Acute respiratory distress syndrome-attributable mortality in critically ill patients with sepsis

Hospital-free Days: A Pragmatic and Patient-centered Outcome for Trials Among Critically and Seriously Ill Patients

Hospital-free days (HFDs), alternatively known as "days alive and outside the hospital," is increasingly used as a primary or secondary outcome in randomized trials among critically and seriously ill patients. This novel outcome measure addresses an existing gap in the availability of patient-centered, reliably obtained outcome measures among patients with acute respiratory failure, advanced lung diseases, lung transplantation, and other serious and critical illnesses. Traditional outcomes such as mortality, organ-failure-free days, and longitudinal patient-reported measures have distinct drawbacks that limit their suitability as endpoints in trials of patients with serious illness, particularly those trials with pragmatic designs. By contrast, HFDs provides a summary measure of important health events and is easily calculated from administrative or electronic health record data, thereby balancing the goals of patient-centeredness and pragmatic measurement. However, before HFDs can be widely adopted as an endpoint in trials of patients with respiratory and critical illnesses, several questions must be addressed regarding the optimal definition, measurement, and analysis of HFDs. In this perspective, we outline important considerations relevant to the use of HFDs as a trial endpoint and suggest directions for further development of the measure.

Possible unrecognised liver injury is associated with mortality in critically ill COVID-19 patients

BACKGROUND

Coronavirus disease (COVID-19) with acute respiratory distress syndrome is a life-threatening condition. A previous diagnosis of chronic liver disease is associated with poorer outcomes. Nevertheless, the impact of silent liver injury has not been investigated. We aimed to explore the association of pre-admission liver fibrosis indices with the prognosis of critically ill COVID-19 patients.

METHODS

The work presented was an observational study in 214 patients with COVID-19 consecutively admitted to the intensive care unit (ICU). Pre-admission liver fibrosis indices were calculated. In-hospital mortality and predictive factors were explored with Kaplan-Meier and Cox regression analysis.

RESULTS

The mean age was 59.58 (13.79) years; 16 patients (7.48%) had previously recognised chronic liver disease. Up to 78.84% of patients according to Forns, and 45.76% according to FIB-4, had more than minimal fibrosis. Fibrosis indices were higher in non-survivors [Forns: 6.04 (1.42) versus 4.99 (1.58), p < 0.001; FIB-4: 1.77 (1.17) versus 1.41 (0.91), p = 0.020)], but no differences were found in liver biochemistry parameters. Patients with any degree of fibrosis either by Forns or FIB-4 had a higher mortality, which increased according to the severity of fibrosis (p < 0.05 for both indexes). Both Forns [HR 1.41 (1.11-1.81); p = 0.006] and FIB-4 [HR 1.31 (0.99-1.72); p = 0.051] were independently related to survival after adjusting for the Charlson comorbidity index, APACHE II, and ferritin.

CONCLUSION

Unrecognised liver fibrosis, assessed by serological tests prior to admission, is independently associated with a higher risk of death in patients with severe COVID-19 admitted to the ICU.

Comparative Efficacy of Fentanyl and Morphine in Patients with or At Risk for Acute Respiratory Distress Syndrome: A Propensity Score-Matched Cohort Study

Introduction

Opioids are potent painkillers but can have severe adverse effects in the intensive care unit (ICU). The aim of this study was to compare the outcomes of fentanyl and morphine use among patients at risk for and with acute respiratory distress syndrome (ARDS).

Methods

We developed a dataset of real-world data to enable the comparison of the effectiveness and safety of opioids and the associated outcomes from the Multiparameter Intelligent Monitoring in Intensive Care (MIMIC)-III database and the eICU Collaborative Research Database. Patients who were admitted to the ICU with a diagnosis of or at risk for ARDS and received mechanical ventilation for at least 12 h were included. Patients were enrolled sequentially into one of six groups in three cohorts: treated with fentanyl or not; treated with morphine or not; and treated with fentanyl or morphine. Propensity score matching and multivariable analyses were performed.

