Patent ID: 6402698
Filing Date: 2002-06-11
Classification: A61B

Abstract:
An indirect calorimeter for measuring the metabolic activity of a subject, said analyzer comprising:a respiratory connector-operative to be supported in contact with the subject so as to pass inhaled and exhaled gases as the subject breathes; a flow tube connected at one end to the respiratory connector and at the other end to a source and sink for respiratory gases so as to receive and pass inhaled and exhaled gases; a flow meter operatively connected to said flow tube and adapted to generate electrical signals as a function of the instantaneous volume of inhaled and exhaled gases passing through the flow tube; an oxygen sensor supported on the flow tube so as to generate electrical signals as a function of the instantaneous fraction of oxygen in the inhaled and exhaled gases as they pass through the flow tube; and a computation unit for receiving said electrical output signals from the flow sensor and the oxygen sensor and operative to integrate the electrical signals which are functions of the instantaneous volume of gases passing through the flow tube with the electrical signals which are functions of the instantaneous fraction of oxygen in the gasses passing through the flow tube as the subject breathes over a period of time, the computation unit being operative to compute the oxygen consumption of the subject over the period of time by calculating the integral of the instantaneous flow volumes during inhalation, multiplied by the instantaneous oxygen content measurements at the time of such instantaneous flow volumes, and subtracting from that integral the integral of tile instantaneous flow volume during exhalation multiplied by the instantaneous oxygen content measurements at the time of such instantaneous flow volumes.