Cardiopulmonary exercise testing (CPET) in pulmonary emphysema

In patients affected by chronic obstructive pulmonary disease (COPD), cardiopulmonary response to exercise was never related to the severity of emphysema (E) measured by high resolution computed tomography (HRCT). Sixteen patients (age = 65 +/- 8 yrs; FEV(1) = 54 +/- 18%pred; RV = 160 +/- 28%pred) with moderate to severe E (quantified by lung HRCT as % voxels < -910 HU) were exercised on a cycle-ergometer to exhaustion. Oxygen uptake ((V)over dotO(2)), carbon dioxide output ((V)over dot(CO2)), ventilation ((V)over dot(E)), tidal volume (V(T)), and end-tidal P(CO2) (PET(CO2)) derived variables were measured breath-by-breath. The % of E correlated with: (1) the ratio V(Tpeak)/FEV(1) (r = 0.74; p = 0.001); (2) the (V)over dot(E)/(V)over dot(CO2) slope (r = -0.77; p = 0.0004); (3) PET(CO2) values at peak exercise (r = 0.80; p = 0.0001). Also, the %E was strongly predicted by the following exercise equation: %E(EST) = 58.1 + 11.9 x B(Tpeak)/FEV(1) - 0.8 x Delta(V)over dot(E)/Delta(V)over dot(CO2) (r = 0.94; p < 0.0001). A V(Tpeak)/FEV(1) ratio > 1 is typically observed in severe E patients; furthermore, the (V)over dotE/(V)over dot(CO2) slope and the PETco, peak values decrease and increase respectively as more as the emphysema is severe. (C) 2011 Elsevier B.V. All rights reserved.