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Background Garadacimab, a fully human IgG4 monoclonal antibody, inhibits the kallikrein–kinin pathway at a key initiator, activated coagulation factor XII (FXIIa), and may play a protective role in preventing the progression of COVID-19. This phase 2 study evaluated the efficacy and safety of garadacimab plus standard of care (SOC) versus placebo plus SOC in patients with severe COVID-19. Methods Patients hospitalised with COVID-19 were randomised (1:1) to a single intravenous dose of garadacimab (700 mg) plus SOC or placebo plus SOC. Co-primary endpoint was incidence of endotracheal intubation or death between randomisation and Day 28. All-cause mortality, safety and pharmacokinetic/pharmacodynamic parameters were assessed. Results No difference in incidence of tracheal intubation or death (p = 0.274) or all-cause mortality was observed (p = 0.382). Garadacimab was associated with a lower incidence of treatment-emergent adverse events (60.3% vs 67.8%) and fewer serious adverse events (34 vs 45 events) versus placebo. No garadacimab-related deaths or bleeding events were reported, including in the 45.9% (n = 28/61) of patients who received concomitant heparin. Prolonged activated partial thromboplastin time (aPTT), and increased coagulation factor XII (FXII) levels were observed with garadacimab versus placebo to Day 14, whilst FXIIa-mediated kallikrein activity (FXIIa-mKA) was suppressed to Day 28. Conclusion In patients with severe COVID-19, garadacimab did not confer a clinical benefit over placebo. Transient aPTT prolongation and suppressed FXIIa-mKA showed target engagement of garadacimab that was not associated with bleeding events even with concomitant anticoagulant use. The safety profile of garadacimab was consistent with previous studies in patients with hereditary angioedema. ClinicalTrials. gov Identifier NCT04409509. Date of registration: 28 May, 2020.

We sought to determine whether hyperinflammatory acute respiratory distress syndrome (ARDS) and hypoinflammatory ARDS, which have been associated with differences in plasma biomarkers and mortality risk, also display differences in bronchoalveolar lavage (BALF) biomarker profiles. We then described the relationship between hyperinflammatory ARDS and hypoinflammatory ARDS to novel subphenotypes derived using BALF biomarkers.Secondary analysis of a randomized control trial testing omega-3 fatty acids for the treatment of ARDS.Five North American intensive care units.Adults (n = 88) on invasive mechanical ventilation within 48 hours of ARDS onset.None.We classified 57 patients as hypoinflammatory and 31 patients as hyperinflammatory using a previously validated logistic regression model. Of 14 BALF biomarkers analyzed, interleukin-6 and granulocyte colony stimulating factor were higher among patients with hyperinflammatory ARDS compared with hypoinflammatory ARDS, though the differences were not robust to multiple hypothesis testing. We then performed a de novo latent class analysis of the 14 BALF biomarkers to identify two classes well separated by alveolar profiles. Class 2 (n = 63) displayed significantly higher interleukin-6, von Willebrand factor, soluble programmed cell death receptor-1, % neutrophils, and other biomarkers of inflammation compared with class 1 (n = 25). These BALF-derived classes had minimal overlap with the plasma-derived hyperinflammatory and hypoinflammatory classes, and the majority of both plasma-derived classes were in BALF-derived class 2 and characterized by high BALF biomarkers. Additionally, the BALF-derived classes were associated with clinical severity of pulmonary disease, with class 2 exhibiting lower Pao2 to Fio2 and distinct ventilatory parameters, unlike the plasma-derived classes, which were only related to nonpulmonary organ dysfunction.Hyperinflammatory and hypoinflammatory ARDS subphenotypes did not display significant differences in alveolar biologic profiles. Identifying ARDS subgroups using BALF measurements is a unique approach that complements information obtained from plasma, with potential to inform enrichment strategies in trials of lung-targeted therapies.

