Table 5

Cardiopulmonary exercise test (CPET) peak respiratory responses comparing extremely preterm (EP) children and control children

Mod/sev BPD (mean±SD)No/mild BPD (mean±SD)Control (mean±SD)
RR baseline (breaths/min)*23.0±4.620.2±4.720.6±5.2
RR peak (breaths/min)48.0±12.846.9±10.947.5±12.4
VT/kg baseline (mL/kg)*12.2±4.014.9±6.313.4±5.1
VT/kg peak (mL/kg)†25.7±7.531.9±5.829.5±6.5
VE/kg baseline (mL/kg/min)266±101275±91250±90
VE/kg peak (mL/kg/min)*1393±4281631±4311433±378
Inspiratory capacity baseline (L)1.75±0.561.74±0.741.67±0.58
Inspiratory capacity peak (L)1.84±0.471.85±0.681.94±0.68
SpO2 baseline (%)97.5±2.997.7±2.798.3±1.2
SpO2 peak (%)94.3±4.995.2±4.795.3±4.9
PETO2 peak (mm Hg)103.0±4.8103.8±4.9102.1±10.1
PETCO2 peak (mm Hg)35.6±4.135.6±3.936.1±3.8
VE/VO2 slope27.9±3.327.4±2.726.4±2.8
VE/VCO2 slope*30.5±3.828.9±2.928.6±3.2
BR (%)*18.5±23.615.5±20.924.6±16.9
Expiratory flow limitation (n, %)*16/34 (47%)16/49 (33%)14/59 (24%)
End exercise—dyspnoea4.0±2.84.4±2.23.8±2.4
End exercise—RPE6.0±2.55.6±2.45.0±2.7
  • *p<0.05.

  • †p<0.001.

  • Post hoc ANOVA one-way comparisons (mean±SE).

  • RR baseline: mod/sev BPD 2.8±1.0 breaths/min>no/mild BPD*.

  • VT/kg baseline: mod/sev BPD 2.7±1.1mL/kg<no/mild BPD*.

  • VT/kg peak: mod/sev BPD 6.2±1.4 mL/kg<no/mild BPD†; mod/sev BPD 3.8±1.3 mL/kg<control*; no/mild EP 3.8±1.3 mL/kg>control*.

  • VE/kg peak: mod/sev BPD 233±88 mL/kg/min<no/mild BPD*.

  • VE/VCO2 peak: mod/sev BPD 1.94±0.69<Control*.

  • BR: no/mild BPD 9.0±3.8% <control*.

  • ANOVA, analysis of variance; BPD, bronchopulmonary dysplasia; BR, breathing reserve; mod/sev, moderate/severe, PETCO2, end tidal carbon dioxide tension; PETO2, end tidal oxygen tension; RPE, rating of perceived exertion; RR, respiratory rate; SpO2, oxygen saturation pulse; VCO2, carbon dioxide uptake; VE, minute ventilation; VO2, oxygen uptake; VT, tidal volume.