Implantable fluid delivery device including gas chamber pressure sensor

• US 8,979,825 B2
• Filed: 04/15/2011
• Issued: 03/17/2015
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Gray, John M., Young, Dale A.
• Primary Examiner(s): GILBERT, ANDREW M
• Application Number:
  US13/087,755
• Publication Number:
  US 20120265174A1
• Time in Patent Office: 1,432 Days
• Field of Search: 604/890.1, 604/891.1, 604/505, 604/65, 604/67, 604/131, 604/132, 604/140, 604/141, 604/145, 604/216
• US Class Current: 604/891.1
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion

Abstract

An implantable medical device is configured with a pressure sensor arranged within the device to reliably and accurately measure the pressure within a propellant gas chamber at least partially surrounding a therapeutic fluid reservoir of the device. In one example, a housing of the IMD includes a protrusion that is configured to provide clearance for fluid communication between a propellant gas chamber pressure sensor and the propellant gas chamber.

Claims

1. An implantable fluid delivery device comprising:

a reservoir configured to store a therapeutic fluid;

a housing defining a chamber configured to at least partially surround the reservoir, wherein the chamber is configured to be filled with a propellant gas configured to regulate a pressure within the reservoir; and

a pressure sensor configured to sense a pressure within the chamber,

wherein the housing comprises a protrusion in an annular wall of the housing, the protrusion located at a first circumferential position in the annular wall and extending radially outward further from a central axis of the housing than a second circumferential position in the annular wall, wherein the first and second circumferential positions are in a common plane perpendicular to the central axis, wherein the protrusion is configured to provide clearance for fluid communication between the pressure sensor and the chamber.

2. The device of claim 1, wherein the housing comprises a shield defining the chamber at least partially surrounding the reservoir, wherein the shield comprises a circular first wall and at least a portion of the annular wall extending from the circular first wall, wherein at least a portion of the protrusion is formed in the portion of the annular wall of the shield.

3. The device of claim 2, wherein the housing comprises a bulkhead connected to the shield and configured to receive the pressure sensor.

4. The device of claim 3, further comprising a fluid connection between the pressure sensor and the chamber comprising a channel through the bulkhead from the pressure sensor to the protrusion in the portion of the annular wall of the shield.

5. The device of claim 3, further comprising a weld joint configured to create a hermetic seal between the bulkhead and the shield.

6. The device of claim 1, wherein the housing comprises two circular walls connected by the annular wall, and further comprising a header comprising a catheter junction to which a catheter is configured to be connected to the header, wherein the protrusion is formed in the annular wall circumferentially aligned with the catheter junction.

7. The device of claim 6, wherein the chamber is configured to surround the reservoir such that a periphery of the reservoir is offset from the annular wall of the housing by a first distance, and wherein the first distance between the periphery of the reservoir and the annular wall of the housing is constant around a circumference of the housing, except that the protrusion in the annular wall of the housing offsets the periphery of the reservoir from the annular wall by a second distance that is greater than the first distance.

8. The device of claim 7, wherein the second distance is 9 times larger than the first distance.

9. The device of claim 7, wherein the first distance is in a range from approximately 0.07 millimeters (0.00275 inches) to approximately 0.29 millimeters (0.0115 inches) and the second distance is in a range from approximately 0.76 millimeters (0.030 inches) to approximately 1.54 millimeters (0.060 inches).

10. The device of claim 7, wherein the second distance is defined as a function of a size of a fluid connection between the pressure sensor and the chamber.

11. The device of claim 10, wherein the fluid connection comprises a circular channel through a portion of the housing, and wherein the second distance is defined as a function of a diameter of the circular channel.

12. The device of claim 6, wherein the pressure sensor is connected to the housing adjacent the annular wall of the housing.

13. The device of claim 1, wherein the pressure sensor is connected to the housing adjacent a periphery of the housing.

14. The device of claim 1, further comprising a fluid connection comprising at least one of a channel in the housing or a tube connecting the pressure sensor to the chamber adjacent the protrusion.

15. An implantable fluid delivery device comprising:

a housing comprising two circular walls connected by an annular wall defining a chamber configured to at least partially surround a therapeutic fluid reservoir,

wherein the chamber is configured to be filled with a propellant gas configured to regulate a pressure within the therapeutic fluid reservoir, and

wherein the housing comprises a protrusion in the annular wall, the protrusion located at a first circumferential position in the annular wall and extending radially outward further from a central axis of the housing than a second circumferential position in the annular wall, wherein the first and second circumferential positions are in a common plane perpendicular to the central axis, and wherein the protrusion is configured to provide clearance for fluid communication between the chamber and a pressure sensor configured to sense a pressure within the chamber.

16. The device of claim 15, wherein the housing comprises a shield defining the chamber at least partially surrounding the therapeutic fluid reservoir, wherein the shield comprises one of the two circular walls and at least a portion of the annular wall extending from the one of the two circular walls, and wherein at least a portion of the protrusion is formed in the portion of the annular wall of the shield.

17. The device of claim 16, wherein the housing comprises a bulkhead connected to the shield and configured to receive the pressure sensor.

18. The device of claim 17, further comprising a fluid connection between the pressure sensor and the chamber comprising a channel through the bulkhead from the pressure sensor to the protrusion in the portion of the annular wall of the shield.

19. The device of claim 15, further comprising a header comprising a catheter junction to which a catheter is configured to be connected to the header, wherein the protrusion is formed in the annular wall circumferentially aligned with the catheter junction.

20. The device of claim 15, wherein the chamber is configured to surround the therapeutic fluid reservoir such that a periphery of the therapeutic fluid reservoir is offset from the annular wall of the housing by a first distance, and wherein the first distance between the periphery of the therapeutic fluid reservoir and the annular wall of the housing is constant around a circumference of the housing, except that the protrusion in the annular wall of the housing offsets the periphery of the therapeutic fluid reservoir from the annular wall by a second distance that is greater than the first distance.

21. The device of claim 15, further comprising a fluid connection comprising at least one of a channel in the housing or a tube connecting the pressure sensor to the chamber adjacent the protrusion.

22. An implantable fluid delivery system comprising:

a reservoir configured to store a therapeutic fluid delivered by an implantable fluid delivery device;

a housing defining a chamber configured to at least partially surround the reservoir, wherein the chamber is configured to be filled with a propellant gas configured to regulate a pressure within the reservoir;

a pressure sensor configured to sense a pressure within the chamber; and

means for providing clearance for fluid communication between the pressure sensor and the chamber via an extension of a first circumferential position in an annular wall of the housing radially outward further from a central axis of the housing than a second circumferential position in the annular wall, wherein the first and second circumferential positions are in a common plane perpendicular to the central axis.