X3.4 Clearance of secretions

Patients who regularly expectorate sputum or those with tenacious sputum may benefit from airway clearance techniques (ACTs) during an exacerbation. However, the choice of ACTs during exacerbations requires careful consideration as these episodes result in worsening of airflow limitation and lung hyperinflation, which lead to acute increases in dyspnoea. Patients are also likely to experience significant physical fatigue during an exacerbation and this impacts on the choice of ACT.

A Cochrane Sytematic Review of 9 trials examined the efficacy of ACTs in patients experiencing an exacerbation of COPD (Osadnik 2012). The use of ACTs was associated with a significant short-term reduction in the need for increased ventilatory assistance (odds ratio 0.21, 95% CI 0.05 to 0.85, data from 4 studies involving 171 patients) NNT 12, 95% CI 10-66 [evidence level I],the duration of ventilatory assistance (mean difference of -2.05 days, 95% CI -2.60 to -1.51 compared to control, data from 2 studies of 54 patients) and hospital length of stay (mean difference -0.75 days, 95% CI -1.38 to -0.11 compared to control, data from one study of 35 patients). Airway clearance techniques that utilised positive expiratory pressure (PEP) tended to be associated with a greater reduction in the need for increased ventilatory assistance and hospital length of stay compared to non-PEP based ACTs however the difference was not significant.

With the exception of chest wall percussion, which has been associated with a decrease in FEVand one report of vomiting during treatment involving a head-down tilt position ACTs were not associated with serious adverse effects (Hill 2010, Tang 2010, Osadnik 2012) [evidence level I]. 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 (Osadnik 2012) [evidence level I]. However, the limitations of the 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) limited the ability to  pool data for meta-analysis. A multicentre RCT that involved 90 patients hospitalised with an exacerbation of COPD investigated whether the addition of PEP therapy to usual medical care that included a standardised physical exercise training regimen improved symptoms, QoL and incidence of future exacerbations (Osadnik 2014). Individuals in this study were characterised by evidence of sputum expectoration or a history of chronic sputum production with over 50% of those recruited expectorating purulent sputum, however individuals with primary bronchiectasis were excluded. The authors found no significant between group differences in symptoms or quality of life assessed over a 6-month period following hospital discharge. The incidence of exacerbations during the follow-up period was low and similar in both groups. The findings of this study do not support a routine role for PEP therapy even in patients with purulent sputum who are hospitalised for an exacerbation of COPD.

Given the negative impact that exacerbations have on symptoms such as dyspnoea and fatigue, it is important to decide whether performing ACT is appropriate, and if so choosing the most appropriate technique during this time. The choice of ACT should be guided by a physiotherapist experienced in this type of clinical presentation.