Statin therapy for acute respiratory distress syndrome: an individual patient data meta-analysis of randomised clinical trials

Association between pre-ICU statin use and ARDS mortality in the MIMIC-IV database: a cohort study

Background

Acute respiratory distress syndrome (ARDS) is a severe condition associated with high morbidity, mortality, and healthcare costs. Despite extensive research, treatment options for ARDS are suboptimal.

Methods

This study encompassed patients diagnosed with ARDS from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. Pre-intensive care unit (ICU) statin use was assessed as the exposure variable. Kaplan-Meier survival analysis was conducted to evaluate mortality at 30 and 90 days. Adjusted multivariable Cox models were utilized to estimate hazard ratios. Subgroup analyses and propensity score-matching (PSM) were undertaken for further validation.

Results

Our study comprised 10,042 participants diagnosed with ARDS, with an average age of 61.8 ± 15.3 years. Kaplan-Meier survival analysis demonstrated a significantly lower prevalence of mortality at 30 and 90 days in individuals who used statins before ICU admission. Adjusted multivariable Cox models consistently showed a significant decrease in mortality prevalence associated with pre-ICU statin use. After accounting for confounding factors, patients who used statins before ICU admission experienced a 39% reduction in 30-day mortality and 38% reduction in 90-day mortality. We found a significant decrease in ICU stay (0.84 days) for those who used statins before ICU admission. These results were supported by subgroup analyses and PSM.

Conclusion

This large cohort study provides evidence supporting the association between pre-ICU statin use, reduced risk of death, and shorter ICU stay in patients with ARDS, thereby suggesting the potential benefits of statin use in critically ill patients.

Acute respiratory distress syndrome heterogeneity and the septic ARDS subgroup

Acute respiratory distress syndrome (ARDS) is an acute diffuse inflammatory lung injury characterized by the damage of alveolar epithelial cells and pulmonary capillary endothelial cells. It is mainly manifested by non-cardiogenic pulmonary edema, resulting from intrapulmonary and extrapulmonary risk factors. ARDS is often accompanied by immune system disturbance, both locally in the lungs and systemically. As a common heterogeneous disease in critical care medicine, researchers are often faced with the failure of clinical trials. Latent class analysis had been used to compensate for poor outcomes and found that targeted treatment after subgrouping contribute to ARDS therapy. The subphenotype of ARDS caused by sepsis has garnered attention due to its refractory nature and detrimental consequences. Sepsis stands as the most predominant extrapulmonary cause of ARDS, accounting for approximately 32% of ARDS cases. Studies indicate that sepsis-induced ARDS tends to be more severe than ARDS caused by other factors, leading to poorer prognosis and higher mortality rate. This comprehensive review delves into the immunological mechanisms of sepsis-ARDS, the heterogeneity of ARDS and existing research on targeted treatments, aiming to providing mechanism understanding and exploring ideas for accurate treatment of ARDS or sepsis-ARDS.

Orexin A alleviates LPS-induced acute lung injury by inhibiting macrophage activation through JNK-mediated autophagy

Crosstalk between the central nervous system and immune system by the neuroendocrine and autonomic nervous systems is critical during the inflammatory response. Exposure to endotoxin alters the activity of hypothalamic homeostatic systems, resulting in changed transmitter release within the brain. This study investigated the effects and cellular molecular mechanisms of neurogenic and exogenous orexin-A (OXA) in LPS-induced acute lung injury (ALI). We found the production of OXA in the hypothalamus and lungs was both decreased following LPS infection. LPS-induced lung injury including the destruction of the structure, inflammatory cell infiltration, and pro-inflammatory cytokines generation was aggravated in mice in which orexin neurons were lesioned with the neurotoxin orexin-saporin (orexin-SAP). Administration of exogenous OXA greatly improved lung pathology and reduced inflammatory response. Orexin receptors were found in cultured mouse bone marrow-derived macrophages (BMDMs) and lung macrophages (LMs), adoptive transfer of OXA-treated macrophages showed alleviative lung injury compared to adoptive transfer of macrophages without OXA treatment. Mechanistically, it is the induction of autophagy via JNK activation that is responsible for OXA to suppress macrophage-derived pro-inflammatory cytokine production. These findings highlight the importance of neuro-immune crosstalk and indicate that OXA may be a potential therapeutic agent in the treatment of ALI.

