A modified photo- and magnetoacoustic multigas analyzer applied in gas exchange measurements

• Published in: Journal of applied physiology (1985) Vol. 76; no. 6; p. 2832
• Main Authors: Clemensen, P, Christensen, P, Norsk, P, Grønlund, J
• Format: Journal Article
• Language: English
• Published: United States 01.06.1994
• Subjects: Adult; Blood Gas Analysis - instrumentation; Blood Volume - physiology; Carbon Dioxide - blood; Cardiac Output - physiology; Electron Spin Resonance Spectroscopy; Exercise - physiology; Functional Residual Capacity - physiology; Humans; Male; Pulmonary Diffusing Capacity - physiology; Pulmonary Gas Exchange; Respiratory Dead Space - physiology; Respiratory Mechanics - physiology; Spectrophotometry, Infrared
• ISSN: 8750-7587
• DOI: 10.1152/jappl.1994.76.6.2832

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.