Prone positioning of nonintubated patients with acute hypoxemic respiratory failure

Since the early pandemic, prone positioning has been broadly utilized for nonintubated patients (so-called 'awake prone positioning, APP') with coronavirus disease 2019 (COVID-19) induced acute hypoxemic respiratory failure (AHRF).Numerous clinical studies have been conducted to investigate the effects of APP on oxygenation, intubation, and mortality. However, several questions remain unclear, such as the patient populations who benefit most from APP, the best length of daily duration on APP, how to improve adherence to APP, and the mechanisms of APP efficacy.APP has been shown to improve oxygenation for patients with COVID-19 induced AHRF and is a safe treatment. However, the benefits of reducing intubation rates are only seen in moderate-to-severe patients who are undergoing HFNC treatment. In these patients, APP should be initiated early and with a target of at least 8 h/day of APP. Pillows under the body and patients-healthcare team collaboration to find the optimal position is essential to enhance patients' adherence. Oxygenation improvement and changes in the lung ultrasound findings may help to identify those patients who are more likely to avoid the need for intubation.