Patent ID: 6942623

Claim:
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.