Table. Baseline Characteristicsa.
| SUPPORT15,16 (n = 1316) |
COT17 (n = 1201) |
BOOST NZ18 (n = 340) |
BOOST II UK19,20 (n = 973) |
BOOST II AUS19,20 (n = 1135) |
Spo2 Target | ||
|---|---|---|---|---|---|---|---|
| Lower (n = 2480) |
Higher (n = 2485) |
||||||
| Mothers at Birth | |||||||
| Use of antenatal corticosteroids, No. (%) | |||||||
| None | 50 (3.8) | 131 (10.9) | 38 (11.2) | 88 (9.0) | 106 (9.3) | 215 (8.7) | 198 (8.0) |
| Partial courseb | 326 (24.8) | 259 (21.6) | 89 (26.2) | 272 (28.0) | 293 (25.8) | 609 (24.6) | 630 (25.4) |
| Full course | 939 (71.4) | 807 (67.4) | 213 (62.6) | 607 (62.4) | 727 (64.1) | 1648 (66.5) | 1645 (66.3) |
| Type of delivery, No. (%) | |||||||
| Normal vaginal | 433 (32.9) | 462 (38.6) | 149 (43.8) | 593 (61.1) | 511 (45.0) | 1064 (43.0) | 1084 (43.7) |
| Instrumental vaginal | 0 | 3 (0.3) | 5 (1.5) | 0 | 18 (1.6) | 10 (0.4) | 16 (0.6) |
| Cesarean | 883 (67.1) | 732 (61.2) | 186 (54.7) | 378 (38.9) | 600 (52.9) | 1400 (56.5) | 1379 (55.5) |
| Infants at Birth | |||||||
| Birth weight, mean (SD), g | 830 (193) | 837 (193) | 879 (194) | 821 (185) | 825 (184) | 829 (187) | 836 (192) |
| Girls, No. (%) | 604 (45.9) | 546 (45.5) | 160 (47.1) | 456 (46.9) | 546 (48.1) | 1169 (47.1) | 1143 (46.0) |
| Gestational age, wk | |||||||
| Median (IQR) | 26.3 (25.3-27.1) |
26.0 (25.0-27.0) |
26.2 (25.2-27.0) |
26.1 (25.0-27.1) |
26.1 (25.1-27.0) |
26.0 (25.0-27.0) |
26.0 (25.0-27.0) |
| <26, No. (%) | 565 (42.9) | 512 (42.6) | 144 (42.4) | 431 (44.3) | 481 (42.4) | 1063 (42.9) | 1070 (43.1) |
| ≥26, No. (%) | 751 (57.1) | 689 (57.4) | 196 (57.6) | 542 (55.7) | 654 (57.6) | 1417 (57.1) | 1415 (56.9) |
| Small for gestational age, No. (%) | |||||||
| Defined by trial investigatorsc | 96 (7.3) | 105 (8.7) | 30 (8.8) | 147 (15.2) | 158 (13.9) | 267 (10.8) | 269 (10.8) |
| Defined by NeOProMd | 210 (16.0) | 105 (8.7) | 30 (8.8) | 113 (11.6) | 158 (13.9) | 302 (12.2) | 314 (12.6) |
| Apgar score at 5 min, median (IQR)e | 7 (6-8) | 7 (6-8) | 8 (6-9) | 7 (6-8) | 7 (6-8) | 7 (6-8) | |
| Admission temperature, mean (SD), °C | 36.2 (0.9) | 36.4 (0.9) | 36.4 (1.0) | 36.6 (0.9) | 36.0 (1.0) | 36.3 (1.0) | 36.3 (0.9) |
| Inborn, No. (%)f | 1316 (100) | 1105 (92.0) | 316 (92.9) | 854 (88.0) | 1049 (92.4) | 2327 (93.8) | 2313 (93.1) |
| Inspired oxygen concentration immediately prior to randomization, median (IQR), %e,g | 21 (21-25) | 21 (21-25) | 21 (21-24) | 21 (21-25) | 21 (21-25) | ||
| Infants at Randomization | |||||||
| Oximeter calibration software, No. (%) | |||||||
| Original | 1316 (100) | 564 (47.0) | 340 (100) | 228 (23.4) | 692 (61.0) | 1569 (63.3) | 1571 (63.2) |
| Revised | 0 | 563 (46.9) | 0 | 745 (76.6) | 443 (39.0) | 879 (35.4) | 872 (35.1) |
| Mixed | 0 | 74 (6.2) | 0 | 0 | 0 | 32 (1.3) | 42 (1.7) |
| Time intervention started <6 h, No. (%)e | 1283 (99.2) | 53 (4.4) | 56 (16.5) | 119 (10.5) | 752 (38.0) | 759 (38.3) | |
| Positive airway pressure, No. (%)e | |||||||
| With endotracheal tubeh | 835 (63.9) | 925 (77.0) | 230 (67.6) | 714 (63.0) | 1337 (67.3) | 1367 (68.5) | |
| Without endotracheal tubei | 449 (34.4) | 242 (20.1) | 109 (32.1) | 410 (36.2) | 621 (31.3) | 589 (29.5) | |
| Oxygen treatment without positive airway pressure, No. (%)e | 11 (0.8) | 3 (0.2) | 0 | 1 (0.1) | 9 (0.5) | 6 (0.3) | |
| No respiratory support, No. (%)e | 12 (0.9) | 31 (2.6) | 1 (0.3) | 9 (0.8) | 20 (1.0) | 33 (1.7) | |
Abbreviations: AUS, Australia; BOOST, Benefits Of Oxygen Saturation Targeting; COT, Canadian Oxygen Trial; IQR, interquartile range; NZ, New Zealand; Spo2, oxygen saturation as measured by pulse oximetry; SUPPORT, Surfactant, Positive Pressure and Pulse Oximetry Randomized Trial; UK, United Kingdom.
Denominators include the total number of infants with a known outcome.
Mother did not receive the full 2 doses within 48 hours before birth.
Defined using trial-specific definitions.
Defined as less than the 10th percentile using charts from Kramer et al.28
Data were not available from BOOST II UK for this variable.
Indicates infant was born in the treating center.
Data were not available from SUPPORT for this variable.
Includes all forms of positive pressure ventilation.
Includes all other forms of respiratory support including continuous positive airway pressure and nasal cannula oxygen (high or low flow).