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Updated: May 7, 2026

Breath Collection from Children for Disease Biomarker Discovery
Published on: February 14, 2019
Impact of different breathing protocols on multiple-breath washout outcomes in children
Sophie Yammine1, Florian Singer2, Per Gustafsson3
1Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Basel UKBB, Switzerland.
Background:
To standardize multiple-breath washout (MBW) measurements, 1L tidal volume (VT) protocols were suggested. The effect on MBW derived ventilation inhomogeneity (VI) indices is unclear.
Methods:
We compared VI indices from free breathing MBW at baseline to 1L VT MBW performed in triplicates in 35 children (20 with CF). Mean (range) age was 12.8 (7.0-16.7) years, weight 42 (20-64) kg and height 151 (117-170) cm.
Results:
Baseline lung clearance index (LCI) increased from mean (SD) 11.0 (2.2) to 13.0 (2.6), p = 0.011, in CF and from 6.8 (0.5) to 7.7 (1.4), p = 0.004, in controls. Moment ratio and Scond similarly increased. While change in VI indices was heterogeneous in individuals, decrease in functional residual capacity was most strongly associated with LCI increase.
Conclusion:
MBW protocols strongly influence measures of VI. The 1L VT MBW protocol leads to overestimation of VI and is not recommended in children.
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