Table 1. Baseline Characteristics of the Full, Unmatched, and Propensity Score–Matched Cohorts by iNO Status.
| Characteristic | Full Cohort, No. (%) | Matched Cohort, No. (%) | ||||
|---|---|---|---|---|---|---|
| iNO Within First 7 d (n = 185) | No iNO Within First 7 d (n = 582) | Standardized Difference (Absolute Value) | Exposed (n = 151) | Referent (n = 151) | Standardized Difference (Absolute Value) | |
| Maternal Characteristics | ||||||
| Prolonged rupture of membrane | 89 (48.1) | 335 (57.6) | 0.19 | 77 (51.0) | 77 (51.0) | 0 |
| Oligohydramnios | 13 (7.0) | 87 (14.9) | 0.26 | 13 (8.6) | 15 (9.9) | 0.05 |
| Antenatal steroids given | 163 (88.1) | 462 (79.4) | 0.24 | 131 (86.8) | 133 (88.1) | 0.04 |
| Infant Characteristics | ||||||
| Respiratory diagnosis group | ||||||
| Pulmonary hypoplasia without PPHN | 46 (24.9) | 478 (82.1) | 1.40 | 46 (30.5) | 46 (30.5) | 0 |
| Pulmonary hypoplasia with PPHN | 139 (75.1) | 104 (17.9) | 105 (69.5) | 105 (69.5) | ||
| Gestational age, mean (SD), wk | 26.8 (1.7) | 26.1 (1.8) | 0.42 | 26.7 (1.7) | 26.7 (1.6) | 0 |
| Birth weight, mean (SD), kg | 1.04 (0.29) | 0.90 (0.28) | 0.49 | 1.02 (0.30) | 1.03 (0.27) | 0.03 |
| Birth size assessment | ||||||
| Small for gestational age | 10 (5.4) | 62 (10.7) | 0.19 | 10 (6.6) | 7 (4.6) | 0.09 |
| Appropriate for gestational age | 141 (76.2) | 444 (76.3) | 0.002 | 113 (74.8) | 112 (74.2) | 0.02 |
| Large for gestational age | 34 (18.4) | 76 (13.1) | 0.15 | 28 (18.5) | 32 (21.2) | 0.07 |
| Sex | ||||||
| Male | 108 (58.4) | 341 (58.6) | 0.004 | 87 (57.6) | 89 (58.9) | 0.03 |
| Female | 77 (41.6) | 241 (41.4) | 64 (42.4) | 62 (41.1) | ||
| Race/ethnicity | ||||||
| White | 97 (52.4) | 311 (53.4) | 0.02 | 79 (52.3) | 78 (51.7) | 0.01 |
| Asian | 1 (0.5) | 16 (2.7) | 0.17 | 1 (0.7) | 1 (0.7) | 0 |
| Black | 41 (22.2) | 131 (22.5) | 0.01 | 32 (21.2) | 37 (24.5) | 0.08 |
| Hispanic | 30 (16.2) | 93 (16.0) | 0.01 | 25 (16.6) | 26 (17.2) | 0.02 |
| Other | 16 (8.6) | 31 (5.3) | 0.13 | 14 (9.3) | 9 (6.0) | 0.13 |
| Calendar yeara | ||||||
| 2000-2004 | 18 (9.7) | 193 (33.2) | 0.71 | 18 (11.9) | 27 (17.9) | 0.14 |
| 2005-2009 | 62 (33.5) | 202 (34.7) | 51 (33.8) | 51 (33.8) | ||
| 2010-2014 | 105 (56.8) | 187 (32.1) | 82 (54.3) | 73 (48.3) | ||
| Inborn/outborn status | ||||||
| Inborn | 160 (86.5) | 548 (94.2) | 0.26 | 131 (86.8) | 135 (89.4) | 0.08 |
| Outborn | 25 (13.5) | 34 (5.8) | 20 (13.2) | 16 (10.6) | ||
| Surfactant given | 172 (93.0) | 472 (81.1) | 0.36 | 139 (92.1) | 137 (90.7) | 0.05 |
| Maximal respiratory support over days 0-2 | ||||||
| Room air | 0 | 7 (1.2) | 0.45 | 0 | 0 | 0.03 |
| Nasal CPAP | 0 | 6 (1.0) | 0 | 0 | ||
| Conventional mechanical ventilation | 10 (5.4) | 117 (20.1) | 9 (6.0) | 10 (6.6) | ||
| High-frequency oscillatory ventilation | 175 (94.6) | 452 (77.7) | 142 (94.0) | 141 (93.4) | ||
| At least 1 vasopressor reported on days 0-3 | 154 (83.2) | 309 (53.1) | 0.68 | 122 (80.8) | 122 (80.8) | 0 |
Abbreviations: CPAP, continuous positive airway pressure; iNO, inhaled nitric oxide; PPHN, persistent pulmonary hypertension of the newborn.
a
This is categorized for presentation purposes.