Pleural effusion is a common clinical condition. Congestive heart
failure (CHF) is the most frequent cause of pleural effusions, which typically
are transudates, but occasional patients with CHF are found to have
exudates in the absence of an appa
rent cause other than CHF, and the
presence of CHF does not always explain exudative effusions in those
patients. We aimed to determine the incidence, clinical significance of such
exudative effusions and to study the effects of diuretics on characteristics of
pleural fluid in patients with CHF accompanied with pleural effusion.