Patent ID: 6468222
Filing Date: 2002-10-22
Classification: A61B,G01N

Abstract:
An indirect calorimeter for measuring the metabolic rate of a subject, said calorimeter comprising:a respiratory connector configured to be supported in contact with the subject so as to pass inhaled and exhaled gases as the subject breathes; a flow pathway operable to receive and pass 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 a flow tube through which the inhaled and exhaled gases pass, and an outer housing surrounding said flow tube, and 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 the instantaneous flow volume of inhaled and exhaled gases passing through said flow pathway; a component gas concentration sensor operable to generate electrical signals as a function of the instantaneous fraction of a predetermined component gas in the exhaled gases as the gases pass through said flow pathway; and a computation unit operable to receive said electrical signals from said flow meter and said concentration sensor and operative to calculate at least one respiratory parameter for the subject as the subject breathes through the calorimeter.