Results

Fentanyl was associated with higher in-hospital mortality in the propensity score-matched model but not in the linear regression model. The use of morphine was associated with a higher in-hospital mortality in both models. Both fentanyl and morphine were associated with longer duration of mechanical ventilation, ICU stay, and hospitalization and a decreased likelihood of being discharged home in both models. Notably, compared with morphine, fentanyl was associated with a lower mortality and an increased likelihood of being discharged home.

Conclusions

Both fentanyl and morphine were independent risk factors for worse outcomes in patients with or at risk for ARDS. Compared with morphine, fentanyl may be preferred in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40268-021-00338-3.

Macrophage migration inhibitory factor as a diagnostic and predictive biomarker in sepsis: meta-analysis of clinical trials

The hunt for useful sepsis biomarkers is ongoing. Macrophage migration inhibitory factor (MIF) was implicated as a biomarker in sepsis, but its diagnostic and prognostic value has remained unclear in human studies. Here, we aimed at clarifying the value of MIF as a sepsis biomarker with the meta-analysis of clinical trials. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials databases were searched until December 2019. From the included studies, blood MIF levels and indicators of disease severity were extracted in septic and control patient groups. Twenty-one eligible studies were identified, including data from 1876 subjects (of which 1206 had sepsis). In the septic patients, blood MIF levels were significantly higher than in healthy controls with a standardized mean difference (SMD) of 1.47 (95% confidence interval, CI: 0.96-1.97; p < 0.001) and also higher than in patient groups with nonseptic systemic inflammation (SMD = 0.94; CI: 0.51-1.38; p < 0.001). Markedly greater elevation in blood MIF level was found in the more severe forms of sepsis and in nonsurvivors than in less severe forms and in survivors with SMDs of 0.84 (CI: 0.45-1.24) and 0.75 (CI: 0.40-1.11), respectively (p < 0.001 for both). In conclusion, blood MIF level is more elevated in systemic inflammation caused by infection (i.e., sepsis) compared to noninfectious causes. In more severe forms of sepsis, including fatal outcome, MIF levels are higher than in less severe forms. These results suggest that MIF can be a valuable diagnostic and prognostic biomarker in sepsis given that well-designed clinical trials validate our findings.

Comparative Effectiveness of Midazolam, Propofol, and Dexmedetomidine in Patients With or at Risk for Acute Respiratory Distress Syndrome: A Propensity Score-Matched Cohort Study

Background: Sedatives are commonly used in patients with or at risk for acute respiratory distress syndrome (ARDS) during mechanical ventilation. To systematically compare the outcomes of sedation with midazolam, propofol, and dexmedetomidine in patients with or at risk for ARDS.

Methods: We developed a dataset of real-world data to enable the comparison of the effectiveness and safety of sedatives and the associated outcomes from the MIMIC-III database and the eICU Collaborative Research database. We performed a systematic study with six cohorts to estimate the relative risks of outcomes among patients administered different sedatives. Propensity score matching was performed to generate a balanced 1:1 matched cohort and to identify potential prognostic factors. The outcomes included hospital mortality, duration of mechanical ventilation, length of intensive care unit stay, length of hospitalization, and likelihood of being discharged home.

Results: We performed 60 calibrated analyses among all groups and outcomes with 17,410 eligible patients. Sedation with dexmedetomidine was associated with a lower in-hospital mortality rate than sedation with midazolam and propofol or sedation without dexmedetomidine (p < 0.001). When compared with no sedation, the use of midazolam, propofol or dexmedetomidine was associated with a longer ICU stay and longer hospitalization duration (p < 0.01). Patients treated with midazolam were relatively less likely to be discharged home (p < 0.05).

Conclusion: Patients treated with dexmedetomidine had a reduced risk of mortality. These data suggest that dexmedetomidine may be the preferred sedative in patients with or at risk for ARDS.

