title: Performance of an exhaled nitric oxide and carbon dioxide sensor using quantum cascade laser-based integrated cavity output spectroscopy.
abstract: Exhaled nitric oxide (NO) is an important biomarker in asthma and other respiratory disorders. The optical performance of a NOCO(2) sensor employing integrated cavity output spectroscopy (ICOS) with a quantum cascade laser operating at 5.22 microm capable of real-time NO and CO(2) measurements in a single breath cycle is reported. A NO noise-equivalent concentration of 0.4 ppb within a 1-sec integration time is achieved. The off-axis ICOS sensor performance is compared to a chemiluminescent NO analyzer and a nondispersive infrared (NDIR) CO(2) absorption capnograph. Differences between the gas analyzers are assessed by the Bland-Altman method to estimate the expected variability between the gas sensors. The off-axis ICOS sensor measurements are in good agreement with the data acquired with the two commercial gas analyzers. This work demonstrates the performance characteristics and merits of mid-infrared spectroscopy for exhaled breath analysis.
authors.affiliation: Rice University, Rice Quantum Institute, 6100 Main Street, Houston, Texas 77005 and Baylor College of Medicine, Medical Scientist Training Program, 1 Baylor Plaza, Houston, Texas 77030.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: McCurdy
authors.forename: Yury
authors.initials: Y
authors.lastname: Bakhirkin
authors.forename: Gerard
authors.initials: G
authors.lastname: Wysocki
authors.forename: Frank K
authors.initials: FK
authors.lastname: Tittel
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods; D002245:Carbon Dioxide / Q000032:analysis*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000378:metabolism*; D011659:Pulmonary Gas Exchange; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000295:instrumentation* / Q000379:methods; D018511:Systems Integration
chemical_list: D002245:Carbon Dioxide; D009569:Nitric Oxide