Prone positioning in non-intubated COVID-19 patients with acute respiratory failure may transiently improve blood oxygenation levels

1. Non-intubated patients with COVID-19-related pneumonia had substantial, yet non-sustained, improvements in their PaO₂/FiO₂ ratio by over 50% after 10 minutes of prone positioning.

2. Patients who had sustained responses to prone positioning were generally prone positioned earlier and had higher inflammatory responses; however, rates of intubation between responders and non-responders were comparable.

Evidence Rating Level: 2 (Good)

Study Rundown: There has been a substantial increase in the burden of acute respiratory failure requiring intensive care and invasive ventilation among hospitalized patients due to the COVID-19 pandemic. Prone positioning has been shown to improve oxygenation, improve alveolar recruitment and decrease risks of mortality and ventilator-induced lung injury in the setting of acute respiratory distress syndrome. However, this strategy has not been examined in non-ventilated, spontaneously breathing patients requiring supplemental oxygen therapy.

This single-center, prospective cohort study examined the feasibility and efficacy of three hours of prone positioning in 56 non-intubated adult patients with COVID-19-related pneumonia requiring supplemental oxygen or continuous positive airway pressure in Monza, Italy. Prone positioning was associated with improvements in oxygenation from baseline to 10 minutes post-proning, but the improvements were not maintained after return to supine positioning in 50% of patients. The subset of patients with sustained response tended to be proned earlier and had significantly lower platelets and higher inflammatory markers than non-responders; however, intubation rates were comparable between responders and non-responders. Important limitations included lack of a control group and potential selection bias with non-consecutive enrolment, enrolment of patients requiring both CPAP and conventional oxygen therapy, and a single-centre design.

Click to read the study in The Lancet Respiratory Medicine

Click to read an accompanying editorial in The Lancet Respiratory Medicine

Relevant Reading: Prone positioning improves oxygenation in spontaneously breathing nonintubated patients with hypoxemic acute respiratory failure: A retrospective study

In-Depth [prospective cohort]: This single-center, prospective cohort study aimed to test the feasibility and efficacy of prone positioning in non-intubated patients with COVID-19-related pneumonia in Monza, Italy. Fifty-six patients aged 18-75 with confirmed COVID-19-related pneumonia requiring supplemental oxygen or continuous positive airway pressure (CPAP) were included; of note, patients with impending requirement of invasive ventilation were excluded. Oyxgenation was assessed at baseline (timepoint SP₁) and 10 minutes after assisted prone positioning (timepoint PP₁), and patients were supinated after 3 hours of pronation; measurements were repeated 1 hour after supination (timepoint SP₂). Amongst 47 (83.9%) patients who tolerated prone positioning, data was available from 46. Findings showed that blood oxygenation improved by over 50% from baseline to 10 minutes after prone positioning (SP₁ vs. PP₁ PaO₂/FiO₂ ratio difference 104.9mmHg; 95% CI 10.9 to 134.0). However, this improvement was not maintained on average after supine positioning was resumed (SP₁ vs. SP₂ PaO₂/FiO₂ ratio difference 12.3mmHg; 95% CI -10.9 to 35.5; p=0.29). Improvements in blood oxygenation were maintained in 23 (50%) patients; these individuals were proned earlier and had significantly lower platelets and higher inflammatory markers than non-responders. Intubation rates were comparable between responders and non-responders (30% vs. 26%; p=0.74). Important limitations include lack of a control group and potential selection bias with non-consecutive enrolment, enrolment of patients requiring both CPAP and conventional oxygen therapy, and a single-centre design. Overall, this study suggests that prone positioning of non-intubated patients with COVID-19-related acute respiratory failure is feasible, and might provide significant, if transient, benefit to oxygenation levels.

Image: PD

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