All patients considered for thoracotomy should have preoperative spirometry. Patients meeting the criteria outlined below should also have quantitative radionuclide perfusion scanning. Patients felt to be at high risk on the basis of predicted postoperative FEV1 should be considered for exercise assessment. If exercise assessment is performed, an MVO2 of < 10-15 mL/kg/min or a predicted postoperative MVO2 < 10 mL/kg/min identifies a patient at very high risk for complications and mortality. Limited available data support the use of preoperative risk indices to identify patients at high risk (See Table 4). Lung volume reduction surgery may provide new approaches in selected patients with significant obstructive lung disease and concomitant lung cancer.