title: System of automated gas-exchange analysis for the investigation of metabolic processes.
abstract: Conventional gas-exchange instruments are confined to the measurement of O(2) consumption (VO(2)) and CO(2) production (VCO(2)) and are subject to a variety of errors. This handicaps the performance of these devices at inspired O(2) fraction (FI(O(2))) > 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 (13)CO(2) production. The average error for VO(2) and VCO(2) over the FI(O(2)) 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 (13)CO(2) to within 3.4%. This device reduces the sources of error that thwart other instruments at FI(O(2)) > 0. 40 and demonstrates the capacity to explore other expressions of metabolic activity in exhaled gases related to the excretion of (13)CO(2).
authors.affiliation: Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
authors.forename: S
authors.initials: S
authors.lastname: Miodownik
authors.forename: V A
authors.initials: VA
authors.lastname: Carlon
authors.forename: E
authors.initials: E
authors.lastname: Ferri
authors.forename: B
authors.initials: B
authors.lastname: Burda
authors.forename: J A
authors.initials: JA
authors.lastname: Melendez
mesh_terms: D002153:Calorimetry, Indirect / Q000295:instrumentation* / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism; D002247:Carbon Isotopes; D006801:Humans; D008168:Lung / Q000378:metabolism*; D013058:Mass Spectrometry; D010101:Oxygen Consumption / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*
chemical_list: D002247:Carbon Isotopes; D002245:Carbon Dioxide