Few surveys have focused on physician moral distress, burnout, and professional fulfilment. We assessed physician wellness and coping during the COVID-19 pandemic.Cross-sectional survey using four validated instruments.Sixty-two sites in Canada and the United States.Attending physicians (adult, pediatric; intensivist, nonintensivist) who worked in North American ICUs.None.We analysed 431 questionnaires (43.3% response rate) from 25 states and eight provinces. Respondents were predominantly male (229 [55.6%]) and in practice for 11.8 ± 9.8 years. Compared with prepandemic, respondents reported significant intrapandemic increases in days worked/mo, ICU bed occupancy, and self-reported moral distress (240 [56.9%]) and burnout (259 [63.8%]). Of the 10 top-ranked items that incited moral distress, most pertained to regulatory/organizational ( n = 6) or local/institutional ( n = 2) issues or both ( n = 2). Average moral distress (95.6 ± 66.9), professional fulfilment (6.5 ± 2.1), and burnout scores (3.6 ± 2.0) were moderate with 227 physicians (54.6%) meeting burnout criteria. A significant dose-response existed between COVID-19 patient volume and moral distress scores. Physicians who worked more days/mo and more scheduled in-house nightshifts, especially combined with more unscheduled in-house nightshifts, experienced significantly more moral distress. One in five physicians used at least one maladaptive coping strategy. We identified four coping profiles (active/social, avoidant, mixed/ambivalent, infrequent) that were associated with significant differences across all wellness measures.Despite moderate intrapandemic moral distress and burnout, physicians experienced moderate professional fulfilment. However, one in five physicians used at least one maladaptive coping strategy. We highlight potentially modifiable factors at individual, institutional, and regulatory levels to enhance physician wellness.

Family members of critically ill patients with COVID-19 have described increased symptoms of Post-Traumatic Stress Disorder (PTSD). Little is known about how these symptoms may change over time.We studied changes in PTSD symptoms in family members of critically ill patients with COVID-19 over 12-months.This prospective, multi-site observational cohort study recruited participants at 12 hospitals in 5 states. Calls were made to participants at 3-4 months, 6-months, and 12-months post-patient admission to the ICU.There were 955 eligible family members, of whom 330 (53.3% of those reached) consented to participate. Complete longitudinal data was acquired for 115 individuals (34.8% of consented). PTSD symptoms were measured by the Impact of Events Scale-6 (IES-6), with a score of ≥10 identifying significant symptoms. At 3-months, the mean IES-6 score was 11.9±6.1 with 63.6% having significant symptoms, decreasing to 32.9% at one year (mean IES-6 score 7.6±5.0). Three clusters of symptom evolution emerged over time: persistent symptoms (34.8%, n=40), recovered symptoms (33.0%, n=38) and non-development of symptoms (32.2%, n=37). While participants identifying as Hispanic demonstrated initially higher adjusted IES-6 scores (2.57 points higher [95% CI: 1.1, 4.1, p =0.001]), they also demonstrated a more dramatic improvement in adjusted scores over time (4.7 greater decrease at 12 months [95% CI: 3.2-6.3, p.001]).One year later, some family members of patients with COVID-19 continue to experience significant symptoms of PTSD. Further studies are needed to better understand how various differences contribute to increased risk for these symptoms.

Background: Patients receiving dialysis have unmet palliative care needs. Limited access to palliative care is a key barrier to its integration into routine dialysis care. Objective: To determine the feasibility and acceptability of telepalliative care in rural dialysis units. Methods: This was a single-arm pilot clinical trial. The target population was patients with kidney failure receiving outpatient dialysis in a rural U.S. state. Feasibility was measured by one-month completion rate. Acceptability was measured using an adapted telemedicine questionnaire. Results: We recruited 39 patients with mean age 71.2 years to undergo a telepalliative care consultation while receiving dialysis. Four specialty palliative care clinicians (three physicians and one nurse practitioner) conducted the visits. The recruitment rate was 40% (39/96), scheduling rate was 100% (39/39), and one-month completion rate was 77% (30/39). Thirty-six patient participants (14 women and 22 men) completed the baseline survey. Audiovisual aspects of the visit were rated highly. More than 80% reported the visit being at least as good as an in-person visit and 41% felt the teleconsult was better. Eighty-one percent of patients felt the appointment was relevant to them, 58% felt they learned new things about their condition, and 27% reported the appointment changed the way they think about dialysis. Discussion: Telepalliative care is acceptable to patients receiving dialysis and is a feasible approach to integrating palliative care in rural dialysis units. The study was registered with Clinicaltrials.gov (NCT03744117).

