Mechanical ventilation in sepsis-induced acute lung injury/acute respiratory distress syndrome: an evidence-based review

Effect of Dopamine as a Vascular Endothelial Growth Factor Antagonist on the Development of Acute Lung Injury in Sepsis Patients

BACKGROUND

Sepsis is a dysregulated host immune response stemming from a systemic inflammatory response to microbial invasion, encompassing bacteria, viruses, and other pathogens. The vascular endothelial growth factor (VEGF) was initially identified for its potent induction of endothelial permeability. Studies have proposed a therapeutic role of dopamine in mitigating VEGF-induced permeability, shedding light on its potential in acute respiratory distress syndrome (ARDS) management.

MAIN OBJECTIVE

To determine the effect of dopamine as an inhibitor of VEGF and to prevent the progression of sepsis to acute lung injury (ALI) and ARDS.

METHODS

A total of 154 critical care unit patients with a diagnosis of sepsis were randomized into two groups: Group I (control group) and Group II (Study group). Both received standard treatment, as per ICU protocol. In addition, the study group (Group II) received a dopamine infusion of 2 micrograms/kg/min. Baseline routine investigation, procalcitonin, and chest X-ray were done. Day one and day seven blood samples were stored for analysis of VEGF levels. Murray's score and sequential organ failure assessment (SOFA) score (organ dysfunction) were calculated from day one to day seven.

RESULTS

VEGF levels on day seven were significantly lower in the study group compared to the control group (p<0.05). The PaO2/FiO2 ratio at day seven was significantly increased in the study group than in the control group, indicating an improvement in oxygenation status in the study group. There was a mean ICU stay of 9.3 days in the study group versus 11.6 days in the control group (p<0.05). The SOFA score showed a significant improvement in the study group from day five onwards, indicating a therapeutic effect of dopamine on organ dysfunction in sepsis.

CONCLUSION

Dopamine reduces VEGF and lung injury mediated by increased endothelial permeability.

Chinese Society of Cardiology guidelines on the diagnosis and treatment of adult fulminant myocarditis

Fulminant myocarditis is an acute diffuse inflammatory disease of myocardium. It is characterized by acute onset, rapid progress and high risk of death. Its pathogenesis involves excessive immune activation of the innate immune system and formation of inflammatory storm. According to China's practical experience, the adoption of the "life support-based comprehensive treatment regimen" (with mechanical circulation support and immunomodulation therapy as the core) can significantly improve the survival rate and long-term prognosis. Special emphasis is placed on very early identification,very early diagnosis,very early prediction and very early treatment.

Identification and Analysis of PANoptosis-Related Genes in Sepsis-Induced Lung Injury by Bioinformatics and Experimental Verification

Purpose

Sepsis-induced lung injury (SLI) is a serious complication of sepsis. PANoptosis, a novel form of inflammatory programmed cell death that is not yet to be fully investigated in SLI. Our research aims to screen and validate the signature genes of PANoptosis in SLI by bioinformatics and in vivo experiment.

Methods

SLI-related datasets were downloaded from NCBI Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) of SLI were identified and intersected with the PANoptosis gene set to obtain DEGs related to PANoptosis (SPAN_DEGs). Then, Protein-Protein Interaction (PPI) network and functional enrichment analysis were conducted based on SPAN_DEGs. SVM-REF, LASSO and RandomForest three algorithms were combined to identify the signature genes. The Nomogram and ROC curves were performed to predict diagnostic value. Immune infiltration analysis, correlation analysis and differential expression analysis were used to explore the immunological characterization, correlation and expression levels of the signature genes. Finally, H&E staining and qRT-PCR were conducted for further verification in vivo experiment.

Results

Twenty-four SPAN_DEGs were identified by intersecting 675 DEGs with the 277 PANoptosis genes. Four signature genes (CD14, GSDMD, IL1β, and FAS) were identified by three machine learning algorithms, which were highly expressed in the SLI group, and had high diagnostic value in the diagnostic model. Moreover, immune infiltration analysis showed that most immune cells and immune-related functions were higher in the SLI group than those in the control group and were closely associated with the signature genes. Finally, it was confirmed that the cecum ligation and puncture (CLP) group mice showed significant pathological damage in lung tissues, and the mRNA expression levels of CD14, IL1β, and FAS were significantly higher than the sham group.

Conclusion

CD14, FAS, and IL1β may be the signature genes in PANoptosis to drive the progression of SLI and involved in regulating immune processes.

Lung single-cell RNA profiling reveals response of pulmonary capillary to sepsis-induced acute lung injury

Background

Sepsis-induced acute lung injury (ALI) poses a significant threat to human health. Endothelial cells, especially pulmonary capillaries, are the primary barriers against sepsis in the lungs. Therefore, investigating endothelial cell function is essential to understand the pathophysiological processes of sepsis-induced ALI.

Methods

We downloaded single-cell RNA-seq expression data from GEO with accession number GSE207651. The mice underwent cecal ligation and puncture (CLP) surgery, and lung tissue samples were collected at 0, 24, and 48 h. The cells were annotated using the CellMarker database and FindAllMarkers functions. GO enrichment analyses were performed using the Metascape software. Gene set enrichment Analysis (GSEA) and variation Analysis (GSVA) were performed to identify differential signaling pathways. Differential expression genes were collected with the "FindMarkers" function. The R package AUCell was used to score individual cells for pathway activities. The Cellchat package was used to explore intracellular communication.

Results

Granulocytes increased significantly as the duration of endotoxemia increased. However, the number of T cells, NK cells, and B cells declined. Pulmonary capillary cells were grouped into three sub-clusters. Capillary-3 cells were enriched in the sham group, but declined sharply in the CLP.24 group. Capillary-1 cells peaked in the CLP.24 group, while Capillary-2 cells were enriched in the CLP.48 group. Furthermore, we found that Cd74+ Capillary-3 cells mainly participated in immune interactions. Plat+ Capillary-1 and Clec1a+ Capillary-2 are involved in various physiological processes. Regarding cell-cell interactions, Plat+ Capillary-1 plays the most critical role in granulocyte adherence to capillaries during ALI. Cd74+ Capillary cells expressing high levels of major histocompatibility complex (MHC) and mainly interacted with Cd8a+ T cells in the sham group.

Conclusion

Plat+ capillaries are involved in the innate immune response through their interaction with neutrophils via ICAM-1 adhesion during endotoxemia, while Cd74+ capillaries epxressed high level of MHC proteins play a role in adaptive immune response through their interaction with T cells. However, it remains unclear whether the function of Cd74+ capillaries leans towards immunity or tolerance, and further studies are needed to confirm this.

The Relationship Between Hospital Capability and Mortality in Sepsis: Development of a Sepsis-Related Hospital Capability Index

OBJECTIVES

Regionalized sepsis care could improve sepsis outcomes by facilitating the interhospital transfer of patients to higher-capability hospitals. There are no measures of sepsis capability to guide the identification of such hospitals, although hospital case volume of sepsis has been used as a proxy. We evaluated the performance of a novel hospital sepsis-related capability (SRC) index as compared with sepsis case volume.

DESIGN

Principal component analysis (PCA) and retrospective cohort study.

SETTING

A total of 182 New York (derivation) and 274 Florida and Massachusetts (validation) nonfederal hospitals, 2018.

PATIENTS

A total of 89,069 and 139,977 adult patients (≥ 18 yr) with sepsis were directly admitted into the derivation and validation cohort hospitals, respectively.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We derived SRC scores by PCA of six hospital resource use characteristics (bed capacity, annual volumes of sepsis, major diagnostic procedures, renal replacement therapy, mechanical ventilation, and major therapeutic procedures) and classified hospitals into capability score tertiles: high, intermediate, and low. High-capability hospitals were mostly urban teaching hospitals. Compared with sepsis volume, the SRC score explained more variation in hospital-level sepsis mortality in the derivation (unadjusted coefficient of determination [ R2 ]: 0.25 vs 0.12, p < 0.001 for both) and validation (0.18 vs 0.05, p < 0.001 for both) cohorts; and demonstrated stronger correlation with outward transfer rates for sepsis in the derivation (Spearman coefficient [ r ]: 0.60 vs 0.50) and validation (0.51 vs 0.45) cohorts. Compared with low-capability hospitals, patients with sepsis directly admitted into high-capability hospitals had a greater number of acute organ dysfunctions, a higher proportion of surgical hospitalizations, and higher adjusted mortality (odds ratio [OR], 1.55; 95% CI, 1.25-1.92). In stratified analysis, worse mortality associated with higher hospital capability was only evident among patients with three or more organ dysfunctions (OR, 1.88 [1.50-2.34]).

CONCLUSIONS

The SRC score has face validity for capability-based groupings of hospitals. Sepsis care may already be de facto regionalized at high-capability hospitals. Low-capability hospitals may have become more adept at treating less complicated sepsis.

