Does physiotherapy affect Lung Clearance Index in Cystic Fibrosis patients ?

Abstract

Background: Lung clearance index (LCI) is increasingly used as a study endpoint for therapeutic interventions in cystic fibrosis (CF) patients. Aim: To assess the short-term effect of chest physiotherapy (CP) on LCI among stable CF patients of varying severity. Methods: Thirty stable CF patients (6-26 years, 26% colonized with Pseudomonas Aeruginosa) participated in the study. N2 - MBW (Nitrogen Multiple Breath Washout) and spirometry measurements were conducted, followed by 30 min of supervised PEP mask chest physiotherapy. MBW and spirometry measurement were repeated 15 and 60 min after CP. Results: Baseline lung clearance index (LCI) (range) was 10.9 (7.3; 20.4) and baseline FEV1% predicted was 97.7% (61.8; 146.2). LCI measures were not significantly influenced by chest physiotherapy. LCI (95% confidence interval) increased non-significantly 0.02 (-0.41; 0.37), (p: 0.920), 15 min after chest physiotherapy and increased non-significantly 0.42 (-0.95; 0.11), (p: 0.109), one hour after chest physiotherapy. All spirometric measures did not change significantly. Conclusions: Chest physiotherapy performed immediately prior to N2MBW has no consistent effect on LCI. In future trials using LCI as an endpoint, the timing of CP in relation to MBW should be considered a possible bias. However, further studies on the effect of chest physiotherapy on multiple breath washout measures are warranted.