Innovations in Evaluating Statin Benefit and Efficacy in Staphylococcus aureus Intracellular Infection Management

An emerging therapeutic approach in the treatment of infectious disease is to augment the host response through repurposing of well-tolerated, non-antibiotic, host-directed therapeutics. Earlier retrospective studies identify a positive association between statin use and a decreased risk of death due to sepsis or bacteremia. However, more recent randomized control trials fail to detect a therapeutic benefit in these complex infection settings. It is postulated that unrecognized biases in certain observational studies may have led to an overestimation of benefit and that statin use is instead a marker for health status, wealth, and demographic characteristics which may separately affect death due to infection. What remains unresolved is that in vitro and in vivo evidence reproducibly indicates that statin pharmacology limits infection and augments immunomodulatory responses, suggesting that therapeutic benefits may be attainable in certain infection settings, such as intracellular infection by S. aureus. Carefully considering the biological mechanisms capable of driving the relationship between statins and infections and constructing a methodology to avoid potential biases in observational studies would enable the examination of protective effects against infection and limit the risk of underestimating statin efficacy. Such an approach would rely on the examination of statin use in defined infection settings based on an underlying mode-of-action and pharmacology, where the inhibition of HMG-CoA-reductase at the rate-limiting step in cholesterol biosynthesis diminishes not only cholesterol levels but also isoprenoid intermediates central to host cell invasion by S. aureus. Therapeutic benefit in such settings, if existent, may be of clinical importance.

Presence of comorbidities alters management and worsens outcome of patients with acute respiratory distress syndrome: insights from the LUNG SAFE study

Background

The impact of underlying comorbidities on the clinical presentation, management and outcomes in patients with ARDS is poorly understood and deserves further investigation.

Objectives

We examined these issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study.

Methods

In this secondary analysis of the patient cohort enrolled in the LUNG SAFE study, our primary objective was to determine the frequency, and impact of comorbidities on the management and ICU survival of patients with ARDS. Secondary outcomes relating to comorbidities included their impact on ventilatory management, the development of organ failures, and on end-of-life care.

Results

Of 2813 patients in the study population, 1692 (60%) had 1 or more comorbidities, of whom 631 (22.4%) had chronic respiratory impairment, 290 (10.3%) had congestive heart failure, 286 (10.2%) had chronic renal failure, 112 (4%) had chronic liver failure, 584 (20.8%) had immune incompetence, and 613 (21.8%) had diabetes. Multiple comorbidities were frequently present, with 423 (25%) having 2 and 182 (11%) having at least 3 or more comorbidities. The use of invasive ventilation (1379 versus 998, 82 versus 89%), neuromuscular blockade (301 versus 249, 18 versus 22%), prone positioning (97 versus 104, 6 versus 9%) and ECMO (32 versus 46, 2 versus 4%) were each significantly reduced in patients with comorbidities as compared to patients with no comorbidity (1692 versus 1121, 60 versus 40%). ICU mortality increased from 27% (n = 303) in patients with no comorbidity to 39% (n = 661) in patients with any comorbidity. Congestive heart failure, chronic liver failure and immune incompetence were each independently associated with increased ICU mortality. Chronic liver failure and immune incompetence were independently associated with more decisions to limitation of life supporting measures.

Conclusions

Most patients with ARDS have significant comorbidities, they receive less aggressive care, and have worse outcomes. Enhancing the care of these patients must be a priority for future clinical studies.

Trial registration LUNG-SAFE is registered with ClinicalTrials.gov, number NCT02010073.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13613-022-01015-7.

Pleiotropic Effects of Statins: New Therapeutic Approaches to Chronic, Recurrent Infection by Staphylococcus aureus

An emergent approach to bacterial infection is the use of host rather than bacterial-directed strategies. This approach has the potential to improve efficacy in especially challenging infection settings, including chronic, recurrent infection due to intracellular pathogens. For nearly two decades, the pleiotropic effects of statin drugs have been examined for therapeutic usefulness beyond the treatment of hypercholesterolemia. Interest originated after retrospective studies reported decreases in the risk of death due to bacteremia or sepsis for those on a statin regimen. Although subsequent clinical trials have yielded mixed results and earlier findings have been questioned for biased study design, in vitro and in vivo studies have provided clear evidence of protective mechanisms that include immunomodulatory effects and the inhibition of host cell invasion. Ultimately, the benefits of statins in an infection setting appear to require attention to the underlying host response and to the timing of the dosage. From this examination of statin efficacy, additional novel host-directed strategies may produce adjunctive therapeutic approaches for the treatment of infection where traditional antimicrobial therapy continues to yield poor outcomes. This review focuses on the opportunistic pathogen, Staphylococcus aureus, as a proof of principle in examining the promise and limitations of statins in recalcitrant infection.