Association between the timing of ICU admission and mortality in patients with hospital-onset sepsis: a nationwide prospective cohort study

BACKGROUND

Based on sparse evidence, the current Surviving Sepsis Campaign guideline suggests that critically ill patients with sepsis be admitted to the intensive care unit (ICU) within 6 h. However, limited ICU bed availability often makes immediate transfer difficult, and it is unclear whether all patients will benefit from early admission to the ICU. Therefore, the purpose of this study was to determine the association between the timing of ICU admission and mortality in patients with hospital-onset sepsis.

METHODS

This nationwide prospective cohort study analyzed patients with hospital-onset sepsis admitted to the ICUs of 19 tertiary hospitals between September 2019 and December 2020. ICU admission was classified as either early (within 6 h) or delayed (beyond 6 h). The primary outcome of in-hospital mortality was compared using logistic regression adjusted for key prognostic factors in the unmatched and 1:1 propensity-score-matched cohorts. Subgroup and interaction analyses assessed whether in-hospital mortality varied according to baseline characteristics.

RESULTS

A total of 470 and 286 patients were included in the early and delayed admission groups, respectively. Early admission to the ICU did not significantly result in lower in-hospital mortality in both the unmatched (adjusted odds ratio [aOR], 1.35; 95% confidence interval [CI], 0.99-1.85) and matched cohorts (aOR, 1.38; 95% CI, 0.94-2.02). Subgroup analyses showed that patients with increasing lactate levels (aOR, 2.10; 95% CI, 1.37-3.23; P for interaction = 0.003), septic shock (aOR, 2.06; 95% CI, 1.31-3.22; P for interaction = 0.019), and those who needed mechanical ventilation (aOR, 1.92; 95% CI, 1.24-2.96; P for interaction = 0.027) or vasopressor support (aOR, 1.69; 95% CI, 1.17-2.44; P for interaction = 0.042) on the day of ICU admission had a higher risk of mortality with delayed admission.

CONCLUSIONS

Among patients with hospital-onset sepsis, in-hospital mortality did not differ significantly between those with early and delayed ICU admission. However, as early intensive care may benefit those with increasing lactate levels, septic shock, and those who require vasopressors or ventilatory support, admission to the ICU within 6 h should be considered for these subsets of patients.

Sichen Formula Ameliorates Lipopolysaccharide-Induced Acute Lung Injury via Blocking the TLR4 Signaling Pathways

Purpose

Sichen (SC) formula is a classic prescription of Tibetan medicine. Due to its potential anti-inflammatory effect, the SC formula has been clinically used to treat respiratory diseases for many years in the Chinese Tibet region. The present study aimed to investigate the anti-inflammatory effect of SC and explore the underlying mechanisms.

Methods

SC formula was characterized by HPLC analysis. The acute lung injury (ALI) mouse model was induced by direct intratracheal lipopolysaccharide (LPS) instillation, and bronchoalveolar lavage fluid (BALF) and lung tissues were collected. Meanwhile, RAW264.7 macrophages were stimulated by LPS. The contents of inflammatory mediators in the culture medium were determined by ELISA. Protein levels were determined by immunohistochemical staining or Western blotting. Nuclear localization of NF-κB, AP-1, and IRF3 was performed using immunofluorescence and Western blotting.

Results

In the LPS-induced ALI mouse model, SC treatment suppressed the secretion of inflammatory mediators (TNF-α, IL-6, IL-1β, MCP-1, MIP-1α, and RANTES) in BALF. SC treatment hindered the recruitment of macrophages. SC treatment also inhibited the expression of CD68, p-p65, and TLR4 in the lung tissue. In the LPS-exposed RAW264.7 cells, the cell viability was not changed up to 400 μg/mL of SC. SC concentration-dependently suppressed the production of nitric oxide, prostaglandin E2, TNF-α, IL-6, MCP-1, MIP-1α, and RANTES in LPS-challenged RAW264.7 cells. The expression levels of iNOS, COX-2, p-p38, p-JNK, p-ERK, p-TBK1, p-IKKα/β, p-IκB, p-p65, p-c-Jun, and p-IRF3 were decreased after SC treatment. Moreover, the nuclear translocation of p65, c-Jun, and IRF3 was also blocked by SC treatment.

Conclusion

SC treatment inhibited the inflammatory responses in LPS-induced ALI mouse model/RAW264.7 macrophages. The underlying mechanism of this action may be closely associated with the suppression of TLR4 signaling pathways. These research findings provide further pharmacological justifications for the medicinal use of SC in the management of respiratory diseases.

Neutrophil Extracellular Traps Induce Alveolar Macrophage Pyroptosis by Regulating NLRP3 Deubiquitination, Aggravating the Development of Septic Lung Injury

Background

Uncontrolled inflammation is a typical feature of sepsis-related lung injury. The key event in the progression of lung injury is Caspase-1-dependent alveolar macrophage (AM) pyroptosis. Similarly, neutrophils are stimulated to release neutrophil extracellular traps (NETs) to participate in the innate immune response. This study aims to illustrate the specific mechanisms by which NETs activate AM at the post-translational level and maintain lung inflammation.

Methods

We established a septic lung injury model by caecal ligation and puncture. We found elevated NETs and interleukin-1b (IL-1β) levels in the lung tissues of septic mice. Western blot and immunofluorescence analyses was utilized to determine whether NETs promote AM pyroptosis and whether degrading NETs or targeting the NLRP3 inflammasome had protective effects on AM pyroptosis and lung injury. Flow cytometric and co-immunoprecipitation analyses verified intracellular reactive oxygen species (ROS) levels and the binding of NLRP3 and ubiquitin (UB) molecules, respectively.

Results

Increased NETs production and IL-1β release in septic mice were correlated with the degree of lung injury. NETs upregulated the level of NLRP3, followed by NLRP3 inflammasome assembly and caspase-1 activation, leading to AM pyroptosis executed by the activated fragment of full-length gasdermin D (FH-GSDMD). However, the opposite effect was observed in the context of NETs degradation. Furthermore, NETs markedly elicited an increase in ROS, which facilitated the activation of NLRP3 deubiquitination and the subsequent pyroptosis pathway in AM. Removal of ROS could promote the binding of NLRP3 and ubiquitin, inhibit NLRP3 binding to apoptosis-associated spotted proteins (ASC) and further alleviate the inflammatory changes in the lungs.

Conclusion

In summary, these findings indicate that NETs prime ROS generation, which promotes NLRP3 inflammasome activation at the post-translational level to mediate AM pyroptosis and sustain lung injury in septic mice.

Effects of combination therapy with Shenfu Injection in critically ill patients with septic shock receiving mechanical ventilation: A multicentric, real-world study

Background: Septic shock has increasingly become a cause of death threatening human survival. Shenfu Injection (SFI), a patented Chinese medicine, has been widely used in the treatment of patients with sepsis and cardiovascular diseases domestically. We sought to examine whether combination therapy with SFI can improve clinical outcomes in critically ill patients undergoing mechanical ventilation (MV).

Methods: This real-world, multicenter retrospective trial enrolled consecutive adult patients with sepsis requiring MV from four medical/surgical intensive care units (ICUs) in China between August 2016 and September 2021. Patients were identified from the medical information department database of each center and assigned to either of two groups (SFI or control) on the basis of the initial treatment received. The primary outcome was 28-day all-cause mortality, and the durations of vasopressor therapy and MV, the ICU length of stay, and costs were assessed as secondary outcomes. Subsequently, we performed a meta-analysis of randomized controlled trials (RCTs) on SFI published before July 2021 to verify our conclusions.

Results: 2311 mechanically ventilated patients with septic shock (1128 patients in the SFI group and 1183 in the control group) were analyzed. The survival probability during the first 28 days after admission in the SFI group was greater than that in the control group [p &lt; 0.01 by log-rank test; hazard ratio (HR), 0.56; 95% confidence interval (CI), 0.39–0.72]. Patients in the SFI group also experienced a significantly reduced duration of vasopressor therapy [7.28 (95% CI, 6.14–8.42) vs. 12.06 (95% CI, 10.71–13.41) days, p &lt; 0.001], more ventilator-free days [6.49 (95% CI, 5.42–7.55) vs. 10.84 (95% CI, 9.59–12.09) days, p &lt; 0.001], a shorter ICU length of stay [18.48 (95% CI, 17.59–19.38) vs. 23.77 (95% CI, 22.47–25.07) days, p &lt; 0.001], and more time free from organ failure [14.23 (95% CI, 12.94–15.52) vs. 19.07 (95% CI, 16.09–22.05) days, p &lt; 0.001]. No major adverse effects were reported in either group.

Conclusion: Among critically ill patients requiring MV, combination therapy with SFI can improve the survival probability without any obvious adverse reactions.

