Table 3– Static lung volumes and diffusion capacity at 8 and 12 yrs
8 yrsSubjects n12 yrsSubjects n
RV/TLCspiro %22.1±8.35621.1±7.030
RV/TLCpleth %29.4±8.24026.5±6.825
FRCpleth/spiro1.22±0.22501.09±0.1128
VTA32 (64)13 (46)
DL,COc SDS0.32±1.629-0.28±1.522
KCOc SDS-0.95±1.1***22-0.41±1.218
  • Data are presented as mean±sd or n (%), unless otherwise stated. RV: residual volume; TLC: total lung capacity; spiro: determined by helium dilution spirometry; pleth: determined by body plethysmography; FRC: functional residual capacity; VTA: volume trapped air; DL,COc: diffusing capacity of the lung for carbon monoxide, corrected for haemoglobin; KCOc: diffusion capacity corrected for alveolar volume and haemoglobin. For VTA, the number (%) of patients with significant VTA (defined as FRCpleth/spiro >1.10) is shown. ***: p<0.001, significantly below normal (SDS=0) at 8 yrs.