Influence of rosuvastatin treatment on cerebral inflammation and nitro-oxidative stress in experimental lung injury in pigs

BACKGROUND

Many patients with acute respiratory distress syndrome (ARDS) suffer from cognitive impairment after hospital discharge. Different mechanisms have been implicated as potential causes for this impairment, inter alia cerebral inflammation. A class of drugs with antioxidant and anti-inflammatory properties are β-HMG-CoA-reductase inhibitors ("statins"). We hypothesized that treatment with rosuvastatin attenuates cerebral cytokine mRNA expression and nitro-oxidative stress in an animal model of acute lung injury.

METHODS

After approval of the institutional and state animal care committee, we performed this prospective randomized controlled animal study in accordance with the international guidelines for the care and use of laboratory animals. Thirty-two healthy male pigs were randomized to one of four groups: lung injury by central venous injection of oleic acid (n = 8), statin treatment before and directly after lung injury (n = 8), statin treatment after lung injury (n = 8), or ventilation-only controls (n = 8). About 18 h after lung injury and standardized treatment, the animals were euthanised, and the brains and lungs were collected for further examinations. We determined histologic lung injury and cerebral and pulmonal cytokine and 3-nitrotyrosine production.

RESULTS

We found a significant increase in hippocampal IL-6 mRNA after lung injury (p < 0.05). Treatment with rosuvastatin before and after induction of lung injury led to a significant reduction of hippocampal IL-6 mRNA (p < 0.05). Cerebral 3-nitrotyrosine was significantly higher in lung-injured animals compared with all other groups (p < 0.05 vs. animals treated with rosuvastatin after lung injury induction; p < 0.001 vs. all other groups). 3-Nitrotyrosine was also increased in the lungs of the lung-injured pigs compared to all other groups (p < 0.05 each).

CONCLUSIONS

Our findings highlight cerebral cytokine production and nitro-oxidative stress within the first day after induction of lung injury. The treatment with rosuvastatin reduced IL-6 mRNA and 3-nitrotyrosine concentration in the brains of the animals. In earlier trials, statin treatment did not reduce mortality in ARDS patients but seemed to improve quality of life in ARDS survivors. Whether this is attributable to better cognitive function because of reduced nitro-oxidative stress and inflammation remains to be elucidated.

Association between antecedent statin use and decreased mortality in hospitalized patients with COVID-19

The coronavirus disease 2019 (COVID-19) can result in a hyperinflammatory state, leading to acute respiratory distress syndrome (ARDS), myocardial injury, and thrombotic complications, among other sequelae. Statins, which are known to have anti-inflammatory and antithrombotic properties, have been studied in the setting of other viral infections, but their benefit has not been assessed in COVID-19. This is a retrospective analysis of patients admitted with COVID-19 from February 1^st through May 12^th, 2020 with study period ending on June 11^th, 2020. Antecedent statin use was assessed using medication information available in the electronic medical record. We constructed a multivariable logistic regression model to predict the propensity of receiving statins, adjusting for baseline sociodemographic and clinical characteristics, and outpatient medications. The primary endpoint includes in-hospital mortality within 30 days. A total of 2626 patients were admitted during the study period, of whom 951 (36.2%) were antecedent statin users. Among 1296 patients (648 statin users, 648 non-statin users) identified with 1:1 propensity-score matching, statin use is significantly associated with lower odds of the primary endpoint in the propensity-matched cohort (OR 0.47, 95% CI 0.36-0.62, p < 0.001). We conclude that antecedent statin use in patients hospitalized with COVID-19 is associated with lower inpatient mortality.

Effect of Pravastatin Pretreatment and Hypercapnia on Intestinal Microvascular Oxygenation and Blood Flow During Sepsis

INTRODUCTION

In septic patients, adequate microvascular oxygenation (μHBO2) of the intestine is vital for their outcome. Recent studies suggest that statins can ameliorate septic microcirculation in a variety of tissues. However, the effect on intestinal microvascular oxygenation and blood flow is largely unknown. Furthermore, there are indications that statin therapy might not be beneficial in the presence of hypercapnia, as observed in septic acute respiratory distress syndrome (ARDS) patients. Therefore, the present study explores the effect of pravastatin with and without additional moderate acute hypercapnia on intestinal microvascular oxygenation and blood flow in experimental sepsis.

METHODS

Forty male Wistar rats were randomized into four groups. Half of the animals received 0.2 mg • kg pravastatin s.c., the other half received the same volume as vehicle (NaCl 0.9%). After 18 h, colon ascendens stent peritonitis surgery was conducted in all animals to induce sepsis. Twenty-four hours after surgery, baseline was established and the animals were subjected to either 120 min of normocapnic (pCO2 40 ± 6 mm Hg) or moderate hypercapnic (pCO2 72 ± 10 mm Hg) ventilation. Microcirculatory oxygenation (μHBO2) and perfusion (μflow) of the colon were continuously recorded using tissue reflectance spectrophotometry and laser Doppler, respectively.

