Exhaled pH, exhaled nitric oxide, and induced sputum cellularity in obese patients with obstructive sleep apnea syndrome.

Airway inflammation plays an important role in obstructive sleep apnea syndrome as well as in obesity. Increasingly, researchers are studying airway inflammation noninvasively and are studying the new markers of airways inflammation. The aim of this study was to measure pH in the exhaled breath condensate (EBC), the exhaled nitric oxide (NO), and the inflammatory cell profile in the induced sputum of obese patients with and without obstructive sleep apnea syndrome (OSAS). The pH in EBC, the exhaled NO, and the induced sputum cells were measured in 30 obese patients with OSAS (OOs), in 20 obese patients without OSAS (ONOs), and in 10 healthy patients (HPs). Levels of pH in EBC were lower in OOs and in ONOs than in HPs. Furthermore, the concentrations of exhaled NO and the percentages of neutrophils in the induced sputum were greater in OOs and in ONOs than in HPs. No significant differences were found between OO and ONO for other measurements of airway inflammation. This study shows the presence of airway's inflammation in obese patients with and without OSAS and indicates that the "exhaled acidopnea" as well as exhaled NO and sputum neutrophils are good tools to measure airway inflammation in these subjects.