Respiratory therapy systems and methods using a gas mixing circuit

Patent metadata

Field	Value
Publication number	US-9662468-B2
Application number	US-201214345670-A
Country	US
Kind code	B2
Filing date	Sep 27, 2012
Priority date	Oct 5, 2011
Publication date	May 30, 2017
Grant date	May 30, 2017

Abstract

Systems and methods for mixing at least two gases for delivery to the airway of a subject use a gas mixing circuit having a diffusion portion. The diffusion portion may be configured to elongate the shape of the cross-section of the path through the gas mixing circuit in a particular direction and/or orientation. As a result, the gas concentration profile of the gas mixture after the gas mixing circuit is more uniform than the gas concentration profile after the merging of multiple gases.

First claim

What is claimed is:

1. A respiratory therapy system configured to mix at least two gases for delivery to the airway of a subject, the respiratory therapy system comprising:
a pressure generator configured to generate a pressurized flow of a first gas for delivery to the airway of a subject, in accordance with a therapeutic regimen;
a gas coupler configured to fluidly couple the respiratory therapy system to a gas supply to transfer a second gas from the gas supply through the gas coupler;
a gas merging circuit configured to merge the first gas from the pressure generator with the second gas from the gas supply into a gas mixture having (i) a percentage concentration of the first gas and (ii) a first gas concentration profile at a cross-section of an output of the gas merging circuit after being merged by the gas merging circuit, wherein the first gas concentration profile at the cross-section of the output of the gas merging circuit includes a first sample standard deviation of a spatial distribution of sample values of percentage concentrations of the first gas; and
a gas mixing circuit configured to further mix the gas mixture of the first gas with the second gas that has the first gas concentration profile along a flow path formed within the gas mixing circuit, wherein the gas mixing circuit comprises:
(i) an inlet configured to receive the gas mixture of the first gas and the second gas from the output of the gas merging circuit, wherein a cross-section transverse to a longitudinal axis of the flow path formed within the gas mixing circuit at the inlet has a first cross-sectional shape;
(ii) a diffusion portion coupled between a first transitional portion and a second transitional portion, wherein the first transitional portion, the diffusion portion and the second transitional portion are configured to further mix the gas mixture of the first gas and the second gas through turbulent diffusion, wherein a cross-section transverse to the longitudinal axis of the flow path formed within the gas mixing circuit at the diffusion portion has a second cross-sectional shape that is elongated along a particular orientation of the second cross-sectional shape with respect to a similar orientation of the first cross-sectional shape to enhance turbulent diffusion of the gas mixture to more uniformly mix the gas mixture as the gas mixture travels through the diffusion portion; and
(iii) an outlet configured to receive the gas mixture that has been mixed within the diffusion portion, and to guide the gas mixture to a respiratory circuit for delivery to the airway of the subject,
wherein the gas mixture guided by the outlet has a second gas concentration profile at a given cross-section of the outlet that is more uniform than the first gas concentration profile at the cross-section of the output of the merging circuit, wherein the second gas concentration profile at the given cross-section of the outlet includes a second sample standard deviation of a spatial distribution of sample values of percentage concentrations of the first gas, and wherein the second sample standard deviation comprises a value that is less than half of a value of the first sample standard deviation, and
wherein the first cross-sectional shape of the cross-section of the flow path at the inlet has a maximum inlet dimension and a minimum inlet width transverse to the maximum inlet dimension, and wherein the second cross-sectional shape of the cross-section of the flow path at the diffusion portion has a maximum diffusion dimension greater than the maximum inlet dimension and a minimum diffusion width, transverse to the maximum diffusion dimension, that is less than the minimum inlet width.

2. The respiratory therapy system of claim 1 , wherein the first cross-sectional shape of the cross-section of the flow path at the inlet has a maximum inlet dimension and a minimum inlet width transverse to the maximum inlet dimension, and wherein the second cross-sectional shape of the cross-section of the flow path at the diffusion portion has a maximum diffusion dimension at least twice the maximum inlet dimension and a minimum diffusion width, transverse to the maximum diffusion dimension, that is less than half the minimum inlet width.

3. The respiratory therapy system of claim 1 , wherein a cross-section of the second cross-sectional shape is elongated along a horizontal orientation, wherein the gas merging circuit comprises a first inlet configured to receive the first gas and a second inlet configured to receive the second gas, wherein the first inlet is arranged relative to the second inlet according to a vertical orientation, and wherein the vertical orientation is substantially perpendicular to the horizontal orientation.

4. The respiratory therapy system of claim 1 , wherein the second cross-sectional shape is elongated along a horizontal orientation, wherein the first gas concentration profile at the cross-section of the output of the gas merging circuit includes a first area and a second area, wherein the first area comprises a highest quartile of concentration of the first gas, wherein the second area comprises a lowest quartile of the concentration of the first gas, and wherein a line through a centroid of the first area and a centroid of the second area has a vertical orientation that is transverse to the horizontal orientation.

5. The respiratory therapy system of claim 1 , wherein the gas mixing circuit is configured to mix the first gas with the second gas such that a pressure drop across the gas mixing circuit is less than 10 cm H 2 O for a flow rate of the gas mixture of 250 liters per minute.

6. The respiratory therapy system of claim 1 , wherein the gas mixing circuit further comprises one or more obstructions disposed within the diffusion portion, wherein the one or more obstructions are configured to promote turbulence within the gas mixing circuit, and wherein the one or more obstructions include bluff bodies.

7. A method for mixing at least two gases for delivery to the airway of a subject, the method comprising:
providing a flow of a first gas to a first inlet of a gas merging circuit;
fluidly coupling a second flow of a second gas to a second inlet of the gas merging circuit, at the same time as the provision of the flow of the first gas, wherein the gas merging circuit merges the first gas with the second gas into a gas mixture having (i) a percentage concentration of the first gas and (ii) a first gas concentration profile at a cross-section of an output of the gas merging circuit after being merged by the gas merging circuit, wherein the first gas concentration profile at the cross-section of the output of the gas merging circuit includes a first sample standard deviation of a spatial distribution of sample values of percentage concentrations of the first gas;
receiving the gas mixture of the first gas and the second gas at an inlet of a gas mixing circuit from the output of the gas merging circuit, wherein a cross-section transverse to a longitudinal axis of a flow path at the inlet has a first cross-sectional shape;
diffusing, via turbulent diffusion in a gas mixing circuit, the gas mixture from the inlet of the gas mixing circuit through a first transitional portion, a diffusion portion, and a second transitional portion, wherein a cross-section transverse to the longitudinal axis of the flow path at the diffusion portion has a second cross-sectional shape that is elongated along a particular orientation of the second cross-sectional shape with respect to a similar orientation of the first cross-sectional shape to enhance turbulent diffusion of the gas mixture to more uniformly mix the gas mixture as the gas mixture travels through the diffusion portion; and
delivering, via an outlet of the gas mixing

Assignees

• Koninklijke Philips Nv

Inventors

• Kelly Eamonn
• Le Bang Romans

Classifications

• A61M16/12 Primary

  by mixing different gases · CPC title

• A61M2016/0027

  pressure meter · CPC title

• A61M2016/0036

  in the breathing tube and used in both inspiratory and expiratory phase · CPC title

• A61M2205/52

  with memories providing a history of measured variating parameters of apparatus or patient · CPC title

• A61M2016/1025

  the O2 concentration · CPC title