Table 2

Breathing pattern, ventilatory response to CO2, P01 and dyspnoea perception (Borg scale) at baseline (prior to rebreathing)

ControlsCOPD FECOPD IEp Value
N=10N=14N=20FE vs IE
Respiratory rate, /min14.60±3.9716.60±3.4815.75±4.610.5
Tidal volume, L1.18±0.321.24±0.371.08±0.350.3
Minute ventilation (VE), L/min16.79±4.7019.78±3.6116.50±4.580.1
Tidal volume/inspiratory Capacity, %0.6±0.20.6±0.10.5
PetCO2, mm Hg46.15±3.1149.23±4.3550.73±6.420.2
P01, cm H2O1.13±0.483.88±2.08*2.15±1.20*<0.001
Borg score0.20±0.420.82±1.030.97±1.970.3
  • Results are expressed as mean±SD.

  • *p<0.05 vs controls.

  • FE, frequent exacerbation; IE, infrequent exacerbation; PetCO2, end-tidal carbon dioxide tension; P01, mouth occlusion pressure 0.1 s after onset of inspiration.