IMPORTANCE: The psychological symptoms associated with having a family member admitted to the intensive care unit (ICU) during the COVID-19 pandemic are not well defined. OBJECTIVE: To examine the prevalence of symptoms of stress-related disorders, primarily posttraumatic stress disorder (PTSD), in family members of patients admitted to the ICU with COVID-19 approximately 90 days after admission. DESIGN, SETTING, AND PARTICIPANTS: This prospective, multisite, mixed-methods observational cohort study assessed 330 family members of patients admitted to the ICU (except in New York City, which had a random sample of 25% of all admitted patients per month) between February 1 and July 31, 2020, at 8 academic-affiliated and 4 community-based hospitals in 5 US states. EXPOSURE: Having a family member in the ICU with COVID-19. MAIN OUTCOMES AND MEASURES: Symptoms of PTSD at 3 months, as defined by a score of 10 or higher on the Impact of Events Scale 6 (IES-6). RESULTS: A total of 330 participants (mean [SD] age, 51.2 [15.1] years; 228 [69.1%] women; 150 [52.8%] White; 92 [29.8%] Hispanic) were surveyed at the 3-month time point. Most individuals were the patients’ child (129 [40.6%]) or spouse or partner (81 [25.5%]). The mean (SD) IES-6 score at 3 months was 11.9 (6.1), with 201 of 316 respondents (63.6%) having scores of 10 or higher, indicating significant symptoms of PTSD. Female participants had an adjusted mean IES-6 score of 2.6 points higher (95% CI, 1.4-3.8; P

Macrophages are important mediators of skeletal muscle function in both healthy and diseased states. In vivo specific depletion of macrophages provides an experimental method to understand physiological and patho-physiological effects of macrophages. Systemic depletion of macrophages can deplete skeletal muscle macrophages but also alters systemic inflammatory responses and metabolism, which confounds the muscle specific effects of macrophage depletion. The primary aim of this manuscript is to evaluate two methods of murine intramuscular macrophage depletion in an acute lung injury-associated indirect skeletal muscle wasting mouse model. Adult C57BL/6 (WT) and Macrophage Fas-Induced Apoptosis (MaFIA, C57BL/6-Tg) mice received clodronate liposomes or the dimerization drug AP20187 through intramuscular injection of the tibialis anterior muscle compartment, respectively. Vehicle control was injected in the contralateral muscle. We demonstrate intramuscular AP20187 in the MaFIA mouse depletes macrophages but causes an infiltration of CD45 intermediate neutrophils. In contrast, intramuscular clodronate liposomes successfully depletes macrophages without an associated increase in CD45 intermediate cells. In conclusion, intramuscular clodronate is effective for selective depletion of muscle macrophages without eliciting acute inflammation seen with AP20187 in MaFIA mice. This technique is an important tool to study the functional roles of macrophages in skeletal muscle.

Preventing, treating, and promoting recovery from critical illness due to pulmonary disease are foundational goals of the critical care community and the National Heart, Lung, and Blood Institute. Decades of clinical research in acute respiratory distress syndrome, acute respiratory failure, pneumonia, and sepsis have yielded improvements in supportive care, which have translated into improved patient outcomes. Novel therapeutics have largely failed to translate from promising pre-clinical findings into improved patient outcomes in late-phase clinical trials. Recent advances in personalized medicine, "big data", causal inference using observational data, novel clinical trial designs, pre-clinical disease modeling, and understanding recovery from acute illness promise to transform the methods of pulmonary and critical care clinical research. To assess the current state, research priorities, and future directions for adult pulmonary and critical care research, the NHLBI assembled a multidisciplinary working group of investigators. This working group identified recommendations for future research, including: (1) focusing on understanding the clinical, physiological, and biological underpinnings of heterogeneity in syndromes, diseases, and treatment-response with the goal of developing targeted, personalized interventions; (2) optimizing pre-clinical models by incorporating comorbidities, co-interventions, and organ support; (3) developing and applying novel clinical trial designs; and (4) advancing mechanistic understanding of injury and recovery in order to develop and test interventions targeted at achieving long-term improvements in the lives of patients and families. Specific areas of research are highlighted as especially promising for making advances in pneumonia, acute hypoxemic respiratory failure, and acute respiratory distress syndrome.

