IPFT | IPFT indices | Unit | Children with ARI episode(s) during infancy (n=173), median (IQR) | Children without documented ARI episode during infancy (n=52), median (IQR) | P-value |

TBFVL | V_{T}/kg | mL/kg | 11.3 (9.7–13.5) | 11.6 (10.2–13.8) | 0.7 |

MTEF | mL/s | 130 (107–157) | 120 (98–138) | 0.05 | |

t_{PTEF}/t_{E} | % | 39.6 (30.5–50.1) | 37.7 (29.6–46.8) | 0.19 | |

TEF_{25} | mL/s | 153 (124–185) | 135 (110–173) | 0.02 | |

TEF_{10} | mL/s | 121 (97–148) | 107 (82–139) | 0.04 | |

TEF_{25}/PTEF | % | 79.7 (72.1–85.9) | 76.1 (68.6–83.8) | 0.04 | |

TEF_{50}/PTEF | % | 89.8 (86.1–93.1) | 87.3 (85.5–89.2) | 0.002 | |

RTC | Vʹ_{max,FRC} | mL/s | 57.5 (0–105) | 50 (0–95) | 0.8 |

RVRTC | FEV _{0.5} | mL | 58.2 (41.6–81.6) | 68 (45.3–101.8) | 0.04 |

FEV _{0.75} | mL | 79.4 (58.1–106.9) | 89.9 (69.6–125.1) | 0.02 | |

FEV_{1.0} | mL | 96.8 (74.4–124.8) | 112.5 (77.3–139.7) | 0.04 | |

FEV | ml | 119.4 (85.6–144.3) | 137 (117.9–164.5) | 0.004 | |

MEF_{25} | mL/s | 125 (90–185) | 177.5 (100–310) | 0.01 | |

MEF_{10} | mL/s | 80 (60–135) | 130 (70–260) | 0.003 | |

FEF_{25–75} | mL/s | 154.7 (103.6–216.2) | 212.5 (123.2–301.9) | 0.01 | |

PEF | mL/s | 252.5 (180–355) | 282.5 (205–400) | 0.14 |

FEF

_{25-75}, forced expiratory flow between 25-75% of FVC; FEV, forced expiratory volume; FEV_{0.5}/FEV_{0.75}/FEV_{1.0}, forced expiratory volume in 0.5/0.75/1.0 sec, maximum expiratory flow at 25% or 10% of FVC (MEF_{25}/MEF_{10}); IPFT, infants pulmonary function test; MTEF, mid tidal expiratory flow; PEF, peak expiratory flow; RTC, rapid thoracoabdominal compression; RVRTC, raised volume rapid thoracoabdominal compression; TBFVL, tidal breathing flow-volume loop; TEF_{10}or TEF_{25}or TEF_{50}/PTEF, ratio of TEF_{10}, TEF_{25}or TEF_{50}to peaked tidal expiratory flow; TEF_{10}/TEF_{25}/TEF_{50}, tidal expiratory flow when 10/25 50 % of*V*_{T}remaining for expiration; t_{PTEF}/t_{E}, the ratio of time to peak tidal expiratory flow to total expiratory time; Vʹ_{max, FRC}, maximal flow at functional residual capacity; V_{T}/Kg, tidal volume per unit bodyweight.