Differences between preterm participants with and without expiratory flow limitation (EFL)
| With EFL | Without EFL | |
| Subjects n | 45 | 61 |
| BPD | 34 (76%)* | 30 (49%) |
| Male | 28 (62%) | 43 (70%) |
| Gestation PMA weeks | 27.0 (25.0–29.2) | 28.6 (25.3–30.2) |
| Mechanical ventilation days | 5.0 (1.3–30.1) | 2.0 (0.0–13.5) |
| CPAP days | 6.5 (1.0–24.9) | 5.6 (0.6–15.7) |
| Supplemental oxygen days | 74.0 (28.0–94.5)* | 22.0 (1.0–83.5) |
| FEV1 z-score | −1.31±0.96* | −0.12±0.83 |
| FVC z-score | −0.40 (−0.57–0.78) | 0.22 (−0.51–1.13) |
| FEV1/FVC z score | −1.85±0.89* | −0.71±0.83 |
| V′O2 peak L·min−1 | 1.54 (1.40–1.78) | 1.63 (1.42–1.86) |
| V′O2 peak mL·kg·min−1 | 49.6 (43.2–52.3) | 47.5 (42.4–52.3) |
| Peak RQ | 1.03 (1.01–1.05) | 1.01 (0.99–1.02) |
| Maximum heart rate beats·min−1 | 197 (187–207) | 195 (186–202) |
| VT L·kg−1 | 25 (22–28) | 25 (22–28) |
| fR breaths·min−1 | 62 (53–70) | 60 (52–69) |
| Maximum V′E L·min−1·kg−1 | 1.55 (1.36–1.74) | 1.43 (1.30–1.67) |
| Breathing reserve % | 31.1 (26.4–35.6) | 35.5 (29.3–38.5) |
| Exercise symptoms | 21 (48%) | 23 (40%) |
| Docter diagnosed asthma ever | 23 (52%)* | 17 (29%) |
| Current asthma medication | 4 (9%) | 10 (17%)* |
Data are presented as mean±sd, median (interquartile range) or n (%), unless otherwise stated. Not all children completed every question in the symptom questionnaire. BPD: bronchopulmonary dysplasia; PMA: postmenstrual age; CPAP: continuous positive airway pressure; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; V′O2: oxygen uptake; RQ: respiratory quotient; VT: tidal volume; fR: respiratory frequency; V′E: minute ventilation. *: p<0.05.