Bilateral pleural effusion is a common clinical finding with an incidence of 1535 in patients with pleural effusion or on intensive care units. Congestive cardiac failure and neoplastic pleural effusion remain the common causes of bilateral pleural effusions.

In this pilot study, cellular red blood cell count, nucleated cell count, differential cell count and biochemical total protein, lactate dehydrogenase, glucose parameters of pleural fluid were analysed on both sides in 27 patients who underwent ultrasound guided bilateral thoracocentesis on the same day. The aetiologies of the pleural effusions were congestive cardiac failure n12, postcoronary artery bypass graft n13, renal failure n1, and malignant constrictive pericarditis n1. The results showed that the cellular and biochemical measurements of the pleural fluid on one side did not differ and correlated well with those on the other side. This study shows that, unless there is a specific clinical indication, bilateral diagnostic thoracocentesis is not routinely required as it rarely provides any more information than can be obtained by examining the fluid from one pleural cavity. Limitations of the study included small sample size, retrospective study design and, most importantly, limited aetiological causes of pleural effusionsnamely, congestive cardiac failure and postcoronary artery bypass graft in the study group.

Further large scale prospective studies in patients with bilateral pleural effusions of diverse aetiology are required before implementing this recommendation in clinical practice.