Respiratory pause detector

Patent metadata

Field	Value
Publication number	US-9848800-B1
Application number	US-90548910-A
Country	US
Kind code	B1
Filing date	Oct 15, 2010
Priority date	Oct 16, 2009
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

Respiratory rate can be calculated from an acoustic input signal using time domain and frequency domain techniques. Confidence in the calculated respiratory rate can also be calculated using time domain and frequency domain techniques. Overall respiratory rate and confidence values can be obtained from the time and frequency domain calculations. The overall respiratory rate and confidence values can be output for presentation to a clinician.

First claim

What is claimed is:

1. A method of detecting respiratory pauses from acoustic sensor data, the method comprising:
receiving acoustic data from an acoustic sensor coupled with a patient, the acoustic data reflecting physiological sounds generated by the patient;
obtaining, by a processor, a first frequency spectrum from the acoustic data;
partitioning, by the processor, the first frequency spectrum into a plurality of frequency bins according at least to a sampling rate associated with the first frequency spectrum and a second frequency spectrum, each of the plurality of frequency bins corresponding to a different frequency range;
determining, by the processor, an amount of energy in the first frequency spectrum partitioned in each of the plurality of frequency bins;
determining, by the processor, a first count of frequency bins of the plurality of frequency bins for which the amount of energy in the first frequency spectrum partitioned in the plurality of frequency bins exceeds a plurality of spectral bias values associated with the plurality of frequency bins, the plurality of spectral bias values depending at least on ambient noise energy;
determining, by the processor, a first spectral density value for the first frequency spectrum from the first count;
characterizing, by the processor, the first frequency spectrum as indicating presence of broadband sounds rather than narrowband sounds by at least comparing the first spectral density value and a spectral density threshold, the broadband sounds being associated with respiration and the narrowband sounds being associated with a respiratory pause event; detecting, by the processor, the respiration in response to characterizing the first frequency spectrum as indicating presence of the broadband sounds;
adjusting, by the processor, the spectral density threshold to obtain an adjusted spectral density threshold different from the spectral density threshold;
obtaining, by the processor, the second frequency spectrum from the acoustic data, the second frequency spectrum being different from the first frequency spectrum; partitioning, by the processor, the second frequency spectrum into the plurality of frequency bins according at least to the sampling rate;
determining, by the processor, an amount of energy in the second frequency spectrum partitioned in each of the plurality of frequency bins;
determining, by the processor, a second count of frequency bins of the plurality of frequency bins for which the amount of energy in the second frequency spectrum partitioned in the plurality of frequency bins exceeds the plurality of spectral bias values, the second count being the same as the first count;
determining, by the processor, a second spectral density value for the second frequency spectrum from the second count;
characterizing, by the processor, the second frequency spectrum as indicating presence of the narrowband sounds rather than the broadband sounds by at least comparing the second spectral density value and the adjusted spectral density threshold; and
in response to characterizing the second frequency spectrum as indicating presence of the narrowband sounds, detecting, by the processor, the respiratory pause event and
outputting, by the processor, an indication of the respiratory pause event to a display for presentation to a user.

2. A system for detecting respiratory pauses from acoustic sensor data, the system comprising:
an input configured to receive acoustic data from an acoustic sensor coupled with a patient, the acoustic data reflecting physiological sounds generated by the patient; and
a processor in communication with the input, the processor being configured to:
obtain a first frequency spectrum and a second frequency spectrum from the acoustic data,
partition the first frequency spectrum and the second frequency spectrum into a plurality of frequency bins according at least to a sampling rate associated with the first frequency spectrum and the second frequency spectrum, each of the plurality of frequency bins corresponding to a different frequency range,
determine an amount of energy in the first frequency spectrum partitioned in each of the plurality of frequency bins and an amount of energy in the second frequency spectrum partitioned in each of the plurality of frequency bins,
determine a first count of frequency bins of the plurality of frequency bins for which the amount of energy in the first frequency spectrum partitioned in the plurality of frequency bins exceeds a spectral bias,
determine a second count of frequency bins of the plurality of frequency bins for which the amount of energy in the second frequency spectrum partitioned in the plurality of frequency bins exceeds the spectral bias value,
determine a first spectral density value for the first frequency spectrum from the first count and a second spectral density value for the second frequency spectrum from the second count,
characterize the first frequency spectrum as either indicating presence of narrowband sounds or indicating presence of broadband sounds from a comparison of the first spectral density value and a spectral density threshold, the narrowband sounds being associated with a respiratory pause event and the broadband sounds being associated with respiration,
in response to characterizing the first frequency spectrum as indicating presence of the narrowband sounds, detect the respiratory pause event and output a first indication of the respiratory pause event to a display for presentation to a user,
in response to characterizing the first frequency spectrum as indicating presence of the broadband sounds, detect the respiration,
adjust the spectral density threshold to obtain an adjusted spectral density threshold different from the spectral density threshold,
characterize the second frequency spectrum as either indicating presence of the narrowband sounds or indicating presence of the broadband sounds from a comparison of the second spectral density value and the adjusted spectral density threshold,
in response to characterizing the second frequency spectrum as indicating presence of the narrowband sounds, detect the respiratory pause event and output a second indication of the respiratory pause event to the display for presentation to the user, and
in response to characterizing the second frequency spectrum as indicating presence of the broadband sounds, detect the respiration,

wherein when the first count and the second count are both a first value, the processor is configured to characterize the first frequency spectrum as indicating presence of the narrowband sounds and the second frequency spectrum as indicating presence of the broadband sounds.

3. The system of claim 2 , wherein the first frequency spectrum reflects the physiological sounds generated by the patient at a first time, and the second frequency spectrum reflects the physiological sounds generated by the patient at a second time subsequent to the first time.

4. The system of claim 2 , further comprising the acoustic sensor.

5. A method of detecting respiratory pauses from acoustic sensor data, the method comprising:
receiving acoustic data from an acoustic sensor coupled with a patient, the acoustic data reflecting physiological sounds generated by the patient;
obtaining, by a processor, a plurality of frequency spectrums from the acoustic data;
partitioning, by the processor, each of the plurality of frequency spectrums into a plurality of frequency bins according at least to a sampling rate associated with the plurality of frequency spectrums, each of the plurality of frequency bins corresponding to a different frequency range;
determining, by the processor, an amount of energy in each of the plurality of frequency spectrums partitioned in each of the plurality of freq

Assignees

• Lee Sung Uk
• Sierra Gilberto
• Masimo Corp

Inventors

• Lee Sung Uk
• Sierra Gilberto

Classifications

• A61B5/7257

  using Fourier transforms · CPC title

• A61B5/08

  Measuring devices for evaluating the respiratory organs · CPC title

• A61B5/0816 Primary

  Measuring devices for examining respiratory frequency (measuring frequency of electric signals G01R23/00) · CPC title

• A61B7/003

  Detecting lung or respiration noise · CPC title

• A61B5/7221

  Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217) · CPC title