RESULTS

In normocapnic septic animals μHBO2 decreased over time (-8.4 ± 8.7%; P < 0.05 vs. baseline), whereas after pravastatin pretreatment μHBO2 remained constant (-1.9 ± 5.7% vs. baseline). However, in hypercapnic septic animals pretreated with pravastatin μHBO2 declined significantly over time (-8.9 ± 11.8%; P < 0.05 vs. baseline) and was significantly lower compared with normocapnic pravastatin-pretreated animals. μflow did not change over time in any group.

CONCLUSION

Pravastatin pretreatment ameliorates the intestinal microvascular oxygenation in sepsis and thus seems to prevent intestinal hypoxia. Furthermore, we demonstrated that additional hypercapnia abolishes this effect, indicating why septic ARDS patients might not benefit from pravastatin therapy.

Statins as an adjunctive therapy for COVID-19: the biological and clinical plausibility

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has infected millions of individuals and has claimed hundreds of thousands of human lives worldwide. Patients with underlying cardiovascular conditions are at high risk for SARS-CoV-2 infection, and COVID-19 patients have high incidence of cardiovascular complications such as acute cardiac injury, arrhythmias, heart failure, and thromboembolism. The disease has no approved proven effective therapy and hence repurposing of existing approved drugs has been considered as the fastest treatment approach. Statins have been shown to exhibit lipid lowering dependent and independent cardiovascular protective effects as well as favorable effects in various other pathophysiological states. These beneficial properties of statins are a result of their multiple pleotropic effects that include, anti-inflammatory, immunomodulatory, antithrombotic and antimicrobial properties. In this review, we provide a comprehensive description of the mechanisms of the pleotropic effects of statins, the relevant pre-clinical and clinical data pertinent to their role in infections and acute lung injury, the possible cardiovascular benefits of statins in COVID-19, and the implications of the therapeutic potential of statins in COVID-19 disease. We conclude with the rationale for conducting randomized controlled trials of statins in COVID-19 disease.

Soluble PD-L1 improved direct ARDS by reducing monocyte-derived macrophages

Acute respiratory distress syndrome (ARDS) is common in intensive care units (ICUs), although it is associated with high mortality, no effective pharmacological treatments are currently available. Despite being poorly understood, the role of programmed cell death protein 1 (PD-1) and PD-ligand 1 (PD-L1) axis in ARDS may provide significant insights into the immunosuppressive mechanisms that occur after ARDS. In the present study, we observed that the level of soluble PD-L1 (sPD-L1), a potential activator of the PD-1 pathway, was upregulated in survivors of direct ARDS than in non-survivors. Administration of sPD-L1 in mice with direct ARDS relieved inflammatory lung injury and improved the survival rate, indicating the protective role of sPD-L1 in direct ARDS. Using high-throughput mass cytometry, we found a marked decrease in the number of lung monocyte-derived macrophages (MDMs) with proinflammatory markers, and the protective role of sPD-L1 diminished in ARDS mice with monocyte/macrophage depletion. Furthermore, PD-1 expression increased in the MDMs of patients and mice with direct ARDS. Finally, we showed that sPD-L1 induced MDM apoptosis in patients with direct ARDS. Taken together, our results demonstrated that the engagement of sPD-L1 on PD-1 expressing macrophages resulted in a decrease in pro-inflammatory macrophages and eventually improved direct ARDS. Our study identified a prognostic indicator for patients with direct ARDS and a potential target for therapeutic development in direct ARDS.

Pharmacological management of adult patients with acute respiratory distress syndrome

INTRODUCTION

There is still no definite drug for acute respiratory distress syndrome (ARDS) that is capable of reducing either short-term or long-term mortality. Therefore, great efforts are being made to identify a pharmacological approach that can be really effective.

AREAS COVERED

This review focuses on current challenges and future directions in the pharmacological management of ARDS, regardless of anti-infective treatments. The authors have excluded small randomized controlled trials (RCTs) with less than 60 patients because those studies do not have statistical power for outcome data, and also anecdotal trials but have considered the last meta-analysis on any drug.

EXPERT OPINION

There has been substantial progress in our knowledge of ARDS over the past two decades and many drugs have been used in its treatment. Nevertheless, effective targeted pharmacological treatments for ARDS are still lacking. The likely reason why a pharmacological approach is beneficial for some patients, but harmful for others is that ARDS is an extremely heterogeneous syndrome. To overcome this issue, a precision approach for ARDS, whereby therapies are specifically targeted to patients most likely to benefit, has been proposed. At present, however, the application of this approach seems to be a difficult task.