Summary Background Pharmacokinetics (PK) of pharmaceuticals and pharmaconutrients are poorly understood in critically ill patients, and dosing is often based on healthy subject data. This might be particularly problematic with enteral medications due to metabolic abnormalities and impaired gastrointestinal tract absorption common in critically ill patients. Utilizing enteral fish oil, this study was undertaken to better understand and define PK of enteral omega-3 fatty acids (eicospentaenoic acid [EPA] and docosahexaenoic acid [DHA]) in critically ill patients with severe sepsis. Materials and methods Healthy volunteers (n = 15) and mechanically ventilated (MV) adults with severe sepsis (n = 10) were recruited and received 9.75 g EPA and 6.75 g DHA daily in two divided enteral doses of fish oil for 7 days. Volunteers continued their normal diet without other sources of fish oil, and sepsis patients received standard enteral feeding. Blood was collected at frequent intervals during the 14-day study period. Peripheral blood mononuclear cells (PMBCs) and neutrophils were isolated and analyzed for membrane fatty acid (FA) content. Mixed linear models and t-tests were used to analyze changes in FA levels over time and FA levels at individual time points, respectively. PK parameters were obtained based on single compartment models of EPA and DHA kinetics. Results Healthy volunteers were 41.1 ± 10.3 years; 67% were women. In patients with severe sepsis (55.6 ± 13.4 years, 50% women), acute physiologic and chronic health evaluation (APACHE) II score was 27.2 ± 8.8 at ICU admission and median MV duration was 10.5 days. Serum EPA and DHA were significantly lower in sepsis vs. healthy subjects over time. PBMC EPA concentrations were generally not different between groups over time, while PBMC DHA was higher in sepsis patients. Neutrophil EPA and DHA concentrations were similar between groups. The half-life of EPA in serum and neutrophils was significantly shorter in sepsis patients, whereas other half-life parameters did not vary significantly between healthy volunteers and sepsis patients. Conclusions While incorporation of n-3 FAs into PBMC and neutrophil membranes was relatively similar between healthy volunteers and sepsis patients receiving identical high doses of fish oil for one week, serum EPA and DHA were significantly lower in sepsis patients. These findings imply that serum concentrations and EPA and DHA may not be the dominant driver of leukocyte membrane incorporation of EPA and DHA. Furthermore, lower serum EPA and DHA concentrations suggest that either these n-3 FAs were being metabolized rapidly in sepsis patients or that absorption of enteral medications and pharmaconutrients, including fish oil, may be impaired in sepsis patients. If enteral absorption is impaired, doses of enteral medications administered to critically ill patients may be suboptimal.

During critical illness, several neuroendocrine, inflammatory, immune, adipokine, and gastrointestinal tract hormone pathways are activated; some of which are more intensified among obese compared with nonobese patients. Nutrition support may mitigate some of these effects. Nutrition priorities in obese critically ill patients include screening for nutritional risk, estimation of energy and protein requirement, and provision of macronutrients and micronutrients.Estimation of energy requirement in obese critically ill patients is challenging because of variations in body composition among obese patients and absence of reliable predictive equations for energy expenditure. Whereas hypocaloric nutrition with high protein has been advocated in obese critically ill patients, supporting data are scarce. Recent studies did not show differences in outcomes between hypocaloric and eucaloric nutrition, except for better glycemic control. Sarcopenia is common among obese patients, and the provision of increased protein intake has been suggested to mitigate catabolic changes especially after the acute phase of critical illness. However, high-quality data on high protein intake in these patients are lacking. Micronutrient deficiencies among obese critically ill patients are common but the role of their routine supplementation requires further study.An individualized approach for nutritional support may be needed for obese critically ill patients but high-quality evidence is lacking. Future studies should focus on nutrition priorities in this population, with efficient and adequately powered studies.

Summary Background Infection with influenza virus causes substantial morbidity and mortality globally, although antiviral treatments are available. Previous studies have suggested that anti-influenza immune plasma could be beneficial as treatment, but they were not designed as randomised, blinded, placebo-controlled trials. Therefore, we aimed to prospectively evaluate the clinical efficacy of high-titre immune plasma compared with standard low-titre plasma to improve outcomes in patients with severe influenza A infection. Methods We did this randomised, double-blind, phase 3 trial at 41 US medical centres to assess the efficacy of high-titre anti-influenza plasma (haemagglutination inhibition antibody titre ≥1:80) compared with low-titre plasma (≤1:10). Children and adults with PCR-confirmed influenza A infection, a National Early Warning score of 3 or greater, and onset of illness within 6 days before randomisation were eligible. Patients were randomly assigned (2:1) using an interactive web response system to receive either two units (or paediatric equivalent) of high-titre plasma (high-titre group) or low-titre plasma (low-titre group), and were followed up for 28 days from randomisation. High-titre and low-titre plasma had the same appearance. Randomisation was stratified by severity (in intensive care unit, not in intensive care but requiring supplemental oxygen, or not in intensive care and not requiring supplemental oxygen) and age ( 1 indicates improvement in clinical status across all categories for the high-titre vs the low-titre group). The primary analysis was done in the intention-to-treat population, excluding two participants who did not receive plasma. This trial is registered with ClinicalTrials.gov , NCT02572817 . Findings Participants were recruited between Jan 26, 2016, and April 19, 2018. Of 200 participants enrolled (177 adults and 23 children), 140 met the criteria for randomisation and were assigned to the high-titre group (n=92) or to the control low-titre group (n=48). One participant from each group did not receive plasma. At baseline, 60 (43%) of 138 participants were in intensive care and 55 (71%) of 78 participants who were not in intensive care required oxygen. 93% of planned plasma infusions were completed. The study was terminated in July, 2018, when independent efficacy analysis showed low conditional power to detect an effect of high-titre plasma even if full accrual (150 participants) was achieved. The proportional OR for improved clinical status on day 7 was 1·22 (95% CI 0·65–2·29, p=0·54). 47 (34%) of 138 participants experienced 88 serious adverse events: 32 (35%) with 60 events in the high-titre group and 15 (32%) with 28 events in the low-titre group. The most common serious adverse events were acute respiratory distress syndrome (ARDS; four [4%] vs two [4%]), allergic transfusion reactions (two [2%] vs two [4%]), and respiratory distress (three [3%] vs none). 65 (47%) participants experienced 183 adverse events: 42 (46%) with 126 events in the high-titre group and 23 (49%) with 57 events in the low-titre group. The most common adverse events were anaemia (four [3%] vs two [4%]) and ARDS (four [3%] vs three [5%]). Ten patients died during the study (six [7%] in the high-titre group vs four [9%] in the low-titre group, p=0·73). The most common cause of death was worsening of acute respiratory distress syndrome (two [2%] vs two [4%] patients). Interpretation High-titre anti-influenza plasma conferred no significant benefit over non-immune plasma. Although our study did not have the precision to rule out a small, clinically relevant effect, the benefit is insufficient to justify the use of immune plasma for treating patients with severe influenza A. Funding National Institute of Allergy and Infectious Diseases of the National Institutes of Health (Bethesda, MD, USA).

