Richard W. Light

In this prospective study of 150 pleural effusions, the utility of pleural-fluid cell counts, protein levels, and lactic dehydrogenase (LDH) levels for the separation of transudates from exudates was evaluated. According to preset diagnostic criteria, 47 of the effusions were classified as transudates and 103 as exudates. Three characteristics were found, each of which was associated with over 70% of the exudates and, at most, one of the transudates: [1] a pleural fluid-to-serum protein ratio greater than 0.5; [2] a pleural fluid LDH greater than 200 IU; and [3] a pleural fluid-to-serum LDH ratio greater than 0.6. Moreover, all but one exudate had at least one of these three characteristics, whereas only one transudate had any of the three. The simultaneous use of both the pleural-fluid protein and LDH levels better differentiates transudates from exudates than does the use of either of these values individually.

Although their clinical efficacy is unclear and they may cause serious adverse effects, systemic glucocorticoids are a standard treatment for patients hospitalized with exacerbations of chronic obstructive pulmonary disease (COPD). We conducted a double-blind, randomized trial of systemic glucocorticoids (given for two or eight weeks) or placebo, in addition to other therapies, for exacerbations of COPD. Most other care was standardized over the six-month period of follow-up. The primary end point was treatment failure, defined as death from any cause or the need for intubation and mechanical ventilation, readmission to the hospital for COPD, or intensification of drug therapy.

A 70-year-old man with an 80-pack-year history of smoking and a history of congestive heart failure presents with increasing shortness of breath. He also has aching chest pain on the right side that worsens with deep inspiration. He is afebrile. The chest radiograph reveals asymmetrical bilateral pleural effusions, with more fluid on the right. How should this patient be evaluated?