| 摘要 |
An indirect calorimeter operative to measure the respiratory oxygen consumption per unit time of a subject includes a respiratory connector operative to be supported in contact with a subject, so as to pass respiratory gases as the subject breathes into the respiratory connector, and a bi-directional flow meter having an ultrasonic flow transducer that bi-directionally transmits and receives ultrasonic signals to the transducer to generate a signal as a function of the volume of gases passing through the flow meter. The indirect calorimeter also includes a gas concentration sensor operative to generate a signal as a function of an instantaneous carbon dioxide content of gases passing by the gas concentration sensor. The indirect calorimeter further includes a computing device operative to receive signals from the flow meter and the gas concentration sensor, and conduits interconnecting the respiratory connector, the flow meter and the gas concentration sensor, so that the subject's inhalations and exhalations pass through the flow meter and the subject's exhalations pass over the gas concentration sensor and the computer is operative to receive the signals from the gas concentration sensor and the flow meter to calculate the subject's oxygen consumption.
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