Rationale: Serial measurements of alveolar macrophage (AM) transcriptional changes in patients with acute respiratory distress syndrome (ARDS) could identify cell-specific biological programs that ...

BackgroundTo help mitigate the burden of health care on US economy, public policymakers and health care legislation have been focusing on reducing hospital readmissions. Respiratory complications have been identified among the commonest of adverse events in neurologic patients. The goal of our study was to better understand respiratory complications and their contribution to rehospitalizations in patients with seizures.MethodsWe used the 2013 Nationwide Readmission Database to analyze unplanned 30-day readmission rate (30RR). The study population comprised of patients with index hospital discharge diagnosis of generalized convulsive epilepsy and status epilepticus. Patients under 18 years of age, who died during hospitalization or who had missing demographic data, were excluded. Patients hospitalized in December were also excluded due to lack of 30-day follow-up. The primary outcome of interest was 30-day readmission. The causes of readmission were determined by corresponding International Classification of Diseases, Ninth Revision, Clinical Modification codes.ResultsThe 30RR was highest in patients with index hospitalization discharge diagnosis of status epilepticus, followed by generalized convulsive epilepsy (intractable), followed by generalized convulsive epilepsy (nonintractable). While seizure was the most common reason for readmission, contribution of respiratory complications to readmissions was 7.85%, 12.39%, and 6.93%, respectively. Pneumonia/aspiration pneumonitis and respiratory insufficiency accounted for the majority of the readmissions in all subgroups.ConclusionsRespiratory complications are the leading nonseizure cause of 30-day unplanned readmissions in patients with generalized convulsive epilepsy and status epilepticus. Further research on identifying appropriate interventions to reduce readmissions from respiratory causes may improve outcomes for patients in these epilepsy subgroups.

Muscle may contribute to the systemic inflammatory environment during critical illness, but leukocyte interaction and cytokine influence on muscle and its response has not been fully explored in this context. Using an in vivo model of intratracheal lipopolysaccharide (IT LPS)-induced acute lung injury, we show that skeletal muscle rapidly responds with expression of proinflammatory genes, which may be explained by migration of LPS into the circulation. Treatment of mature C2C12 myotubes with LPS at a level achieved in the circulation following IT LPS elicited a proinflammatory cytokine expression profile similar to that of in vivo murine muscle following IT LPS. Stimulation with toll-like receptor (TLR) 2 and 3 agonists provoked comparable responses in C2C12 myotubes. Additionally, co-cultures of C2C12 myotubes and bone marrow-derived macrophages (BMDM) identified the capacity of macrophages to increase myotube proinflammatory gene expression, with tumor necrosis factor-α (TNFα) gene and protein expression largely attributable to BMDM. To investigate the contribution of TNFα in the synergy of the co-culture environment, C2C12 myotubes were treated with recombinant TNFα, co-cultures were established using TNF-deficient BMDM, and co-cultures were also depleted of TNFα using antibodies. To determine whether the in vitro observations were relevant in vivo, mice received intramuscular administration of LPS ± TNFα or TNFα-neutralizing antibodies and showed that TNFα is both sufficient and necessary to induce synergistic cytokine release from muscle. Taken together, these data demonstrate how skeletal muscle tissue may contribute proinflammatory cytokines following acute endotoxin injury and the potential of leukocytes to augment this response via TNFα secretion.

