Patent ID: 6955650

Claim:
An indirect calorimeter, comprising: a respiratory connector configured to be supported in contact with a subject so as to pass inhaled and exhaled gases as said subject breathes; a hygiene barrier module operatively connected to said respiratory connector, such that said inhaled and exhaled gases pass therethrough said hygiene barrier module for blocking a predetermined pathogen from said exhaled gases; a flow pathway operatively connected to said hygiene barrier module for receiving and passing said inhaled and exhaled gases, said flow pathway having a first end in fluid communication with said respiratory connector and a second end in fluid communication with a source and sink for respiratory gases, said flow pathway comprising: (1) a flow tube through which said inhaled and exhaled gases pass, (2) an outer housing surrounding said flow tube, and (3) a chamber disposed between said flow tube and said first end, said chamber being a concentric chamber surrounding one end of said flow tube and being defined between said flow tube and said outer housing; a flow meter configured to generate electrical signals as a function of an instantaneous flow volume of said inhaled and exhaled gases passing through said flow pathway; a component gas concentration sensor operable to generate electrical signals as a function of an instantaneous fraction of a predetermined component gas in said exhaled gases passing through said flow pathway; and a computation unit operable to receive said electrical signals from said flow meter and said concentration sensor and to calculate at least one respiratory parameter for said subject as said subject breathes through said calorimeter.