System and method for analysis of the upper airway and a respiratory pressure support system

• US 10,376,224 B2
• Filed: 01/19/2015
• Issued: 08/13/2019
• Est. Priority Date: 01/27/2014
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Aarts, Ronaldus Maria, Kahlert, Joachim, Van Bruggen, Michel Paul Barbara, Ouweltjes, Okke
• Primary Examiner(s): Nathithithadha, Navin
• Application Number:
  US15/111,205
• Publication Number:
  US 20160354040A1
• Time in Patent Office: 1,667 Days
• Field of Search: 600529-543
• CPC Class Codes: A61B 2562/0204 Acoustic sensors
• CPC Class Codes: A61B 5/0826 Detecting or evaluating apnoea events A61B5/4818 takes precedence
• CPC Class Codes: A61B 5/085 Measuring impedance of respiratory organs or lung elasticity
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61B 5/1072 measuring distances on the body, e.g. measuring length, height or thickness A61B5/1076 takes precedence
• CPC Class Codes: A61B 5/4818 Sleep apnoea
• CPC Class Codes: A61B 5/4836 Diagnosis combined with treatment in closed-loop systems or methods A61B5/0036 takes precedence
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/7282 Event detection, e.g. detecting unique waveforms indicative of a medical condition A61B5/4094, A61B5/4818, A61B5/349, A61B5/0823 take precedence
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 16/0683 Holding devices therefor
• CPC Class Codes: A61M 16/0816 Joints or connectors
• CPC Class Codes: A61M 16/0875 Connecting tubes
• CPC Class Codes: A61M 2230/005 Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/40 Respiratory characteristics

Abstract

A system for analysis of the upper airway has at least two sensors are provided along a flow path leading to the mouth and/or nose of a user. A relation is derived between the two sensor signals, and this is interpreted to detect at least the presence of upper airway obstructions, and preferably also the location and/or extent of such obstructions.

Claims

1. A system for airway obstruction detection, the system comprising:

a passageway for communication with a user'"'"'s airway;

a first acoustic sensor positioned at a first location on the passageway, wherein the first acoustic sensor outputs a first signal;

a second acoustic sensor positioned at a second location on the passageway, wherein the second acoustic sensor outputs a second signal; and

a processor configured to

determine a parameter of the passageway based on (i) the first location and the second location of the sensors and (ii) a relationship between the first signal and the second signal, wherein the relationship between the first signal and the second signal causes cancellation of sound source properties, and wherein the parameter varies in dependence on the presence of an obstruction of the airway, and

detect the presence of the obstruction of the airway based on the parameter.

2. A system as claimed in claim 1, further comprising a detector for interpreting the parameter to detect the presence of the obstruction of the airway.

3. A system as claimed in claim 2, wherein the detector is further adapted to detect a location or an extent of the obstruction of the airway.

4. A system as claimed in claim 1, wherein the passageway comprises a tube and the first and second sensors are positioned at first and second locations along the tube, which has a first end which is for terminating at the mouth and/or nose of a user.

5. A system as claimed in claim 1 wherein the processor is adapted to derive an acoustic transfer function from the sensor signals and derive the parameter in the form of an acoustic impedance from the acoustic transfer function.

6. A system as claimed in claim 5, comprising a Fourier transform processing arrangement for processing the outputs of the first and second sensors before processing to derive the acoustic transfer function, and optionally further comprising an averaging arrangement for averaging the Fourier transformed signals before the processing to derive the acoustic transfer function.

7. A system as claimed in claim 5, wherein the acoustic impedance is obtained as a complex impedance in the frequency domain and wherein the processor is further optionally adapted to obtain a time domain impulse response, and derive therefore an airway diameter as a function of distance.

8. A system as claimed in claim 1, wherein the first acoustic sensor is closer to the user'"'"'s airway than the second acoustic sensor.

9. The system as claimed in claim 1, wherein the relationship comprises a ratio of the first signal and the second signal that cancels the source sound properties in the first signal and the second signal.

10. The system as claimed in claim 1, wherein the first signal and the second signal comprise only ambient noise received from noise sources external to the system, and noise generated by the user.

11. A system as claimed in claim 1, wherein the passageway comprises a tube, wherein the tube is flexible.

12. A system as claimed in claim 1, wherein the parameter comprises an acoustic impedance.

13. A patient interface device comprising:

a mask for delivering a gas to the nose and/or mouth of a patient;

a first acoustic sensor positioned at a first location on a passageway connected to the mask, wherein the first acoustic sensor outputs a first signal;

a second acoustic sensor positioned at a second location on the passageway connected to the mask, wherein the second acoustic sensor outputs a second signal; and

a processor configured to

determine a parameter of the passageway based on the first location and the second location of the sensors and a relationship between the first signal and the second signal, wherein the relationship between the first signal and the second signal causes cancellation of sound source properties, and

detect the presence of an obstruction of the airway based on the parameter.

14. A patient interface device as claimed in claim 13, wherein the first acoustic sensor is closer to the mouth and/or nose of the patient than the second acoustic sensor.

15. A respiratory pressure support system comprising:

a source of pressurized air;

a pressure control unit for controlling the air pressure; and

a patient interface device comprising;

a mask for delivering a gas to the nose and/or mouth of a patient;

a first acoustic sensor positioned at a first location on a passageway connected to the mask, wherein the first acoustic sensor outputs a first signal;

a second acoustic sensor positioned at a second location on the passageway connected to the mask, wherein the second acoustic sensor outputs a second signal; and

a processor configured to

determine a parameter of the passageway based on (i) the first location and the second location of the sensors and (ii) a relationship between the first signal and the second signal, wherein the relationship between the first signal and the second signal causes cancellation of sound source properties, and

detect the presence of the obstruction of the airway based on the parameter,

wherein the respiratory pressure support system is configured to provide the pressurized air to the patient past the sensors, and wherein the respiratory pressure support system is configured to control the air pressure in dependence on the detected presence of the obstruction of the airway.

16. A respiratory pressure support system as claimed in claim 15, wherein the first acoustic sensor is closer to the mouth and/or nose of the patient than the second acoustic sensor.

17. A method for airway obstruction detection, comprising:

providing a first acoustic sensor at a first location on a passageway for communication with a user'"'"'s airway, wherein the first acoustic sensor outputs a first signal;

providing a second acoustic sensor at a second location on the passageway, wherein the second acoustic sensor outputs a second signal;

determining a parameter of the passageway based on (i) the first location and the second location of the sensors and (ii) a relationship between the first signal and the second signal, wherein the relationship between the first signal and the second signal causes cancellation of sound source properties; and

detecting the presence of an obstruction of the airway based on the parameter.

18. A method as claimed in claim 17, comprising providing the first and second sensors at first and second locations along a tube which has a first end terminating at the mouth and/or nose of a user.

19. A method as claimed in claim 17, comprising deriving an acoustic transfer function from the sensor signals and deriving the parameter in the form of an acoustic impedance from the acoustic transfer function.

20. A method as claimed in claim 17, wherein the first acoustic sensor is closer to the mouth and/or nose of the patient than the second acoustic sensor.