Unilateral or Bilateral Thoracocentesis for Bilateral Pleural Effusion. A Prospective Study.

INTRODUCTION: In the absence of firm recommendations, we analyzed whether unilateral thoracic puncture is sufficient for bilateral pleural effusion (PE), or if the procedure needs to be performed in both sides.

MATERIALS AND METHODS: Prospective study of patients seen consecutively for bilateral PE during a period of 3 years and 9 months. All patients underwent simultaneous bilateral thoracocentesis. The standard protocol variables collected in our hospital served as study parameters. Size of PE, presence of chest pain or fever, or accompanying lung abnormalities, different attenuation values on chest computed tomography, presence of loculated pleural fluid, and radiological resolution in a single side were also evaluated.

RESULTS: A total of 36 patients (19 men; mean age 68.5 ± 16.5 years) were included. The etiology of the effusion was different in each side in only 2 patients (5.6%). In 6/32 cases (18.8%), the biological analysis of the pleural fluid (in terms of transudate/exudate) from both sides did not correspond with the etiological diagnosis of the effusion. Correlation between biochemical parameters analyzed in the fluid from both sides (Pearson's correlation coefficient) ranged between 0.74 (LDH) and 0.998 (NT-proBNP). As different diagnoses in each side were found in only 2 patients, the circumstances in which bilateral diagnostic thoracocentesis would be necessary could not be determined.

CONCLUSIONS: Simultaneous bilateral thoracocentesis does not appear to be recommendable. Larger series are needed to establish which factors might suggest the need for simultaneous puncture of both PE.