NONINVASIVE ARTERIAL PRESSURE WAVEFORM MEASUREMENT WITH CAPACITANCE AND OTHER SENSING

20230110841

17/898641

August 30, 2022

A system can include one or more electrodes; a sensor structure configured to position electrodes over a surface of a body that includes an artery. A capacitance sensing circuit can be coupled to the electrodes and configured to acquire capacitance values of the electrodes over a predetermined time period. The capacitance values can correspond to a distance between the body surface and the at least one electrode. Processor circuits can be configured to generate APW data from the capacitance values. Corresponding methods and devices are also disclosed.

Cypress Semiconductor Corporation (San Jose, CA, US)

1. A system, comprising: at least one electrode; a sensor structure configured to position the at least one electrode over a surface of a body that includes an artery; a capacitance sensing circuit coupled to the at least one electrode and configured to acquire capacitance values of the at least one electrode over a predetermined time period, the capacitance values corresponding to a distance between the body surface and the at least one electrode; and processor circuits configured to generate arterial pressure waveform (APW) data from the capacitance values.

2. The system of claim 1, wherein: the at least one electrode comprises an array of electrodes; and the capacitance sensing circuit acquires capacitance values for each electrode of the array.

3. The system of claim 1, wherein: the sensor structure includes a compressible high permittivity material configured to be positioned between the at least one electrode and the surface of the body.

4. The system of claim 1, further including: the at least one electrode comprises a plurality of electrodes; a noise sensing circuit configured to determine a signal-to-noise ratio (SNR) for each electrode; and the processor circuits are configured to exclude capacitance values for electrodes having SNRs below a predetermined limit from the generation of APW data.

5. The system of claim 1, wherein: the at least one electrode comprises a plurality of electrodes; a noise sensing circuit configured to determine a signal-to-noise ratio (SNR) for each electrode; and electrode selection circuits configured to in a first sensing operation, sequentially connect electrodes the capacitance sensing circuit, and in a second sensing operation, exclude electrodes having a SNR below a predetermined threshold from being connected to the capacitance sensing circuit.

6. The system of claim 1, wherein: the capacitance sensing circuit is configured to sense a self-capacitance of the at least one electrode.

7. The system of claim 1, wherein: the at least one electrode comprises a plurality of electrodes; and the capacitance sensing circuit is configured to sense a mutual capacitance between at least two of the electrodes.

8. The system of claim 1, wherein: the sensor structure comprises a band having the at least one electrode disposed on an inner surface of the band.

9. The system of claim 1, wherein: the sensor structure comprises an adhesive configured to attach the sensor structure to the body surface.

10. The system of claim 1, further including: at least one display configured to display an APW from the APW data.

11. A method, comprising: by operation of a sensor structure, positioning at least one electrode over a body surface proximate an artery; over a predetermined time period, sensing capacitance values for the at least one electrode; storing the capacitance values in a memory; and generating arterial pressure waveform (APW) data from the stored capacitance values.

12. The method of claim 11, wherein: positioning at least one electrode includes positioning an array of electrodes over the body surface; and sensing capacitance values includes sensing a capacitance of each of the electrodes.

13. The method of claim 11, further including: mapping capacitance values to blood pressure values with blood pressure readings from another device.

14. The method of claim 11, further including: generating APW data includes determining local minima and maxima for the capacitance values.

15. A device, comprising: a plurality of input/output (IO) connections coupled to a substrate; capacitance sense circuits formed with the substrate and configured to generate capacitance values for at least one of the IOs; memory circuits formed with the substrate and configured to store the capacitance values; and processor circuits formed with the substrate and configured to generate arterial pressure waveform (APW) data from the stored capacitance values.

16. The device of claim 15, wherein: the capacitance sense circuits are configured to sense a self-capacitance of the at least one IO.

17. The device of claim 15, wherein: the capacitance sense circuits are configured to sense a mutual capacitance between at least two of thelOs.

18. The device of claim 15, wherein: the capacitance sense circuits comprises a sigma-delta analog-to-digital conversion (ADC) circuits; and multiplexer circuits configured to selectively connect the IOs to the sigma-delta ADC circuit.

19. The device of claim 15, further including: wireless circuits formed with the substrate and configured to wirelessly transmit the APW data from the device to another device.

20. The device of claim 15, further including: the capacitance sense circuits are configured to detect noise on at least one of the IOs; the processor circuits are further configured to determine a signal-to-noise ratio (SNR) for each IO with respect to the APW; and selection circuits formed with the substrate and configured to couple all IOs to the capacitance sense circuits in a SNR sensing operation, and couple IOs having a SNR above a predetermined threshold to generate capacitance values for generating the APW values.

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edspap.20230110841