ABSTRACT
In healthy individuals, mucociliary clearance and cough mechanisms are normally effective and efficient for defense on secretion encumbrance, but may become ineffective if these systems malfunction and in the presence of excessive bronchial secretions. Mucus secretion and clearance are extremely important for airway integrity and pulmonary defense. It has been estimated that mucus secretion volume is between 10 and 100 mL/day in healthy subjects (1).
