least one outlet conduit, in fluid communication with the chamber(s), to facilitate the passage of infusate from the chamber(s) to a delivery site;

a flow resistor network including at least one flow restrictor positioned relative to the outlet conduit;

at least one pressure sensing device to measure a pressure differential across at least a portion of the flow restrictor network;

at least one valve, positioned relative to the outlet conduit, to selectively control an infusate output from the device; and

a controller, coupled to the at least one pressure sensing device and to the at least one valve, to control an operation of the at least one valve based on measured values obtained by the at least one pressure sensing device.

2. A device in accordance with claim 1, wherein a first pressure sensing device, which is one of the at least one pressure sensing device, is adapted to measure an infusate pressure across the at least one valve.

3. A device in accordance with claim 1, wherein a first pressure sensing device is adapted to measure an infusate pressure prior to the at least one flow restrictor, and a second pressure sensing device is adapted to measure an infusate pressure subsequent to the at least one flow restrictor, and wherein the first pressure sensing device and the second pressure sensing device are two of the at least one pressure sensing device.

4. A device in accordance with claim 1, further comprising a temperature sensor to measure an infusate temperature, and the controller is further coupled to the temperature sensor.

5. A device in accordance with claim 4, wherein the controller is adapted to control the at least one valve based also on measured values obtained by the temperature sensor.

6. An infusion device for implantation in a living body having a collapsible infusate chamber, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet having a flow resistance, the device comprising:

a pressure sensing mechanism to measure an infusate pressure differential across at least a portion of the flow resistance;

a valve, which defines at least in part the flow resistance, to selectively obstruct the outlet flow path; and

a controller, coupled to the pressure sensing mechanism and the valve, to control an operation of the valve based on measured values obtained by the pressure sensing mechanism,

wherein a prescribed dose to be delivered by the device consists of a plurality of unit dose cycles, each unit dose cycle being defined by an open-close cycle of the valve, and

wherein the controller is adapted to regulate an operational timing of the open-close cycle of the valve to deliver a constant unit dose amount for each dose cycle.

7. A device in accordance with claim 6, further comprising a flow resistor, which defines at least in part the flow resistance, positioned relative to the outlet conduit.

8. A device in accordance with claim 7, wherein the pressure sensing mechanism includes a first pressure sensing device to measure an infusate pressure upstream of the flow restrictor and a second pressure sensing device to measure an infusate pressure downstream of the flow restrictor.

9. A device in accordance with claim 6, wherein the pressure sensing mechanism is further adapted to measure an infusate pressure across the valve.

10. A device in accordance with claim 6, further comprising a temperature sensor to measure an infusate temperature, and the controller is further coupled to the temperature sensor.

11. A device in accordance with claim 10, wherein the controller is adapted to control the valve based also on measured values obtained by the temperature sensor.

12. A device in accordance with claim 6, wherein the controller varies a duty cycle of the open-close cycle of the valve within a prescribed cycle period.

13. A device in accordance with claim 6, wherein the controller varies a period of the open-close cycle.

15. A device in accordance with claim 14, wherein the operational timing that is subject to regulation by the controller is a duty cycle of the open-close cycle of the valve.

17. A device in accordance with claim 16, wherein the operational timing that is subject to regulation by the controller is a duty cycle of the open-close cycle of the valve.

19. A device in accordance with claim 18, wherein the operational timing that is subject to regulation by the controller is a duty cycle of the open-close cycle of the valve.

14. An infusion device for implantation in a living body having a collapsible infusate chamber to transiently store an active agent-containing infusate, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet having a flow resistance, the device comprising:

a pressure sensing mechanism to measure an infusate pressure differential across at least a portion of the flow resistance;

a valve, which defines at least in part the flow resistance, to selectively obstruct the outlet flow path; and

a controller, coupled to the pressure sensing mechanism and the valve, to control an operation of the valve based on measured values obtained by the pressure sensing mechanism,

wherein a prescribed dose, to be delivered over a prescribed dose period, consists of a plurality of unit dose cycles, each unit dose cycle being defined by an open-close cycle of the valve, and

wherein the controller is adapted to regulate an operational timing of the open-close cycle of the valve to compensate for changes in the active agent-containing infusate, thereby maintaining a prescribed dose of active agent over the prescribed dose period.

