What it takes for a cough to expel mucus from the airway

Cough is one of the most common symptoms for seeking medical care. Patients with impaired cough due to neuromuscular disease or postoperative sedation suffer high rates of atelectasis and pneumonia due to the failure to clear secretions from the airways, and there is evidence that a heightened cough reflex improves health. Chief among airway secretions is mucus, and, in PNAS, Button et al analyze the biophysical requirements for a cough to separate adherent mucus from an airway wall. Before diving into the details, it is worth reviewing what is known about the biochemistry of mucus and the forces generated by a cough.