Integrating bulk and single-cell sequencing reveals the phenotype-associated cell subpopulations in sepsis-induced acute lung injury

The dysfunctional immune response and multiple organ injury in sepsis is a recurrent theme impacting prognosis and mortality, while the lung is the first organ invaded by sepsis. To systematically elucidate the transcriptomic changes in the main constituent cells of sepsis-injured lung tissue, we applied single-cell RNA sequencing to the lung tissue samples from septic and control mice and created a comprehensive cellular landscape with 25044 cells, including 11317 immune and 13727 non-immune cells. Sepsis alters the composition of all cellular compartments, particularly neutrophils, monocytes, T cells, endothelial, and fibroblasts populations. Our study firstly provides a single-cell view of cellular changes in septic lung injury. Furthermore, by integrating bulk sequencing data and single-cell data with the Scissors-method, we identified the cell subpopulations that are most associated with septic lung injury phenotype. The phenotypic-related cell subpopulations identified by Scissors-method were consistent with the cell subpopulations with significant composition changes. The function analysis of the differentially expressed genes (DEGs) and the cell-cell interaction analysis further reveal the important role of these phenotype-related subpopulations in septic lung injury. Our research provides a rich resource for understanding cellular changes and provides insights into the contributions of specific cell types to the biological processes that take place during sepsis-induced lung injury.

Deep Learning Chest CT for Clinically Precise Prediction of Sepsis-Induced Acute Respiratory Distress Syndrome: A Protocol for an Observational Ambispective Cohort Study

Background: Sepsis commonly causes acute respiratory distress syndrome (ARDS), and ARDS contributes to poor prognosis in sepsis patients. Early prediction of ARDS for sepsis patients remains a clinical challenge. This study aims to develop and validate chest computed tomography (CT) radiomic-based signatures for early prediction of ARDS and assessment of individual severity in sepsis patients. Methods: In this ambispective observational cohort study, a deep learning model, a sepsis-induced acute respiratory distress syndrome (SI-ARDS) prediction neural network, will be developed to extract radiomics features of chest CT from sepsis patients. The datasets will be collected from these retrospective and prospective cohorts, including 400 patients diagnosed with sepsis-3 definition during a period from 1 May 2015 to 30 May 2022. 160 patients of the retrospective cohort will be selected as a discovering group to reconstruct the model and 40 patients of the retrospective cohort will be selected as a testing group for internal validation. Additionally, 200 patients of the prospective cohort from two hospitals will be selected as a validating group for external validation. Data pertaining to chest CT, clinical information, immune-associated inflammatory indicators and follow-up will be collected. The primary outcome is to develop and validate the model, predicting in-hospital incidence of SI-ARDS. Finally, model performance will be evaluated using the area under the curve (AUC) of receiver operating characteristic (ROC), sensitivity and specificity, using internal and external validations. Discussion: Present studies reveal that early identification and classification of the SI-ARDS is essential to improve prognosis and disease management. Chest CT has been sought as a useful diagnostic tool to identify ARDS. However, when characteristic imaging findings were clearly presented, delays in diagnosis and treatment were impossible to avoid. In this ambispective cohort study, we hope to develop a novel model incorporating radiomic signatures and clinical signatures to provide an easy-to-use and individualized prediction of SI-ARDS occurrence and severe degree in patients at early stage.

Endothelial Poldip2 regulates sepsis-induced lung injury via Rho pathway activation

AIMS

Sepsis-induced lung injury is associated with significant morbidity and mortality. Previously, we showed that heterozygous deletion of polymerase δ-interacting protein 2 (Poldip2) was protective against sepsis-induced lung injury. Since endothelial barrier disruption is thought to be the main mechanism of sepsis-induced lung injury, we sought to determine if the observed protection was specifically due to the effect of reduced endothelial Poldip2.

METHODS AND RESULTS

Endothelial-specific Poldip2 knock-out mice (EC-/-) and their wild-type littermates (EC+/+) were injected with saline or lipopolysaccharide (18 mg/kg) to model sepsis-induced lung injury. At 18 h post-injection mice, were euthanized and bronchoalveolar lavage (BAL) fluid and lung tissue were collected to assess leucocyte infiltration. Poldip2 EC-/- mice showed reduced lung leucocyte infiltration in BAL (0.21 ± 0.9×106 vs. 1.29 ± 1.8×106 cells/mL) and lung tissue (12.7 ± 1.8 vs. 23 ± 3.7% neutrophils of total number of cells) compared to Poldip2 EC+/+ mice. qPCR analysis of the lung tissue revealed a significantly dampened induction of inflammatory gene expression (TNFα 2.23 ± 0.39 vs. 4.15 ± 0.5-fold, IκBα 4.32 ± 1.53 vs. 8.97 ± 1.59-fold), neutrophil chemoattractant gene expression (CXCL1 68.8 ± 29.6 vs. 147 ± 25.7-fold, CXCL2 65 ± 25.6 vs. 215 ± 27.3-fold) and a marker of endothelial activation (VCAM1 1.25 ± 0.25 vs. 3.8 ± 0.38-fold) in Poldip2 EC-/- compared to Poldip2 EC+/+ lungs. An in vitro model using human pulmonary microvascular endothelial cells was used to assess the effect of Poldip2 knock-down on endothelial activation and permeability. TNFα-induced endothelial permeability and VE-cadherin disruption were significantly reduced with siRNA-mediated knock-down of Poldip2 (5 ± 0.5 vs. 17.5 ± 3-fold for permeability, 1.5 ± 0.4 vs. 10.9 ± 1.3-fold for proportion of disrupted VE-cadherin). Poldip2 knock-down altered expression of Rho-GTPase-related genes, which correlated with reduced RhoA activation by TNFα (0.94 ± 0.05 vs. 1.29 ± 0.01 of relative RhoA activity) accompanied by redistribution of active-RhoA staining to the centre of the cell.

CONCLUSION

Poldip2 is a potent regulator of endothelial dysfunction during sepsis-induced lung injury, and its endothelium-specific inhibition may provide clinical benefit.

Association of pulmonary arterial pressure with volume status in patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation

Background

Data on pulmonary hemodynamic parameters in patients with acute respiratory distress syndrome (ARDS) receiving extracorporeal membrane oxygenation (ECMO) are scarce.

Methods

The associations between pulmonary artery catheter parameters for the first 7 days of ECMO, fluid balance, and hospital mortality were investigated in adult patients (aged ≥19 years) who received venovenous ECMO for refractory ARDS between 2015 and 2017.

Results

Twenty patients were finally included in the analysis (median age, 56.0 years; interquartile range, 45.5-68.0; female, n=10). A total of 140 values were collected for each parameter (i.e., 7 days×20 patients). Net fluid balance was weakly but significantly correlated with systolic and diastolic pulmonary arterial pressures (PAPs; r=0.233 and P<0.001; r=0.376 and P<0.001, respectively). Among the mechanical ventilation parameters, above positive end-expiratory pressure was correlated with systolic PAP (r=0.191 and P=0.025), and static compliance was negatively correlated with diastolic PAP (r=-0.169 and P=0.048). Non-survivors had significantly higher systolic PAPs than in survivors. However, in multivariate analysis, there was no significant association between mean systolic PAP and hospital mortality (odds ratio, 1.500; 95% confidence interval, 0.937-2.404; P=0.091).

Conclusion

Systolic PAP was weakly but significantly correlated with net fluid balance during the early ECMO period in patients with refractory ARDS receiving ECMO.

Electroacupuncture Alleviates LPS-Induced ARDS Through α7 Nicotinic Acetylcholine Receptor-Mediated Inhibition of Ferroptosis

Acute respiratory distress syndrome (ARDS) is an uncontrollable, progressive pulmonary inflammatory disease, and as a common clinical critical disease, there is no effective treatment available. Electroacupuncture (EA) therapy is a type of traditional Chinese medicine physiotherapy that can alleviate the inflammatory response. However, the potential mechanism of EA in the treatment of ARDS is not yet clear. Ferroptosis is a new type of programmed cell death characterized by intracellular iron accumulation and lipid peroxidation. Recently, emerging evidence has shown that ferroptosis is closely related to the occurrence and development of ARDS caused by various pathological factors. Here, we further investigated whether EA-mediated inhibition of ferroptosis in lung tissue could attenuate lipopolysaccharide (LPS)-induced ARDS and explored its underlying mechanisms. In this study, mice were administered LPS intraperitoneally to establish a model of LPS-induced ARDS. We found that EA stimulation could not only reduce the exudation of inflammatory cells and proteins in the alveolar lumen but also significantly alleviate the pathological changes of lung tissue, inhibit the production of proinflammatory cytokines and improve the survival rate of mice. Concurrently, we also found that ferroptosis events occurred in the lung tissue of LPS-induced ARDS mice, manifested by elevated iron levels, ROS production and lipid peroxidation. Intriguingly, our results showed that EA stimulation at the Zusanli (ST36) acupoint activated α7 nicotinic acetylcholine receptor (α7nAchR) in lung tissue mainly through the sciatic nerve and cervical vagus nerve, thus exerting anti-ferroptosis and pulmonary protective effects. Additionally, these effects were eliminated by methyllycaconitine (MLA), a selective antagonist of α7nAchR. In vitro experiments, activation of α7nAchR protected alveolar epithelial cells from LPS-induced ferroptosis. Furthermore, our experiments showed that the pulmonary protective effects of EA stimulation were effectively reversed by erastin, a ferroptosis activator. Collectively, we demonstrated that EA stimulation could alleviate LPS-induced ARDS by activating α7nAchR to inhibit LPS-induced ferroptosis in alveolar epithelial cells. Targeting and regulating ferroptosis in alveolar epithelial cells may be a potential intervention approach for the treatment of LPS-induced ALI/ARDS in the future.

