The use of non-invasive ventilation for the relief of dyspnoea in exacerbations of chronic obstructive pulmonary disease; a systematic review.

BACKGROUND AND OBJECTIVE: Non-invasive ventilation (NIV) improves outcomes in patients with acute exacerbations of COPD (AECOPD); however, the efficacy in relieving dyspnoea is uncertain. The objective of this systematic review was to identify, synthesize and interpret the data regarding the relief of dyspnoea afforded by NIV in patients admitted with acute respiratory failure occurring during AECOPD. METHODS: Randomized controlled trials (RCTs) comparing usual medical care (UMC) to UMC plus NIV and reporting dyspnoea as a patient-reported outcome were identified by searching relevant databases and manual searching. The full text of potentially relevant articles was retrieved. Data describing the impact of NIV on dyspnoea was extracted. RESULTS: Four RCTs met the review criteria. One found NIV did not relieve dyspnoea. The other three RCTs reported NIV relieving dyspnoea. The degree of dyspnoea relief was clinically significant in two of these three studies. However, in all but one RCT, methodological or reporting limitations constrain the confidence that can be had in this conclusion. CONCLUSIONS: Limited data exist to determine if NIV relieves subjective dyspnoea in AECOPD. Due to limitations in these studies, it is not possible to definitively conclude if NIV relieves dyspnoea. Standardized reporting and analysis of patient reported outcomes will facilitate objective comparisons of interventions with respect to symptom relief. Future studies involving NIV should routinely incorporate patient reported outcomes in order to answer the important clinical question: 'Does NIV relieve dyspnoea?'