Improvements in lung function, exercise, and quality of life in hypercapnic COPD patients after lung volume reduction surgery

Study objective: To determine the impact of preoperative resting hypercapni a on patient outcome after bilateral lung volume reduction surgery (LVRS). Methods: We prospectively examined morbidity, mortality, quality of life (Q OL), and physiologic outcome, including spirometry, gas exchange, and exerc ise performance in 15 patients with severe emphysema and a resting PaCO2 of > 45 mm Hg (group 1), and compared the results with those from 31 patients with a PaCO2 of < 45 mm Hg (group 2). Results: All preoperative physiologic and QOL indices were more impaired in the hypercapnic patients than in the eucapnic patients. The hypercapnic pa tients exhibited a lower preoperative FEV1, a lower diffusing capacity of t he lung for carbon monoxide, a lower ratio of PaO2 to the fraction of inspi red oxygen, a lower 6-min walk distance, and higher oxygen requirements. Ho wever, after surgery both groups exhibited improvements in FVC (group 1, p < 0.01; group 2, p < 0.001), FEV1 (group 1, p = 0.04; group 2, p < 0.001), total lung capacity (TLC; group 1, p = 0.02; group 2, p < 0.001), residual volume (RV; group 1, p = 0.002; group 2, p < 0.001), RV/TLC ratio (group 1, p = 0.03; group 2, p < 0.001), Pace, (group 1, p = 0.002; group 2, p = 0.0 2), 6-min walk distance (group 1, p = 0.005; group 2, p < 0.001), oxygen co nsumption at peak exercise (group 1, p = 0.02; group 2, p = 0.02), total ex ercise time (group 1, p = 0.02; group 2, p = 0.02), and the perceived overa ll QOL scores (group 1, p 0.001; group 2, p < 0.001). However, because the magnitude of improvement was similar in both groups, and the hypercapnic gr oup was more:impaired, the spirometry, lung volumes, and 6-min walk distanc e remained significantly lower post-LVRS in the hypercapnic patients. There mas no difference in mortality between the groups (p = 0.9). Conclusions: Patients with moderate to severe resting hypercapnia exhibit s ignificant improvements in spirometry, gas exchange, perceived QOL, and exe rcise performance after bilateral LVRS. The maximal achievable improvements in postoperative lung function are related to preoperative level of functi on; however, the magnitude of improvement can be expected to be similar to patients with lower resting PaCO2 levels. Patients should not be excluded f rom LVRS based solely on the presence of resting hypercapnia. The long-term benefit of LVRS in hypercapnic patient remains to be determined.