Physiologic assessment of lung function in patients undergoing laser photoresection of tracheobronchial tumors

We performed YAG laser photoresection in 11 patients with tracheal or mainstem bronchial obstruction due to malignant or benign disorders. We used maximal inspiratory-expiratory flow-volume loops and expiratory volume-time plots to assess air flow limitation. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1), peak expiratory flow (PEF) and iso-volume maximal flows at 50 percent of forced inspiratory and expiratory volume were calculated. Spirograms and flow-volume loops were repeated within 12 to 72 hours of laser resection. All patients had flattened expiratory limbs on their flow-volume loops. All spirometric parameters increased significantly following laser photoresection. In particular, peak flow improved in all patients, and FEV1 improved in nine of 11 patients, even though four patients had moderate to severe obstructive ventilatory defects which persisted after resection and were probably due to longstanding chronic obstructive pulmonary disease. We conclude that flow-volume loops and spirometry are helpful in assessing the site and nature of malignant large airway obstructive processes and, moreover, provide reliable information for evaluating the efficacy of laser photoresection. Serial physiologic studies indicate changes in the caliber of the upper airways and can be used as a simple means of following these patients.