
Chronic bronchitis (CB) is a clinical term used to designate a particular pattern of persistent muco-productive cough. CB is characterized by enlarged mucus-producing cells. CB is NOT a specific disease entity. Underlying pathologies vary and are often obscure. Criteria for a diagnosis of CB are presence of a productive cough greater than 25 cc / per day for at least three months during each of two consecutive years.
In patients with severe CB, excess secretions become thick and tenacious as a result of recurrent infectious exacerbations, making cough clearance difficult. In addition, inflammatory by-products associated with refractory infection damage the mucociliary structures that advance mucus from lower to central airways, resulting in ever-worsening secretion retention.
Effective removal of excess respiratory secretions, combined with antibiotics and other drugs, can moderate episodes of acute illness and significantly slow disease progression. Many physicians prescribe high-frequency chest compression (HFCC) airway clearance therapy (ACT) for CB patients who cannot mobilize and clear airway secretions without therapeutic intervention.