Prone position reduces the risk of patients with mild or moderate COVID-19 progressing to severe or even critical cases: a retrospective study

BACKGROUND: To investigate whether prone position can reduce the risk of patients with mild or moderate COVID-19 who progress to severe or critical illness. METHODS: The prone position group was treated in prone position on the day of admission in addition to conventional treatment. Indicators such as saturation of pulse oximetry (SpO(2)), heart rate, blood pressure, respiratory rate, and prone position-related adverse events were recorded before prone ventilation, 5 min after prone position and 30 min after prone position. Meanwhile, the cases of severe and critical patients, the percentage of transformation and the final clinical outcome of this group were analyzed. Conversion rates and mortality were calculated for patients with mild or moderate COVID-19 retrieved from the database who received only conventional care without combined prone positioning as control group. RESULTS: (1) A total of 34 patients were included in prone position group. There were significant differences in SpO(2) between the first 4 days after admission and the day of discharge (F = 3.17, P < 0.001). (2) The main complications were back and neck muscle soreness (55.9%), followed by abdominal distension (8.9%). (3) In control group, a total of 4873 cases of mild and moderate patients were included from 19 literatures, with an average deterioration rate of 22.7% and mortality rate of 1.7%. (4) In prone position group, there were no severe or critical transformation cases and also no death cases. The prone position group had a significantly lower deterioration rate when compared with the control group (χ(2) = 9.962, P < 0.01). CONCLUSION: Prone position improves SpO(2) in patients with mild or moderate COVID-19. It can also reduce the percentage of mild or moderate patients progressing to severe or critical patients. The application of prone position is a simple, feasible, safe and effective treatment method in such patients.