UNASSIGNED: A thorough understanding of the pathogenic mechanisms elicited by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) still requires further research. Until recently, only a restricted number of autopsies have been performed, therefore limiting the accurate knowledge of the lung injury associated with SARS-CoV-2. A multidisciplinary European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group of Forensic and Post-mortem Microbiology-ESGFOR team conducted a non-systematic narrative literature review among coronavirus 2019 disease (COVID-19) pneumonia cases assessing the histopathological (HP) effects of positive airways pressure. HP lung features were recorded and compared between mechanically ventilated (>24 hours) and control (ventilation <24 hours) patients. A logistic regression analysis was performed to identify associations between mechanical ventilation (MV) and HP findings.
UNASSIGNED: A PubMed and MEDLINE search was conducted in order to identify studies published between March 1st 2020 and June 30th 2021.
UNASSIGNED: Seventy patients (median age: 69 years) from 24 studies were analysed, among whom 38 (54.2%) underwent MV longer than 24 hours. Overall, main HP features were: diffuse alveolar damage (DAD) in 53 (75.7%), fibrosis (interstitial/intra-alveolar) in 43 (61.4%), vascular damage-including thrombosis/emboli- in 41 (58.5%), and endotheliitis in only 8 (11.4%) patients. Association of DAD, fibrosis and vascular damage was detected in 30 (42.8%) patients. Multivariate analysis, adjusted by age and gender, identified MV >24 hours as an independent variable associated with DAD (OR =5.40, 95% CI: 1.48-19.62), fibrosis (OR =3.88, 95% CI: 1.25-12.08), vascular damage (OR =5.49, 95% CI: 1.78-16.95) and association of DAD plus fibrosis plus vascular damage (OR =6.99, 95% CI: 2.04-23.97).
UNASSIGNED: We identified that patients mechanically ventilated >24 hours had a significantly higher rate of pulmonary injury on histopathology independently of age and gender. Our findings emphasize the importance of maintaining a protective ventilator strategy when subjects with COVID-19 pneumonia undergo intubation.

A meta-analysis was conducted to investigate the effects of the 45° semi-recumbent position on the clinical outcomes of mechanically ventilated patients.
The PubMed, Embase, and Cochrane medical databases were searched using the keywords \"45°\", \"head-of-bed elevation\", and \"semi-recumbent\". All relevant randomized controlled trials (RCTs) published between 2005 and 2021 were obtained. The Cochrane system for randomized intervention was adopted and the RevMan 5.3.5 software was used to construct forest plots and funnel plots to assess the risk of bias for the included studies.
A total of 128 literatures were initially screened for this meta-analysis, and 7 studies were finally included, with a total of 740 patients. Meta-analysis revealed that the incidence of ventilator-associated pneumonia (VAP) was significantly lower in patients in the 45° semi-recumbent position compared to patients in the 30° semi-recumbent position [odds ratio (OR) =0.48; 95% confidence interval (CI): 0.28 to 0.84; Z=2.59; P=0.009]. Furthermore, the incidence of gastric reflux was significantly lower in patients in the 45° semi-recumbent position compared to patients in the 30° semi-recumbent position (OR =0.50; 95% CI: 0.27 to 0.96; Z=2.09; P=0.04). Meta-analysis demonstrated that the incidence of pressure sores was significantly higher in patients in the 45° semi-recumbent position compared to patients in the 30° semi-recumbent position (OR =1.88; 95% CI: 1.05 to 3.36; Z=2.11; P=0.03).
The 45° semi-recumbent position can reduce the incidence of VAP and gastric reflux in patients undergoing mechanical ventilation (MV), but it may also increase the risk of pressure sores. Thus, consideration should be made based on a comprehensive understanding of the patient\'s condition and physical state.

BACKGROUND: ICU-acquired weakness (ICU-AW) is characterized by neuromuscular damage such as limb weakness, yet the cause of ICU-AW remains unclear, which significantly increases the time a patient spends on mechanical ventilation (MV)/in ICU and can even affect a patient\'s survival rate and quality of life after being discharged. Pulmonary rehabilitation (PR)-related measures can effectively improve the ICU-AW situation, but in the specific implementation actions, many obstacles have been produced, and the treatment effect has been controversial, especially in the application process of mechanically ventilated patients. This study aims to confirm the efficacy of using MV alongside PR for patients with ICU-AW.
METHODS: We obtained related randomized controlled trials (RCTs) from Chinese and English databases. All RCTs relevant to the use of PR in ICU-AW patients were retrieved from the following databases from their date of inception through January 31th, 2021: PubMed, EMBASE, The Cochrane Central Register of Controlled Trials, CINAHL, Joanna Briggs Institute (JBI), Web of Science, The Wanfang Database, and CNKI. This literature underwent screening, quality evaluation, and index data extraction by two independent researchers. The evaluation data were meta-analyzed with RevMan 5.3 software (Cochrane, London, UK).
RESULTS: In total, we analyzed 15 articles which included 1,710 patients. We found that using PR alongside MV can effectively improve a patient\'s Medical Research Council (MRC) muscle strength score [mean difference (MD) =4.92, P=0.07], reduce the prevalence of ICU-AW [odds ratio (OR) =0.24, P<0.001], and shorten both MV duration [standardized mean difference (SMD) =-1.50, P<0.001] and ICU stay (SMD =-0.68, P=0.03).
CONCLUSIONS: Implementing PR alongside MV can effectively reduce ICU-AW in patients. However, our standardized cluster PR study still requires further clarification to confirm how various intervention methods can reduce ICU-AW.

The mortality of acute respiratory distress syndrome (ARDS) remains high, and mechanical ventilation (MV) is an essential means of treatment. During MV, people realize the benefits of spontaneous breathing and the disadvantages of uncontrolled spontaneous breathing. Current methods of monitoring spontaneous breathing include oesophageal manometry, P0.1, and diaphragm function monitoring. However, these methods have limitations and deficiencies. The driving pressure is a new indicator that reflects the strain of the lung, which indicates the volumetric injury of the lung and is independently associated with mortality in ARDS patients. Moreover, in recent studies, driving pressure monitoring has been shown to be feasible in assisted support ventilation. This review summarizes the current state of spontaneous breathing and examines whether it is convenient to monitor driving pressure during spontaneous breathing to achieve lung protection ventilation.