Effects of lung resection on pulmonary function and exercise capacity.

The effects of lung resection on exercise capacity and perception of symptoms were studied in 47 patients aged 39-73 (mean 58.3) years. Twenty had a pneumonectomy and 27 a lobectomy, all for lung cancer. Forced expiratory volume, maximal inspiratory and expiratory pressures, and progressive maximal one minute incremental cycle ergometer exercise performance were measured before and after surgery. Breathlessness and leg discomfort were assessed with a modified Borg scale (0-10). Mean FEV1 decreased from 79% (SD 22%) to 53% (11%) of the predicted value after pneumonectomy and from 89% (22%) to 74% (18%) after lobectomy. Exercise capacity, measured as the highest work load completed, Wmax, decreased from 78% (25%) to 58% (28%) predicted in the pneumonectomy group and from 77% (21%) to 67% (20%) in the lobectomy group. There was only a weak relation between changes in FEV1 and changes in Wmax (r = 0.54, r2 = 0.30). The slope of the relation between the intensity of dyspnoea and work load or the intensity of dyspnoea and ventilation increased significantly after pneumonectomy, but not after lobectomy. Leg discomfort increased more rapidly when related to work load after both pneumonectomy and lobectomy. After resection dyspnoea was rarely the only limiting factor at maximal exercise. It is concluded that (1) change in FEV1 is a poor predictor of change in exercise capacity after lung resection; (2) pneumonectomy results in a 25% decrease in Wmax and in an appreciable increase in dyspnoea during exercise; (3) lobectomy has little or no effect on Wmax or the intensity of postoperative dyspnoea; (4) after both pneumonectomy and lobectomy leg discomfort makes an important contribution to exercise limitation.