X3.4 Clearance of secretions

Patients who regularly expectorate sputum or those with tenacious sputum may benefit from airway clearance techniques during an exacerbation. Two systematic reviews of the use of airway clearance techniques in patients experiencing an AECOPD have been published (Hill et al., 2010, Tang et al., 2010). With the exception of chest wall percussion, which was associated with a decrease in FEV₁, airway clearance techniques were not associated with adverse effects(Hill et al., 2010, Tang et al., 2010) [evidence level I]. In individuals with copious secretions, mechanical vibration and positive expiratory therapy (PEP) therapy increased sputum expectoration (Hill et al., 2010) [evidence level I]. There is some evidence that techniques that apply a positive pressure to the airways may reduce either the requirement for, or the duration of, non-invasive positive pressure ventilation and hospital length of stay in patients with hypercapnic respiratory failure (Hill et al., 2010). Airway clearance techniques applied during an exacerbation do not appear to improve measures of resting lung function or produce any consistent changes in gas exchange (Hill et al., 2010, Tang et al., 2010) [evidence level I]. However, the limitations of these studies included in the systematic reviews (i.e. considerable diversity in patients’ characteristics and application of specific techniques, small sample sizes in some of the studies, large variety of outcome measures) prohibited meta-analyses from being undertaken.