Alternative outcomes for the multiple breath washout in children with CF

J Cyst Fibros. 2015 Jul;14(4):490-6. doi: 10.1016/j.jcf.2014.12.008. Epub 2015 Jan 8.


Background: The lung clearance index (LCI) measured by multiple-breath washout (MBW) has been proposed as an outcome for clinical trials; however, MBW is time consuming and LCI can be affected by breathing pattern. We aimed to evaluate moment ratios and abbreviated LCI in school-aged children with mild-to-moderate CF lung disease.

Methods: Using existing data from three studies we assessed the sensitivity of moment ratios and abbreviated LCIs to (i) detect mild-to-moderate CF lung disease and (ii) detect treatment effects after 4 weeks of hypertonic saline or dornase alfa inhalation. MBW was measured by respiratory mass spectrometry using 4% ""sulphur hexafluoride as a tracer gas.

Results: Compared to the traditional LCI, moment ratios and abbreviated LCIs were similarly sensitive to detect CF lung disease. Moment ratios consistently demonstrated treatment effects, whereas abbreviated LCIs were less sensitive.

Conclusions: Both moment ratios and abbreviated LCI are suitable to differentiate health from disease. Sensitivity is decreased for abbreviated LCIs in interventional studies in mild CF lung disease.

Keywords: Clinical trials; Cystic fibrosis; Multiple breath washout.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Adolescent
  • Breath Tests / methods*
  • Child
  • Cross-Sectional Studies
  • Cystic Fibrosis / complications
  • Cystic Fibrosis / diagnosis*
  • Cystic Fibrosis / therapy
  • Deoxyribonuclease I / therapeutic use
  • Female
  • Humans
  • Male
  • Outcome Assessment, Health Care
  • Recombinant Proteins / therapeutic use
  • Respiratory Function Tests
  • Saline Solution, Hypertonic / therapeutic use
  • Sensitivity and Specificity


  • Recombinant Proteins
  • Saline Solution, Hypertonic
  • Deoxyribonuclease I
  • dornase alfa