Functional effects of pneumonectomy and bilobectomy for lung cancer

28 patients with lung cancer had pulmonary function studies before and 3 months to 3 years after pneumonectomy or bilobectomy. Preoperative profiles showed a slight obstructive pattern with air trapping and perturbated gas exchange. The obstructive pattern was not related to endoscopy findings, but the alveoloarterial gradient oxygen gradient was smaller in those with complete lobar occlusion. After surgery, the volume loss was related to the amount resected, being greater after right pneumonectomy than after left pneumonectomy and least after bilobectomy. The obstructive pattern remained unchanged. Diffusion of carbon monoxide decreased significantly less than volumes after pneumonectomy but proportionally after bilobectomy. Those with increased alveoloarterial oxygen gradient or increased physiologic dead space experienced a significant improvement of their gas exchange after surgery.