Association Between Antecedent Statin Use and Decreased Mortality in Hospitalized Patients with COVID-19

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), can result in a hyperinflammatory state, leading to acute respiratory distress syndrome (ARDS), myocardial injury, and thrombotic complications, among other sequelae. Statins, which are known to have anti-inflammatory and antithrombotic properties, have been studied in the setting of other viral infections and ARDS, but their benefit has not been assessed in COVID-19. Thus, we sought to determine whether antecedent statin use is associated with lower in-hospital mortality in patients hospitalized for COVID-19. This is a retrospective analysis of patients admitted with COVID-19 from February 1^st through May 12^th, 2020 with study period ending on June 11^th, 2020. Antecedent statin use was assessed using medication information available in the electronic medical record. We constructed a multivariable logistic regression model to predict the propensity of receiving statins, adjusting for baseline socio-demographic and clinical characteristics, and outpatient medications. The primary endpoint included in-hospital mortality within 30 days. A total of 2626 patients were admitted during the study period, of whom 951 (36.2%) were antecedent statin users. Among 1296 patients (648 statin users, 648 non-statin users) identified with 1:1 propensity-score matching, demographic, baseline, and outpatient medication information were well balanced. Statin use was significantly associated with lower odds of the primary endpoint in the propensity-matched cohort (OR 0.48, 95% CI 0.36 – 0.64, p<0.001). We conclude that antecedent statin use in patients hospitalized with COVID-19 was associated with lower inpatient mortality. Randomized clinical trials evaluating the utility of statin therapy in patients with COVID-19 are needed.

Future Trends in Nebulized Therapies for Pulmonary Disease

Aerosol therapy is a key modality for drug delivery to the lungs of respiratory disease patients. Aerosol therapy improves therapeutic effects by directly targeting diseased lung regions for rapid onset of action, requiring smaller doses than oral or intravenous delivery and minimizing systemic side effects. In order to optimize treatment of critically ill patients, the efficacy of aerosol therapy depends on lung morphology, breathing patterns, aerosol droplet characteristics, disease, mechanical ventilation, pharmacokinetics, and the pharmacodynamics of cell-drug interactions. While aerosol characteristics are influenced by drug formulations and device mechanisms, most other factors are reliant on individual patient variables. This has led to increased efforts towards more personalized therapeutic approaches to optimize pulmonary drug delivery and improve selection of effective drug types for individual patients. Vibrating mesh nebulizers (VMN) are the dominant device in clinical trials involving mechanical ventilation and emerging drugs. In this review, we consider the use of VMN during mechanical ventilation in intensive care units. We aim to link VMN fundamentals to applications in mechanically ventilated patients and look to the future use of VMN in emerging personalized therapeutic drugs.

Increased mortality of acute respiratory distress syndrome was associated with high levels of plasma phenylalanine

Background

There is a dearth of drug therapies available for the treatment of acute respiratory distress syndrome (ARDS). Certain metabolites play a key role in ARDS and could serve as potential targets for developing therapies against this respiratory disorder. The present study was designed to determine such “functional metabolites” in ARDS using metabolomics and in vivo experiments in a mouse model.

Methods

Metabolomic profiles of blood plasma from 42 ARDS patients and 28 healthy controls were captured using Ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) assay. Univariate and multivariate statistical analysis were performed on metabolomic profiles from blood plasma of ARDS patients and healthy controls to screen for “functional metabolites”, which were determined by variable importance in projection (VIP) scores and P value. Pathway analysis of all the metabolites was performed. The mouse model of ARDS was established to investigate the role of “functional metabolites” in the lung injury and mortality caused by the respiratory disorder.

Results

The metabolomic profiles of patients with ARDS were significantly different from healthy controls, difference was also observed between metabolomic profiles of the non-survivors and the survivors among the ARDS patient pool. Levels of Phenylalanine, D-Phenylalanine and Phenylacetylglutamine were significantly increased in non-survivors compared to the survivors of ARDS. Phenylalanine metabolism was the most notably altered pathway between the non-survivors and survivors of ARDS patients. In vivo animal experiments demonstrated that high levels of Phenylalanine might be associated with the severer lung injury and increased mortality of ARDS.

Conclusion

Increased mortality of acute respiratory distress syndrome was associated with high levels of plasma Phenylalanine.

