Objective To determine whether higher positive end- expiratory pressure (PEEP) could provide a survival advantage for patients without acute respiratory distress syndrome (ARDS) compared with lower PEEP. Methods Eligible studies were identified through searches of Embase, Cochrane Library, Web of Science, Medline, and Wanfang database from inception up to 1 June 2021. Trial sequential analysis (TSA) was used in this meta-analysis. Data synthesis Twenty-seven randomized controlled trials (RCTs) were identified for further evaluation. Higher and lower PEEP arms included 1330 patients and 1650 patients, respectively. A mean level of 9.6±3.4 cmH 2 O was applied in the higher PEEP groups and 1.9±2.6 cmH 2 O was used in the lower PEEP groups. Higher PEEP, compared with lower PEEP, was not associated with reduction of all-cause mortality (RR 1.03; 95% CI 0.91–1.18; P =0.627), and 28-day mortality (RR 1.07 ; 95% CI 0.92–1.24; P =0.365). In terms of risk of ARDS (RR 0.43; 95% CI 0.24–0.78; P =0.005), duration of intensive care unit (MD -1.04; 95%CI-1.36 to −0.73; P < 0.00001), and oxygenation (MD 40.30; 95%CI 0.94 to 79.65; P = 0.045), higher PEEP was superior to lower PEEP. Besides, the pooled analysis showed no significant differences between groups both in the duration of mechanical ventilation (MD 0.00; 95%CI-0.13 to 0.13; P = 0.996) and hospital stay (MD -0.66; 95%CI-1.94 to 0.61; P = 0.309). More importantly, lower PEEP did not increase the risk of pneumonia, atelectasis, barotrauma, hypoxemia, or hypotension among patients compared with higher PEEP. The TSA analysis showed that the results of all-cause mortality and 28-day mortality might be false-negative results. Conclusions Our results suggest that a lower PEEP ventilation strategy was non-inferior to a higher PEEP ventilation strategy in ICU patients without ARDS, with no increased risk of all-cause mortality and 28-day mortality. Further high-quality RCTs should be performed to confirm these findings.

The objective of this study was to assess whether convalescent plasma therapy could offer survival advantages for patients with novel coronavirus disease 2019 (COVID-19). An electronic search of Pubmed, Web of Science, Embase, Cochrane library and MedRxiv was performed from January 1st, 2020 to April 1st, 2022. We included studies containing patients with COVID-19 and treated with CCP. Data were independently extracted by two reviewers and synthesized with a random-effect analysis model. The primary outcome was 28-d mortality. Secondary outcomes included length of hospital stay, ventilation-free days, 14-d mortality, improvements of symptoms, progression of diseases and requirements of mechanical ventilation. Safety outcomes included the incidence of all adverse events (AEs) and serious adverse events (SAEs). The Cochrane risk-of-bias assessment tool 2.0 was used to assess the potential risk of bias in eligible studies. The heterogeneity of results was assessed by I^2 test and Q statistic test. The possibility of publication bias was assessed by conducting Begg and Egger test. GRADE (Grading of Recommendations Assessment, Development and Evaluation) method were used for quality of evidence. This study had been registered on PROSPERO, CRD42021273608. 32 RCTs comprising 21478 patients with Covid-19 were included. Compared to the control group, COVID-19 patients receiving CCP were not associated with significantly reduced 28-d mortality (CCP 20.0% vs control 20.8%; risk ratio 0.94; 95% CI 0.87-1.02; p = 0.16; I² = 8%). For all secondary outcomes, there were no significant differences between CCP group and control group. The incidence of AEs (26.9% vs 19.4%,; risk ratio 1.14; 95% CI 0.99-01.31; p = 0.06; I² = 38%) and SAEs (16.3% vs 13.5%; risk ratio 1.03; 95% CI 0.87-1.20; p = 0.76; I² = 42%) tended to be higher in the CCP group compared to the control group, while the differences did not reach statistical significance. In all, CCP therapy was not related to significantly improved 28-d mortality or symptoms recovery, and should not be viewed as a routine treatment for COVID-19 patients.Trial registration numberCRD42021273608. Registration on February 28, 2022Systematic review registrationhttps://www.crd.york.ac.uk/prospero/, Identifier CRD42022313265.

Objectives To investigate the risk factors for death in anti-melanoma differentiation–associated protein-5-positive dermatomyositis-associated interstitial lung disease (ILD). Methods Studies were identified by searching PubMed, Embase, Web of Science, and Cochrane Library. We calculated pooled risk ratios (RRs) or standardized mean differences (SMDs) and 95% confidence intervals (CIs) using random-effects models. Results Twenty studies were selected. Factors that may increase death risk included older age (SMD: 0.62, 95% CI: 0.42–0.81), elevated Krebs von den Lungen-6 (SMD: 0.66, 95% CI: 0.47–0.86), lactate dehydrogenase (SMD: 0.87, 95% CI: 0.72–1.02), C-reactive protein (SMD: 0.62, 95% CI: 0.44–0.80), ferritin (SMD: 0.93, 95% CI: 0.71–1.15), creatine kinase (SMD: 0.28, 95% CI: 0.13–0.44), neutrophil (SMD: 0.34, 95% CI: 0.04–0.64), neutrophil-to-lymphocyte ratio (SMD: 0.52, 95% CI: 0.24–0.79), aspartate aminotransferase (SMD: 0.70, 95% CI: 0.45–0.94), shorter disease duration (SMD: −0.44, 95% CI: −0.67 to −0.21), rapidly progressive ILD (RR: 4.08, 95% CI: 3.01–5.54), fever (RR: 1.98, 95% CI: 1.46–2.69), dyspnoea (RR: 1.63, 95% CI: 1.32–2.02), and anti-Ro52 antibody positive (RR: 1.28, 95% CI: 1.11–1.49). Female (RR: 0.86, 95% CI: 0.78–0.94), increased albumin (SMD: −1.20, 95% CI: −1.76 to −0.64), lymphocyte (SMD: −0.49, 95% CI: −0.67 to −0.30), and arthralgia (RR: 0.53, 95% CI: 0.37–0.78) were protective factors. Conclusion Older age, shorter disease duration, rapidly progressive ILD, fever, dyspnoea, anti-Ro52 antibody positive, and some inflammatory markers were risk factors for death in patients with anti-melanoma differentiation–associated protein-5-positive dermatomyositis-associated ILD.