Resumen de Short-term airway clearance management in people with stable bronchiectasis
Background Daily sputum expectoration is one of the most common respiratory symptoms in people with bronchiectasis. It is associated with poor health outcomes and negative impacts on social life. Although the use of airway clearance techniques (ACTs) and hyperosmolar agents is recommended to more easily manage chronic productive cough, the quality of evidence is still low-moderate and the level of recommendation ranges from weak to strong in bronchiectasis. However, there is a need to evaluate in-depth the short-term effects of airway clearance therapeutic approaches that are so far under-investigated in bronchiectasis in order to design optimal long-term future trials in this field. Therefore, the aims of this thesis were to investigate what is the short-term effectiveness of airway clearance therapeutic approaches in adults with clinically stable bronchiectasis and how to correctly interpret the clinical benefits observed after these interventions.
Methods Two randomised, three-way crossover trials were conducted to compare the short-term effectiveness of three slow-expiratory ACTs (autogenic drainage, slow-expiration with glottis opened in lateral posture [ELTGOL] and temporary positive expiratory pressure [TPEP]) and three inhaled saline solutions (hypertonic saline [HS], hyaluronic acid + HS [HA + HS] and isotonic saline [IS]) in people with bronchiectasis. Wet sputum weight during sessions was selected as the primary outcome in both trials. Moreover, an ad hoc analysis was performed using the sputum samples of both studies to evaluate the reliability of 24-hour sputum weight and the minimal important difference (MID) after short-term airway clearance sessions in bronchiectasis. Finally, a feasibility study was conducted to examine the potential use of computerised adventitious respiratory sounds (ARS) as an outcome measure to assess the short-term effects of airway clearance sessions in bronchiectasis.
Results (1) Autogenic drainage and ELTGOL enhanced greater sputum expectoration compared to TPEP during sessions in individuals with stable bronchiectasis; the participants preferred autogenic drainage; (2) the HA + HS solution was as efficacious as HS solution and greater than IS in improving sputum expectoration, but with a better safety profile than HS in people with bronchiectasis. Thus, they selected it as the preferred solution; (3) the wet sputum weight was an acceptable reliable measure over 24 hours, but the level of agreement was slightly wide, particularly for greater expectoration levels. Moreover, a reduction of at least 6.4 g in the amount of sputum expectorated during the 24 hours following an airway clearance intervention, or a relative change of approximately -17% from baseline, was the estimated MID; (4) computerised ARS was a feasible outcome; the expiratory coarse crackles appeared to be the most appropriate outcome for use in future studies.
Conclusion The findings of this thesis highlight which short-term airway clearance approach are more efficacious in people with clinically stable bronchiectasis. Therefore, the next step is to design and conduct long-term trials to explore these airway clearance therapeutic approaches.