Analysis of the correlation between the longitudinal trajectory of SOFA scores and prognosis in patients with sepsis at 72 hour after admission based on group trajectory modeling

Background

To identify the distinct trajectories of the Sequential Organ Failure Assessment (SOFA) scores at 72 h for patients with sepsis in the Medical Information Mart for Intensive Care (MIMIC)-IV database and determine their effects on mortality and adverse clinical outcomes.

Methods

A retrospective cohort study was carried out involving patients with sepsis from the MIMIC-IV database. Group-based trajectory modeling (GBTM) was used to identify the distinct trajectory groups for the SOFA scores in patients with sepsis in the intensive care unit (ICU). The Cox proportional hazards regression model was used to investigate the relationship between the longitudinal change trajectory of the SOFA score and mortality and adverse clinical outcomes.

Results

A total of 16,743 patients with sepsis were included in the cohort. The median survival age was 66 years (interquartile range: 54-76 years). The 7-day and 28-day in-hospital mortality were 6.0% and 17.6%, respectively. Five different trajectories of SOFA scores according to the model fitting standard were determined: group 1 (32.8%), group 2 (30.0%), group 3 (17.6%), group 4 (14.0%) and group 5 (5.7%). Univariate and multivariate Cox regression analyses showed that, for different clinical outcomes, trajectory group 1 was used as the reference, while trajectory groups 2-5 were all risk factors associated with the outcome (P < 0.001). Subgroup analysis revealed an interaction between the two covariates of age and mechanical ventilation and the different trajectory groups of patients' SOFA scores (P < 0.05).

Conclusion

This approach may help identify various groups of patients with sepsis, who may be at different levels of risk for adverse health outcomes, and provide subgroups with clinical importance.

Paediatrics: how to manage septic shock

Background

Septic shock is a common critical illness associated with high morbidity and mortality in children. This article provides an updated narrative review on the management of septic shock in paediatric practice.

Methods

A PubMed search was performed using the following Medical Subject Headings: "sepsis", "septic shock" and "systemic inflammatory response syndrome". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies and reviews. The search was limited to the English literature and specific to children.

Results

Septic shock is associated with high mortality and morbidity. The outcome can be improved if the diagnosis is made promptly and treatment initiated without delay. Early treatment with antimicrobial therapy, fluid therapy and vasoactive medications, and rapid recognition of the source of sepsis and control are the key recommendations from paediatric sepsis management guidelines.

Conclusion

Most of the current paediatric sepsis guideline recommendations are based on the adult population; therefore, the research gaps in paediatric sepsis management should be addressed.

Diagnostic value of miR-155 for acute lung injury/acute respiratory distress syndrome in patients with sepsis

Objective

We aimed to investigate the diagnostic value of microRNA-155 (miR-155) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) in patients with sepsis.

Methods

In this prospective study, we used Spearman correlation analysis to investigate relationships between miR-155 expression and inflammatory factors, oxygenation ratio (PaO₂/FiO₂), and ALI/ARDS score, and used area under the receiver operating characteristic curve (AU-ROC) to evaluate miR-155's diagnostic accuracy for ALI/ARDS in patients with sepsis.

Results

In total, 156 patients with sepsis were enrolled in our study, of which 41 had ALI and 32 had ARDS. miR-155 expression in plasma of patients with sepsis and ALI/ARDS was significantly higher than that of patients with sepsis but no ALI/ARDS. The miR-155 level in patients with sepsis and ALI/ARDS was positively correlated with interleukin (IL)-1β and tumor necrosis factor (TNF)-α levels and ALI/ARDS score, but negatively correlated with PaO₂/FiO₂. The AU-ROC of plasma miR-155 for diagnosis of sepsis with ALI/ARDS was 0.87, and plasma miR-155, IL-1β, and TNF-α had high sensitivity and specificity for the diagnosis of sepsis with ALI/ARDS.

Conclusion

miR-155 is highly expressed in plasma of patients with septic ALI/ARDS; it is positively correlated with lung function and can be used for early diagnosis.

Hypoxia-inducible factor prolyl-hydroxylase inhibitor roxadustat (FG-4592) alleviates sepsis-induced acute lung injury

Acute lung injury (ALI) is one of the most severe outcomes of sepsis which still waiting for effective treatment method. Roxadustat (FG-4592) which is often used for treatment of anemia in patients with chronic kidney disease (CKD), its affection on LPS-induced ALI haven't been evaluated. MH-S and MLE-12 cell injury and ALI mouse model was induced LPS. Several assays were used to explore the role of FG-4592 in reducing the damage caused by LPS. FG-4592 treatment significantly upregulated HIF-1α and HO-1 and strikingly attenuated inflammation in vivo and in vitro. Furthermore, septic mice overexpressing HIF-1α had high level of survival rate and lower expression of inflammatory factors while down-regulation can enhance the damage of LPS. HIF-1α has a protective effect on acute lung injury in LPS induced septic mice. FG-4592 treatment remarkably ameliorated the LPS-induced lung injury through the stabilization of HIF-1α. Besides the role in treating CKD anemia, the clinical use of FG-4592 also might be extended to ALI.

Effects of Fusu mixture (Wen-Shen-Qian-Yang Method) on sepsis-induced acute respiratory distress syndrome

INTRODUCTION

Sepsis is the most common etiology of acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Capillary leakage caused by lung endothelial injury is the central cause of ARDS. The results of research in modern medicine in reducing endothelial damage and restoring endothelial functions are limited. In the previous clinical observations, we found that the Fusu mixture not only improves the clinical symptoms but also reduces the leakage of pulmonary capillaries. Therefore, the purpose of this study is to determine the clinical efficacy of the Fusu mixture combined with Western medicine in the treatment of ARDS caused by sepsis and to explore the mechanism of traditional Chinese medicine.

METHODS

This is a prospective, single-center, randomized, single-blind, and controlled clinical study involving 620 eligible patients. The patients will be randomly divided into 2 groups: the Western medicine treatment group and the combination of Chinese and Western medicine treatment group. After 14 days of intervention, the clinical efficacy and safety of the Fusu mixture on sepsis-induced ARDS patients will be observed. The primary outcome will be measured as 28-day mortality. The secondary outcome indices include inflammatory markers (CRP, PCT, IL-6, TNF - α), APACHE II score, SOFA score, days without a ventilator, blood gas analysis (Lac, PaO2 / FiO2), intensive care unit hospital stay time, intensive care unit mortality. Simultaneously, the analysis of the exploratory results will be carried out to analyze the possible mechanism of Fusu mixture in the treatment of sepsis-induced ARDS by the high-throughput sequencing and bioinformatics.

DISCUSSION

The purpose of this study is to evaluate the clinical efficacy of Fusu mixture in the treatment of sepsis-induced ARDS and explore its possible mechanism of action. If successful, it will provide evidence-based adjuvant therapy for the clinical treatment of ARDS.

Evaluation of clinical efficacy of integrated traditional Chinese and Western medicine in the treatment of acute respiratory distress syndrome

INTRODUCTION

Acute respiratory distress syndrome (ARDS) is a common disease in critically ill patients that has a high incidence and mortality rate worldwide. At present, there is no specific treatment for ARDS. Traditional Chinese medicine has been shown to have good potential in preventing and treating ARDS, especially in reducing the dosages of Western medicines and therefore, adverse drug reactions. The purpose of this study is to compare the clinical efficacy of integrated Chinese and Western medicine to that of Western medicine alone in the treatment of ARDS.

METHODS

We are proposing a prospective, multicenter, randomized, double-blind, placebo-controlled study in which 110 eligible patients would be enrolled and randomly divided into a Western medicine treatment group and an integrated Chinese and Western medicine treatment group. After 2 weeks of interventions and 1 year of follow-up, the clinical efficacy and safety of Jiawei qianyang dan in ARDS patients would be observed. The outcomes measured would include the Traditional Chinese medicine symptom score, the oxygenation index (PɑO2/FiO2), extravascular pulmonary water index, duration of mechanical ventilation, number of ICU hospitalization days, and the 28-day mortality rate for the 2 groups before and after treatment. The all-cause mortality rate, respiratory failure mortality rate, and readmission rate after 1 year of follow-up will be statistically analyzed and safety will be evaluated.

