Calibration methods in respiratory calorimetry.
Methods for calibration of respiratory gas exchange measurement systems are evaluated. A new method is described in which O2 is removed from the subject chamber or gas stream and measured gravimetrically in a small combustion chamber containing steel wool. The "Fe-burner" method was tested by comparison with the N2-injection method and found to be of similar accuracy. The new method is easy to perform, quick, and readily applicable to both open- and closed-circuit respiratory systems. It has a rate of O2 uptake that can be adjusted to be similar to the rate by an experimental subject (10-600 kg). Complete calibration of open- and closed-circuit indirect calorimetric systems can be achieved when the Fe-burner method, involving measurement of O2 uptake, is combined with the gravimetric injection of specific gases (CO2, methane) produced by the subject.
D002138:Calibration; D002151:Calorimetry / Q000295:instrumentation / Q000379:methods*; D007501:Iron; D009584:Nitrogen; D010101:Oxygen Consumption; D011659:Pulmonary Gas Exchange
D007501:Iron; D009584:Nitrogen