Baseline characteristics
| Characteristic n=15 | Definition | Statistics | Results |
| Gestational age | weeks, days | Median (IQR) | 26.4 (25.3–27.6) |
| Birth weight | g | Median (IQR) | 945 (740–1120) |
| Postnatal age | days | Median (IQR) | 19 (17–24) |
| Gender | Female/male | n | 4/11 |
| Ventilation mode | Invasive ventilation/CPAP | n | 2/13 |
| Average FiO2 over 24 hours prestudy | Fraction | Median (IQR) | 0.26 (0.24–0.29) |
| Weight at study entry | g | Median (IQR) | 1197 (1021–1300) |
| Allocation | Oxygenie first/CLiO2 first | n | 7/8 |
CPAP, continuous positive airway pressure; FiO2, fraction of inspired oxygen.