Patient Self-Inflicted Lung Injury in ARDS: From Physiological Concept to Clinical Syndrome

In acute respiratory distress syndrome (ARDS), spontaneous breathing is often encouraged to preserve lung function, yet excessive patient-generated inspiratory effort can paradoxically worsen injury, a phenomenon termed patient self-inflicted lung injury (P-SILI). In mechanically heterogeneous lungs, uncontrolled effort amplifies regional stress, strain, and mechanical power, driving alveolar overdistension, cyclic recruitment-derecruitment, pendelluft, and inflammation. Cardiovascular consequences include elevated right ventricular afterload, impaired left ventricular filling, and exacerbation of pulmonary edema. While moderate spontaneous breathing may improve aeration in mild injury, evidence shows that vigorous effort in severe ARDS accelerates histological damage and regional lung stress. Early bedside assessment of respiratory drive and inspiratory effort identifies patients at highest risk, enabling targeted interventions. Strategies to preserve protective spontaneous breathing while limiting injurious effort include individualized positive end-expiratory pressure, titrated sedation, prone positioning, and short-term neuromuscular blockade. By integrating continuous physiological monitoring with personalized ventilatory management, clinicians can mitigate P-SILI, protect the diaphragm, and optimize outcomes. Future studies are needed to test physiology-guided interventions and establish evidence-based approaches to safely harness the benefits of spontaneous breathing in ARDS.