Toracocentesis

The new england journal of medicine

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Thoracentesis
Todd W. Thomsen, M.D., Jennifer DeLaPena, M.D., and Gary S. Setnik, M.D.
INDICATIONS
From the Department ofEmergency Medicine, Mount Auburn Hospital, Cambridge, MA (T.W.T., G.S.S.); the Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Boston (J.D.); and the Division of EmergencyMedicine, Harvard Medical School, Boston (T.W.T., J.D., G.S.S.). Address reprint requests to Dr. Thomsen at the Department of Emergency Medicine, Mount Auburn Hospital, 330 Mount Auburn St., Cambridge, MA02238, or at tthomsen@mah.harvard.edu. N Engl J Med 2006;355:e16.
Copyright © 2006 Massachusetts Medical Society.

Thoracentesis is a valuable diagnostic procedure in a patient with pleural effusionof unknown causation. Analysis of the pleural fluid will allow its categorization as either a transudate (a product of unbalanced hydrostatic forces) or an exudate (a product of increased capillarypermeability or lymphatic obstruction) (Table 1). If the effusion seems to have an obvious source (e.g., in an afebrile patient with congestive heart failure and bilateral pleural effusions), diagnosticthoracentesis may be deferred while the underlying process is treated. The need for the procedure should be reconsidered if there is no appropriate response to therapy.1 Thoracentesis, as atherapeutic procedure, may dramatically reduce respiratory distress in patients presenting with large effusions.
CONTRAINDICATIONS

There are limited data on the safety of thoracentesis in patients who areusing anticoagulant medications or those with coagulopathy or thrombocytopenia. One small study suggests that the procedure is safe and that fresh-frozen plasma is not needed in patients with mildelevations of the prothrombin time or partial-thromboplastin time (0.5 >0.6 >2/3 upper limit of normal for serum

Criteria for differentiation Ratio of pleural fluid protein to serum protein Ratio of...