Trial registration

Chinese Clinical Trial Registry, ChiCTR1800015930. Registered 29 April 2018, http://www.chictr.org.cn/edit.aspx?pid=25609&htm=4

Acute Respiratory Distress Syndrome as an Organ Phenotype of Vascular Microthrombotic Disease: Based on Hemostatic Theory and Endothelial Molecular Pathogenesis

Acute respiratory distress syndrome (ARDS) is a life-threatening noncardiogenic circulatory disorder of the lungs associated with critical illnesses such as sepsis, trauma, and immune and collagen vascular disease. Its mortality rate is marginally improved with the best supportive care. The demise occurs due to progressive pulmonary hypoxia and multi-organ dysfunction syndrome (MODS) with severe inflammation. Complement activation is a part of immune response against pathogen or insult in which membrane attack complex (MAC) is formed and eliminates microbes. If complement regulatory protein such as endothelial CD59 is underexpressed, MAC may also cause pulmonary vascular injury to the innocent bystander endothelial cell of host and provokes endotheliopathy that causes inflammation and pulmonary vascular microthrombosis, leading to ARDS. Its pathogenesis is based on a novel "two-path unifying theory" of hemostasis and "two-activation theory of the endothelium" promoting molecular pathogenesis. Endotheliopathy activates two independent molecular pathways: inflammatory and microthrombotic. The former triggers the release inflammatory cytokines and the latter promotes exocytosis of unusually large von Willebrand factor multimers (ULVWF) and platelet activation. Inflammatory pathway initiates inflammation, but microthrombotic pathway more seriously produces "microthrombi strings" composed of platelet-ULVWF complexes, which become anchored on the injured endothelial cells, and causes disseminated intravascular microthrombosis (DIT). DIT is a hemostatic disease due to lone activation of ULVWF path without activated tissue factor path. It leads to endotheliopathy-associated vascular microthrombotic disease (EA-VMTD), which orchestrates consumptive thrombocytopenia, microangiopathic hemolytic anemia, and MODS. Thrombotic thrombocytopenic purpura (TTP)-like syndrome is the hematologic phenotype of EA-VMTD. ARDS is one of organ phenotypes among MODS associated with TTP-like syndrome. The most effective treatment of ARDS can be achieved by counteracting the activated microthrombotic pathway based on two novel hemostatic theories.

Pharmacological agents for adults with acute respiratory distress syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a life-threatening condition caused by direct or indirect injury to the lungs. Despite improvements in clinical management (for example, lung protection strategies), mortality in this patient group is at approximately 40%. This is an update of a previous version of this review, last published in 2004.

OBJECTIVES

To evaluate the effectiveness of pharmacological agents in adults with ARDS on mortality, mechanical ventilation, and fitness to return to work at 12 months.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, and CINAHL on 10 December 2018. We searched clinical trials registers and grey literature, and handsearched reference lists of included studies and related reviews.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) comparing pharmacological agents with control (placebo or standard therapy) to treat adults with established ARDS. We excluded trials of nitric oxide, inhaled prostacyclins, partial liquid ventilation, neuromuscular blocking agents, fluid and nutritional interventions and medical oxygen. We excluded studies published earlier than 2000, because of changes to lung protection strategies for people with ARDS since this date.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion, extracted data, and assessed risks of bias. We assessed the certainty of evidence with GRADE.

