title: Exhaled nitric oxide monitoring by quantum cascade laser: comparison with chemiluminescent and electrochemical sensors.
abstract: Fractional exhaled nitric oxide (F(E)NO) is considered an indicator in the diagnostics and management of asthma. In this study we present a laser-based sensor for measuring F(E)NO. It consists of a quantum cascade laser (QCL) combined with a multi-pass cell and wavelength modulation spectroscopy for the detection of NO at the sub-part-per-billion by volume (ppbv, 110(-9)) level. The characteristics and diagnostic performance of the sensor were assessed. A detection limit of 0.5 ppbv was demonstrated with a relatively simple design. The QCL-based sensor was compared with two market sensors, a chemiluminescent analyzer (NOA 280, Sievers) and a portable hand-held electrochemical analyzer (MINO, Aerocrine AB, Sweden). F(E)NO from 20 children diagnosed with asthma and treated with inhaled corticosteroids were measured. Data were found to be clinically acceptable within 1.1 ppbv between the QCL-based sensor and chemiluminescent sensor and within 1.7 ppbv when compared to the electrochemical sensor. The QCL-based sensor was tested on healthy subjects at various expiratory flow rates for both online and offline sampling procedures. The extended NO parameters, i.e. the alveolar region, airway wall, diffusing capacity, and flux were calculated and showed a good agreement with the previously reported values.
authors.affiliation: Radboud University, Life Science Trace Gas Facility, Molecular and Laser Physics, Institute for Molecules and Materials, PO Box 9010, 6500 GL Nijmegen, The Netherlands.
authors.forename: Julien
authors.initials: J
authors.lastname: Mandon
authors.forename: Marieann
authors.initials: M
authors.lastname: Högman
authors.forename: Peter J F M
authors.initials: PJ
authors.lastname: Merkus
authors.forename: Jan
authors.initials: J
authors.lastname: van Amsterdam
authors.forename: Frans J M
authors.initials: FJ
authors.lastname: Harren
authors.forename: Simona M
authors.initials: SM
authors.lastname: Cristescu
mesh_terms: D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000378:metabolism; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods*; D002648:Child; D055664:Electrochemical Techniques; D045853:Exhalation; D006801:Humans; D054023:Lasers, Semiconductor; D008163:Luminescent Measurements; D009569:Nitric Oxide / Q000032:analysis*
chemical_list: D009569:Nitric Oxide