Management of airway clearance in neuromuscular disease

The clearance of airway secretions from the lungs is normally supported by the mucociliary escalator and by cough. These protective mechanisms provide an effective means of pulmonary-hygiene maintenance in healthy individuals. Patients with neuromuscular disease that affects the respiratory pump (the muscles of breathing) can experience mild to profound limitation in both ventilation and cough. Neuromuscular respiratory insufficiency, when left untreated, can substantially impact quality of life and life expectancy. In most cases of neuromuscular disease, respiratory failure and pneumonia are the primary causes of death. Invasive mechanical ventilation and tracheal suctioning have been successfully used when needed to support respiratory insufficiency in this population. These modalities, though supportive, have been associated with substantial morbidity when used in patients with neuromuscular disease. The advent of noninvasive ventilation as a means of supporting chronic neuromuscular respiratory insufficiency has spurred the development of noninvasive cough-augmentation therapy to support airway clearance. Unfortunately, the need to support cough clearance is not always addressed, and few guidelines for the management of cough insufficiency have existed until relatively recently. An understanding of neuromuscular respiratory pathophysiology and the modes of effective noninvasive cough support are key in the evaluation and management of neuromuscular diseases. This review is meant to provide a basic understanding of cough mechanics, and the pathophysiology and management of neuromuscular cough insufficiency.