Time point to perform lung function tests evaluating the effects of an airway clearance therapy session in cystic fibrosis

Respir Care. 2014 Oct;59(10):1537-41. doi: 10.4187/respcare.02823. Epub 2014 May 20.


Background: Lung function parameters are used as end points in most clinical and therapeutic trials in cystic fibrosis (CF) and to evaluate the effects of airway clearance techniques. The aim of the study was to identify at what time point after a physiotherapy session spirometry (FEV1 and FVC) should be performed to obtain the highest result compared to baseline and to determine whether there are inter-individual and intra-individual differences in children and adults with CF.

Methods: This was a prospective study. Twenty-four subjects with CF and mean FVC 70 ± 30% and FEV1 61 ± 30% of predicted were included. Each subject performed spirometry before their airway clearance session and then immediately after, 30 min after, and 1, 2, and 3 h after their physiotherapy session for 2 consecutive days.

Results: In adult subjects, mean FEV1 improved 30 min (P < .001), 1 h (P < .002), and 2 h (P < .006) after physiotherapy compared to baseline. In pediatric subjects, it improved immediately after the session but was not statistically significant for recommendation. There were no intra-individual variations, but there were inter-individual variations (not statistically significant).

Conclusions: Performing spirometry 30 min (adults) and immediately (children) after a session might be optimal if individual peak time values cannot be used.

Keywords: chest physiotherapy; cystic fibrosis; spirometry; time point.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cystic Fibrosis / physiopathology*
  • Cystic Fibrosis / therapy*
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Physical Therapy Modalities*
  • Prospective Studies
  • Respiratory Therapy / methods*
  • Spirometry
  • Sweden
  • Treatment Outcome