16. An infusion device for implantation in a living body having a collapsible infusate chamber to transiently store an active agent-containing infusate, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet having a flow resistance, the device comprising:

a temperature sensing device to measure an infusate temperature;

a valve, which defines at least in part the flow resistance, to selectively obstruct the outlet flow path; and

a controller, coupled to the temperature sensing device and the valve, to control an operation of the valve based on measured values obtained by the temperature sensing device,

wherein a prescribed dose, to be delivered over a prescribed dose period, consists of a plurality of unit dose cycles, each unit dose cycle being defined by an open-close cycle of the valve, and

wherein the controller is adapted to regulate an operational timing of the open-close cycle of the valve based on a change in infusate temperature measured by the temperature sensing device.

18. An infusion device for implantation in a living body having a collapsible infusate chamber to transiently store an infusate, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet having a flow resistance, the device comprising:

a pressure sensing mechanism to measure an infusate pressure differential across at least a portion of the flow resistance;

a valve, which defines at least in part the flow resistance, to selectively obstruct the outlet flow path; and

a controller, coupled to the pressure sensing mechanism and the valve, to control an operation of the valve based on measured values obtained by the pressure sensing mechanism,

wherein a prescribed dose, to be delivered over a prescribed dose period, consists of a plurality of unit dose cycles, each unit dose cycle being defined by an open-close cycle of the valve, and

wherein the controller is adapted to regulate an operational timing of the open-close cycle of the valve based on a change in flow resistance.

20. An infusion device for implantation in a living body having a collapsible infusate chamber to transiently store an infusate, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet having a flow resistance, the device comprising:

a pressure sensing mechanism to measure an infusate pressure differential across at least a portion of the flow resistance;

a valve, which defines at least in part the flow resistance, to selectively obstruct the outlet flow path; and

a controller, coupled to the pressure sensing mechanism and the valve, to control an operation of the valve based on measured values obtained by the pressure sensing mechanism,

wherein a prescribed dose, to be delivered over a prescribed dose period, consists of a plurality of unit dose cycles, each unit dose cycle being defined by an open-close cycle of the valve, and

wherein the controller is adapted to selectively regulate an operational timing of the open-close cycle of the valve in accordance with a volume then-determined to be present within the infusate chamber.

21. A device in accordance with claim 20, wherein the operational timing that is subject to regulation by the controller is a duty cycle of the open-close cycle of the valve.

22. An infusion device for implantation in a living body having a collapsible infusate chamber, an energy source to collapse the chamber, and an outlet flow path, having a flow resistance, that extends between the chamber and a device outlet, the device comprising:

a flow restrictor, positioned relative to the outlet flow path, which defines in part the flow resistance;

a valve, which defines in part the flow resistance, to selectively obstruct the outlet flow path;

a pressure sensing device to measure an infusate pressure across at least a portion of the flow resistance; and

a controller, coupled to the pressure sensing device and the valve, to control an operation of the valve to selectively obstruct the outlet flow path,

wherein the controller is adapted to assess whether the flow resistance has undesirably changed based on measured values obtained from the pressure sensing device.

23. A device in accordance with claim 22, wherein the pressure sensing mechanism includes a first pressure sensing device to measure an infusate pressure upstream of the valve and a second pressure sensing device to measure an infusate pressure downstream of the valve.

24. A device in accordance with claim 22, wherein the pressure sensing mechanism is further adapted to measure an infusate pressure across the flow restrictor, and the controller is adapted to control the valve based also on measured infusate pressure values across the flow restrictor.

25. A device in accordance with claim 22, wherein the controller is adapted to identify a change in the flow resistance upstream of the valve based on measured values obtained from the pressure sensing mechanism.

26. A device in accordance with claim 22, wherein the controller is adapted to identify a change in the flow resistance downstream of the valve based on measured values obtained from the pressure sensing mechanism.

28. A method in accordance with claim 27, wherein the open-close cycle is defined by a fixed period.

30. A method in accordance with claim 29, wherein a plurality of prescribed dose periods define a flow period, and further comprising the step of dividing the flow period into the plurality of prescribed dose periods.

31. A method in accordance with claim 29, wherein the operational timing that is subject to regulation by the controller is a duty cycle of the open-close cycle of the valve.

32. A method in accordance with claim 29, further comprising the step of measuring an infusate temperature, wherein the step of modifying is effected also in accordance with a measured temperature.

33. A method in accordance with claim 29, further comprising the steps of:

actuating the valve so as to effect a change in an occluded state of the outlet flow path; and

measuring a transient pressure profile across the valve.

34. A method in accordance with claim 33, wherein the infusion device is adapted to communicate with a controller external to the patient, and further comprising the step of transmitting a signal to the controller, wherein the signal corresponds to the measured pressure profile.

