ELASTANCE OF THE PLEURAL SPACE - A PREDICTOR FOR THE OUTCOME OF PLEURODESIS IN PATIENTS WITH MALIGNANT PLEURAL EFFUSION

Background: In patients who have malignant pleural effusion, it is dif ficult to diagnose trapped lung before thoracoscopy, thoracostomy, and drainage of the effusion. Predicting the outcome of pleurodesis in pa tients who have malignant pleural effusion without trapped lung is als o difficult. Objective: To investigate the factors that may be useful in diagnosing trapped lung and predicting the outcome of pleurodesis. Design: Prospective cohort study. Setting: University medical center. Patients: 65 patients with symptomatic malignant pleural effusion. Int ervention: A chest tube was inserted for drainage of the effusion, and pleurodesis was done using bleomycin as the sclerosant. Measurements: The pH and glucose levels of the effusion and the elastance of the pl eural space (defined as the decline in pleural fluid pressure in cm H2 O after removal of 500 mt of effusion) were measured. The outcome of p leurodesis was evaluated 1 month after the chest tube was removed. Res ults: Patients with an elastance of 19 cm H2O or more had a higher inc idence of trapped lung (11 of 14 patients) than did those with an elas tance less than 19 cm H2O (3 of 51 patients) (P < 0.001). None of the 14 patients with an elastance of 19 cm H2O or more and none of the 14 patients with a trapped lung had successful pleurodesis. Forty-two of 43 patients with an elastance less than 19 cm H2O who did not have a t rapped lung had successful pleurodesis. Elastance seemed to be the bes t predictor for trapped lung and outcome of pleurodesis, although outc ome was also correlated with pH and glucose levels of the effusion. Lo w-dose bleomycin (30 mg) is as effective as the usual dose of bleomyci n (60 mg) for pleurodesis. Conclusion: In patients with symptomatic ma lignant pleural effusion, measurement of the elastance of the pleural space is a simple and effective method for the diagnosis of trapped lu ng and prediction of the outcome of chemical pleurodesis with bleomyci n.