Evaluation of the elastic and viscous components of bronchial mucus before and after S-carboxymethylcysteine-Lys treatment.

The rheological profile of bronchial secretions from patients suffering from chronic bronchitis has been evaluated using the forced sinusoidal oscillations technique, which allows dynamic tests to be carried out. In these tests the shear stress can be plotted versus the strain on a XY plotter, to obtain Lissajous figures. As bronchial mucus is a viscoelastic fluid, elliptic figures were obtained that can be broken down into an elastic component separate from the viscous component. By applying this method to the study of the S-carboxymethylcysteine action on bronchial mucus, it is possible to observe that the improvement in the rheological characteristics of the mucus, after treatment, is mainly due to a decrease in viscosity rather than to a decrease in elasticity.