Table 2.
Range for total sample and explanations of variables used
| Variable | Minimum | Maximum | Explanation |
| Age_D | 1 | 31 | Age in days (~ = time on ventilator) |
| APGAR_1 | 0 | 9 | APGAR Score at 1 minute |
| APGAR5_1 | -2 | 7 | Difference between APGAR at 1 and 5 minutes |
| BE | -7.5 | 6 | Base excess content in blood |
| BP | 28.5 | 67 | Blood pressure |
| CurrWeight | 808 | 1600 | Current weight |
| dBE | -4.5 | 1.7 | Change in base excess since last measurement |
| dBP | -13.7 | 27.0 | Change in blood pressure since last measurement |
| dFIO2 | -30.0 | 21.8 | Change in FiO2 since last measurement |
| dHCO3 | -3.0 | 4.0 | Change in HCO3 since last measurement |
| dIErat | -3.5 | 2.8 | Change in I:E ratio since last measurement |
| dINSP | 0.0 | 1.0 | Change in INSP since last measurement |
| dMAP | -2.4 | 1.1 | Change in MAP since last measurement |
| dPaCO2 | -6.4 | 22.0 | Change in PaCO2 since last measurement |
| dPaO2 | -63.3 | 50.0 | Change in PaO2 since last measurement |
| dPEEP | -3.0 | 1.3 | Change in PEEP since last measurement |
| dPH | -0.2 | 0.1 | Change in pH since last measurement |
| dPIP | -3.0 | 2.4 | Change in PIP since last measurement |
| dPulse | -27.0 | 42.0 | Change in heart rate since last measurement |
| dRATE | -15.0 | 10.6 | Change in ventilatory breathing rate since last m. |
| dRRatio | -3.3 | 3.4 | Change in rate ratio (spont. vs. vent.) since last m. |
| dSaO2 | -4.0 | 15.0 | Change in SaO2 since last measurement |
| dTIME | 0.3 | 51.6 | Time between last two blood gases analyses |
| dVT | -1.8 | 2.5 | Change in VT |
| FiO2 | 20 | 60 | Oxygen content in air delivered by ventilator |
| Gst_age | 25 | 35 | Gestational age |
| HCO3 | 16 | 35 | Bicarbonate content in blood |
| IEratio | 1 | 17.2 | I : E ratio (inspiratory to expiratory time) |
| INSP | 0.23 | 0.5 | Inspiratory time |
| Lag | 0.25 | 17.5 | Lag time between last blood gas result and extubation |
| MAP | 4.2 | 10.9 | Mean airway pressure |
| PaCO2 | 23 | 65 | Partial pressure of carbon dioxide in blood |
| PaO2 | 23 | 228 | Partial pressure of oxygen in blood |
| PEEP | 3 | 5 | Positive end-expiratory pressure |
| pH | 7.24 | 7.58 | Acidity or alkalinity of blood |
| PIP | 10 | 21 | Peak inspiratory pressure |
| Pulse | 112 | 187 | Heart rate |
| R_ratio | 0.4 | 6.0 | Ratio: spontaneous breathing rate/ventilatory rate |
| Rate | 10 | 60 | Ventilatory breathing rate |
| Saline | 0 | 26 | Saline bolus within 24 hours prior to extubation |
| SaO2 | 79 | 100 | Oxygen saturation in blood |
| Theoph | 0 | 8.3 | Theophilline bolus within 24 hours prior to extubation |
| VT | 3 | 15.7 | Tidal volume |
| TXBETAME | 0 | 1 | Maternal betamethasone |