Effects of inhaled saline and oxygen on noninvasive markers of airway and lung function

Introduction: Inhalation challenges have been shown to induce pulmonary effects, e.g. an increase in 8-isoprostane levels in exhaled breath condensate (EBC) by hyperoxic air. The current study examined the sensitivity of noninvasive measures such as bronchial (FeNO) and alveolar (NOalv) nitric oxide, diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO), and hydrogen peroxide (H 2 O 2 ) in EBC to detect alterations induced by oxidative or osmotic inhalative stress. Methods: 20 healthy nonsmoking subjects aged 19-50y inhaled nebulised 3% hypertonic saline solution (HSS) over 20 min and 100% O 2 at a flow of 5l/min over 30 min on two days. Before and after inhalation spirometry, multiflow exhaled NO, DLCO and DLNO were measured and EBC was collected and analysed for H 2 O 2 using an optimised procedure with inhalation filter. Results: HSS inhalation induced a median decrease in FEV 1 of 3% (P 2 O 2 . Results for NOalv were ambiguous in both inhalation groups. Hyperoxic air did not cause significant changes in any other parameter. Conclusion: These results suggest that HSS inhalation not only causes slight airway obstruction but also induces alterations of fluid balance in the lung periphery that can be detected via DLNO but not DLCO. DLNO could thus be of clinical value in the diagnosis of mild pulmonary edema, e.g. related to cardiac dysfunction. Supported by German Statutory accident insurance (DGUV), Berlin.