Precision medicine in acute respiratory distress syndrome: workshop report and recommendations for future research

Acute respiratory distress syndrome (ARDS) is a devastating critical illness that can be triggered by a wide range of insults and remains associated with a high mortality of around 40%. The search for targeted treatment for ARDS has been disappointing, possibly due to the enormous heterogeneity within the syndrome. In this perspective from the European Respiratory Society research seminar on "Precision medicine in ARDS", we will summarise the current evidence for heterogeneity, explore the evidence in favour of precision medicine and provide a roadmap for further research in ARDS. There is evident variation in the presentation of ARDS on three distinct levels: 1) aetiological; 2) physiological and 3) biological, which leads us to the conclusion that there is no typical ARDS. The lack of a common presentation implies that intervention studies in patients with ARDS need to be phenotype aware and apply a precision medicine approach in order to avoid the lack of success in therapeutic trials that we faced in recent decades. Deeper phenotyping and integrative analysis of the sources of variation might result in identification of additional treatable traits that represent specific pathobiological mechanisms, or so-called endotypes.

Repurposed Tocilizumab in Patients with Severe COVID-19

The coronavirus disease 2019 (COVID-19) has caused a global pandemic, resulting in considerable morbidity and mortality. Tocilizumab, an inhibitor of IL-6, has been widely repurposed as a treatment of severely ill patients without robust evidence supporting its use. In this study, we aimed to systematically describe the effectiveness of treatment and prevention of the cytokine storms in COVID-19 patients with tocilizumab. In this multicentered retrospective and observational cohort study, 65 patients with COVID-19 receiving tocilizumab and 130 not receiving tocilizumab were propensity score matched at a ratio of 2:1 based on age, sex, and comorbidities from January 20, 2020 to March 18, 2020 in Wuhan, China. After adjusting for confounding, the detected risk for in-hospital death was lower in the tocilizumab group versus nontocilizumab group (hazard ratio = 0.47; 95% confidence interval = 0.25-0.90; p = 0.023). Moreover, use of tocilizumab was associated with a lower risk of acute respiratory distress syndrome (odds ratio = 0.23; 95% confidence interval = 0.11-0.45; p < 0.0001). Furthermore, patients had heightened inflammation and more dysregulated immune cells before treatment, which might aggravate disease progression. After tocilizumab administration, abnormally elevated IL-6, C-reactive protein, fibrinogen, and activated partial thromboplastin time decreased. Tocilizumab may be of value in prolonging survival in patients with severe COVID-19, which provided a novel strategy for COVID-19-induced cytokine release syndrome. Our findings could inform bedside decisions until data from randomized, controlled clinical trials become available.

Effect and mechanism of phospholipid scramblase 4 (PLSCR4) on lipopolysaccharide (LPS)-induced injury to human pulmonary microvascular endothelial cells

Background

Previous experiments revealed phospholipid scramblase 4 (PLSCR4) mRNA to be significantly increased in a lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) model of human pulmonary microvascular endothelial cells (HPMECs); however, the effect of PLSCR4 and its mechanism have not been reported to date. The PLSCR family is thought to mediate the transmembrane movement of phospholipids (PS), and has been found to be involved in pyroptosis through combing with gasdermin D (GSDMD). We therefore speculated that PLSCR4 may contribute to cell death via pyroptosis.

Methods

To investigate the effect and mechanism of PLSCR4 in ARDS, we constructed an in vitro model of LPS-induced ARDS in HPMECs transfected with PLSCR4 small interfering RNA (siRNA) or scramble siRNA (sc siRNA). After 4 h of LPS stimulation, western blotting, immunoprecipitation, enzyme-linked immunosorbent assay (ELISA), tracer flux assays, and fluorescence assays were used to study the relationship between PLSCR4 and pyroptosis with regards to their impact on ARDS. We also established an ARDS mouse model which was pretreated with a liquid complex of PLSCR4 siRNA/sc siRNA-lipofectamine 2000 through the fundus venous plexus. Finally, we used DNA pull-down and protein profiling to study the potential transcription factor of PLSCR4.

