Effectiveness of hypertonic saline nebulization in airway clearance in children with non-cystic fibrosis bronchiectasis: A randomized control trial

INTRODUCTION

Failure to expectorate mucus resulting in progressive airway damage is the hallmark of bronchiectasis. Therefore effective airway clearance techniques (ACT) is the key step in its management. The aim of this study was to evaluate the efficacy of 3% hypertonic saline (HS) pre-medication in ACT in children with non cystic fibrosis (non-CF) bronchiectasis.

METHODS

In this randomized crossover control trial five to 15 year old children, diagnosed with non-CF bronchiectasis were randomized either to receive 200 µg of inhaled salbutamol followed by HS nebulization (test) or only 200 µg of inhaled salbutamol, before chest physiotherapy which is the conventional ACT (controls) for 8 weeks. Inhaled salbutamol was administered via a pressurized metered dosed inhaler with a valved holding chamber. After completion of first phase both groups went through one month washout period, before being crossed over to the opposite arms in the second phase. Spirometric parameters and number of exacerbations were recorded at the end of phase I, washout period and phase II.

RESULTS

Fifty two out of 63 enrolled completed the study. Baseline characteristics of the two groups were similar. A significantly higher mean improvement was seen in predicted forced expiratory volume in 1 s in the HS arm during phase 1 (HS = 14.15 ± 5.50 vs. conventional = 5.04 ± 5.55, p = .001) and phase II (HS = 10.81 ± 5.51 vs. conventional = 3.54 ± 5.13, p = .001) compared to conventional ACT arm. HS group showed a significantly higher mean improvement in predicted forced vital capacity in phase I (HS = 13.77 ± 5.73 vs. conventional = 7.54 ± 4.90, p = .001) and phase II, (HS = 9.42 ± 7.00 vs. conventional = 4.42 ± 4.00, p = .003). Mean number of exacerbations experienced by a single child during phase I (2 months) were significantly less (p = .001) in HS arm (0.42 ± 0.64) compared to that of conventional arm (1.30 ± 1.05) butthis difference was not significant in phase II (HS = 0.65 ± 0.74 and conventional = 1.03 ± 0.77, p = .074).

CONCLUSION

Incorporating HS nebulization into ACT is an effective strategy to improve dynamic lung volumes and morbidity in children with non-CF bronchiectasis.

Secretion properties, clearance, and therapy in airway disease

Chronic airway diseases like cystic fibrosis, chronic bronchitis, asthma, diffuse panbronchiolitis, and bronchiectasis are all associated with chronic inflammation. The airway mucosa responds to infection and inflammation in part by surface mucous (goblet) cell and submucosal gland hyperplasia and hypertrophy with mucus hypersecretion. Products of inflammation including neutrophil derived DNA and filamentous actin, effete cells, bacteria, and cell debris all contribute to mucus purulence and, when this is expectorated it is called sputum. Mucus is usually cleared by ciliary movement, and sputum is cleared by cough.

These airway diseases each are associated with the production of mucus and sputum with characteristic composition, polymer structure, and biophysical properties. These properties change with the progress of the disease making it possible to use sputum analysis to identify the potential cause and severity of airway diseases. This information has also been important for the development of effective mucoactive therapy to promote airway hygiene.

The role of mucus in cough research

Cough is a defense mechanism for promoting airway hygiene when mucociliary clearance is ineffective due to increased mucus secretion, inflammation, infection, or ciliary dysfunction. Secretions can contribute to airflow limitation and chronic hypersecretion can worsen airway inflammation with retained inflammatory cells and mediators. The focus of the Second Annual Cough Conference has been on cough as a troublesome symptom; but to understand the importance and effectiveness of cough clearance, it is critical to understand airway secretions. The biophysical properties of mucus and phlegm determine how readily these secretions can be cleared by coughing.