Table 1.
Analysis variables
| Variable | Definition |
|---|---|
| Temperature | |
| Body | Abdominal skin temp in oC |
| Hypothermia | Body temp < 36.5oC |
| Hyperthermia | Body temp > 37.2oC |
| Euthermia | Body temp 36.5oC to 37.2oC |
| Hypothermic episode | Begins when body temp < 36.5oC & ends when body temp ≥ 36.5oC (in min) |
| Hyperthermic episode | Begins when body temp < 37.2oC & ends when body temp ≥ 37.2oC (in min) |
| Acute Respiratory Morbidity | |
| Desaturation | SpO2 < 90% |
| Brady/Desaturation | Heart rate < 100 & SpO2 < 90% |
| Apnea | Time of apnea plus 15 min prior & 5 min after |
| FiO2 increase | Time of FiO2 increase plus 15 min prior to & 5 min after |
| RS increase | Time of PIP, PEEP, or RR increase plus 15 min prior to & 5 min after |
| Chronic Respiratory Morbidity | |
| CRMR | Diagnosis of BPD or SD |
| BPD | FiO2 > 21% at 28 DOL or 36 weeks PMA |
| SD | No diagnosis of BPD, but receiving scheduled diuretic dosing for respiratory symptoms at 36 weeks PMA |
| Covariates | |
| Chorioamnionitis | Maternal diagnosis of chorioamnionitis |
| GA | Gestational age at birth in weeks |
| Birthweight | Birthweight in grams |
| SGA | Birthweight < 10th percentile on growth curve |
| Sex | Female or Male |
| Apgar Scores | Apgar score at 1 & 5 minutes |
| Surfactant | Received at least one dose of surfactant |
| Infection | Sepsis or presumed sepsis during the first 14 DOL |
temp temperature; FiO2 fraction of inspired air; SpO2 peripheral capillary oxygen saturation; min minute; RS respiratory support; BPD bronchopulmonary dysplasia; SD scheduled diuretics dosing; CRMR chronic respirtory morbidity risk; DOL days of life; PMA postmenstrual age; GA gestational age; SGA small for gestational age; IUGR intrauterine growth restriction