Results

It was found that when the expression of PLSCR4 was elevated, the concentration of interleukin 1 beta (IL-1β) and IL-18 decreased, along with barrier damage (P<0.05). Furthermore, HPMEC injury was reduced with more distribution of PS and N-terminal cleavage product (GSDMD-NT) of GSDMD on the external side of cell membrane. However, the pyroptosis-relevant proteins of GSDMD and caspase-1 were not obviously changed (P<0.05); we further found that when PLSCR4 was depressed, the lung injury was aggravated in the mice. In the DNA pull-down assay, P62280 remarkably increased, which suggested that P62280 might be the transcription factor for PLSCR4.

Conclusions

PLSCR4 alleviated pyroptosis by transporting PS to the outside of the membrane, blocking the formation of pyroptosis pores composed of GSDMD. Moreover, P62280 might be the transcription factor of PLSCR4. These insults may provide useful insights into the clinical treatment of ARDS.

P53 deficiency potentiates LPS-Induced acute lung injury in vivo

Acute Lung Injury (ALI) and Acute Respiratory Distress Syndrome (ARDS) represent a significant cause of morbidity and mortality in critically ill hospitalized patients. Emerging evidence suggest that the expression levels of P53 in the lungs are associated with the supportive effects of heat shock protein 90 inhibitors and growth hormone releasing hormone antagonists in the endothelium. In the current study, we employed an in vivo model of intratracheal administration of lipopolysaccharides (LPS)-induced ALI to investigate the role of P53 in counteracting LPS-induced lung inflammatory responses. In wild type mice, LPS induced the expression of IL-1α, IL-1β, and TNFα in the lungs, increased bronchoalveolar lavage fluid protein concentration, and activated cofilin. Remarkably; those responses were more potent in P53 knockout mice, suggesting the crucial role of P53 in orchestrating rigorous endothelial defenses against inflammatory stimuli. The present study supports previous endeavors on the protective role of P53 against lung inflammatory disease, and enrich our knowledge on the development of medical countermeasures against ARDS.

Phenotypes and personalized medicine in the acute respiratory distress syndrome

Although the acute respiratory distress syndrome (ARDS) is well defined by the development of acute hypoxemia, bilateral infiltrates and non-cardiogenic pulmonary edema, ARDS is heterogeneous in terms of clinical risk factors, physiology of lung injury, microbiology, and biology, potentially explaining why pharmacologic therapies have been mostly unsuccessful in treating ARDS. Identifying phenotypes of ARDS and integrating this information into patient selection for clinical trials may increase the chance for efficacy with new treatments. In this review, we focus on classifying ARDS by the associated clinical disorders, physiological data, and radiographic imaging. We consider biologic phenotypes, including plasma protein biomarkers, gene expression, and common causative microbiologic pathogens. We will also discuss the issue of focusing clinical trials on the patient's phase of lung injury, including prevention, administration of therapy during early acute lung injury, and treatment of established ARDS. A more in depth understanding of the interplay of these variables in ARDS should provide more success in designing and conducting clinical trials and achieving the goal of personalized medicine.

Extracellular histones in lung dysfunction: a new biomarker and therapeutic target?

Extracellular histones released from injured or dying cells following trauma and other severe insults can act as potent damage-associated molecular patterns. In fact, elevated levels of histones are present in human circulation in hyperinflammatory states such as acute respiratory distress syndrome and sepsis. The molecular mechanisms owing to histone-induced pathologies are at the very beginning of elucidating. However, neutralization of histones with antibodies, histone-binding or histone-degrading proteins, and heparan sulfates have shown promising therapeutic effects in pre-clinical acute respiratory distress syndrome and sepsis models. Various cell types undergoing necrosis and apoptosis or activated neutrophils forming neutrophil extracellular traps have been implicated in excessive release of histones which further augments tissue injury and may culminate in multiple organ failure. At the molecular level, an uncontrolled inflammatory cascade has been considered as the major event; however, histone-activated coagulation and thrombosis represent additional pathologic events reflecting coagulopathy. Furthermore, epigenetic regulation and chemical modifications of circulating histones appear to be critically important in their biological functions as evidenced by increased cytotoxicity associated with citrullinated histone. Herein, we will briefly review the current knowledge on the role of histones in acute respiratory distress syndrome and sepsis, and discuss the future potential of anti-histone therapy for treatment of these life-threatening disorders.

