Lung function and exercise variables for children who completed a successful maximal exercise test
| BPD | Non-BPD | Term controls | |
| Subjects n | 64 | 42 | 43 |
| FEV1 z-score | −0.83 (−1.57– −0.17)#,¶ | 0.09 (−0.91–0.37) | 0.04 (−0.57–0.61) |
| FVC z-score | −0.09 (−0.65–0.87)# | 0.37 (−0.25–0.97) | 0.24 (−0.65–0.86) |
| FEV1/FVC z-score | −1.35 (−2.59– −0.80)# | −0.87 (−1.52– −0.41)# | −0.42 (−1.06–0.48) |
| TLC z-score | −0.28 (−0.92–0.53) | 0.25 (−0.50–0.78) | −0.12 (−1.06–0.48) |
| FRC z-score | 0.29 (−0.64–0.87) | 0.71 (−0.19–1.91)# | −0.07 (−0.68–0.36) |
| RV z-score | −0.21 (−1.05–0.30) | 0.01 (−0.85–0.77) | −0.33 (−1.16–0.71) |
| V′O2 peak L·min−1 | 1.53 (1.40–1.76)#,¶ | 1.78 (1.49–1.95) | 1.69 (1.45–2.17) |
| V′O2 peak mL·kg−1·min−1 | 47.7 (42.8–53.2) | 46.1 (42.5–51.7) | 48.1 (45.5–52.4) |
| V′O2 at AT mL·kg−1·min−1 | 26.6 (13.9–47.2) | 31.0 (15.8–38.8) | 34.7 (13.6–45.3) |
| Peak RQ | 1.01 (0.98–1.02)# | 1.03 (1.01–1.06) | 1.04 (1.02–1.06) |
| Peak heart rate beats·min−1 | 196 (187–205) | 195 (185–202) | 200 (195–206) |
| Peak VT mL·kg−1 | 24 (21–27) | 27 (23–30) | 28 (24–31) |
| Peak fR breaths·min−1 | 64 (54–72)¶ | 54 (49–63) | 58 (54–68) |
| Peak V′E L·min−1·kg−1 | 1.53 (1.36–1.72) | 1.40 (1.30–1.68) | 1.55 (1.42–1.81) |
| Breathing reserve % | 34.0 (28.2–35.8) | 37.2 (27.0–38.3) | 34.4 (30.0–37.1) |
| EFL n (%) | 34 (53%)#,¶ | 11 (26%) | 12 (28%) |
| EFL%VT | 27.5 (0.0–60.0)#,¶ | 0.0 (0.0–26.5) | 0.0 (0.0–25.0) |
| ΔIC mL | 25 (−83–193) | 110 (−78–225) | 25 (−90–203) |
| ΔEELV mL | −30 (−145–200) | −50 (−180–170) | −15 (−175–137) |
| ΔEILV mL | 397 (146–557) | 371 (238–648) | 368 (157–723) |
| EELV %TLC rest | 32.0 (27.5–37.4) | 32.1 (28.0–35.1) | 30.1 (25.8–34.9) |
| EELV %TLC peak | 31.8 (28.4–35.9) | 31.9 (27.6–36.6) | 29.9 (27.0–33.7) |
Data are presented as median (interquartile range), unless otherwise stated. BPD: bronchopulmonary dysplasia; non-BPD: preterm children without BPD; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity; TLC: total lung capacity; FRC: functional residual capacity; RV: residual volume; V′O2: oxygen uptake; AT: anaerobic threshold; RQ: respiratory quotient; VT: tidal volume; fR: respiratory frequency; V′E: minute ventilation; EFL%VT: percentage of tidal volume assessed as meeting or exceeding the maximum flow–volume loop; IC: inspiratory capacity; EELV: end expiratory lung volume; EILV: end inspiratory lung volume. #: p<0.05 compared with healthy term controls; ¶: p<0.05 compared with non-BPD.