Systems and methods for non-invasive respiratory rate measurement

• US 9,943,267 B2
• Filed: 12/02/2016
• Issued: 04/17/2018
• Est. Priority Date: 12/02/2015
• Status: Active Grant

• Current Assignee: Itamar Medical SPRY 2021 Limited Partnership
• Original Assignee: Spry Health, Inc. (Asahi Kasei Corporation)
• Inventors: Ferber, Elad, Cobut, Pierre-Jean, Narayanan, Ramkrishnan, Gungor, Derya Gol
• Primary Examiner(s): JANG, CHRISTIAN YONGKYUN
• Application Number:
  US15/368,477
• Publication Number:
  US 20170156593A1
• Time in Patent Office: 501 Days
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/0008 Temperature signals
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0064 Body surface scanning
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02125 of pulse wave propagation time
• CPC Class Codes: A61B 5/02141 Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits A61B5/02233, A61B5/0235 take precedence
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0806 by whole-body plethysmography measuring blood flow using plethysmography A61B5/0295; impedance plethysmography A61B5/053; measuring volume of the body or parts thereof A61B5/1073
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/117 Identification of persons methods or arrangements for recognising patterns, e.g. fingerprints, G06F18/00, G06V40/00; identification of persons by analysing their voice or speech G10L17/00
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/4872 Body fat
• CPC Class Codes: A61B 5/6802 : Sensor mounted on worn items
• CPC Class Codes: A61B 5/6816 : Ear lobe
• CPC Class Codes: A61B 5/6823 : Trunk, e.g., chest, back, abdomen, hip
• CPC Class Codes: A61B 5/6824 : Arm or wrist
• CPC Class Codes: A61B 5/6829 : Foot or ankle
• CPC Class Codes: A61B 5/7203 : for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/721 : using a separate sensor to detect motion or using motion information derived from signals other than the physiological signal to be measured
• CPC Class Codes: A61B 5/7221 : Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61B 5/7264 : Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems neural networks per se G06N3/00; expert systems per se G06N5/00
• CPC Class Codes: A61B 5/7267 : involving training the classification device
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/7278 : Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61B 5/7435 : Displaying user selection data, e.g. icons in a graphical user interface
• CPC Class Codes: G16H 40/67 : for remote operation

Abstract

Systems and methods for non-invasive respiratory rate measurement are disclosed. In some embodiments, a system comprises a wearable member including an energy transmitter configured to project energy into tissue of a user. An energy receiver generates a multichannel signal based on a first received portion of the energy, the received portion of energy being received through the tissue of the user. A respiratory rate calculation system includes a pre-processing module for filter noise from the signal. A spectrum module determines a spectrum of the signal. A respiratory rate processing module determines a first respiratory rate from the spectrum of the signal. A noise reference and one or more second respiratory rates are obtained. A third respiratory rate is determined based on the first respiratory rate, the noise reference, and the one or more second respiratory rates. A communication module provides a message based on the third respiratory rate.

Claims

1. A system comprising:

a wearable member including;

an energy transmitter configured to project energy into tissue of a user; and

an energy receiver configured to generate a multichannel signal based on a first received portion of the energy, the first received portion of the energy being received through the tissue of the user; and

a respiratory rate calculation system including;

a pre-processing module configured to filter noise from the multichannel signal;

a spectrum module configured to determine a spectrum of the multichannel signal;

a respiratory rate processing module configured to;

determine a first respiratory rate from the spectrum of the multichannel signal;

obtain a noise reference;

obtain one or more second respiratory rates; and

determine a third respiratory rate based on the first respiratory rate, the noise reference, and the one or more second respiratory rates; and

a communication module configured to provide a message including or being based on the third respiratory rate.

2. The system of claim 1, wherein the energy transmitter includes a first light source and a second light source, the first light source configured to project the energy at a first wavelength, and the second light source configured to project the energy at a second wavelength.

3. The system of claim 2, wherein the energy projected by the first light source and the energy projected by the second light source each have the same wavelength.

4. The system of claim 1, wherein the pre-processing module is configured to filter the noise from the multichannel signal using a trained respiratory rate classifier configured to determine filter parameters for the pre-processing module.

5. The system of claim 4, wherein the trained respiratory rate classifier comprises a respiratory rate classifier trained using ground truth data and one or more feature vectors generated from the multichannel signal.

6. The system of claim 5, wherein the one or more feature vectors include a set of features extracted from the multichannel signal, the set of features including any of optical ratio features, heart rate, signal level and range features, and signal metric features.

7. The system of claim 1, wherein the spectrum module determines the spectrum of the multichannel signal based on a spectral density of the multichannel signal.

8. The system of claim 1, wherein the one or more second respiratory rates comprise one or more previously obtained respiratory rates associated with the user.

9. The system of claim 1, wherein the multichannel signal comprises a multichannel photoplethysmogram (PPG) signal.

10. A method comprising:

projecting, by a wearable member, energy into tissue of a user;

generating, by the wearable member, a multichannel signal based on a first received portion of the energy, the first received portion of the energy being received through the tissue of the user;

filtering, by a respiratory calculation system, noise from the multichannel signal;

determining, by the respiratory calculation system, a spectrum of the multichannel signal;

determining, by the respiratory calculation system, a first respiratory rate from the spectrum of the multichannel signal;

obtaining, by the respiratory calculation system, a noise reference;

obtaining, by the respiratory calculation system, one or more second respiratory rates;

determining, by the respiratory calculation system, a third respiratory rate based on the first respiratory rate, the noise reference, and the one or more second respiratory rates; and

providing, by the respiratory calculation system, a message including or being based on the third respiratory rate.

11. The method of claim 10, wherein the energy is projected using a first light source and a second light source, the first light source configured to project the energy at a first wavelength, and the second light source configured to project the energy at a second wavelength.

12. The method of claim 11, wherein the energy projected by the first light source and the energy projected by the second light source each have the same wavelength.

13. The method of claim 10, wherein the noise is filtered from the multichannel signal using a trained respiratory rate classifier configured to determine filter parameters for the respiratory calculation system.

14. The method of claim 13, wherein the trained respiratory rate classifier comprises a respiratory rate classifier trained using ground truth data and one or more feature vectors generated from the multichannel signal.

15. The method of claim 14, wherein the one or more feature vectors include a set of features extracted from the multichannel signal, the set of features including any of optical ratio features, heart rate, signal level and range features, and signal metric features.

16. The method of claim 10, wherein the spectrum is determined based on a spectral density of the multichannel signal.

17. The method of claim 10, wherein the one or more second respiratory rates comprise one or more previously obtained respiratory rates associated with the user.

18. The method of claim 10, wherein the multichannel signal comprises a multichannel photoplethysmogram (PPG) signal.

19. A system comprising:

a processor; and

memory storing instructions that, when executed by the processor, cause the processor to;

control an energy transmitter to project energy into tissue of a user;

generate a multichannel signal based on a first received portion of the energy, the first received portion of the energy being received through the tissue of the user;

filter noise from the multichannel signal;

determine a spectrum of the multichannel signal;

determine a first respiratory rate from the spectrum of the multichannel signal;

obtain a noise reference;

obtain one or more second respiratory rates;

determine a third respiratory rate based on the first respiratory rate, the noise reference, and the one or more second respiratory rates; and

provide a message including or being based on the third respiratory rate.