Purpose High flow nasal cannula (HFNC) is a relatively recent respiratory support technique which delivers high flow, heated and humidified controlled concentration of oxygen via the nasal route. Recently, its use has increased for a variety of clinical indications. To guide clinical practice, we developed evidence-based recommendations regarding use of HFNC in various clinical settings. Methods We formed a guideline panel composed of clinicians, methodologists and experts in respiratory medicine. Using GRADE, the panel developed recommendations for four actionable questions. Results The guideline panel made a strong recommendation for HFNC in hypoxemic respiratory failure compared to conventional oxygen therapy (COT) (moderate certainty), a conditional recommendation for HFNC following extubation (moderate certainty), no recommendation regarding HFNC in the peri-intubation period (moderate certainty), and a conditional recommendation for postoperative HFNC in high risk and/or obese patients following cardiac or thoracic surgery (moderate certainty). Conclusions This clinical practice guideline synthesizes current best-evidence into four recommendations for HFNC use in patients with hypoxemic respiratory failure, following extubation, in the peri-intubation period, and postoperatively for bedside clinicians. Electronic supplementary material The online version of this article (10.1007/s00134-020-06312-y) contains supplementary material, which is available to authorized users.

Objectives There is an incomplete understanding of the host humoral immune response to severe acute respiratory syndrome (SARS)‐coronavirus (CoV)‐2, which underlies COVID‐19, during acute infection. Host factors such as age and sex as well as the kinetics and functionality of antibody responses are important factors to consider as vaccine development proceeds. The receptor‐binding domain of the CoV spike (RBD‐S) protein mediates host cell binding and infection and is a major target for vaccine design to elicit neutralising antibodies. Methods We assessed serum anti‐SARS‐CoV‐2 RBD‐S IgG, IgM and IgA antibodies by a two‐step ELISA and neutralising antibodies in a cross‐sectional study of hospitalised COVID‐19 patients of varying disease severities. Anti‐RBD‐S IgG levels were also determined in asymptomatic seropositives. Results We found equivalent levels of anti‐RBD‐S antibodies in male and female patients and no age‐related deficiencies even out to 93 years of age. The anti‐RBD‐S response was evident as little as 6 days after onset of symptoms and for at least 5 weeks after symptom onset. Anti‐RBD‐S IgG, IgM and IgA responses were simultaneously induced within 10 days after onset, with anti‐RBD‐S IgG sustained over a 5‐week period. Anti‐RBD‐S antibodies strongly correlated with neutralising activity. Lastly, anti‐RBD‐S IgG responses were higher in symptomatic COVID‐19 patients during acute infection compared with asymptomatic seropositive donors. Conclusion Our results suggest that anti‐RBD‐S IgG reflect functional immune responses to SARS‐CoV‐2, but do not completely explain age‐ and sex‐related disparities in COVID‐19 fatalities.

Objectives There is an incomplete understanding of the host humoral immune response to severe acute respiratory syndrome (SARS)‐coronavirus (CoV)‐2, which underlies COVID‐19, during acute infection. Host factors such as age and sex as well as the kinetics and functionality of antibody responses are important factors to consider as vaccine development proceeds. The receptor‐binding domain of the CoV spike (RBD‐S) protein mediates host cell binding and infection and is a major target for vaccine design to elicit neutralising antibodies. Methods We assessed serum anti‐SARS‐CoV‐2 RBD‐S IgG, IgM and IgA antibodies by a two‐step ELISA and neutralising antibodies in a cross‐sectional study of hospitalised COVID‐19 patients of varying disease severities. Anti‐RBD‐S IgG levels were also determined in asymptomatic seropositives. Results We found equivalent levels of anti‐RBD‐S antibodies in male and female patients and no age‐related deficiencies even out to 93 years of age. The anti‐RBD‐S response was evident as little as 6 days after onset of symptoms and for at least 5 weeks after symptom onset. Anti‐RBD‐S IgG, IgM and IgA responses were simultaneously induced within 10 days after onset, with anti‐RBD‐S IgG sustained over a 5‐week period. Anti‐RBD‐S antibodies strongly correlated with neutralising activity. Lastly, anti‐RBD‐S IgG responses were higher in symptomatic COVID‐19 patients during acute infection compared with asymptomatic seropositive donors. Conclusion Our results suggest that anti‐RBD‐S IgG reflect functional immune responses to SARS‐CoV‐2, but do not completely explain age‐ and sex‐related disparities in COVID‐19 fatalities., Antibodies to severe acute respiratory syndrome‐coronaviruses‐2 spike arise within 1 week after COVID‐19 symptoms and are not affected by patient age or biological sex. Neutralising activity correlates with receptor‐binding domain reactivity and may reflect viral replication rather than acute protection.

