[In vitro mucociliary clearance: observations in subjects exposed to acute inhalation of nitrous vapors].

Acute inhalation of nitrous vapours did not cause any damage to the respiratory apparatus detectable via spirometric or X-ray tests in the four workers who were actually exposed and kept under observation during the two months following the explosion of a tank containing nitric acid. However, measurement of the coefficient of relative transport speed in vitro of tracheo-bronchial secretions revealed alterations of the mucus related to specific situations, such as during acute inhalation of nitrous vapours and upon resuming work. The coefficient of relative speed, obtained with the in vitro technique on the palate of the frog, thus proved to be reliable in monitoring irritation of the mucus secreting apparatus of workers accidentally exposed to acute inhalation of nitrous vapours.