Newborn characteristics | NCPAP (n=34) | nHFOV (n=34) | P value |

PO_{2} 1 hour after intervention, mmHg | 59.88 (14.87) | 58.17 (21.66) | 0.70 |

PCO_{2} 1 hour after intervention, mmHg | 38.59 (8.30) | 40.79 (7.82) | 0.26 |

HCO_{3} 1 hour after intervention | 21.83 (2.46) | 22.07 (2.51) | 0.69 |

BE 1 hour after intervention | −2.9 (−3.9 to −1.9) | −2.1 (−4.1 to −1.09) | 0.57* |

pH 1 hour after intervention | 7.36 (0.07) | 7.36 (0.06) | 0.73 |

Values in table are frequency (%) for categorical, mean (SD) for normally distributed continuous variables and median (IQR; Q1: first quartile, Q3: third quartile) for non-normally distributed continuous variables.

*Resulted from non-parametric Mann-Whitney U test and other p values are based on applying independent samples t-test. Multiple testing adjustment based on Bonferroni approach was applied for calculating the p values.

BE, base excess; HCO

_{3}, bicarbonate; NCPAP, nasal continuous positive airway pressure; PCO_{2}, partial pressure of carbon dioxide; PO_{2}, partial pressure of oxygen; nHFOV, nasal high-frequency oscillatory ventilation.