INTRODUCTION:Prone ventilation is a well-established strategy in patients with severe ARDS as it has been shown to improve survival and mortality. However, in intubated patients with COVID-19 pneumonia, the data are limited, with no substantial evidence supporting its use. This meta-analysis is the first to examine the mortality benefit of prone ventilation in intubated COVID-19 patients. METHODS:A systematic search according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in Medline, Embase, and Web of Science databases was conducted in January 2022 for published studies assessing the mortality benefit of prone ventilation in intubated COVID-19 patients.RESULTS: Four hundred sixty-seven studies were identified. Of those, five studies met the inclusion criteria studies were included. The total number of patients included in the studies was 4247 patients. In four studies, ARDS prevalence was reported. The prone group had a higher prevalence of severe ARDS rates than the supine group. No significant difference was found between prone or supine groups in ICU mortality (OR: 1.39; 95%CI: 0.80-2.43; p=0.24). Regarding overall mortality, No difference was detected between the prone or the supine groups (OR: 1.04; 95%CI: 0.57-1.87; p = 0.9), with significant heterogeneity (I2= 93; p < 0.001). The length of hospital stay (LOS) was reported in two studies. Our analysis showed that LOS did not differ between the prone and supine groups (SMD: 0.77; 95%CI: -0.33-1.86; p=0.17). CONCLUSIONS:Prone ventilation in intubated COVID-19 patients does not offer a mortality benefit. Randomized controlled trials are warranted to confirm this finding and clarify whether specific subpopulations may benefit from prone ventilation.

Whether prone positioning of patients undergoing mechanical ventilation for COVID-19 pneumonia has benefits over supine positioning is not clear. We conducted a systematic review with meta-analysis to determine whether prone versus supine positioning during ventilation resulted in different outcomes for patients with COVID-19 pneumonia. We searched Ovid Medline, Embase, and Web of Science for prospective and retrospective studies up through April 2023. We included studies that compared outcomes of patients with COVID-19 after ventilation in prone and supine positions. The primary outcomes were three mortality measures: hospital, overall, and intensive care unit (ICU). Secondary outcomes were mechanical ventilation days, intensive care unit (ICU) length of stay, and hospital length of stay. We conducted risk of bias analysis and used meta-analysis software to analyze results. Mean difference (MD) was used for continuous data, and odds ratio (OR) was used for dichotomous data, both with 95% CIs.Significant heterogeneity (I 2 ) was considered if I 2 was >50%. A statistically significant result was considered if the p-value was <0.05. Of 1787 articles identified, 93 were retrieved, and seven retrospective cohort studies encompassing 5216 patients with COVID-19 were analyzed. ICU mortality was significantly higher in the prone group (OR 2.22, p=0.0004). No statistically significant difference was observed between prone and supine groups for hospital mortality (OR, 0.95; 95% CI, 0.66-1.37; p=0.78) or overall mortality (OR, 1.08; 95% CI, p=0.71). Studies that analyzed primary outcomes had significant heterogeneity. Hospital length of stay was significantly higher in the prone than in the supine group (MD, 6.06; 95 % CI, p<0.0001). ICU length of stay and days of mechanical ventilation did not differ between the two groups. In conclusion, mechanical ventilation with prone positioning for all patients with COVID-19 pneumonia may not provide a mortality benefit over supine positioning.

In the article, it has been mentioned that prone positioning provided a mortality benefit to intubated patients with COVID-19, as opposed to the patients who did not undergo prone positioning. It was reported that of the patients who underwent prone positioning, 77.4% died, as opposed to 83.9% of patients who did not. The authors mentioned some limitations of the study, but we think it needs to be addressed.Several factors affected the outcomes. Firstly patients' demographics were different in both groups. In the supine group, 15.6% of patients were above 80 years old, as opposed to 1.6% in the prone group. Secondly, comorbid conditions were more frequent in the supine group as opposed to the prone group of patients as follows: Congestive heart failure (9% vs 1.6%), chronic kidney disease (12.6% vs 6.5%), and smoking history (6.5% vs 1.6%). Thirdly, critical COVID-19 patients were 67.8% in the supine group as opposed to 46.8% in the prone group. Lastly, the treatment provided differed in both groups, where more patients in the supine group were treated in converted floor intensive care beds (69.8% vs 58.1%) compared to the prone group.

We have read the article entitled "Prone Positioning in intubated and mechanically ventilated patients with SARS-CoV-2" by Chen et al., published in the Journal of Clinical Anesthesia (2021 August) (Chen et al., 2021)[1]. We congratulate the authors for this successful publication and make some contributions.In the article, it has been mentioned in the conclusion that a prolonged prone position is a safe and feasible option to extend survival in patients with COVID-19. It was reported that among the patients that died within 14 days of intensive care admission, 11.8% received prolonged prone positioning, while 52.2% did not. The authors mentioned some study limitations, but it is incomplete.

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