Wireless Flow Sensor

• US 20090107233A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Integra LifeSciences Switzerland Sàrl
• Original Assignee: Codman & Shurtleff Incorporated (Johnson & Johnson)
• Inventors: Kassem, Salim
• Granted Patent: US 8,454,524 B2
• Time in Patent Office: Days
• US Class Current: 73/272.R
• CPC Class Codes: A61B 5/0015 characterised by features of the telemetry system
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/0075 by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy A61B5/0071 takes precedence
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 27/006 Cerebrospinal drainage; Accessories therefor, e.g. valves

Abstract

Devices and methods useful for non-invasively measuring and indicating a rate of fluid flow are disclosed. In one embodiment, a sensor housing adapted to received fluid flow therethrough is provided. A radio frequency tag and a masking element can be disposed in the sensor housing. The masking element and the radio frequency tag can be configured to move relative to one another. The relative positions or movement can alter the response of the radio frequency tag to a wireless signal (which can be emitted from an external reading device, for example) and thereby indicate a rate of fluid flowing through the housing. For example, in some embodiments, the masking element can selectively cover at least part of the radio frequency tag in correspondence to the flow rate, which can change a characteristic of the radio frequency tag'"'"'s response to the wireless signal.

Claims

1. An implantable sensor for measuring fluid flow, comprising:

a sensor housing adapted to receive fluid flow therethrough;

a radio frequency tag disposed within the sensor housing and adapted to interact with a wireless signal and to produce a response thereto; and

a masking element disposed in the sensor housing, the masking element and the radio frequency tag configured to move relative to one another to alter the response of the radio frequency tag and thereby indicate a rate of fluid flowing through the sensor housing.

2. The implantable sensor of claim 1, wherein the masking element comprises a conductive member that alters the response of the radio frequency tag.

3. The implantable sensor of claim 2, wherein the masking element covers at least a portion of the radio frequency tag.

4. The implantable sensor of claim 1, wherein at least one characteristic of the response corresponds to the flow rate, the at least one characteristic being selected from the group consisting of:

resonant frequency, harmonic spectra, decay characteristic, and Q factor.

5. The implantable sensor of claim 1, further comprising a valve assembly adapted to control a rate of fluid flowing through the sensor housing, the valve assembly being in fluid communication with the sensor housing.

6. The implantable sensor of claim 1, wherein the masking element is configured to rotate around an axis thereof in relation to the flow rate of fluid through the sensor housing.

7. The implantable sensor of claim 6, wherein the masking element comprises a disk formed at least in part of a conductive material to selectively mask part of the radio frequency tag, the masking element being configured to rotate around an axis thereof to mask different parts of the radio frequency tag such that the response of the radio frequency tag to the wireless signal is periodic.

8. The implantable sensor of claim 7, wherein the part of the disk formed of the conductive material has a shape that is selected from the group consisting of a spiral and a plurality of discrete conductive sections.

9. The implantable sensor of claim 1, wherein the radio frequency tag comprises a disk having an asymmetrical antenna, the masking element configured to mask at least part of the antenna.

10. The implantable sensor of claim 1, wherein the masking element comprises a wedge formed at least in part of a conductive material and the masking element is configured to translate in relation to the flow rate of fluid through the sensor housing.

11. An implantable sensor, comprising:

a sensor housing adapted to receive fluid flow therethrough; and

a conductive member disposed within the valve assembly and configured to selectively cover at least a portion of a radio frequency tag and thereby alter a response thereof to a received wireless signal to indicate a rate of fluid flowing through the sensor housing.

12. The implantable sensor of claim 11, wherein the response has at least one measurable characteristic selected from the group consisting of resonant frequency, harmonic spectra, decay characteristic, and Q factor.

13. The implantable sensor of claim 11, wherein the conductive member is configured to move relative to the radio frequency tag.

14. The implantable sensor of claim 11, wherein the radio frequency tag is configured to move relative to the conductive member.

15. The implantable sensor of claim 14, wherein the radio frequency tag comprises a disk having an asymmetrical antenna formed thereon.

16. The implantable sensor of claim 11, further comprising a valve assembly adapted to control a rate of fluid flowing through the sensor housing, the valve assembly being in fluid communication with the sensor housing.

17. The implantable sensor of claim 11, wherein the conductive member forms part of a rotatable disk.

18. A method for measuring fluid flow, comprising:

positioning a sensor housing between an inlet tube and an outlet tube, the sensor housing having a radio frequency tag disposed therein;

transmitting a wireless signal to a radio frequency tag disposed within a sensor housing having fluid flowing therethrough from a reading device; and

wirelessly receiving a response from the radio frequency tag that indicates a rate of fluid flowing through the sensor housing.

19. The method of claim 18, wherein the response received from the radio frequency tag changes in relation to the rate of fluid flowing through the sensor housing.

20. The method of claim 18, further comprising coupling an inlet tube mated to the sensor housing to a catheter within a patient'"'"'s ventricle, and coupling an outlet tube mated to the sensor housing to a drainage catheter for draining the patient'"'"'s cerebrospinal fluid.

21. The method of claim 18, further comprising coupling the sensor housing to a valve assembly adapted to control a rate of fluid flowing through the sensor housing.

22. The method of claim 18, wherein the response from the radio frequency tag is a periodic signal.

23. The method of claim 18, further comprising analyzing the response to detect any of resonant frequency, harmonic spectra, decay characteristic, and Q factor of the radio frequency tag.

24. The method of claim 18, further comprising receiving a response from the radio frequency tag that communicates data previously stored therein.