How to Estimate Pleural Effusion Volume Using Ultrasound

Quantifying pleural effusion volume is essential for effective clinical management, as it helps assess the severity and extent of the condition, directly influencing diagnosis and therapeutic decisions. Accurate measurement allows monitoring the response to treatment and adjusting interventions such as drainage or thoracentesis, ensuring that patients receive appropriate care. Furthermore, it minimizes risks associated with inadequate management, such as excessive drainage, which may lead to complications [1].Ultrasound allows estimation of pleural effusion volume either qualitatively or quantitatively. In the qualitative approach, the effusion is categorized as minimal, moderate, or massive. The quantitative approach uses different formulas for more precise volume assessment. For example, it is possible to estimate the severity of a hemothorax: an intrapleural blood volume 1000 mL as a massive hemothorax [2].Compared with chest radiography, ultrasound offers significant advantages: it is non-invasive, low-cost, widely accessible, and allows frequent repetition. Additionally, it does not expose the patient to radiation. The sensitivity and reliability of thoracic ultrasound exceed those of radiography. While upright chest X-ray requires at least 150 mL of fluid for detection, ultrasound can identify volumes as small as 5 mL, with 100% sensitivity [3].