Researchers from the University of Oxford in the United Kingdom found that a pleural adherence score derived from thoracic ultrasound (TUS) at 24 hours post-talc administration is predictive of long-term pleurodesis success in patients with symptomatic malignant pleural effusion (MPE). Findings were published in CHEST.

Pleural Effusion

A pleural effusion is an abnormal accumulation of pleural fluid within the pleural space. The most common cause of pleural effusion is congestive heart failure, which tends to have a better prognosis, compared to less common causes of pleural effusions associated with cirrhosis or malignancy. The pleural space lies between the chest wall and lung, and usually contains a small amount of fluid, which helps the two spaces be connected to each other.

A pleural effusion forms when there is an imbalance between the production and absorption of the fluid in the pleural space. Fluid gets into the pleural space either by osmosis from normal venous and pulmonary circulation, or by direct leakage from damaged vessels in the venous and pulmonary circulation system. While the lung lymphatic system is responsible for absorbing this fluid, it can only absorb a small volume of fluid. Fluid tends to accumulate first in the interstitium and then in the pleural space.

In this observational cohort pilot study (ClinicalTrials.gov Identifier: NCT02625675), the researchers recruited patients who were scheduled to undergo chest tube drainage and talc slurry pleurodesis for the treatment of symptomatic MPE (n=18). Immediately before and 24 hours after talc slurry administration, participants underwent a TUS to identify pleural adherence scores for the affected hemithorax.

The TUS scans were recorded by 2 independent blinded assessors. Rate of pleurodesis success at 1- and 3-month follow-up comprised the primary outcome. At 24 hours following talc instillation, a lower pleural adherence score was observed in participants who suffered pleurodesis failure compared with participants who experienced pleurodesis success (difference, 6.27; 95% CI, 3.94-8.59). None of the 11 participants who experienced pleurodesis success at 1-month follow-up experienced delayed failure prior to death (4/11; 36.4%) or at 3-month follow-up (7/11; 63.6%).

The mean TUS-associated pain score on the visual analogue scale was 8.9 mm (SD, 12.9; 95% CI, 1.8-16.1). The TUS scoring was consistent with both assessors (intraclass correlation coefficient, 0.762; 95% CI, 0.605-0.872; P <.001), and patients reported a high level of acceptability of TUS examination. Limitations of the analysis included the small number of patients as well as recruitment from a center with TUS and pleural disease expertise.