title: A modified photo- and magnetoacoustic multigas analyzer applied in gas exchange measurements.
abstract: The feasibility of replacing a conventional mass spectrometer (MS) with a specially modified multicomponent (O2, CO2, Freon 22, and SF6) acoustic infrared and paramagnetic (IR/PM) gas analyzer in inert gas-rebreathing and metabolic gas exchange measurements has been investigated. Rebreathing variables were determined simultaneously with the MS and IR/PM analyzers in duplicate measurements at rest and during submaximal exercise in 10 subjects. The differences (means +/- SD, IR/PM - MS) were 0.028 +/- 0.048 liters [functional residual capacity (FRC)], 0.18 +/- 0.38 l/min [cardiac output (Qc)], -0.006 +/- 0.030 l/min [O2 consumption (VO2)], and -33 +/- 108 ml [combined lung tissue and capillary blood volume (Vti,c)]. The coefficients of variation on repeated estimates were 5.8% (FRC), 5.4% (Qc), 6.2% (VO2), and 17% (Vti,c) with the IR/PM analyzer and 5.9% (FRC), 4.2% (Qc), 5.0% (VO2), and 9.8% (Vti,c) with the MS. The differences (IR/PM - MS) obtained in mixed-expirate measurements were -0.006 +/- 0.020 l/min (VO2) and 0.020 +/- 0.021 l/min (CO2 production). Breath-by-breath estimates of VO2 and CO2 production with the IR/PM analyzer were, on average, 2.4 and 4.4% higher than the MS estimates, respectively. Our results demonstrate that the IR/PM gas analyzer, when appropriately modified, can substitute for a complex MS in a variety of noninvasive pulmonary gas exchange measurements.
authors.affiliation: Department of Research and Development, Innovision, Odense, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Clemensen
authors.forename: P
authors.initials: P
authors.lastname: Christensen
authors.forename: P
authors.initials: P
authors.lastname: Norsk
authors.forename: J
authors.initials: J
authors.lastname: Grønlund
mesh_terms: D000328:Adult; D001784:Blood Gas Analysis / Q000295:instrumentation*; D001810:Blood Volume / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002302:Cardiac Output / Q000502:physiology; D004578:Electron Spin Resonance Spectroscopy; D015444:Exercise / Q000502:physiology; D005652:Functional Residual Capacity / Q000502:physiology; D006801:Humans; D008297:Male; D011653:Pulmonary Diffusing Capacity / Q000502:physiology; D011659:Pulmonary Gas Exchange; D012126:Respiratory Dead Space / Q000502:physiology; D015656:Respiratory Mechanics / Q000502:physiology; D013055:Spectrophotometry, Infrared
chemical_list: D002245:Carbon Dioxide