We performed multivariable analysis of potential risk factors (including cytomegalovirus [CMV] reactivation) for clinical outcomes by day 28 (death or continued hospitalization, ventilator-free days, intensive care unit (ICU)-free days, hospital-free days) from pooled cohorts of 2 previous prospective studies of CMV-seropositive adults with sepsis. CMV reactivation at any level, >100 IU/mL, >1000 IU/mL, peak viral load, and area under the curve were independently associated with the clinical outcomes. We identified the potential effect size of CMV on outcomes that could be used as end points for future interventional trials of CMV prevention using antiviral prophylaxis in ICU patients with sepsis.

Background and Rationale: ICU clinicians regularly care for patients who lack capacity, an applicable advance directive, and an available surrogate decision-maker. Although there is no consensus on terminology, we refer to these patients as “unrepresented.” There is considerable controversy about how to make treatment decisions for these patients, and there is significant variability in both law and clinical practice. Purpose and Objectives: This multisociety statement provides clinicians and hospital administrators with recommendations for decision-making on behalf of unrepresented patients in the critical care setting. Methods: An interprofessional, multidisciplinary expert committee developed this policy statement by using an iterative consensus process with a diverse working group representing critical care medicine, palliative care, pediatric medicine, nursing, social work, gerontology, geriatrics, patient advocacy, bioethics, philosophy, elder law, and health law. Main Results: The committee designed its policy recommendations to promote five ethical goals: 1) to protect highly vulnerable patients, 2) to demonstrate respect for persons, 3) to provide appropriate medical care, 4) to safeguard against unacceptable discrimination, and 5) to avoid undue influence of competing obligations and conflicting interests. These recommendations also are intended to strike an appropriate balance between excessive and insufficient procedural safeguards. The committee makes the following recommendations: 1) institutions should offer advance care planning to prevent patients at high risk for becoming unrepresented from meeting this definition; 2) institutions should implement strategies to determine whether seemingly unrepresented patients are actually unrepresented, including careful capacity assessments and diligent searches for potential surrogates; 3) institutions should manage decision-making for unrepresented patients using input from a diverse interprofessional, multidisciplinary committee rather than ad hoc by treating clinicians; 4) institutions should use all available information on the patient’s preferences and values to guide treatment decisions; 5) institutions should manage decision-making for unrepresented patients using a fair process that comports with procedural due process; 6) institutions should employ this fair process even when state law authorizes procedures with less oversight. Conclusions: This multisociety statement provides guidance for clinicians and hospital administrators on medical decision-making for unrepresented patients in the critical care setting.

Alveolar macrophages (AM) play a central role in initiation and resolution of lung inflammation, but the integration of these opposing core functions is poorly understood. AM expression of cholesterol 25-hydroxylase (CH25H), the primary biosynthetic enzyme for 25-hydroxycholesterol (25HC), far exceeds the expression of macrophages in other tissues, but no role for CH25H has been defined in lung biology. As 25HC is an agonist for the antiinflammatory nuclear receptor, liver X receptor (LXR), we speculated that CH25H might regulate inflammatory homeostasis in the lung. Here, we show that, of natural oxysterols or sterols, 25HC is induced in the inflamed lung of mice and humans. Ch25h(–/–) mice fail to induce 25HC and LXR target genes in the lung after LPS inhalation and exhibit delayed resolution of airway neutrophilia, which can be rescued by systemic treatment with either 25HC or synthetic LXR agonists. LXR-null mice also display delayed resolution, suggesting that native oxysterols promote resolution. During resolution, Ch25h is induced in macrophages upon their encounter with apoptotic cells and is required for LXR-dependent prevention of AM lipid overload, induction of Mertk, efferocytic resolution of airway neutrophilia, and induction of TGF-β. CH25H/25HC/LXR is, thus, an inducible metabolic axis that programs AMs for efferocytic resolution of inflammation.

