Vol. 89, Issue 1, 373-378, July 2000
SPECIAL COMMUNICATION
System of automated gas-exchange analysis for the
investigation of metabolic processes
Saul
Miodownik1,
Vittoria Arslan
Carlon2,
Enrico
Ferri2,3,
Brian
Burda1, and
Jose A.
Melendez2
Departments of 1 Medical Physics and 2 Anesthesiology
and Critical Care Medicine, Memorial Sloan-Kettering Cancer Center, New
York, New York 10021; and 3 Department of Anesthesiology and
Intensive Care, University of Ferrara, Ferrara, Italy
44100
Conventional gas-exchange instruments are
confined to the measurement of O2 consumption
(
O2) and CO2 production
(CO2) and are subject to a variety of
errors. This handicaps the performance of these devices at inspired
O2 fraction (FIO2) > 0.40 and limits their applicability to indirect calorimetry only. We
describe a device based on the automation of the Douglas bag technique that is capable of making continuous gas-exchange measurements of
multiple species over a broad range of experimental conditions. This
system is validated by using a quantitative methanol-burning lung model
modified to provide reproducible 13CO2
production. The average error for O2 and
CO2 over the FIO2 range of 0.21-0.8. is 2.4 and
0.8%, respectively. The instrument is capable of determining the
differential atom% volume of known references of
13CO2 to within 3.4%. This device reduces the
sources of error that thwart other instruments at
FIO2 > 0.40 and demonstrates the
capacity to explore other expressions of metabolic activity in exhaled gases related to the excretion of 13CO2.
oxygen consumption; carbon dioxide production; 13CO2; metabolic cart; indirect calorimetry; expired gas analysis; mass spectrometer; Douglas bag
