Table 2

Spirometry and multiple breath inert gas washout (MBW) measurements

ParameterMean (SD) z-scores
FEV1 (n=27)*−1.59 (1.44)
FVC (n=27)*−0.71 (1.36)
FEF25–75 (n=27)*−2.11 (1.39)
FEV1/FVC ratio (n=27)*−1.40 (1.08)
LCI (n=27)7.58 (5.57)
Scond (n=23)9.64 (4.08)
Sacin (n=23)5.99 (4.60)
FRCSF6, ml (n=27)1649 (603)
  • * Spirometry parameters calculated using the British growth reference charts.

  • MBW z-scores calculated using Swedish normative data.

  • FEV1, forced expiratory volume in 1 s; FRC, functional residual capacity; FVC, forced vital capacity; FEF25–75, forced expiratory flow at 25–75% of FVC; LCI, lung clearance index; Scond and Sacin, normalised phase III slope indices (see text for explanation).