MAIN RESULTS

We included 48 RCTs with 6299 participants who had ARDS; two included only participants with mild ARDS (also called acute lung injury). Most studies included causes of ARDS that were both direct and indirect injuries. We noted differences between studies, for example the time of administration or the size of dose, and because of unclear reporting we were uncertain whether all studies had used equivalent lung protection strategies.We included five types of agents as the primary comparisons in the review: corticosteroids, surfactants, N-acetylcysteine, statins, and beta-agonists. We included 15 additional agents (sivelestat, mesenchymal stem cells, ulinastatin, anisodimine, angiotensin-converting enzyme (ACE) inhibitor, recombinant human ACE2 (palifermin), AP301, granulocyte-macrophage colony stimulating factor (GM-CSF), levosimendan, prostacyclins, lisofylline, ketaconazole, nitroglycerins, L-2-oxothiazolidine-4-carboxylic acid (OTZ), and penehyclidine hydrochloride).We used GRADE to downgrade outcomes for imprecision (because of few studies and few participants), for study limitations (e.g. high risks of bias) and for inconsistency (e.g. differences between study data).Corticosteroids versus placebo or standard therapyCorticosteroids may reduce all-cause mortality within three months by 86 per 1000 patients (with as many as 161 fewer to 19 more deaths); however, the 95% confidence interval (CI) includes the possibility of both increased and reduced deaths (risk ratio (RR) 0.77, 95% CI 0.57 to 1.05; 6 studies, 574 participants; low-certainty evidence). Due to the very low-certainty evidence, we are uncertain whether corticosteroids make little or no difference to late all-cause mortality (later than three months) (RR 0.99, 95% CI 0.64 to 1.52; 1 study, 180 participants), or to the duration of mechanical ventilation (mean difference (MD) -4.30, 95% CI -9.72 to 1.12; 3 studies, 277 participants). We found that ventilator-free days up to day 28 (VFD) may be improved with corticosteroids (MD 4.09, 95% CI 1.74 to 6.44; 4 studies, 494 participants; low-certainty evidence). No studies reported adverse events leading to discontinuation of study medication, or fitness to return to work at 12 months (FTR).Surfactants versus placebo or standard therapyWe are uncertain whether surfactants make little or no difference to early mortality (RR 1.08, 95% CI 0.91 to 1.29; 9 studies, 1338 participants), or whether they reduce late all-cause mortality (RR 1.28, 95% CI 1.01 to 1.61; 1 study, 418 participants). Similarly, we are uncertain whether surfactants reduce the duration of mechanical ventilation (MD -2.50, 95% CI -4.95 to -0.05; 1 study, 16 participants), make little or no difference to VFD (MD -0.39, 95% CI -2.49 to 1.72; 2 studies, 344 participants), or to adverse events leading to discontinuation of study medication (RR 0.50, 95% CI 0.17 to 1.44; 2 studies, 88 participants). We are uncertain of these effects because we assessed them as very low-certainty. No studies reported FTR.N-aceytylcysteine versus placeboWe are uncertain whether N-acetylcysteine makes little or no difference to early mortality, because we assessed this as very low-certainty evidence (RR 0.64, 95% CI 0.32 to 1.30; 1 study, 36 participants). No studies reported late all-cause mortality, duration of mechanical ventilation, VFD, adverse events leading to study drug discontinuation, or FTR.Statins versus placeboStatins probably make little or no difference to early mortality (RR 0.99, 95% CI 0.78 to 1.26; 3 studies, 1344 participants; moderate-certainty evidence) or to VFD (MD 0.40, 95% CI -0.71 to 1.52; 3 studies, 1342 participants; moderate-certainty evidence). Statins may make little or no difference to duration of mechanical ventilation (MD 2.70, 95% CI -3.55 to 8.95; 1 study, 60 participants; low-certainty evidence). We could not include data for adverse events leading to study drug discontinuation in one study because it was unclearly reported. No studies reported late all-cause mortality or FTR.Beta-agonists versus placebo controlBeta-blockers probably slightly increase early mortality by 40 per 1000 patients (with as many as 119 more or 25 fewer deaths); however, the 95% CI includes the possibility of an increase as well as a reduction in mortality (RR 1.14, 95% CI 0.91 to 1.42; 3 studies, 646 participants; moderate-certainty evidence). Due to the very low-certainty evidence, we are uncertain whether beta-agonists increase VFD (MD -2.20, 95% CI -3.68 to -0.71; 3 studies, 646 participants), or make little or no difference to adverse events leading to study drug discontinuation (one study reported little or no difference between groups, and one study reported more events in the beta-agonist group). No studies reported late all-cause mortality, duration of mechanical ventilation, or FTR.

AUTHORS' CONCLUSIONS

We found insufficient evidence to determine with certainty whether corticosteroids, surfactants, N-acetylcysteine, statins, or beta-agonists were effective at reducing mortality in people with ARDS, or duration of mechanical ventilation, or increasing ventilator-free days. Three studies awaiting classification may alter the conclusions of this review. As the potential long-term consequences of ARDS are important to survivors, future research should incorporate a longer follow-up to measure the impacts on quality of life.

Simvastatin and ML141 Decrease Intracellular Streptococcus pyogenes Infection

BACKGROUND

Recurrent pharyngotonsillitis due to Streptococcus pyogenes develops regardless of whether infecting strains are resistant or susceptible to first-line antimicrobials. Causation for recurrent infection is associated with the use of first-line antimicrobials that fail to penetrate deep tissue and host cell membranes, enabling intracellular S. pyogenes to survive throughout repeated rounds of antimicrobial therapy.

OBJECTIVE

To determine whether simvastatin, a therapeutic approved for use in the treatment of hypercholesterolemia, and ML141, a first-in-class small molecule inhibitor with specificity for human CDC42, limit host cell invasion by S. pyogenes.

METHODS

Assays to assess host cell invasion, bactericidal activity, host cell viability, actin depolymerization, and fibronectin binding were performed using the RAW 267.4 macrophage cell line and Human Umbilical Vein Endothelial Cells (HUVEC) infected with S. pyogenes (90-226) and treated with simvastatin, ML141, structural analogs of ML141, or vehicle control.