MicroRNA-31-5p Exacerbates Lipopolysaccharide-Induced Acute Lung Injury via Inactivating Cab39/AMPKα Pathway

Acute lung injury (ALI) and the subsequent acute respiratory distress syndrome remain devastating diseases with high mortality rates and poor prognoses among patients in intensive care units. The present study is aimed at investigating the role and underlying mechanisms of microRNA-31-5p (miR-31-5p) on lipopolysaccharide- (LPS-) induced ALI. Mice were pretreated with miR-31-5p agomir, antagomir, and their negative controls at indicated doses for 3 consecutive days, and then they received a single intratracheal injection of LPS (5 mg/kg) for 12 h to induce ALI. MH-S murine alveolar macrophage cell lines were cultured to further verify the role of miR-31-5p in vitro. For AMP-activated protein kinase α (AMPKα) and calcium-binding protein 39 (Cab39) inhibition, compound C or lentiviral vectors were used in vivo and in vitro. We observed an upregulation of miR-31-5p in lung tissue upon LPS injection. miR-31-5p antagomir alleviated, while miR-31-5p agomir exacerbated LPS-induced inflammation, oxidative damage, and pulmonary dysfunction in vivo and in vitro. Mechanistically, miR-31-5p antagomir activated AMPKα to exert the protective effects that were abrogated by AMPKα inhibition. Further studies revealed that Cab39 was required for AMPKα activation and pulmonary protection by miR-31-5p antagomir. We provide the evidence that endogenous miR-31-5p is a key pathogenic factor for inflammation and oxidative damage during LPS-induced ALI, which is related to Cab39-dependent inhibition of AMPKα.

Extracorporeal multiorgan support including CO2-removal with the ADVanced Organ Support (ADVOS) system for COVID-19: A case report

A substantial part of COVID-19-patients suffers from multi-organ failure (MOF). We report on an 80-year old patient with pulmonary, renal, circulatory, and hepatic failure. We decided against the use of extracorporeal membrane oxygenation (ECMO) due to old age and a SOFA-score of 13. However, the patient was continuously treated with the extracorporeal multi-organ- “ADVanced Organ Support” (ADVOS) device (ADVITOS GmbH, Munich, Germany). During eight 24h-treatment-sessions blood flow (100–300 mL/min), dialysate flow (160–320 mL/min) and dialysate pH (7.6–9.0) were adapted to optimize arterial PaCO₂ and pH. Effective CO₂ removal and correction of acidosis could be demonstrated by mean arterial- versus post-dialyzer values of pCO₂ (68.7 ± 13.8 vs. 26.9 ± 11.6 mmHg; p < 0.001). The CO₂-elimination rate was 48 ± 23mL/min. The initial vasopressor requirement could be reduced in parallel to pH-normalization. Interruptions of ADVOS-treatment repeatedly resulted in reversible deteriorations of p_aCO₂ and pH. After 95 h of continuous extracorporeal decarboxylating therapy the patient had markedly improved circulatory parameters compared to baseline. In the context of secondary pulmonary infection and progressive liver failure, the patient had a sudden cardiac arrest. In accordance with the presumed patient will, we decided against mechanical resuscitation. Irrespective of the outcome we conclude that extracorporeal CO₂ removal and multiorgan-support were feasible in this COVID-19-patient. Combined and less invasive approaches such as ADVOS might be considered in old-age-COVID-19 patients with MOF.