The Short Term Influence of Chest Physiotherapy on Lung Function Parameters in Children With Cystic Fibrosis and Primary Ciliary Dyskinesia

Airway clearance therapy (ACT) is one of the cornerstone treatment modalities to improve mucociliary clearance for patients with bronchiectasis. The progression of lung disease in patients with bronchiectasis can be evaluated by spirometry and multiple breath washout (MBW) and it is advised to monitor these on a regular basis. However, the short term effect of ACT on spirometry and MBW parameters is insufficiently clear and this variability may impact standardization. For cystic fibrosis (CF), available literature refutes a short time effect on spirometry and MBW parameters in children, however, for primary ciliary dyskinesia (PCD) no data are available. We performed a single-center, prospective cross-over study to evaluate the short term effect of a single ACT session using positive expiratory pressure mask on forced expiratory volume in 1 s (FEV(1)) and lung clearance index (LCI), derived from MBW, compared to no ACT (control) in pediatric patients with CF and PCD. A total of 31 children were included: 14 with PCD and 17 with CF. For the whole group, there was no difference in median change of FEV(1) pp between the treatment and the control group (p 0.969), nor in median change of LCI (p 0.294). For the CF subgroup, the mean change in FEV(1) pp with ACT was −1.4% (range −9 to + 5) versus −0.2% (range −6 to + 5) for no ACT (p 0.271), the mean change in LCI with ACT was + 0.10 (range −0.7 to + 1.2) versus + 0.17 (range −0.5 to + 2.8) for no ACT (p 0.814). In the PCD subgroup, the mean change in FEV(1) pp with ACT was + 1.0 (range −7 to + 8) versus −0.3 (range −6 to + 5) for no ACT (p 0.293) and the mean change in LCI with ACT was −0.46 (range −3.7 to + 0.9) versus −0.11 (range −1.4 to + 1.3) for no ACT (p 0.178). There was no difference between PCD and CF for change in FEV(1) pp after ACT (p = 0.208), nor for LCI (p = 0.095). In this small group of pediatric patients, no significant short-term effect of chest physiotherapy on FEV(1) pp nor LCI in PCD and CF values nor variability was documented.