Mechanisms of exertional dyspnea in postsurgical patients with non-small cell lung cancer

The aim of the current study was to investigate the factors contributing to exertional dyspnea in individuals who received thoracic surgery with curative intent for non-small cell lung cancer (NSCLC). It was hypothesized that greater neuromechanical uncoupling (NMU: an imbalance between ventilatory effort and output) would result in greater dyspnea and exercise intolerance in NSCLC. Using a cross-sectional design, postsurgical NSCLC patients (n=22) performed a pulmonary function test, an incremental cycling cardiopulmonary exercise test (CPET) and constant-load exercise at 75% maximum work rate to symptom limitation. Dyspnea was measured using the multidimensional dyspnea profile and ventilatory parameters and esophageal pressures were measured continuously. Dyspnea was higher in patients with NSCLC compared to age and sex-matched controls at an absolute isoload in the CPET (p<0.05). NMU was unchanged during exercise and was similar to controls (p>0.05) despite reduced ventilatory capacity (VEpeak>85%MVV) and ventilatory constraint (VTpeak/TLC, p<0.05) in NSCLC. VO2peak was reduced in NSCLC (17.8±4.5 vs. 25.3±3.6 ml/kg/min, p<0.01) and was accompanied by lower VE, IC, IRV and SpO2 at peak exercise (p<0.05). Peak dyspnea was not different between groups (p>0.05). Constant-load exercise time was reduced in NSCLC, as was IC and IRV at end-exercise (p<0.05). We observed no differences in dyspnea or NMU between NSCLC and controls during consta...
Source: European Respiratory Journal - Category: Respiratory Medicine Authors: Tags: Clinical respiratory physiology, exercise and functional imaging Source Type: research