https://pubmed.ncbi.nlm.nih.gov/38113557

This study presents a real-time detection system for simultaneously measuring fractional exhaled nitric oxide (FeNO) and end-tidal carbon dioxide (ETCO2) using quantum cascade laser absorption spectroscopy (QCLAS), offering a potential tool for distinguishing and diagnosing asthma and chronic obstructive pulmonary disease (COPD).