RESULTS

Simvastatin and ML141 decreased intracellular infection by S. pyogenes in a dose-dependent manner. Inhibition by simvastatin persisted following 1 h washout whereas inhibition by ML141 was reversed. During S. pyogenes infection, actin stress fibers depolymerized in vehicle control treated cells, yet remained intact in simvastatin and in ML141 treated cells. Consistent with the previous characterization of ML141, simvastatin decreased host cell binding to fibronectin. Structural analogs of ML141, designated as the RSM series, decreased intracellular infection through non-cytotoxic, nonbactericidal mechanisms.

CONCLUSION

Our findings demonstrate the potential of repurposing simvastatin and of developing CDC42-targeted therapeutics for eradicating intracellular S. pyogenes infection to break the cycle of recurrent infection through a host-directed approach.

Preadmission Statin Therapy Is Associated with a Lower Incidence of Acute Kidney Injury in Critically Ill Patients: A Retrospective Observational Study

This study aimed to investigate the association between preadmission statin use and acute kidney injury (AKI) incidence among critically ill patients who needed admission to the intensive care unit (ICU) for medical care. Medical records of patients admitted to the ICU were reviewed. Patients who continuously took statin for >1 month prior to ICU admission were defined as statin users. We investigated whether preadmission statin use was associated with AKI incidence within 72 h after ICU admission and whether the association differs according to preadmission estimated glomerular filtration rate (eGFR; in mL min⁻¹ 1.73 m⁻²). Among 21,236 patients examined, 5756 (27.1%) were preadmission statin users and 15,480 (72.9%) were non-statin users. Total AKI incidence within 72 h after ICU admission was 31% lower in preadmission statin users than in non-statin users [odds ratio (OR), 0.69; 95% confidence interval (CI), 0.61–0.79; p < 0.001]. This association was insignificant among individuals with eGFR <30 mL min⁻¹ 1.73 m⁻² (p > 0.05). Our results suggested that preadmission statin therapy is associated with a lower incidence of AKI among critically ill patients; however, this effect might not be applicable for patients with eGFR <30 mL min⁻¹ 1.73 m⁻².

Approaches and techniques to avoid development or progression of acute respiratory distress syndrome

PURPOSE OF REVIEW

Despite major improvement in ventilation strategies, hospital mortality and morbidity of the acute respiratory distress syndrome (ARDS) remain high. A lot of therapies have been shown to be ineffective for established ARDS. There is a growing interest in strategies aiming at avoiding development and progression of ARDS.

RECENT FINDINGS

Recent advances in this field have explored identification of patients at high-risk, nonspecific measures to limit the risks of inflammation, infection and fluid overload, prevention strategies of ventilator-induced lung injury and patient self-inflicted lung injury, and pharmacological treatments.

SUMMARY

There is potential for improvement in the management of patients admitted to intensive care unit to reduce ARDS incidence. Apart from nonspecific measures, prevention of ventilator-induced lung injury and patient self-inflicted lung injury are of major importance.

Adjunctive therapies during veno-venous extracorporeal membrane oxygenation

Veno-venous extracorporeal membrane oxygenation (VV ECMO) restores gas exchanges in severely hypoxemic patients. The need for adjunctive therapies usually originates either from refractory hypoxemia during ECMO (defined as the persistence of low blood oxygen levels despite extracorporeal support) or from the attempt to give a specific therapy for acute respiratory distress syndrome (ARDS). In this review, therapeutic strategies to treat refractory and persistent hypoxemia during ECMO are evaluated. In the second part, therapies that can be added on top of VV ECMO to address inflammation and altered vascular permeability in ARDS are examined. The therapies currently available often allow for an effective treatment of hypoxemia during ECMO. ARDS is still lacking a specific therapy, with low-grade evidence sustaining the majority of currently used drugs.

Major publications in the critical care pharmacotherapy literature: January-December 2017

PURPOSE

To summarize selected meta-analyses and trials related to critical care pharmacotherapy published in 2017. The Critical Care Pharmacotherapy Literature Update (CCPLU) Group screened 32 journals monthly for impactful articles and reviewed 115 during 2017. Two meta-analyses and eight original research trials were reviewed here from those included in the monthly CCPLU. Meta-analyses on early, goal-directed therapy for septic shock and statin therapy for acute respiratory distress syndrome were summarized. Original research trials that were included evaluate thrombolytic therapy in severe stroke, hyperoxia and hypertonic saline in septic shock, intraoperative ketamine for prevention of post-operative delirium, intravenous ketorolac dosing regimens for acute pain, angiotensin II for vasodilatory shock, dabigatran reversal with idarucizumab, bivalirudin versus heparin monotherapy for myocardial infarction, and balanced crystalloids versus saline fluid resuscitation.

CONCLUSION

This clinical review provides perspectives on impactful critical care pharmacotherapy publications in 2017.