Impact of different breathing protocols on multiple-breath washout outcomes in children.
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.


CONCLUSIONS
MBW protocols strongly influence measures of VI. The 1L VT MBW protocol leads to overestimation of VI and is not recommended in children.
Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Basel UKBB, Switzerland.
Sophie
S
Yammine
Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Zurich, Switzerland.
Florian
F
Singer
Department of Pediatrics, Central Hospital, Skoevde, Sweden.
Per
P
Gustafsson
Division of Respiratory Medicine, Department of Pediatrics, University Children's Hospital of Bern, Switzerland; University Children's Hospital of Basel UKBB, Switzerland. Electronic address: philipp.latzin@ukbb.ch.
Philipp
P
Latzin
D000293:Adolescent; D001944:Breath Tests / Q000379:methods*; D002648:Child; D057186:Comparative Effectiveness Research; D003430:Cross-Sectional Studies; D003550:Cystic Fibrosis / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D017063:Outcome Assessment, Health Care / Q000379:methods / Q000592:standards; D012123:Pulmonary Ventilation; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods / Q000592:standards; D012720:Severity of Illness Index
Children; Clinical use; Cystic fibrosis; Lung physiology; Respiratory function test