Table 3 Duration (mean days (95% CI)) of O2 therapy in all infants and separated by the outcome variable groups.
| Era 1 1997–8 | Era 2 1999–2000 | Era 3 2001–2 | Era 4 2003–4 | p Value | |
|---|---|---|---|---|---|
| All infants | 25.3 (23.3,26.3) | 26.1 (24.3, 27.2) | 28.6 (26.8, 29.3) | 28 (26.6, 29.1) | 1 v. 3, 1 v 4, 2 v 4: <0.05 |
| O2<28 days | 7 (6.5 to 7.4) | 7 (6.5 to 7.5) | 7.3 (6.8 to 7.8) | 7.5 (7.0 to 8.0) | NS |
| O2 28 days | 40.5 (38.6 to 42.6) | 41.6 (39.8 to 43.5) | 42.6 (40.7 to 44.5) | 42.2 (40.5 to 43.9) | NS |
| O2 36 weeks | 92.3 (86.3 to 98.3) | 92.0 (86.2 to 97.8) | 86.6 (81.7 to 91.5) | 82.1 (77.4 to 86.9) | 1 v. 4: <0.05, others: NS |
NS, non‐significant.
Values are given after adjustment for start of prenatal care, maternal hypertension, ethnic origin, antenatal steroid therapy, multiple births, mode of delivery, resuscitation in the delivery room, appropriateness for gestational age and respiratory distress syndrome.