Validation of oxygen consumption measurements during artificial ventilation.
We describe a system for the absolute calibration of indirect calorimeters, under the conditions of artificial ventilation and increased inspired O2 concentration, in which butane, at a measured flow rate, is burned downstream of an artificial lung. One milliliter of butane requires 6.4 ml O2 for its combustion, and the respiratory quotient is 0.615. With the closed-circuit O2-replenishment method there was no significant systematic error in the measurement of either O2 consumption or CO2 output and a random error with a SD of 8.3 ml/min for O2 consumption and 6.3 ml/min for CO2 output. There were no significant differences in the errors with inspired O2 concentrations between 23.8 and 59.5% and O2 consumptions between 89 and 366 ml/min.
Nunn
J F
JF
Division of Anaesthesia, Clinical Research Centre, Harrow, Middlesex, United Kingdom.
Makita
K
K
Royston
B
B
D002073:Butanes; D002151:Calorimetry / Q000379:methods*; D002153:Calorimetry, Indirect / Q000379:methods*; D006801:Humans; D008168:Lung / Q000378:metabolism; D008953:Models, Anatomic; D010101:Oxygen Consumption; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D013147:Spirometry
D002073:Butanes; C046888:butane