Background

The ongoing global pandemic of COVID-19 has led to significant morbidity and mortality, and poses unique challenges to medical system, including severe shortages of medical staff, funding, ICU beds, and the number of mechanical ventilators [1]. While the majority of patients are asymptomatic or mildly infected, about 14% of patients develop more severe disease, mainly acute hypoxic respiratory failure (AHRF). AHRF is characterized by hypoxemia, increased respiratory rate, and respiratory distress [2,15]. Therefore, it is necessary to further explore the implementation strategy of awake prone positioning in the future, so as to provide a scientific guidance for clinical practice.

Limitations

As the first meta-analysis of RCTs data in the current field, the quality of the studies we included is very high, and the statistical heterogeneity between different studies is within an acceptable range, which ensures the reliability of meta-analysis results to a great extent. Although statistical heterogeneity is acceptable, the impact of clinical heterogeneity and methodological heterogeneity on meta-analysis results cannot be estimated. For example, the source of patients includes ICU, general ward, and high-acuity units, and the severity of disease varies among patients in different locations. The amount of time patients were given prone ventilation also varied considerably across studies (Prone positioning for at least 6 h [22], 16 h [37], or encouraged to stay in prone positioning all the time[16]). In addition, blinding of trial implementers and patients was unrealistic in the included studies, but we judged that failure to implement blinding did not affect the effect of the intervention based on the implementation details of the studies. This practice is likely to exaggerate the quality of studies. Also, considering the credibility of the results, we include only published studies, not grey studies that have not been peer reviewed, so we may ignore some important findings. In addition, due to the unavailability of data, it is not possible to estimate the impact of adjuvant therapy on the effectiveness of interventions.

Conclusions

The latest evidence from high-quality RCTs suggests that awake prone positioning is safe and feasible for non-intubated patients with AHRF caused by COVID-19 and does not lead to more adverse events than usual care. Awake prone positioning can significantly reduce the intubation rate without increasing the mortality. However, the implementation strategy of awake prone positioning still needs more research.