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Air contamination with nitric oxide: effect on exhaled nitric oxide response
A Therminarias1, P Flore, A Favre-Juvin
1Faculté de Médecine de Grenoble, TIMC-PRETA CNRS UMR 5525, Laboratoire de Physiologie, La Tronche, France.
American Journal of Respiratory and Critical Care Medicine
|March 28, 1998
Summary
Inhaled nitric oxide (NO) significantly increases exhaled NO levels in healthy individuals. Air pollution containing NO also elevates exhaled NO, with about one-third rejected by the lungs.
Area of Science:
- Respiratory Physiology
- Environmental Health
Background:
- Nitric oxide (NO) plays a crucial role in airway function.
- Exhaled nitric oxide (eNO) is a biomarker for airway inflammation.
- Environmental NO exposure can influence respiratory parameters.
Purpose of the Study:
- To investigate the dose-response relationship between inhaled nitric oxide (NO) concentration and exhaled NO measurements.
- To assess the impact of inhaled NO on exhaled NO concentration (ECNO) and exhaled NO over time (EVNO).
- To evaluate the potential contribution of environmental NO pollution to exhaled NO levels.
Main Methods:
- 10 healthy subjects participated in a controlled study.
- Subjects inhaled NO at concentrations of 0, 20, 49, 98, and 148 ppb from polyethylene bags.
- Continuous measurements of minute ventilation, ECNO, and EVNO were recorded.
Main Results:
- Exhaled NO concentration (ECNO) and quantity (EVNO) were significantly elevated at an inhaled NO concentration of 20 ppb compared to NO-free air.
- Above 20 ppb, ECNO and EVNO showed a linear increase with increasing inhaled NO concentration.
- A portion of inhaled NO (InspVNO) is rejected by the ventilatory pathway, estimated at approximately one-third.
Conclusions:
- Inhaled NO exposure leads to a dose-dependent increase in exhaled NO.
- Air contamination with NO from pollution can significantly elevate exhaled NO, mimicking endogenous NO pathways.
- Understanding inhaled NO dynamics is crucial for interpreting eNO as a biomarker.