Efficacy of Ultrasonography in the Diagnosis of Transudative Pleural Fluids

Abstract

Aims: We aimed to evaluate the efficacy of thoracic ultrasonography (USG) in diagnosis of pleural exudates and transudates using pleural thickness (PT) measurement.

Patients and methods: Patients who underwent investigations for pleural fluid between January 2018 and May 2018 were included in this prospective study. The patients were evaluated using radiologic imaging modalities to detect pleural fluid, and PT was measured using thoracic USG. The patients were then divided into 2 groups according to Light's criteria as transudative pleural fluid (TPF) and exudative pleural fluid (EPF), and the results were compared between the groups.

Results: A total of 73 patients were included in the study. The mean age was 62±15.1 years. Forty-eight patients (65.8%) had EPF and 25 (34.2%) had TPF. Thoracic USG revealed a mean PT of 0.3±0.1 cm in the TPF group and 0.6±0.3 cm in the EPF group (P<0.001). The optimal cut-off value for PT was 0.2 cm in the TPF group. The sensitivity and specificity of thoracic USG were calculated as 87.5% and 56%, respectively.

Conclusion: The measurement of PT using thoracic USG in this study has a high sensitivity but low specificity for identifying transudates from exudates. This approach may be useful in patients who refuse thoracentesis or have a contraindication for the procedure, and in emergency and intensive care unit settings. We recommend further studies to determine the efficacy of thoracic USG studies in patients with pleural fluids.