Nitric oxide breath testing by tunable-diode laser absorption spectroscopy: application in monitoring respiratory inflammation

Chad Roller, Khosrow Namjou, James D. Jeffers, Mark Camp, Adam Mock, Patrick J. McCann, Joe Grego
2002 Applied Optics  
We used a high-resolution mid-IR tunable-laser absorption spectroscopy ͑TLAS͒ system with a single IV-VI laser operating near 5.2 m to measure the level of exhaled nitric oxide ͑eNO͒ in human breath. A method of internal calibration using simultaneous eNO and exhaled CO 2 measurements eliminated the need for system calibration with gas standards. The results observed from internally calibrating the instrument for eNO measurements were compared with measurements of eNO calibrated to gas
more » ... and were found to be similar. Various parameters of the TLAS system for eNO breath testing were examined and include gas cell pressure, exhalation time, and ambient NO concentrations. A reduction in eNO from elevated concentrations ͑ϳ44 parts in 10 9 ͒ to near-normal levels ͑Ͻ20 parts in 10 9 ͒ from an asthmatic patient was observed after the patient had received treatment with an inhaled glucocorticoid anti-inflammatory medication. Such measurements can help in evaluating airway inflammation and in monitoring the effectiveness of anti-inflammatory therapies.
doi:10.1364/ao.41.006018 pmid:12371564 fatcat:irqczskkczd2vbn5v5ve7s7jge