Awake prone position in COVID-19-related acute respiratory failure: a meta-analysis of randomized controlled trials.

BACKGROUND: We aimed to investigate the effects of awake prone positioning (APP) in nonintubated adult patients with acute hypoxemic respiratory failure due to COVID-19. METHODS: The PubMed, Embase, Web of Science and Cochrane Central Register databases were searched up to June 1, 2022. All randomized trials investigating the effects of APP were included in the present meta-analysis. The primary outcome was intubation rate, and the secondary outcomes included the length of intensive care unit (ICU) stay, hospital stay, and mortality. Prescribed subgroup analysis was also conducted. RESULTS: A total of 10 randomized trials enrolling 2324 patients were ultimately included in the present study. The results indicated that APP was associated with a significant reduction in the intubation rate (OR 0.77, 95% CI 0.63 to 0.93, P = 0.007). However, no differences could be observed in the length of ICU stay or hospitalization or mortality. Subgroup analysis suggested that patients in the ICU settings (OR 0.74, 95% CI 0.60 to 0.91, P = 0.004), patients whose median APP time was more than 4 h (OR 0.77, 95% CI 0.63 to 0.93, P = 0.008), and patients with an average baseline SpO2 to FiO2 ratio less than 200 (OR 0.75, 95% CI 0.61 to 0.92) were more likely to benefit from APP, indicated a significantly reduced intubation rate. CONCLUSION: Based on the current evidence, nonintubated adult patients with hypoxemic respiratory failure due to COVID-19 infection who underwent APP were shown to have a significantly reduced intubation rate. However, no differences in ICU or hospital length of stay or mortality could be observed between APP and usual care. REGISTRATION NUMBER: CRD42022337846.

The Association Between Ventilatory Ratio and Mortality of Adult Patients with ARDS: Systematic Review and Meta-Analysis (preprint)

Background: Ventilatory ratio is a simple bedside index of impaired efficiency of ventilation and correlates well with physiological dead space fraction in patients with ARDS. So it was regarded as a dead-space marker associated with mortality in mechanically ventilated adults with ARDS. However, the association between VR and outcome of patients with ARDS remains largely unknown. Methods: : We searched articles in three electronic databases including PubMed, EMBASE and Web of Science. All the English publications up to 1 st Oct. 2021 will be searched without any restriction of countries. All the observational study that investigated the association between ventilatory ratio and the mortality of ARDS patients were identified in this meta-analysis. The main outcome was mortality. Summary estimates of effect using odds ratio (OR) for dichotomous outcomes with accompanying 95% confidence interval (CI) were expressed. Results: : A total of 9 trials enrolling 5638 patients were finally included in this meta-analysis. The results revealed that the use of ventilatory ratio could be significantly related to the mortality in adult ARDS (OR=1.27; 95% CI 1.10 to 1.47; P=0.001). Ventilatory ratio may have the capability of predicting the mortality of NON- COVID-related patients (OR 1.39, 95% CI 1.12 to 1.73 P = 0.003) while it has no predictable significance in patients with COVID (OR 1.18, 95% CI 0.94 to 1.48 P = 0.16). Importantly, the dynamic changes of VR adds more predictable value (OR 1.21 vs 1.19). Conclusion: Our study suggests that ventilatory ratio can be regarded as a valuable marker to predict the mortality of adult patients with ARDS. Compared to patients with COVID, ventilatory ratio is more predictable in patients with NON-COVID. What’s more, the dynamic changes of VR may have the potential to improve the prognostic value.