Associations of Awake Prone Positioning-Induced Changes in Physiology with Intubation: An International Prospective Observational Study in Patients with Acute Hypoxemic Respiratory Failure Related to COVID-19

Introduction: Awake prone positioning has the potential to improve oxygenation and decrease respiratory rate, potentially reducing the need for intubation in patients with acute hypoxemic respiratory failure. We investigated awake prone positioning-induced changes in oxygenation and respiratory rate, and the prognostic capacity for intubation in patients with COVID-19 pneumonia. Methods: International multicenter prospective observation study in critically ill adult patients with COVID-19 receiving supplemental oxygen. We collected data on oxygenation and respiratory rate at baseline, and at 1 h after being placed in prone positioning. The combined primary outcome was oxygenation and respiratory rate at 1 h. The secondary endpoint was treatment failure, defined as need for intubation within 24 h of start of awake prone positioning. Results: Between March 27th and November 2020, 101 patients were enrolled of which 99 were fully analyzable. Awake prone positioning lasted mean of 3 [2–4] h. In 77 patients (77.7%), awake prone positioning improved oxygenation, and in 37 patients (54.4%) it decreased respiratory rate. Twenty-nine patients (29.3%) were intubated within 24 h. An increase in SpO₂/FiO₂ of < 10 (OR 5.1, 95% CI 1.4–18.5, P = 0.01), a failure to increase PaO₂/FiO₂ to > 116 mmHg (OR 3.6, 95% CI 1.2–10.8, P = 0.02), and a decrease in respiratory rate of < 2 breaths/min (OR 3.6, 95% CI 1.3–9.5, P = 0.01) were independent variables associated with need for intubation. The AUC–ROC curve for intubation using a multivariable model was 0.73 (95% CI 0.62–0.84). Conclusions: Awake prone positioning improves oxygenation in the majority of patients, and decreases respiratory rate in more than half of patients with acute hypoxemic respiratory failure caused by COVID-19. One in three patients need intubation within 24 h. Awake prone position-induced changes in oxygenation and respiratory rate have prognostic capacity for intubation within 24 h.