Table 4—

Metabolic data at rest and at peak exerclse of 23 non-flow limited (non-FL) and 29 flow limited (FL) chronic obstructive pulmonary disease patients

RestReak exercise
non-FLFLp-valuenon-FLFLp-value
Pa,O2 mmHg687±260±2<0.0571±2.557±2.1<0.001
Pa,CO2 mmHg38.7±1.343.8±1.20.05438.8±1.648±1.4<0.001
PH7.43±0.017.41±0.01ns7.38±0.017.36±0.01ns
PA–a,O2 mmHg25.8±1.827.3±1.3ns34.4±238.9±1.6ns
VCO2 L·min−10.211±0.010.232±0.01ns1.27±0.070.88±0.04<0.01
VA L·min−16.1±0.55.8±0.3ns23.9±1.713.1±0.8<0.001
VD L0.269±0.020.313±0.03ns0.466±0.040.508±0.03ns
VD L·min−14.28±0.35.2±0.3ns13.8±1.112.8±0.7ns
VD/VT %41±247±2ns37.2±2.649.6±1.9<0.001
Lactate mMol·L−11.3±0.071.1±0.07ns5.93±0.33.97±0.3<0.001
  • Values are presented as mean±sem

  • Pa,O2: arterial oxygen partial pressure

  • Pa,CO2: arterial carbon dioxide partial pressure

  • PA–a,O2: alveolar arterial oxygen partial pressure difference

  • VCO: carbon dioxide production

  • VA: alveolar ventilation

  • VD: physiologic dead space

  • VD: dead space ventilation

  • VD/VT: dead space to tidal volume ratio