DISCUSSION

In this study, we aim to demonstrate the greater clinical efficacy of integrated traditional Chinese and Western medicine in the treatment of ARDS compared to that of Western medicine alone. In order to do this, we hope to provide evidence for the clinically supportive effect of the Jiawei qianyang dan in the treatment of ARDS and therefore demonstrate a more effective treatment.

Down-regulation of miR-133a-3p protects lung tissue against sepsis-induced acute respiratory distress syndrome by up-regulating SIRT1

Introduction

MicroRNA-133a-3p (miR-133a-3p) is a potential gene regulator having an important role in the process of inflammation and lung injury. The present work studied the role of miR-133a-3p in sepsis-mediated acute respiratory distress syndrome (ARDS) and the mechanism involved.

Material and methods

C57BL/6 mice were selected for the study. Protein expression of Bcl-2, cleaved caspase-3 and Bax was assessed by western blot analysis. Expression of mRNA was assessed by RT-PCR. Effects of inflammation were studied by myeloperoxidase (MPO) activity. Quantification of albumin was done by measuring the albumin conjugated with Evan's blue. The alveolar macrophages were separated from the lungs of mice by the bronchoalveolar lavage procedure and were submitted to sepsis challenge in vitro; the macrophages were treated with lipopolysaccharide (LPS).

Results

Treatment of LPS resulted in upregulation of miR-133a-3p in alveolar macrophages. Suppression of miR-133a-3p halted the over-expression of inflammatory cytokines in macrophages and caused remission of histopathologic changes. The ARDS lungs showed a decrease in levels of proinflammatory cytokines and an increase in levels of apoptotic protein, establishing the protective role for miR-133a-3p. The results suggested sirtuin 1 (SIRT1) as a potential target of miR-133a-3p in the macrophages, also showing that expression of SIRT1 was inversely associated with expression of miR-133a-3p. The protective effect of miR-133a-3p down-regulation in LPS-mediated alveolar macrophages and sepsis-induced ARDS could be corrected by a SIRT1 inhibitor.

Conclusions

Down-regulation of miR-133a-3p may exert a protective effect on lung tissue against sepsis-mediated ARDS by up-regulating the levels of SIRT1 via suppressing the inflammatory response and inhibiting the cellular apoptosis in lung tissues.

Effect of Netrin-1 Anti-Inflammatory Factor on Acute Lung Injury in Sepsis Rats

BACKGROUND Acute lung injury (ALI) often occurs early and seriously in the progress of sepsis. Netrin-1 is demonstrated to be an effective anti-inflammatory agent. However, whether netrin-1 can relieve sepsis-induced ALI remains unknown. MATERIAL AND METHODS The sepsis rat model was built with the method of cecal ligation and puncture (CLP). The lung tissue changes were represented as the results of hematoxylin-eosin (HE) staining, wet-to-dry (W/D) ratio, Western blot analysis, and immunohistochemistry. An in vitro lung injury model was simulated with LPS-induced BEAS-2B cells. The cell transfection effects were evaluated by Western blot analysis and RT-qPCR analysis. TNF-alpha, IL-1ß, and IL-6 levels were detected by Western blot analysis in LPS-induced BEAS-2B cells. RESULTS Obvious inflammation caused by sepsis appeared in lung tissues with the increase of the W/D ratio and expression of inflammatory cytokines. Netrin-1 and its receptor UNC5B were reduced in sepsis. However, upregulation of netrin-1 alleviated the levels of inflammation and increased the UNC5B levels in BEAS-2B cells. CONCLUSIONS Netrin-1 protects against ALI in sepsis rats through its anti-inflammation effect and may provide a novel treatment to prevent lung injury caused by sepsis.

Propylene glycol alginate sodium sulphate attenuates LPS-induced acute lung injury in a mouse model

Propylene glycol alginate sodium sulphate, a sulphated polysaccharide, has been used to treat hyperlipidaemia and ischaemia–reperfusion injury of liver. This study aimed to investigate the effect of propylene glycol alginate sodium sulphate on LPS-induced acute lung injury. Propylene glycol alginate sodium sulphate was injected intraperitoneally into male C57BL/6 mice with or without LPS administration. Survival rates were calculated. Serum, bronchoalveolar lavage fluid and lung tissues were collected to determine lung histology, wet/dry ratio, Evans blue albumin permeability, protein levels, the counts of immune cells and the levels of inflammatory cytokines and chemokines. Serum alanine aminotransferase, aspartate transaminase, creatinine and blood urea nitrogen levels were also measured. Additionally, NF-κB signalling was detected in the lung. Propylene glycol alginate sodium sulphate treatment significantly improved the survival of mice suffering from LPS. Lung histological injury, wet/dry ratio, Evans blue albumin permeability, neutrophils and the inflammatory cytokines and chemokines were significantly reduced by propylene glycol alginate sodium sulphate treatment. NF-κB signalling was significantly inhibited by propylene glycol alginate sodium sulphate in the lung of mice subjected to LPS. Furthermore, serum alanine aminotransferase, aspartate transaminase, creatinine and blood urea nitrogen levels were also significantly decreased after propylene glycol alginate sodium sulphate administration. This study suggests that NF-κB signalling and inhibition of pro-inflammatory cytokines, chemokines and neutrophil accumulation may be involved in the process of acute lung injury attenuation by propylene glycol alginate sodium sulphate.

α-1-Acid Glycoprotein Concentration as an Outcome Predictor in Adult Patients with Sepsis

Background

α-1-Acid glycoprotein (AGP) is an acute-phase protein that plays a role in first-line defense against infection and is therefore elevated in sepsis. We tested the hypothesis that AGP levels increase initially in sepsis and decrease after antimicrobial therapy and that these levels may predict treatment outcomes.

Methods

AGP, biomarkers widely used in clinical practice, and maximum 24-h acute physiology and chronic health evaluation (APACHE)-II scores upon emergency department (ED) admission were prospectively evaluated and compared. We further examined changes in AGP concentrations 1, 4, and 7 days after admission and determined the value of AGP that may be used to accurately and reliably predict the prognosis in patients with sepsis.

Results

Mechanical ventilation, white blood cell (WBC) counts, C-reactive protein (CRP) and lactate levels, maximum 24-h APACHE-II scores, and AGP concentrations were significantly higher upon admission in patients with sepsis who died. AGP and lactate concentrations were also significantly higher in non-survivors than in survivors on days 1, 4, and 7. As indicated by the stepwise logistic regression model analysis and area under the curve analysis, AGP was the best prognostic indicator, and the cut-off value for predicting fatality was 1307 μg/mL, and any increase 1-ng/mL in AGP concentration would increase the fatality rate by 0.5%.

Conclusion

Based on our observations, AGP may be a good prognostic predictor in patients with sepsis. In addition, serial AGP levels meet the requirements for predicting outcomes in patients with sepsis.

Lung Compliance and Outcomes in Patients With Acute Respiratory Distress Syndrome Receiving ECMO

BACKGROUND

Limited data are available regarding mechanical ventilation strategies in patients with acute respiratory distress syndrome receiving extracorporeal membrane oxygenation (ECMO).

METHODS

A retrospective analysis of acute respiratory distress syndrome patients on ECMO was conducted in 9 hospitals in Korea. Data on ventilator settings (pre-ECMO and 0, 4, 24, and 48 hours after ECMO) were collected. Based on the effect of the duration and intensity of mechanical ventilator on outcomes, time-weighted average values were calculated for ventilator parameters.

RESULTS

The 56 patients included in the study had a mean age of 55.5 years. The hospital and 6-month mortality rates were 48.1% and 54.0%, respectively, with a median ECMO duration of 9.4 days. After initiation of ECMO, peak inspiratory pressure, above positive end-expiratory pressure, tidal volume, and respiration rate were reduced, while lung compliance did not change significantly. Before and during ECMO support, tidal volume and lung compliance were higher in 6-month survivors than in nonsurvivors. In Cox proportional models, both lung compliance (odds ratio, 0.961; 95% confidence interval, 0.928 to 0.995) and time-weighted average-lung compliance (odds ratio, 0.943; 95% confidence interval, 0.903 to 0.986) were significantly associated with 6-month mortality. Kaplan-Meier curves revealed that patients with higher lung compliance before ECMO had a longer survival time at the 6-month follow-up than did those with lower lung compliance.

CONCLUSIONS

Lung compliance, whether before or during ECMO, may be an important predictor of outcome in acute respiratory distress syndrome patients receiving ECMO. However, this result requires confirmation in larger clinical studies.

