Short-Term Effect of Autogenic Drainage on Ventilation Inhomogeneity in Adult Subjects With Stable Non-Cystic Fibrosis Bronchiectasis.

BACKGROUND: Lung clearance index (LCI), a measure of ventilation inhomogeneity derived from a multiple-breath washout test, is a promising tool for assessing airway function in patients with non-cystic fibrosis bronchiectasis. However, it is unknown whether ventilation inhomogeneity could improve after successful elimination of excessive secretions within bronchiectasis. The objective of this work was to assess the short-term effects of lung secretion clearance using the autogenic drainage technique on standard lung function tests and LCI in subjects with non-cystic fibrosis bronchiectasis. METHODS: Nitrogen-based multiple-breath washout, spirometry, and body plethysmography tests were performed 30 min before autogenic drainage in adults with stable non-cystic fibrosis bronchiectasis. The autogenic drainage session was followed by a 5-min break, after which the tests were repeated in the same order. Sputum expectorated during autogenic drainage was quantified as dry weight and correlated with change between post- and pre-measurements (Delta). Paired t test or Wilcoxon signed-rank tests were used to compare pre- and post-autogenic drainage measurement outcomes. A P value of <=.05 was considered as statistically significant. RESULTS: Twenty-four subjects were studied (18 females, median age [range]: 65 [21-81] y). Mean +/- SD LCI significantly improved after autogenic drainage (10.88 +/- 2.62 vs 10.53 +/- 2.35, P = .042). However, only 20% of subjects with mucus hyperproduction during autogenic drainage had a Delta LCI that exceeded measurement variability. The percent of predicted slow vital capacity (SVC%) also slightly improved (88.7 +/- 19.3% vs 90 +/- 19.1%, P = .02). Delta LCI was inversely related to dry sputum weight (r = -.48, P = .02) and Delta SVC% (r = -.64, P = .001). Delta SVC% also correlated with dry sputum weight (r = 0.46, P = .02). CONCLUSIONS: In adults with non-cystic fibrosis bronchiectasis and mucus hypersecretion, autogenic drainage improved ventilation inhomogeneity. LCI change may be the result of the maximum recruited lung volume and the amount of cleared mucus secretion.