Acute effects of hypertonic saline inhalation on nitric oxide pulmonary diffusing capacity in healthy adults.

Highlights • Acute hypertonic saline solution (HSS) inhalation slightly decreases nitric oxide diffusing capacity. • Interstitial fluid accumulation following HSS inhalation may cause reduced nitric oxide diffusing capacity. • Acute oxygen inhalation (control exposure) has no effect on nitric oxide diffusing capacity. Abstract We investigated acute effects of inhalation of hypertonic saline solution (HSS) and oxygen (O 2 , control exposure) on pulmonary diffusing capacity for nitric oxide (DLNO) and carbon monoxide (DLCO). In a randomized crossover study, 20 healthy, non-smoking subjects were allocated to short-term inhalation of HSS or O 2. Spirometry [(forced expiratory volume in 1 s (FEV 1) and forced vital capacity (FVC)] and combined single-breath DLNO-DLCO measurements were performed before and immediately after inhalation of either HSS or O 2. Percent changes were presented as median values (interquartile range). After HSS inhalation, DLNO, FEV 1 and FVC were decreased by −3.0% (−7.3, 0.5), −3.1% (−4.2, −1.6) and −1.2% (−3.3, 0.6), respectively (all P < 0.05), without significant effect on DLCO. No changes in spirometry and diffusing capacity were observed following O 2 inhalation. Acute inhalation of HSS causes a slight decrease in membrane conductance, probably as a result of fluid imbalance at the alveolar surface and interstitial fluid accumulation, both of which could impair gas exchange. [ABSTRACT FROM AUTHOR]