The evaluation of pleural effusions in patients with heart failure

Purpose To determine the causes of pleural effusions in patients with heart failure, and the association of the characteristics of these statistics with the use of diuretics. Subjects and methods Eighty-one patients with a definite diagnosis of heart failure who underwent thoracentesis were evaluated. Fluids were classified as transudates or exudates using Light’s criteria. Results Forty-one effusions (in 34 patients) were transudates, and 54 (in 47 patients) were exudates. A specific cause was found for 32 of the exudates (27 patients); except for heart failure, no obvious cause was found for the remaining 22 fluids (20 patients). Euxdates with a specific cause for an exudate were more likely to have at least two of Light’s criteria (18 of 27 [67%]) than did exudates without a known cause (2 of 21 [10%]). Intravenous diuretic therapy in the 24 hours before thoracentesis was significantly more common among patients with exudates without a specific cause. Conclusions Patients with heart failure may have exudative pleural effusions without an obvious cause except heart failure.