Spring wing assembly for photoplethysmorgraphic sensor

• US 20070299329A1
• Filed: 06/22/2006
• Published: 12/27/2007
• Est. Priority Date: 06/22/2006
• Status: Active Grant

• Current Assignee: Kestrel Labs, Inc.
• Original Assignee: Kestrel Labs, Inc.
• Inventors: Pologe, Jonas Alexander, Delianides, Theodore Philip
• Granted Patent: US 8,078,251 B2
• Time in Patent Office: Days
• US Class Current: 600/338
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/1464 specially adapted for foetal tissue

Abstract

A photoplethysmographic sensor designed for use on the presenting portion of a fetus during labor and delivery. The sensor has a non-deployed state in which the sensor presents a smaller footprint, or cross sectional area, for transvaginal insertion. Once the sensor is applied to the fetal tissue it is moved into the deployed state, which has a larger footprint or cross sectional area, than the sensor does in the non-deployed state. The deployed state optimizes the physical distance between the light emitter and the photodetector to maximize the photoplethysmographic measurement accuracy from the fetal tissue.

Claims

1. A transvaginal sensor for measuring one or more blood analyte levels or one or more hemodynamic parameters in a tissue-under-test, comprising:

a light emitter for delivery of light to a tissue-under-test,

a photodetector for reception of light from a tissue-under-test,

a sensor body designed to adhere to a tissue-under-test,

a deployable member housing either the light emitter or the photodetector,

the deployable member movably attached to the sensor body,

a plurality of conductors for conducting signals to the light emitter and from the photodetector.

2. The sensor of claim 1 wherein the deployable member has a non-deployed and a deployed state.

3. The sensor of claim 2 wherein the deployable member, positioned in the non-deployed state, causes the sensor to have a smaller cross sectional area than the sensor does with the deployable member in the deployed state.

4. The sensor of claim 1 wherein the light emitter delivers light subcutaneously to a tissue-under-test.

5. The sensor of claim 1 wherein the deployable member separates maternal and fetal tissue as it is deployed.

6. The sensor of claim 2 wherein the deployable member, when in the deployed state, applies a spring force against a tissue-under-test.

7. The sensor of claim 1 wherein a helical needle attached to the sensor body adheres to a tissue-under-test.

8. The sensor of claim 1 including at least two deployable members.

9. The sensor of claim 8 wherein at least one of the deployable members contains the photodetector and at least one other of the deployable members contains the light emitter.

10. The sensor of claim 1 wherein the deployable member is made of a shape memory alloy.

11. A transvaginal sensor for measuring one or more blood analyte levels or one or more hemodynamic parameters in a tissue-under-test, comprising:

a light emitter for subcutaneous delivery of light to a tissue-under-test, a photodetector for conversion of light received from a tissue-under-test into an electronic signal,

a sensor body designed to incorporate a helical needle to adhere to a tissue-under-test,

the helical needle designed to incorporate the light emitter,

a deployable member housing the photodetector,

the deployable member movably attached to the sensor body,

a plurality of conductors for conducting signals to the light emitter and from the photodetector.

12. A method for sensing one or more blood analyte levels or one or more hemodynamic parameters in a tissue-under-test, comprising the steps of:

providing a light emitter in a sensor to emit light into a tissue-under-test,

providing a photodetector in the sensor for reception of light from a tissue-under-test,

movably attaching a deployable member to the sensor,

housing one of the light emitter and the photodetector in the deployable member,

inserting the sensor transvaginally to a tissue-under-test,

deploying the deployable member against the tissue-under-test,

conducting at least one of electrical and optical signals to the light emitter and from the photodetector through a plurality of conductors.

13. The method of claim 12 further comprising the step of increasing a cross sectional area of the sensor as the deployable member changes from a non-deployed state to a deployed state.

14. The method of claim 12 further comprising the step of subcutaneously delivering light to a tissue-under-test.

15. The method of claim 12 further comprising the step of separating maternal and fetal tissues during deployment of the deployable member.

16. The method of claim 13 further comprising the step of applying a spring force against a tissue-under-test when the deployable member is in the deployed state.

17. The method of claim 12 further comprising the step of attaching a helical needle to the sensor body.

18. The method of claim 17 further comprising the step of housing the light emitter at a tip of the helical needle to emit light subcutaneously to a tissue-under-test.

19. The method of claim 12 further comprising the step of movably attaching at least two deployable members to the sensor.

20. The method of claim 19 further comprising the steps of housing the photodetector in one of the deployable members and housing the light emitter in at least one other of the deployable members.

21. The method of claim 12 further comprising the step making the deployable member of a shape memory alloy.

22. The method of claim 21 further comprising the step of selecting a shape memory alloy material for a phase change temperature between 27 and 37 degrees Celsius.

23. A method for sensing one or more blood analyte levels or one or more hemodynamic parameters in a tissue-under-test, comprising the steps of:

providing a helical needle in a sensor for adhering to a tissue-under-test,

housing a light emitter in the helical needle to emit light subcutaneously into a tissue-under-test,

movably attaching a deployable member to the sensor,

housing a photodetector in the deployable member to receive light from a tissue-under-test,

passing the sensor transvaginally to a tissue-under-test,

deploying the deployable member against a tissue-under-test.