Abstract
Lung collapse, commonly associated with conditions such as atelectasis, pneumonia, and acute respiratory distress syndrome, significantly impairs gas exchange and respiratory function. Monitoring lung re-aeration is therefore crucial in evaluating the effectiveness of therapeutic interventions, including non-invasive ventilation, invasive mechanical ventilation, and physiotherapy, which aim to restore lung volume and improve respiratory efficiency. Lung re-aeration involves two key physiological processes such as recruitment and inflation. Both mechanisms improve lung compliance and optimize ventilation-perfusion matching, improving overall respiratory function. LUS has emerged as a promising alternative for assessing lung aeration, supporting its feasibility in detecting and tracking lung re-aeration across various clinical scenarios, and providing real-time insights into lung recruitment and inflation. This review integrates current evidence on the physiological mechanisms of lung collapse and the clinical applications of ultrasound as a tool for monitoring lung re-aeration, highlighting its potential to optimize respiratory management in critically ill patients.