The Comprehensive Systematic Review of What is The Relationship Between Pleural Effusion Characteristics and The Occurrence of Compressive Atelectasis in Adult Patients, as Evaluated Through Radiological Imaging Techniques?

Introduction: Pleural effusions are a common clinical finding across diverse medical and surgical conditions, often leading to respiratory compromise. Compressive atelectasis, the collapse of lung tissue due to external pressure from pleural fluid, is a significant contributor to this morbidity. However, the precise relationship between specific characteristics of the effusion (e.g., volume, composition, laterality) and the occurrence of compressive atelectasis remains inadequately defined in adult populations (Chiumello et al., 2013; Muruganandan et al., 2020). Methods: A comprehensive systematic review was conducted, screening sources based on predefined criteria including adult population, presence of pleural effusion, assessment of effusion characteristics, evaluation of compressive atelectasis via radiological imaging, and appropriate study designs. Data were extracted from 80 heterogeneous sources, encompassing observational studies, randomized trials, and meta-analyses, focusing on population details, effusion characteristics, imaging methods, atelectasis definitions, and reported statistical relationships. Results: Direct evidence quantitatively linking effusion characteristics to compressive atelectasis was scarce. Larger effusion size (e.g., >500 mL) was associated with increased incidence of atelectasis, particularly in specific populations like lung transplant recipients (Krumm et al., 2024). Indirect evidence from drainage studies showed consistent improvements in oxygenation (PaO2/FiO2 ratio) and end-expiratory lung volume post-thoracentesis, especially in mechanically ventilated patients with hypoxemia (Goligher et al., 2011; Vetrugno et al., 2019; Chiu et al., 2024). Key thresholds emerged, suggesting drainage is most beneficial for effusions >400-500 mL or occupying ≥25% of the hemithorax, particularly when baseline P:F ratio is