Mechanical Ventilation in Sepsis: A Reappraisal

Sepsis is the main cause of close to 70% of all cases of acute respiratory distress syndromes (ARDS). In addition, sepsis increases susceptibility to ventilator-induced lung injury. Therefore, the development of a ventilatory strategy that can achieve adequate oxygenation without injuring the lungs is highly sought after for patients with acute infection and represents an important therapeutic window to improve patient care. Suboptimal ventilatory settings cannot only harm the lung, but may also contribute to the cascade of organ failure in sepsis due to organ crosstalk.Despite the prominent role of sepsis as a cause for lung injury, most of the studies that addressed mechanical ventilation strategies in ARDS did not specifically assess sepsis-related ARDS patients. Consequently, most of the recommendations regarding mechanical ventilation in sepsis patients are derived from ARDS trials that included multiple clinical diagnoses. While there have been important improvements in general ventilatory management that should apply to all critically ill patients, sepsis-related lung injury might still have particularities that could influence bedside management.After revisiting the interplay between sepsis and ventilation-induced lung injury, this review will reappraise the evidence for the major components of the lung protective ventilation strategy, emphasizing the particularities of sepsis-related acute lung injury.

Tephrosin attenuates sepsis induced acute lung injury in rats by impeding expression of ICAM-1 and MIP-2

Acute lung injury (ALI), a devastating form of respiratory infections, is characterized by increased edema, release of cytokines, weakened arterial oxygenation and infiltration of neutrophils and lymphocytes. The objective of the research envisaged was to reveal protective effects of tephrosin (TP) in ALI. In the present investigation, sepsis was triggered in rats by cecal ligation and puncture (CLP) method, and TP was administered intraperitonially. Five groups - Group A (control), Group B (Sham group) Group C (infected and untreated), and Group D and E (infected and treated with 25 and 50 mg/kg TP respectively) - of ten rats each, were used for the investigation. Evaluation parameters included measurement of arterial oxygenation, lung water content, protein determination, cytokine determination, neutrophil and lymphocyte count in the bronchoalveolar lavage fluid (BALF). As indicated by histopathological examination, the lung injury score was maximum in group C, but indicated reduction in group D and E. Intracellular adhesion molecule (ICAM)-1 and macrophage inflammatory protein-2 (MIP-2) are known to be important mediators responsible for ALI. Reduction in the ICAM-1 and MIP-2 expression was found to reduce after treatment with TP. In comparison to group D, group E reflected higher magnitude of ICAM-1 and MIP-2 suppression due to administration of higher TP dose. Compared to Group A and B, Group E indicated slightly higher expression of ICAM-1 and MIP-2. The research envisaged thus supports that TP attenuates ICAM-1 and MIP-2 expression in sepsis induced ALI rat model.

Acute downregulation of miR-199a attenuates sepsis-induced acute lung injury by targeting SIRT1

MicroRNA-199a (miR-199a) is a novel gene regulator with an important role in inflammation and lung injury. However, its role in the pathogenesis of sepsis-induced acute respiratory distress syndrome (ARDS) is currently unknown. Our study explored the role of miR-199a in sepsis-induced ARDS and its mechanism of action. First, we found that LPS could upregulate miR-199a in alveolar macrophages. Downregulation of miR-199a inhibited the upregulation of inflammatory cytokines in alveolar macrophages and induced the remission of histopathologic changes, the reduction of proinflammatory cytokines, and the upregulation of apoptosis protein expression in an ARDS lung, showing a protective role for miR-199a. We further identified sirtuin 1 (SIRT1) as a direct target of miR-199a in alveolar macrophages, and the expression of SIRT1 was negatively correlated with the level of miR-199a. The protective role of miR-199a downregulation in LPS-stimulated alveolar macrophages and sepsis-induced ARDS could be attenuated by SIRT1 inhibitor. Taken together, these results indicate that downregulation of miR-199a might protect lung tissue against sepsis-induced ARDS by upregulation of SIRT1 through the suppression of excessive inflammatory responses and the inhibition of cellular apoptosis in lung tissue, suggesting its potential therapeutic effects on sepsis-induced ARDS.

Hypoxia-inducible-factor-1 in trauma and critical care

HIF-1 is a ubiquitous signaling molecule constantly expressed by the body, but is degraded during normoxic conditions. In hypoxic conditions, it persists and is active. Hypoxia is often associated with trauma due to interrupted blood flow, inflammation or other reasons, causing HIF-1 to be active in signaling and recovery. In this review, the function of HIF-1 is examined, as well as its clinical significance with regard to trauma and critical care. Using this information, we then identify potential points of treatment and intervention.

Recruitment manoeuvres for adults with acute respiratory distress syndrome receiving mechanical ventilation

BACKGROUND

Recruitment manoeuvres involve transient elevations in airway pressure applied during mechanical ventilation to open ('recruit') collapsed lung units and increase the number of alveoli participating in tidal ventilation. Recruitment manoeuvres are often used to treat patients in intensive care who have acute respiratory distress syndrome (ARDS), but the effect of this treatment on clinical outcomes has not been well established. This systematic review is an update of a Cochrane review originally published in 2009.

OBJECTIVES

Our primary objective was to determine the effects of recruitment manoeuvres on mortality in adults with acute respiratory distress syndrome.Our secondary objective was to determine, in the same population, the effects of recruitment manoeuvres on oxygenation and adverse events (e.g. rate of barotrauma).

SEARCH METHODS

For this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), Embase (OVID), the Cumulative Index to Nursing and Allied Health Literature (CINAHL, EBSCO), Latin American and Caribbean Health Sciences (LILACS) and the International Standard Randomized Controlled Trial Number (ISRCTN) registry from inception to August 2016.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of adults who were mechanically ventilated that compared recruitment manoeuvres versus standard care for patients given a diagnosis of ARDS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors for additional information.

MAIN RESULTS

Ten trials met the inclusion criteria for this review (n = 1658 participants). We found five trials to be at low risk of bias and five to be at moderate risk of bias. Six of the trials included recruitment manoeuvres as part of an open lung ventilation strategy that was different from control ventilation in aspects other than the recruitment manoeuvre (such as mode of ventilation, higher positive end-expiratory pressure (PEEP) titration and lower tidal volume or plateau pressure). Six studies reported mortality outcomes. Pooled data from five trials (1370 participants) showed a reduction in intensive care unit (ICU) mortality (risk ratio (RR) 0.83, 95% confidence interval (CI) 0.72 to 0.97, P = 0.02, low-quality evidence), pooled data from five trials (1450 participants) showed no difference in 28-day mortality (RR 0.86, 95% CI 0.74 to 1.01, P = 0.06, low-quality evidence) and pooled data from four trials (1313 participants) showed no difference in in-hospital mortality (RR 0.88, 95% CI 0.77 to 1.01, P = 0.07, low-quality evidence). Data revealed no differences in risk of barotrauma (RR 1.09, 95% CI 0.78 to 1.53, P = 0.60, seven studies, 1508 participants, moderate-quality evidence).

AUTHORS' CONCLUSIONS

We identified significant clinical heterogeneity in the 10 included trials. Results are based upon the findings of several (five) trials that included an "open lung ventilation strategy", whereby the intervention group differed from the control group in aspects other than the recruitment manoeuvre (including co-interventions such as higher PEEP, different modes of ventilation and higher plateau pressure), making interpretation of the results difficult. A ventilation strategy that included recruitment manoeuvres in participants with ARDS reduced intensive care unit mortality without increasing the risk of barotrauma but had no effect on 28-day and hospital mortality. We downgraded the quality of the evidence to low, as most of the included trials provided co-interventions as part of an open lung ventilation strategy, and this might have influenced results of the outcome.

Landiolol hydrochloride ameliorates acute lung injury in a rat model of early sepsis through the suppression of elevated levels of pulmonary endothelin-1

Among the dysfunctions and pathologies associated with sepsis, the underlying molecular mechanisms of sepsis-induced acute lung injury (ALI) are poorly understood. Endothelin (ET)-1, a potent vasoconstrictor and pro-inflammatory peptide, is known to be involved in the pathogenesis of ALI in a rat model of sepsis. Here, we investigated whether landiolol hydrochloride, an ultra-short-acting β-blocker, plays a crucial role in ameliorating and attenuating LPS-induced ALI through modulation of the ET-1 system. Male Wistar rats at 8weeks of age were administered with either saline or lipopolysaccharide (LPS) for three hours (3h) and some of the LPS-administered rats were continuously treated with landiolol for 3h. ALI was induced by LPS, including levels of both circulatory and pulmonary TNF-α and IL-6 but [PaO₂] was significantly decreased. LPS also induced a significant increase in levels of pulmonary ET-1 and ET-A receptor, but levels of ET-B receptor, which has vasodilating effects, were remarkably diminished. Further, LPS administration upregulated the pulmonary expression of HIF-1α. Finally, the treatment of LPS-administered rats with landiolol for 3h ameliorated and prevented ALI, normalized the altered levels of pulmonary ET-1 and ET-A receptors. Landiolol also induced significant down-regulation of ET-B receptor in lung tissues in the early hours (phase) of sepsis. However, Landiolol treatment had no effect on the up-regulated inflammatory mediators (TNF-α, IL-6) in both plasma and lung tissues during sepsis, and expression of pulmonary HIF-1α also remained unchanged after landiolol treatment. Collectively, these data led us to conclude that landiolol may ameliorate sepsis-induced ALI via the pulmonary ET system.

