Figures
- Fig. 1.—
The normalised phase-III slope (SnIII) for helium (He) at rest (└), after cold dry-air hyperventilation challenge (CACh: □) and after β2-agonist treatment (
) in subjects with a fall in forced expiratory volume in one second (FEV1) <10% after CACh (nonresponders; n=27), in subjects with a fall of 10–19% (minor responders; n=16) and in those with a fall in FEV1 of ≥20% (major responders; n=12). Data are presented as mean±sem. The brackets indicate statistical comparisons were made within each group. Where no lines are given the symbols indicate comparisons with the major responders for the corresponding situation. *: p<0.05; **: p<0.01; ***: p<0.001. - Fig. 2.—
The normalised phase-III slope (SnIII) for sulphur hexafluoride (SF6) at rest (└), after cold dry-air hyperventilation challenge (CACh: □) and after β2-agonist treatment (
) in subjects with a fallin forced expiratory volume in one second (FEV1) <10% after CACh (nonresponders; n=27), in subjects with a fall of 10–19% (minor responders; n=16) and in those with a fall in FEV1 of ≥20% (major responders; n=12). Data are presented as mean±sem. The brackets indicate statistical comparisons were made within each group. Where no lines are given the symbols indicate comparisons with the major responders for the corresponding situation. *: p<0.05; **: p<0.01; ***: p<0.001. - Fig. 3.—
The normalised phase-III slope (SnIII) for the (sulphur hexafluoride-helium) (SF6-He) difference at rest (└), after cold dry-air hyperventilation challenge (CACh: □), and after β2-agonist treatment (
) in subjects with a fall in the forced expiratory volume in one second (FEV1) <10% after CACh (nonresponders; n=27), in subjects with a fall of 10–19% (minor responders; n=16) and in those with a fall in FEV1 of ≥20% (major responders; n=12). Data are presented as mean±sem. The brackets indicate statistical comparisons were made within each group. Where no lines are given the symbols indicate comparisons with the major responders for the corresponding situation. *: p<0.05; **: p<0.01; ***: p<0.001.
Tables
- Table 1
Demographical data and baseline spirometry findings of all 55 participants (28 males)
Mean±SD Range Age yrs 34.9±2.4 30–40 Weight kg 73±15 54–138 Height cm 173±9 154–190 FEV1 % pred 92±11 64–120 FEV1/VC % 75±7 54–89 -
FEV1: forced expiratory volume in one second
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% pred: % predicted
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VC: vital capacity
-
- Table 2
Forced expiratory volume in one second (FEV1) at rest and after β2-agonist therapy, and the maximum relative fall in FEV1 after cold dry-air hyperventilation challenge (CACh) in the three subgroups
A B C p-values A vs B A vs C B vs C Subjects n 27 16 12 Resting FEV1 % pred 95.3 ±12.5 89.6±7.5 88.2±11.3 ns ns ns Max. fall in FEV1 % 4.7±2.8 14.2±3.1 37.6±8.9 <0.001 <0.001 <0.001 Post-β2 FEV1 % pred 99.1±12.8 92.8±6.3 90.7±12.2 ns ns ns -
Data are presented as mean±sd
-
A: nonresponders
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B: minor responders
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C: major responders
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vs: versus
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% pred: % predicted
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max.: maximum
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ns: nonsignificant
-
- Table 3
Correlation between the forced expiratory volume in one second (FEV1) per cent predicted and normalised phase-III slopes (SnIII) at rest, after cold dry-air hyperventilation challenge (CACh), and after β2-agonist therapy, and between the changes in FEV1 % pred and the normalised phase-III slopes from baseline to postchallenge, in the whole study population, and in the three subgroups
All subjects Subgroup Major responders Minor responders Nonresponders Subjects n 55 12 16 27 Resting FEV1 % pred vs SF6 SnIII·L−1 ns ns ns ns He SnIII·L−1 ns ns ns ns (SF6-He) SnIII·L−1 ns ns ns ns Post-CACh FEV1 % pred vs SF6 SnIII·L−1 0.38 (<0.001) 0.35 (0.044) ns ns He SnIII·L−1 0.48 (<0.001) 0.55 (0.005) ns ns (SF6-He)·SnIII·L−1 0.23 (<0.001) 0.33 (0.049) ns ns Post-β2 therapy FEV1 % pred vs SF6 SnIII·L−1 ns 0.51 (0.013) ns ns He SnIII·L−1 ns 0.60 (0.005) ns ns (SF6-He) SnIII·L−1 ns ns ns ns Change from resting to post-CACh FEV1 % pred vs SF6 SnIII·L−1 0.60 (<0.001) ns ns ns He SnIII·L−1 0.70 (<0.001) ns ns ns (SF6-He) SnIII·L−1 0.36 (0.001) 0.50 (0.010) 0.27 (0.040) ns -
Data are presented as r2 (p-values) from the Pearson correlation test
-
vs: versus
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SF6: sulphur hexafluoride
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He: helium
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ns: nonsignificant
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