Study objectives: To determine the biochemical
characteristics of large pericardial effusions in various disease
states, and to assess their utility as diagnostic tools.
Setting: An academic university hospital in the Western
Cape, South Africa.
Design: Consecutive, prospective
Patients: One hundred ten hospital
patients > 12 years old, who presented to the echocardiography
department with large pericardial effusions, and 12 control subjects
who underwent open-heart surgery (coronary artery bypass graft or
aortic valve replacement).
Measurements: Fluid was
sent for examination of biochemistry, adenosine deaminase,
microbiology, hematology, and cytology. The etiology of each
pericardial fluid sample was established using predetermined
Results: The biochemistry of pericardial
exudates differed significantly from pericardial transudates. Light’s
criteria (whereby an exudate is defined as having one or more of the
following: pleural fluid/serum protein ratio > 0.5; pleural
fluid/serum lactate dehydrogenase [LDH] ratio > 0.6; and/or pleural
fluid LDH level > 200 U/L) were applied to pericardial fluids and
demonstrated to be the most reliable diagnostic tool for identifying
pericardial exudates. The corresponding sensitivity was 98%.
Conclusion: Although laboratory tests are a useful
guideline when assessing the etiology and pathophysiology of
pericardial effusions, the majority of large, clinically significant
pericardial effusions result from exudative causes.