Mixing chamber and expired gas sampling for expired gas analysis indirect calorimetry
First Claim
1. A system for expired gas analysis indirect calorimetry comprising:
- a) a compliant mixing chamber having a capacity such that will accommodate a full exhalation and being partially vented to the environment;
b) a mouthpiece having separate one-way valve means to permit the flow of gas to be inspired therein and the flow of expired gas therefrom, the mouthpiece being operably directly connected to the compliant mixing chamber via said one-way valve means permitting the flow of expired gas therefrom;
c) means to determine the volume of gas entering and exiting said mouthpiece;
d) means to analyze the oxygen and carbon dioxide content of the expired gas from said compliant mixing chamber thereof; and
e) computer means to calculate the metabolic rate of a subject breathing into said mouthpiece based on said determination and analysis, wherein the anatomical dead space in the breathing system of said subject is included in said calculation.
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Accused Products
Abstract
There is provided an improved system for expired gas analysis indirect analysis indirect calorimetry comprising a unique compliant mixing chamber that is directly connected to a mouthpiece that, itself, is unique in providing enhanced saliva and expired moisture trapping capability. The volume of the inspired and expired gas as well as at least the oxygen and carbon dioxide concentrations in the expired gas in the mixing chamber are determined. The metabolic rate of the subject is calculated therefrom taking into account the anatomical dead space in the body of the subject. The mixing chamber is compliant, sized to accommodate a single expiration and partially open to the environment. Preferably, the system also includes means to determine the oxygen and carbon dioxide content of the inspired gas as well.
13 Citations
20 Claims
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1. A system for expired gas analysis indirect calorimetry comprising:
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a) a compliant mixing chamber having a capacity such that will accommodate a full exhalation and being partially vented to the environment;
b) a mouthpiece having separate one-way valve means to permit the flow of gas to be inspired therein and the flow of expired gas therefrom, the mouthpiece being operably directly connected to the compliant mixing chamber via said one-way valve means permitting the flow of expired gas therefrom;
c) means to determine the volume of gas entering and exiting said mouthpiece;
d) means to analyze the oxygen and carbon dioxide content of the expired gas from said compliant mixing chamber thereof; and
e) computer means to calculate the metabolic rate of a subject breathing into said mouthpiece based on said determination and analysis, wherein the anatomical dead space in the breathing system of said subject is included in said calculation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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- 15. A mouthpiece for a breathing apparatus comprising an ovoid body having apertures at the ends thereof for gas to enter and exit, respectively, and a retainer projection to be retained by a subject breathing therethrough, said mouthpiece having a saliva trap extending from said retainer projection from about 50% to about 75% of the circumference of said body in a direction perpendicular to a line bisecting said ends, said saliva trap being from about 10% to about 50% of the width of said body at its widest point and from about 1 to about 3 cm in depth from the inner surface of the body.
Specification