Expiratory Flow Accelerator (EFA) technique on mucus hypersecretion of COPD patients with reduced cough efficiency after a severe exacerbation.

Background
Mucus hypersecretion has a negative impact in chronic obstructive pulmonary disease (COPD). Expiratory Flow Accelerator (EFA) technique removes secretions noninvasively by accelerating expiratory flow. The aim of our study was to compare EFA efficacy with the non-oscillatory positive expiratory pressure (PEP) bottle in airways clearing in COPD with hypersecretion and reduced cough efficiency after severe exacerbation.

Methods
In an exploratory prospective, randomized, open-label study, we analyzed COPD patients with severe airflow obstruction (forced expiratory volume at 1st second-FEV1<50%), mucus hypersecretion (sputum volume >30 ml/die) and reduced cough efficiency (peak cough expiratory flow-PCEF <300 l/min) referred to pulmonary rehabilitation after severe exacerbation. Comparison was made between group using EFA and group using PEP. Primary outcome was change in perceived bronchial encumbrance (visual analogue scale-VAS). Secondary outcomes were changes in peak expiratory flow (PEF), PCEF, lung volumes, arterial blood gases exchanges, maximum inspiratory and expiratory pressure (MIP and MEP), health status (COPD questionnaire score-CCQ) and impact of disease (COPD Assessment Test-CAT).

Results
Twenty seven patients completed the study (14 EFA, 13 PEP). VAS, CAT, and CCQ improved in both groups (p<0.05). A greater improvement in VAS was recorded in the EFA group. Static and dynamic volumes (residual volume-RV and forced vital capacity-FVC) improve in both groups while total lung capacity (TLC) and MIP improved in the EFA group. No significant changes were recorded for arterial blood gases, PEF and PCEF.

Conclusions
EFA technique can enhance airways clearing in these patients, improving lung volumes and inspiratory muscle strength.