Patterns of recruitment and injury in a heterogeneous airway network model

In respiratory distress, lung airways become flooded with liquid and may collapse due to surface-tension forces acting on air-liquid interfaces, inhibiting gas exchange. This paper proposes a mathematical multiscale model for the mechanical ventilation of a network of occluded airways, where air is forced into the network at a fixed tidal volume, allowing investigation of optimal recruitment strategies. The temporal response is derived from mechanistic models of individual airway reopening, incorporating feedback on the airway pressure due to recruitment. The model accounts for stochastic variability in airway diameter and stiffness across and between generations. For weak heterogeneity, the network is completely ventilated via one or more avalanches of recruitment (with airways recruited in quick succession), each characterized by a transient decrease in the airway pressure; avalanches become more erratic for airways that are initially more flooded. However, the time taken for complete ventilation of the network increases significantly as the network becomes more heterogeneous, leading to increased stresses on airway walls. The model predicts that the most peripheral airways are most at risk of ventilation-induced damage. A positive-end-expiratory pressure reduces the total recruitment time but at the cost of larger stresses exerted on airway walls.

Unintentional Continuation of Medications Intended for Acute Illness After Hospital Discharge: A Population-Based Cohort Study

BACKGROUND

Patients are vulnerable to medication-related errors during transitions in care. Patients discharged from acute care hospitals may be at an elevated risk for the unintentional continuation of medications prescribed to prevent or treat complications that are associated with acute illness but are no longer indicated. We sought to evaluate rates of (primary objective) and risk factors for (secondary objective) potentially unintentional medication continuation following hospitalization.

METHODS

A population-based cohort study of more than one million patients 66 years of age or older who were hospitalized in Ontario, Canada, between 2003 and 2011 and followed for 1 year (2004 to 2012). We created distinct cohorts by identifying seniors not previously receiving four classes of medications typically used to treat or prevent complications of acute illness: (1) antipsychotic medications, (2) gastric acid suppressants (histamine-2 blockers and proton pump inhibitors), (3) benzodiazepines, and (4) inhaled bronchodilators and steroids. After excluding documented indications, we followed patients to ascertain whether these medications were continued after hospital discharge, and assessed risk factors for their continuation using generalized estimating equations. The primary outcome was the new dispensation of any of the selected medications within 7 days of hospital discharge.

RESULTS

Prescription without documented indication occurred across all medication classes, from 12,209 patients (1.4 %) for antipsychotic medications to 34,140 patients (6.1 %) for gastric acid suppressants. Risk factors for unintentional continuation varied across medication groups, but rates were consistently higher for older patients, those with multiple comorbidities, and emergency hospitalizations. The largest absolute risk factor across all medications was a hospitalization > 7 days [OR 2.03 (95 % CI 1.94-2.11) for respiratory inhalers, 6.35 (95 % CI 5.91-6.82) for antipsychotic medications]. These medications were often continued at 1 year of follow-up, and accounted for a total additional medication cost of over CAD$18 million for the study population.

CONCLUSION

Discharged patients are at risk of being prescribed and dispensed medications that are typically intended to prevent or treat complications of acute illness, despite having no documented indication for chronic use.

Height measurement in the critically ill patient: A tall order in the critical care unit

Height measurement in the critical care unit is necessary for estimating ideal body weight and providing titrated patient care. In this study, we compare three methods of height assessment and evaluate their level of correlation and inter-observer reproducibility. Heights of 100 consecutive patients were assessed independently by two nurses by supine, four point, and arm span methods. Paired sample t-test, one-way analysis of variance, Tukey's honestly significant difference post-hoc analysis and Bland–Altman plots were performed to assess agreement between measurements. Arm span method showed higher mean height compared to supine and four point methods. Mean heights derived by supine and four point measurements were similar to each other but were significantly different from that of arm span method (P < 0.001). Inter-observer correlation of the measured heights was very good among all three methods. The supine method seems to be easy, accurate, and reproducible in our study.

Retinoic acid promotes the endogenous repair of lung stem/progenitor cells in combined with simvastatin after acute lung injury: a stereological analysis

Background

The treatment of acute respiratory distress syndrome (ARDS), most commonly seen during the organ dysfunction remains unsatisfied. Presently, the stem/progenitor cell-based endogenous repair has been aroused attention enormously. This report investigated the effects of retinoic acid (RA) plus simvastatin (SS) with respect to dynamics of lung repair cells as well as to elucidate the underlying mechanism.

Materials and methods

The experimental Sprague–Dawley rats were divided randomly into normal control (control), sham operated (sham), ARDS, ARDS + vehicle and ARDS + RA + SS groups. ARDS was reproduced through hemorrhagic shock/resuscitation (shock) and subsequent intratracheal LPS (4.5 mg/kg, Escherichia coli serotype O55: B5) injection. The rats were treated by intragastric administration of RA (2 mg/kg/day) and SS (2 mg/kg/day) for 5 days in the ARDS + RA + SS group. Seven days after the first RA-SS injection, a right lower lobe of lung was sampled for histological analysis concerning systemic uniform random sampling method. Immunohistochemistry of inflation-fixed lungs for alveolar type 1 (AT1), alveolar type 2 (AT2) and Clara cells was measured by AQP5, Pro-SPC and CCSP staining respectively. The alveolar cell proliferation and apoptosis were analyzed with Ki67 staining and terminal deoxylnucleotidyl transferase mediated-dUTP nick end labeling (TUNEL) method. Meanwhile, the alveolar cell numerical and surface density (alveolar cells, AT1, AT2, Clara, proliferating and apoptotic cells) were evaluated by stereology.

Results

RA-SS compound exerted anti-inflammatory and pro-repairing effects on respiratory tracts in ARDS induced by hemorrhagic-endotoxin shock. The numerical density and surface density of alveolar cells, AT1 cell fraction, and numerical density of AT2 and Clara cells were significantly increased after treatment with RA-SS compound in ARDS. Concurrently, the Ki67+ alveolar cells were obviously increased while the TUNEL+ alveolar cells were reduced, which was correlated with the attenuation of inflammatory injury and functional repair in injured lung tissues.

Conclusions

Our data convincingly indicated that the prophylactic and therapeutic treatment of RA plus SS had obvious beneficial effect on the remodeling/regeneration of injured pulmonary tissues, suggesting that the underlying mechanisms are related to the re-balance between regeneration and apoptosis in lung stem/progenitor cells.

Lipopolysaccharide challenge induces long pentraxin 3 expression in mice independently from acute lung injury

OBJECTIVE

To determine whether the onset of acute lung injury (ALI) induces the up-regulation of pentraxin 3 (PTX3) expression in mice and whether PTX3 concentration in the biofluid can help recognizing sepsis-induced ALI.

METHODS

Wild-type C57BL/6 mice (12-14 weeks old) were randomly divided into 3 groups. Mice in the group 1 (n=12) and group 2 (n=12) were instilled with lipopolysaccharide via intratracheal or intraperitoneal routes, respectively. Mice in the group 3 (n=8) were taken as blank controls. Pulmonary morphological and functional alterations were measured to determine the presence of experimental ALI. PTX3 expression in the lung was quantified at both protein and mRNA levels. PTX3 protein concentration in blood and bronchoalveolar lavage fluid was measured to evaluate its ability to diagnose sepsis-induced ALI by computing area under receiver operator characteristic curve (AUROCC).

RESULTS

ALI was commonly confirmed in the group 1 but never in the other groups. PTX3 expression was up-regulated indiscriminately among lipopolysaccharide-challenged mice. PTX3 protein concentration in the biofluid was unable to diagnose sepsis-induced ALI evidenced by its small AUROCC. PTX3 concentration in bronchoalveolar lavage fluid did not correlate with that in serum.

CONCLUSIONS

Lipopolysaccharide challenges induced PTX3 expression in mice regardless of the presence of ALI. PTX3 may act as an indicator of inflammatory response instead of organ injury per se.

Low tidal volume pressure support versus controlled ventilation in early experimental sepsis in pigs

Background

In moderate acute respiratory distress syndrome (ARDS) several studies support the usage of assisted spontaneous breathing modes. Only limited data, however, focus on the application in systemic sepsis and developing lung injury. The present study examines the effects of immediate initiation of pressure support ventilation (PSV) in a model of sepsis-induced ARDS.

