Airway Clearance (Pharmacology)

Anna Marie Nathan
University Malaya Medical Centre, Kuala Lumpur, Malaysia

In 2018, Flume et al coined the term the vicious vortex to replace the vicious cycle, as the pathogenesis of bronchiectasis (BE), to further emphasize the importance of reducing endobronchial inflammation and infection in the lung which ultimately causes tissue damage.

Airway clearance is an important part of treatment, in reducing mucus retention, hence why chest physiotherapy is an important management in BE. Adjuncts to physiotherapy are also very important to assist in mucus clearance.

Inhaled hypertonic saline (HS) (6/7%) is a cheap airway clearance technique (ACT) and have been investigated in adults. Majority of the studies show a reduction in mucus viscosity and increased sputum production. Some studies show improvements in quality of life but few have demonstrated significant changes in lung function. Some patients may find HS intolerable, and in these patients, normal saline (NS) maybe useful to.

In our study in children, we found not only improvements in QOL and cough scores, but also significant favourable alterations in microbiome after 3 months of usage ( more even distribution of organisms and significant reduction in Pseudomonas aeruginosa, a common airway/lung pathogen well known to be associated with worsening of BE.

Hyaluronic acid is highly anionic; it can attract water and hypothetically can reduce mucus viscosity. It is usually used together with HS, though it’s use has not proven to be beneficial in studies.

Inhaled dry mannitol powder has also been examined in large studies and found to reduce exacerbations is patients who are severely symptomatic only.

N acetylcysteine has resurfaced the market with new studies demonstrating its efficacy in improving health outcomes (reducing exacerbations, QOl etc).

Erdosteine, which is heralded as more than just a mucolytic but also has anti-inflammatory and anti-bacterial properties may also be useful in bronchiectasis, although studies in adults mainly support its use in COPD.