Intraventricular haemorrhage | 19–21,24–27,29–31,33 | 759 | p=0.02, I^{2}=53% | Risk ratio (M-H, Random, 95% CI) | 0.65 (0.42 to 0.99) |

Periventricular leukomalacia | 19–21,24,25,31,33 | 531 | p=0.92, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 0.33 (0.15 to 0.72) |

Grade 3/4 IVH | 19–21,24–27,29–31,33 | 707 | p=0.32, I^{2}=14% | Risk ratio (M-H, Fixed, 95% CI) | 0.55 (0.39 to 0.79) |

Pneumothorax | 19,20,25,27,28,31,33,35 | 595 | p=0.85, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 0.46 (0.25 to 0.86) |

Failure of mode of ventilation | 19,27,31,33 | 405 | p=0.92, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 0.64 (0.43 to 0.94) |

Supplemental oxygen administration (days) | 21,26 | 133 | p=0.60 I^{2}=0 | Mean difference (IV, Fixed, 95% CI) | −1.68 (−2.47 to −0.88) |

Any episode of hypocarbia | 18,24 | 58 | p=0.34, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 0.56 (0.33 to 0.96) |

Overall incidence air leak | 19,20,24–29,31,33,35 | 726 | p=0.35, I^{2}=10% | Risk ratio (M-H, Fixed, 95% CI) | 0.82 (0.61 to 1.09) |

Patent ductus arteriosus | 19–21,25,27–29,31,33 | 689 | p=0.79, I^{2}=0% | Risk ratio (M-H, Fixed, 95% CI) | 1.01 (0.85 to 1.20) |

Retinopathy of prematurity | 20,21,25,27 | 204 | p=0.06, I^{2}=60% | Risk ratio (IV, Random, 95% CI) | 0.79 (0.21 to 3.00) |

Necrotising enterocolitis | 19–21,24,27,29,31 | 541 | p=0 69, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 0.78 (0.47 to 1.29) |

Any episode of hypercarbia | 18,24 | 58 | p=0.20, I^{2}=40% | Risk ratio (M-H, Random, 95% CI) | 1.39 (0.09 to 21.90) |

Neonatal sepsis | 21,29 | 130 | p=0.35, I^{2}=0 | Risk ratio (M-H, Fixed, 95% CI) | 1.04 (0.60 to 1.81) |

Second dose of surfactant | 34,35 | 116 | p=0.56, I^{2}=0% | Risk ratio (M-H, Fixed, 95% CI) | 1.02 (0.81 to 1.30) |

Pulmonary haemorrhage | 19,24 | 230 | | Risk ratio (M-H, Fixed, 95% CI) | 1.04 (0.21 to 5.03) |

Duration of hospitalisation(days) | 20,21 | 117 | p=0.23, I^{2}=32% | Mean difference (IV, Random, 95% CI) | −1.02 (−12.95 to 10.91) |

Ventilatory parameters |

Peak inspiratory pressure(cm H_{2}O) | 14,22,23,25,30,34,35 | 361 | p<0.0001, I^{2}=87% | Mean difference (IV, Random, 95% CI) | 1.14 (−1.34 to 3.62) |

Mean airway pressure(cm H_{2}O) | 14,22,23,25,30,34,35 | 361 | p=0.25, I^{2}=24.7% | Mean difference (IV, Random, 95% CI) | −0.54 (−1.05 to −0.02) |

Minute ventilation (ml/min) | 14,23,34,35 | 226 | p<0.0001, I^{2}=85% | Standard mean difference (IV, Random, 95% CI) | −0.15 (−0.88 to 0.58) |

Inspired oxygen concentration | 14,22,23,25,30,34,35 | 361 | p=0.97, I^{2}=0% | Mean difference (IV, Fixed, 95% CI) | −0.01 (−0.02 to 0.00) |