35. A method in accordance with claim 33, further comprising the step of assessing a rate of change of a measured pressure profile at or about said actuating step.

36. A method in accordance with claim 29, wherein the infusion device is adapted to communicate with a controller external to the patient, and further comprising the step of transmitting a signal to the controller, wherein the signal is representative of the measured infusate pressure differential.

38. A method in accordance with claim 37, wherein a plurality of prescribed dose periods define a flow period, and further comprising the step of dividing the flow period into the plurality of prescribed dose periods, and

wherein the step of modifying effects a control over the valve to compensate for changes in the active agent-containing infusate, thereby maintaining a prescribed dose of active agent over each prescribed dose period in the flow period.

40. A method in accordance the claim 39, wherein the step of assessing can reveal an undesired flow restriction upstream of the valve based on a rate of change of a measured pressure profile.

41. A method in accordance the claim 39, wherein the step of assessing can reveal an undesired flow restriction downstream of the valve based on a rate of change of a measured pressure profile.

42. A method in accordance the claim 39, wherein the step of assessing can reveal a valve malfunction.

43. A method in accordance the claim 39, wherein the step of assessing can reveal changes in infusate delivery caused by changes in certain properties of the infusate based on a rate of change of a measured pressure profile, the certain properties being of the group of:

physical, chemical, therapeutic, and pharmacological.

44. A method in accordance the claim 39, wherein the step of assessing can reveal a catheter malfunction.

27. A method of controlling infusate output from an implantable infusion device for a prescribed dose period, the device having a collapsible infusate chamber, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet, wherein the outlet flow path includes a restrictor and a valve to selectively and at least partially occlude the outlet flow path, comprising the steps of:

dividing the prescribed dose period into a plurality of unit dose periods, wherein each unit dose period is defined by an open-close cycle of the valve; and

modifying a duty cycle of the open-close cycle of the valve so as to maintain a unit dose for each unit dose period.

29. A method of controlling infusate output from an implantable infusion device for at least one prescribed dose period, the device having a collapsible infusate chamber, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet, wherein the outlet flow path includes a restrictor and a valve to selectively and at least partially occlude the outlet flow path, comprising the steps of:

dividing the prescribed dose period into a plurality of unit dose periods, wherein each unit dose period is defined by an open-close cycle of the valve;

measuring an infusate pressure differential across the restrictor; and

modifying an operational timing of the open-close cycle of the valve, in accordance with a measured infusate pressure differential, so as to maintain a unit dose for each unit dose period.

37. A method of controlling infusate output from an implantable infusion device for at least one prescribed dose period, the device having a collapsible infusate chamber to transiently store an active agent-containing infusate, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet, wherein the outlet flow path includes a restrictor and a valve to selectively and at least partially occlude the outlet flow path, comprising the steps of:

dividing the prescribed dose period into a plurality of unit dose periods, wherein each unit dose period is defined by an open-close cycle of the valve; and

modifying an operational timing of the open-close cycle of the valve to compensate for changes in the active agent-containing infusate, thereby maintaining a prescribed dose of active agent over the prescribed dose period.

39. A method of controlling infusate output from an implantable infusion device for a prescribed dose period, the device having a collapsible infusate chamber, an energy source to collapse the chamber, and an outlet flow path extending between the chamber and a device outlet, wherein the outlet flow path includes a restrictor and a valve to selectively and at least partially occlude the outlet flow path, comprising the steps of:

actuating the valve so as to effect a change in an occluded state of the outlet flow path;

measuring a transient pressure profile across the valve; and

assessing a rate of change of the pressure profile during the actuating step.

45. An infusion device for implantation in a living body, the device comprising:

a variable-volume chamber to receive and transiently store a fluid infusate;

an inlet conduit, which is in fluid communication with the variable-volume chamber;

an energy source to effect an expulsion of stored infusate from the chamber;

an outlet conduit, in fluid communication with the chamber, to facilitate the passage of infusate from the chamber to a delivery site;

a flow restrictor, positioned relative to the outlet conduit, to define a maximum infusate flow rate output from the device;

a first pressure sensing device to measure an infusate pressure upstream of the flow restrictor;

a second pressure sensing device to measure an infusate pressure downstream of the flow restrictor;

a valve to selectively control an infusate output from the device; and

a controller, coupled to the first pressure sensing device, the second pressure sensing device, and the valve, to control an operation of the valve based on measured values obtained by the first and second pressure sensing devices.