Clinical aspects of mucociliary transport in anesthesia and intensive-care medicine

Because it is in direct contact with the environment, the respiratory system is exposed to the continuous action of harmful substances. The mucociliary escalator of the lungs is an important protective transport system by means of which inhaled particles and microorganisms are removed from the tracheobronchial system. Ventilated patients in the intensive-care unit (ICU) frequently have impaired mucus transport, which is associated with the development of retention of secretion and nosocomial pneumonia. Reduced mucociliary clearance is often caused by multiple factors. Previous chronic cigarette smoking or pre-existing chronic bronchitis, suction-induced lesions of the mucus membrane, ventilation with high oxygen concentrations, colonization by potentially pathogenic microorganisms, infection with respiratory viruses, release of inflammatory mediators and inadequate humidification of the inspired gases combine to form a formidable potential insult to the mucociliary clearance mechanism. Beta-mimetics and theophylline, in particular, have a favorable effect on mucociliary transport, whereas the effect of mucolytic agents is controversial.