[Awake prone positioning in critically ill patients: mechanisms, evidence and future directions]

Awake prone positioning (APP), as an essential therapeutic strategy for acute hypoxemic respiratory failure, has demonstrated significant clinical value, especially during the coronavirus disease 2019 (COVID-19) pandemic. This article systematically summarizes three physiological mechanisms underlying the oxygenation improvement associated with APP, namely enhanced ventilation in gravity-dependent regions, reduction of dead space, and optimization of the ventilation-perfusion ratio. Furthermore, we comprehensively analyze clinical evidence regarding the role of APP in reducing intubation rates and improving right ventricular function, and discuss key factors influencing its efficacy, including initiation timing, duration, and respiratory support modalities. Based on recent research findings, we propose a personalized "4T" principle (Timing, Target population, Technique, and Time duration) for optimizing APP implementation. Finally, we highlight promising directions for future research, such as phenotype stratification and development of intelligent monitoring devices, providing evidence-based guidance in COVID-19 related acute respiratory failure patients for clinical practice.