IMPROVEMENT IN PULMONARY-FUNCTION AND ELASTIC RECOIL AFTER LUNG-REDUCTION SURGERY FOR DIFFUSE EMPHYSEMA

Background. Pulmonary function may improve after surgical resection of the most severely affected lung tissue (lung-reduction surgery) in pa tients with diffuse emphysema, The basic mechanisms responsible for th e improvement, however, are not known. Methods. We studied 20 patients with diffuse emphysema before and at least three months after either a unilateral or a bilateral lung-reduction procedure. Clinical benefit was assessed by measurement of the six-minute walking distance and th e transitional-dyspnea index, which is a subjective rating of the chan ge from base line in functional impairment and the threshold for effor t- and task-dependent dyspnea, Pressure-volume relations in the lungs were measured with static expiratory esophageal-balloon techniques, an d right ventricular systolic function was assessed by echocardiography . Results. The patients had significant improvement in the transitiona l-dyspnea index after surgery (P<0.001), The mean (+/-SD) coefficient of retraction, an indicator of elastic recoil of the lung, improved (f rom 1.3+/-0.6 cm of water per liter before surgery to 1.8+/-0.8 after, P<0.001), Sixteen patients with increased elastic recoil had a greate r increase in the distance walked in six minutes than the other four p atients, in whom recoil did not increase (P=0.02), The improved lung r ecoil led to disproportionate decreases in residual volume as compared with total lung capacity (16 percent vs. 6 percent), but the decrease s in both values were significant (P<0.001), Forced expiratory volume in one second increased (from 0.87+/-0.36 to 1.11+/-0.45 liters, P<0.0 01), End-expiratory esophageal pressure also decreased (P=0.002), Thes e improvements in lung mechanics led to a decrease in the partial pres sure of arterial carbon dioxide from 42+/-6 to 38+/-5 mm Hg (P=0.006). Furthermore, the fractional change in right ventricular area, an indi cator of systolic function, increased from 0.33+/-0.11 to 0.38+/-0.10 (P=0.02). Conclusions. Lung-reduction surgery can increase the elastic recoil of the lung in patients with diffuse emphysema, leading to sho rt-term improvement in dyspnea and exercise tolerance. (C) 1996, Massa chusetts Medical Society.