Responsive children | Nonresponsive children | |

Subjects n | 20 | 7 |

Changes in P_{tcO2} % | −25.4±4.8 | −13.4±8.4 |

Changes R_{intinsp} % | +49.1±29.6 | +13.2±11.4 |

Change R_{intexp} % | +34.3±27.9 | +8.8±17.4 |

Discordance between R_{intinsp} and P_{tcO2} n (%, 95% CI) | 11 (55, 34–74) | 0 (0, 0–35) |

R_{int} increase <35% at PD_{20}P_{tcO2} n | 6 | |

R_{int} increase ≥35% before PD_{20}P_{tcO2} n | 5 | |

Discordance between PD_{35}R_{intinsp}+S_{pO2,3%}and P_{tcO2} n | 6 | 0 |

Discordance between R_{intexp} and P_{tcO2} n (%, 95% CI) | 16 (80, 58–92) | 3 (42, 16–75) |

R_{int} increase <35% at PD_{20}P_{tcO2} n | 10 | 0 |

R_{int} increase ≥35% before PD_{20}P_{tcO2} n | 6 | 3 |

Discordance between PD_{35}R_{intexp}+ S_{pO2,3%}and P_{tcO2} n | 9 | 3 |

Data are presented as mean±sd percentage of post-diluent values unless otherwise stated. Changes are at the provocative dose of methacholine causing a 20% decrease in

*P*_{tcO2}(PD_{20}*P*_{tcO2}) in responsive children and at the last dose of methacholine in nonresponsive children. Discordances between*R*_{int}and*P*_{tcO2}changes were assessed at every steps of the test.*R*_{int}changes are more or less than 35% increase from the post-diluent value (PD_{35}*R*_{int}).*R*_{intinsp}: inspiratory interrupter resistance;*R*_{intexp}: expiratory interrupter resistance; PD_{35}*R*_{intinsp}: provocative dose of methacholine causing a 35% decrease in*R*_{intinsp};*S*_{pO2,3%}: at least 3% decrease in transcutaneous saturation of oxygen from the post-diluent value; PD_{35}*R*_{intexp}: provocative dose of methacholine causing a 35% decrease in*R*_{intexp}.