Using Cardiopulmonary Exercise Testing to Understand Dyspnea and Exercise Intolerance in Respiratory Disease

  • Test protocol1
  • Evaluating physiological and perceptual responses
    • determine maximum effort first
    • VO2 peak
      • low VO2 peak is associated with increased mortality. So high VO2 threshold is used (84% for abnormal value)
    • ventilatory demand
      • high Ve/VCO2 = needs higher minute ventilation to keep the same PaCO2 = inefficient ventilation
      • during exercise Ve/VCO2 also rises to target mildly low PaCO2 to compensate for metabolic acidosis
      • high Ve/VCO2 corresponds to high Vd/Vt = elevated deadspace to tidal volume = V/Q mismatch
      • as exercise intensity rises, the linear relationship changes slope at RCP (respiratory compensation point)
      • as exercise intensity rises, Ve/VCO2 value falls to nadir, normally < 34. Above 34 is abnormal.
    • pulmonary gas exchange
    • ventilatory reserve: VE peak to MVV
      • FEV1 x 35-40
      • low is bad
    • dynamic operating lung volumes
    • expiratory flow limitation
    • exertional dyspnea
  • Case examples

Footnotes

  1. Stickland MK, Neder JA, Guenette JA, O’Donnell DE, Jensen D. Using Cardiopulmonary Exercise Testing to Understand Dyspnea and Exercise Intolerance in Respiratory Disease. Chest. 2022;161(6):1505-1516. doi:10.1016/j.chest.2022.01.021 ↩ ↩2