ACOUSTIC RESPIRATORY MONITORING SYSTEMS AND METHODS

• US 20110125060A1
• Filed: 10/14/2010
• Published: 05/26/2011
• Est. Priority Date: 10/15/2009
• Status: Active Grant

• Current Assignee: Masimo Corporation
• Original Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Inventors: Wylie, Mark, Telfort, Valery G.
• Granted Patent: US 10,463,340 B2
• Time in Patent Office: Days
• US Class Current: 600/586
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

An acoustic sensor is provided according to certain aspects for non-invasively detecting physiological acoustic vibrations indicative of one or more physiological parameters of a medical patient. The sensor can include an acoustic sensing element configured to generate a first signal in response to acoustic vibrations from a medical patient. The sensor can also include front-end circuitry configured to receive an input signal that is based at least in part on the first signal and to produce an amplified signal in response to the input signal. In some embodiments, the sensor further includes a compression module in communication with the front-end circuitry and configured to compress portions of at least one of the input signal and the amplified signal according to a first compression scheme, the compressed portions corresponding to portions of the first signal having a magnitude greater than a predetermined threshold level.

Claims

1. An acoustic sensor for non-invasively detecting physiological acoustic vibrations indicative of one or more physiological parameters of a medical patient, comprising:

an acoustic sensing element configured to generate a first signal in response to acoustic vibrations from a medical patient;

front-end circuitry configured to receive an input signal that is based at least in part on the first signal and to produce an amplified signal in response to the input signal; and

a compression module in communication with the front-end circuitry and configured to compress portions of at least one of the input signal and the amplified signal according to a first compression scheme, the compressed portions corresponding to portions of the first signal having a magnitude greater than a predetermined threshold level.

2. The acoustic sensor of claim 1, wherein the compression module is further configured to compress additional portions of at least one of the input signal and the amplified signal according to a second compression scheme, the additional compressed portions corresponding to portions of the first signal having a magnitude less than a predetermined threshold level.

3. The acoustic sensor of claim 1, wherein the compression module is configured to generate the input signal.

4. The acoustic sensor of claim 1, wherein the first compression scheme is selected to increase a dynamic range of the acoustic sensor.

5. The acoustic sensor of claim 1, wherein the first compression scheme is selected based on a dynamic range of the front-end circuitry.

6. The acoustic sensor of claim 1, wherein the first compression scheme is selected such that the front-end circuitry does not produce a distorted output when high-amplitude physiological sounds are detected by the acoustic sensing element, the high-amplitude physiological sounds corresponding to a first signal having a magnitude corresponding to a saturation level of the front-end circuitry.

7. The acoustic sensor of claim 6, wherein the first compression scheme is selected such that the front-end circuitry does not saturate when high-amplitude physiological sounds are detected by the acoustic sensing element.

8. The acoustic sensor of claim 1, wherein the front-end circuitry comprises a preamplifier.

9. The acoustic sensor of claim 1, wherein the first compression scheme comprises executing a logarithmic function.

10. The acoustic sensor of claim 1, wherein the first compression scheme comprises executing a linear function.

11. The acoustic sensor of claim 1, wherein the linear function comprises a piece-wise linear function.

12. The acoustic sensor of claim 1, wherein the first compression scheme comprises executing a non-linear function.

13. The acoustic sensor of claim 1, wherein the sensing element comprises a piezoelectric membrane.

14. An acoustic sensor for non-invasively detecting physiological acoustic vibrations indicative of one or more physiological parameters of a medical patient, comprising:

an acoustic sensing element configured to generate an output signal in response to acoustic vibrations from a medical patient, the acoustic sensing element having an output dynamic range;

front-end circuitry in communication with the acoustic sensing element and having a dynamic range, the dynamic range of the front-end circuitry being less than the output dynamic range of the acoustic sensing element; and

a dynamic range module configured, in response to the output signal, to maintain the output signal'"'"'s intensity within the dynamic range of the front-end circuitry.

15. The acoustic sensor of claim 14, wherein the dynamic range module is configured to process the output signal to maintain the output signal'"'"'s intensity within the dynamic range of the front-end circuitry.

16. The acoustic sensor of claim 14, wherein the dynamic range module is configured to process an output of the front-end circuitry to maintain the output signal'"'"'s intensity within the dynamic range of the front-end circuitry.

17. The acoustic sensor of claim 14, wherein the dynamic range of the front-end circuitry is an input dynamic range.

18. The acoustic sensor of claim 14, wherein the dynamic range module is configured to maintain the output signal'"'"'s intensity within the dynamic range of the front-end circuitry to allow the sensor to process a desired range of physiological intensities without producing a distorted output.

19. The acoustic sensor of claim 18, wherein the desired range of physiological intensities includes normal breathing sounds and loud speech sounds.

20. The acoustic sensor of claim 14, wherein the dynamic range module is configured to compress the output signal of the acoustic sensing element.

21. The acoustic sensor of claim 20, wherein the dynamic range module performs logarithmic compression on at least a portion of the output signal.

22. The acoustic sensor of claim 20, wherein the dynamic range module performs linear compression on at least a portion of the output signal.

23. The acoustic sensor of claim 22, wherein the linear compression comprises piece-wise linear compression.

24. The acoustic sensor of claim 20, wherein the dynamic range module performs non-linear compression on at least a portion of the output signal.

25. A method for increasing the dynamic range of a sensor capable of non-invasively detecting physiological acoustic vibrations indicative of one or more physiological parameters of a medical patient, comprising:

outputting a first signal using a first sensing element and in response to acoustic vibrations from a medical patient;

generating an amplified signal using front-end circuitry and in response an input signal that is based at least in part on the first signal; and

compressing portions of at least one of the input signal and the amplified signal according to a first compression scheme, the compressed portions corresponding to portions of the first signal having a magnitude greater than a predetermined threshold level.