Applied upper-airway resistance instantly affects breath components: a unique insight into pulmonary medicine.

摘要: Respiratory parameters such as flow or rate have complex effects on the exhalation of volatile substances and can hamper clinical interpretation breath biomarkers. We investigated progressively applied upper-airway resistances organic compounds (VOCs) in healthy humans. performed real-time mass-spectrometric determination volatiles 50 subjects with parallel, non-invasive hemodynamic monitoring, breath-resolved spirometry capnometry during controlled tidal breathing (12 breaths/min). Airway resistance was increased by changing mouthpiece diameters from 2.5 cm to 1.0 0.5 cm. At smallest diameter, oxygen uptake (35%↑). Cardiac output decreased (6%↓) but end-tidal PCO2 (8%↑) blood-borne isoprene (19%↑) increased. Carbon dioxide production remained constant. Furan, hydrogen sulphide mirrored isoprene. Despite lowered minute ventilation (4%↓) acetone concentrations (3%↓). Exogenous acetonitrile, propionic acid, isopropanol, limonene mimicked acetone. VOC concentration changes could be modelled through substance volatility. resistance-induced hemodynamics, affect thereby interfere biomarker interpretation. The collateral ventilation, intra-alveolar pressure gradients respiratory mechanics had considered explain kinetics CO2 VOCs. Conventional sampling via smaller (≤1.0 cm, e.g. straw Tedlar bags canisters, etc) will immediately mislead analysis obtained results. Endogenous may probe muscle workload under obstructive conditions. Breath-gas might enhance our understanding diagnosis management lung diseases future.