Indirect lung injury refers to lung damage caused by systemic factors outside the lungs, such as sepsis or severe trauma, leading to inflammation and increased vascular permeability in the pulmonary capillaries. It is clinically important because it can precipitate acute respiratory distress syndrome (ARDS), requiring prompt recognition and supportive management to prevent respiratory failure. A common complication is the development of diffuse alveolar damage, impairing gas exchange and contributing to hypoxaemia.