Patent ID: 8109884

Claim:
A metabolism monitor comprising: a chamber; said chamber further comprising an inlet connected to ambient air to allow said ambient air to enter the chamber, an outlet to allow the chamber air to leave the chamber to said ambient air, wherein the chamber is further adapted to connect to a respiration of a subject; a gas analyzer configured to measure chamber air characteristics; an air flow sensor connected to the inlet or the outlet to measure chamber air flow; and an estimator including a predictor and a corrector, the estimator configured to initialize values of subject variables and of chamber variables, wherein the subject variables comprise a subject oxygen consumption flow rate and a subject carbon dioxide production flow rate, and the chamber variables comprise chamber air levels of oxygen and of carbon dioxide; wherein at each of a plurality of times, the monitor: measures chamber air characteristics, using the gas analyzer, to determine measurement variables, said measurement variables comprising measured chamber air levels of oxygen and of carbon dioxide; measures chamber air flow, using the air flow sensor, to determine values of the air flow entering the chamber, when the air flow sensor is connected to the inlet, or the values of the air flow exiting the chamber, when the air flow sensor is connected to the outlet; generates, using the predictor, the values of anticipated subject variables and of anticipated chamber variables in response to values of subject variables, values of chamber variables, and the measured chamber air flow; and corrects, using the corrector, the values of the subject variables and of the chamber variables in response to the values of the measurement variables, the values of the anticipated subject variables, and the values of the anticipated chamber variables; and whereupon a subject metabolism is monitored in response to the values of the corrected subject variables.