Methods

18 anesthetized pigs received a two-staged continuous lipopolysaccharide infusion to induce lung injury. The animals were randomly assigned to PSV or volume controlled (VCV) lung protective ventilation (tidal volume each 6 ml kg^-1, n = 2x9) over six hours. Gas exchange parameters, hemodynamics, systemic inflammation, and ventilation distribution by multiple inert gas elimination and electrical impedance tomography were assessed. The post mortem analysis included histopathological scoring, wet to dry ratio, and alveolar protein content.

Results

Within six hours both groups developed a mild to moderate ARDS with comparable systemic inflammatory response and without signs of improving gas exchange parameters during PSV. The PSV group showed signs of more homogenous ventilation distribution by electrical impedance tomography, but only slightly less hyperinflated lung compartments by multiple inert gas elimination. Post mortem and histopathological assessment yielded no significant intergroup differences.

Conclusions

In a porcine model of sepsis-induced mild ARDS immediate PSV was not superior to VCV. This contrasts with several experimental studies from non-septic mild to moderate ARDS. The present study therefore assumes that not only severity, but also etiology of lung injury considerably influences the response to early initiation of PSV.

Protective effect of quercetin on lipopolysaccharide-induced acute lung injury in mice by inhibiting inflammatory cell influx

Sepsis may result in lung injury through a complex cascade of events including interstitium infiltration of inflammatory cells. Quercetin, the most abundant dietary flavonoid found in various plants and food products, possesses potent anti-inflammatory and antioxidative properties. The purpose of this study was to investigate whether preventive administration of quercetin could exert beneficial effects on experimental septic acute lung injury induced by lipopolysaccharide (LPS). C57/BL6 mice were challenged with LPS and survival time was monitored from 0–96 h after LPS treatment. Quercetin markedly rescued lethality, improved survival time, and inhibited serum necrosis factor α, interleukin 1β, and interleukin 6, and nitric oxide (NO), and increased IL-10 secretion. Moreover, quercetin decreased lung pathological changes, myeloperoxidase activity, and malondialdehyde levels. Quercetin also reduced the lung permeability changes and neutrophil and macrophage recruitment to the bronchoalveolar lavage fluid compared to the vehicle. Additionally, quercetin significantly reduced COX-2, HMGB1, iNOS expression, and NF-κB p65 phosphorylation. These results suggest that treatment with quercetin in septic mice improved survival time and lung injury. Quercetin may be a promising potential therapeutic reagent for LPS-induced acute lung injury.

Management of sepsis in neutropenic patients: 2014 updated guidelines from the Infectious Diseases Working Party of the German Society of Hematology and Medical Oncology (AGIHO)

Sepsis is a major cause of mortality during the neutropenic phase after intensive cytotoxic therapies for malignancies. Improved management of sepsis during neutropenia may reduce the mortality of cancer therapies. Clinical guidelines on sepsis treatment have been published by others. However, optimal management may differ between neutropenic and non-neutropenic patients. Our aim is to give evidence-based recommendations for haematologist, oncologists and intensive care physicians on how to manage adult patients with neutropenia and sepsis.

[Staphylococcus aureus broncho-pulmonary infections]

Staphylococcus aureus accounts for 2-5% of the etiologies of community-acquired pneumonia. These infections occur mainly in elderly patients with comorbidity, after a respiratory viral infection. S. aureus could also be responsible for necrotizing pneumonia, which occurs in young subjects, also after flu. Necrotizing pneumonia are associated with the production of a particular staphylococcal toxin called Panton-Valentine leukocidin, responsible for pulmonary focal necrosis, occurrence haemoptysis, leucopenia, and death. In Europe, these strains are still predominantly sensitive to anti-staphylococcal penicillin, which must be used at high dosage intravenously in combination with an antibiotic that reduces toxin production such as clindamycin, and intravenous immunoglobulin in severe cases. The mortality rate is estimated at 50%. In addition, S. aureus is one of the pathogens involved in early respiratory infections in cystic fibrosis patients, in whom methicillin resistance plays an important prognostic role. However, the involvement of S. aureus in COPD exacerbations is rare. Finally, S. aureus represents 20 to 30% of cases of hospital-acquired pneumonia, including ventilator-associated pneumonia. In these cases, methicillin-resistance is common and requires the use of glycopeptides or linezolid. The place of new anti-staphylococcal antibiotics such as new generation cephalosporins or tigecyclin remains to be defined.

Massive pulmonary embolism

Massive pulmonary embolism (PE) is a potentially lethal condition, with death usually caused by right ventricular (RV) failure and cardiogenic shock. Systemic thrombolysis (unless contraindicated) is recommended as the first-line treatment of massive PE to decrease the thromboembolic burden on the RV and increase pulmonary perfusion. Surgical pulmonary embolectomy or catheter-directed thrombectomy should be considered in patients with contraindications to fibrinolysis, or those with persistent hemodynamic compromise or RV dysfunction despite fibrinolytic therapy. Critical care management predominantly involves supporting the RV, by optimizing preload, RV contractility, and coronary perfusion pressure and minimizing afterload. Despite these interventions, mortality remains high.

Molecular mechanism of sustained inflation in acute respiratory distress syndrome

BACKGROUND

The aim of this study was to investigate the effect and the potential molecular mechanism of sustained inflation (SI) recruitment maneuvers in acute respiratory distress syndrome (ARDS) in beagle dog following endotracheal suctioning.

METHODS

ARDS was induced in 24 beagle dogs with oleic acid. They had mechanical ventilation support. They were randomized into four groups after the establishment of the ARDS model: non-SI-open group where no SI was applied in beagle dogs with ARDS following open endotracheal suctioning; non-SI-closed group where no SI was applied in beagle dogs with ARDS following closed endotracheal suctioning; SI-open group where SI was applied in beagle dogs with ARDS following open endotracheal suctioning; and SI-closed group where SI was applied in beagle dogs with ARDS following closed endotracheal suctioning. Oxygenation, indexes of respiratory mechanics, and hemodynamic indexes were serially measured during the procedure. The serum protein level, or the messenger RNA in the heart and lung, of inflammation-related cytokines was investigated.

RESULTS

SI in ARDS improved oxygenation, lung compliance, and airway resistance but had no significant effect in the hemodynamic indexes. At molecular level, SI in ARDS neutralized the increases of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 1β [IL-1β], and IL-6), and anti-inflammatory cytokine (IL-10) in the serum. Furthermore, SI in ARDS increased aquaporin 1 and aquaporin 5 messenger RNA in the lung tissue, and decreased IL-6 messenger RNA in the lung and heart tissue.

CONCLUSION

SI in ARDS could improve oxygenation, lung compliance, and airway resistance, which was related to the improved degree of inflammation and better maintained aquaporins.

Anthrax: has the clinical milieu changed since 2001?

Since the anthrax attacks of 2001 (Amerithrax), several important improvements in the knowledge of Bacillus anthracis and the clinical condition it causes have occurred. While much remains to be known about the optimal management of anthrax patients, several approaches that were not widely utilized, available, or known in 2001 would be used in the treatment of critically ill anthrax patients in 2012.

Effects of vagus nerve stimulation and vagotomy on systemic and pulmonary inflammation in a two-hit model in rats

Pulmonary inflammation contributes to ventilator-induced lung injury. Sepsis-induced pulmonary inflammation (first hit) may be potentiated by mechanical ventilation (MV, second hit). Electrical stimulation of the vagus nerve has been shown to attenuate inflammation in various animal models through the cholinergic anti-inflammatory pathway. We determined the effects of vagotomy (VGX) and vagus nerve stimulation (VNS) on systemic and pulmonary inflammation in a two-hit model. Male Sprague-Dawley rats were i.v. administered lipopolysaccharide (LPS) and subsequently underwent VGX, VNS or a sham operation. 1 hour following LPS, MV with low (8 mL/kg) or moderate (15 mL/kg) tidal volumes was initiated, or animals were left breathing spontaneously (SP). After 4 hours of MV or SP, rats were sacrificed. Cytokine and blood gas analysis was performed. MV with 15, but not 8 mL/kg, potentiated the LPS-induced pulmonary pro-inflammatory cytokine response (TNF-α, IL-6, KC: p<0.05 compared to LPS-SP), but did not affect systemic inflammation or impair oxygenation. VGX enhanced the LPS-induced pulmonary, but not systemic pro-inflammatory cytokine response in spontaneously breathing, but not in MV animals (TNF-α, IL-6, KC: p<0.05 compared to SHAM), and resulted in decreased pO(2) (p<0.05 compared to sham-operated animals). VNS did not affect any of the studied parameters in both SP and MV animals. In conclusion, MV with moderate tidal volumes potentiates the pulmonary inflammatory response elicited by systemic LPS administration. No beneficial effects of vagus nerve stimulation performed following LPS administration were found. These results questions the clinical applicability of stimulation of the cholinergic anti-inflammatory pathway in systemically inflamed patients admitted to the ICU where MV is initiated.