Clinical Significance and Prognosis of Non-Expandable Lungs in Patients with Unilateral Pleural Effusion

Non-expandable lung (NEL) is a clinical condition where the lung fails to fully expand after pleural effusion drainage, due to pleural disease or bronchial obstruction. Despite its relevant clinical implications, NEL remains under-researched. This study aimed to evaluate the prevalence and clinical significance of NEL in patients with unilateral exudative pleural effusion and to assess its impact on prognosis, complications, and treatment options.

A retrospective analysis of 518 medical thoracoscopy (MT) procedures performed in a University pulmonology center, from 2010 to 2020 was conducted.

NEL was identified in 24.9% of benign pleural effusions (BPE) and 19.0% of malignant pleural effusions (MPEs). In BPE, NEL was more common in older males and associated with mediastinal shift post-drainage. In MPE, NEL significantly increased diagnostic complications (19.2% vs. 3.2%, p = 0.0002) and reduced the likelihood of receiving specific oncological treatments (50.0% vs. 71.6%, p = 0.005). Survival analysis revealed poorer outcomes for NEL patients. In BPE, NEL was associated with a threefold higher mortality risk over 3 years (HR = 3.142, p = 0.0005). Similarly, MPE patients with NEL had a median survival of 8.5 months compared to 16 months for those with re-expandable lungs (HR = 1.695, p = 0.0008).

These findings highlight NEL as a critical prognostic factor in exudative pleural effusions, warranting further research to improve diagnostic and therapeutic strategies tailored to this condition.