Background Excessive inflammation leading to increased alveolar-capillary barrier permeability remains the pathogenic model for acute respiratory distress syndrome (ARDS). Alveolar macrophage (AM) polarization has been shown to modify the activity of various matrix metalloproteinases (MMPs) that have downstream effects on key ARDS cytokines/chemokines, however the relationship between AMs, MMP28 (the newest member of the MMP family), and ARDS clinical outcomes is unknown.Methods We analyzed bronchoalveolar lavage fluid (BALF) and peripheral blood from subjects previously enrolled in a phase-II trial of omega-3 fatty acids for the treatment of ARDS ( n = 76). In a subset of these patients ( n = 25), we tested for assocations between AM- and peripheral blood monocyte (PBM)-specific MMP28 gene expression and clincal outcomes [ventilator-free days (VFDs), P a O 2 /F i O 2 ratio (P/F ratio), and sequential organ failure assessment score (SOFA)]. We tested for assocations between soluble BALF or plasma MMP28 concentrations and ARDS clinical outcomes and inflammatory mediator concentrations in the entire cohort.Results Increased AM MMP28 gene expression was significantly associated with worse VFDs and P/F ratio ( p < 0.05). Higher BALF MMP28 concentrations were associated with worse P/F, but not VFDs. Increased BALF MMP28 concentrations were associated with increased % neutrophils as well as BALF total protein, IL-6, IL-17A, and MCP-1 concentrations (all p < 0.05). Plasma MMP28 concentrations were not associated with any clinical outcome. Increased PBM MMP28 gene expression was associated with worse P/F ratio but not VFDs.Conclusions Higher AM MMP28 gene expression and BALF MMP28 concentrations are associated with poor clinical outcomes and with increased alveolar inflammatory mediators in patients with ARDS.

Nocturnal ICU staffing gained favor after correlation was shown between intensivist presence and better patient outcomes. We conducted a cross-sectional survey of stakeholders at a tertiary care academic medical center to evaluate the impact of 24-h attending presence on overnight educational environment, learner autonomy, and attending quality of life. Our results showed an improved sense of educational quality along with diminished trainee autonomy. Attending job satisfaction was poor and this was not entirely explained by persistent daytime demands. This identifies areas for initiatives to encourage trainee autonomy and system evaluations of how best to staff attending nocturnal coverage.

Background Hyaluronic acid (HA), an extracellular matrix component, is degraded in response to local tissue injury or stress. In various animal models of lung injury, HA has been shown to play a mechanistic role in modulating inflammation and injury. While HA is present in the lungs of patients with acute respiratory distress syndrome (ARDS), its relationship to patient outcomes is unknown. Methods We studied 86 patients with ARDS previously enrolled in the Phase II Randomized Trial of Fish Oil in Patients with Acute Lung Injury (NCT00351533) at five North American medical centers. We examined paired serum and bronchoalveolar lavage fluid (BALF) samples obtained within 48 hours of diagnosis of ARDS. We evaluated the association of HA levels in serum and BALF with local (lung injury score (LIS)) and systemic (sequential organ failure assessment score (SOFA)) measures of organ dysfunction with regression analysis adjusting for age, sex, race, treatment group, and risk factor for ARDS. Results We found that both day-0 circulating and alveolar levels of HA were associated with worsening LIS (p = 0.04 and p = 0.003, respectively), particularly via associations with degree of hypoxemia (p = 0.02 and p

Recent literature has created considerable confusion about the optimal amount of protein/amino acids that should be provided to the critically ill patient. In fact, the evidentiary basis that directly tries to answer this question is relatively small. As a clinical nutrition research community, there is an urgent need to develop the optimal methods to assess the impact of exogenous protein/amino acid administration in the intensive care unit setting. That assessment can be conducted at various levels: (1) impact on stress response pathways, (2) impact on muscle synthesis and protein balance, (3) impact on muscle mass and function, and (4) impact on the patient's recovery. The objective of this research workshop was to review current literature relating to protein/amino acid administration for the critically ill patient and clinical outcomes and to discuss the key measurement and methodological features of future studies that should be done to inform the optimal protein/amino acid dose provided to critically ill patients.

IntroductionSurvivors of critical illness often experience significant morbidities, including muscle weakness and impairments in physical functioning. This muscle weakness is associated with longer duration mechanical ventilation, greater hospital costs and increased postdischarge impairments in physical function, quality of life and survival. Compared with standard of care, the benefits of greater protein intake combined with structured exercise started early after the onset of critical illness remain uncertain. However, the combination of protein supplementation and exercise in other populations has demonstrated positive effects on strength and function. In the present study, we will evaluate the effects of a combination of early implementation of intravenous amino acid supplementation and in-bed cycle ergometry exercise versus a ‘usual care’ control group in patients with acute respiratory failure requiring mechanical ventilation in an intensive care unit (ICU).Methods and analysisIn this multicentre, assessor-blinded, randomised controlled trial, we will randomise 142 patients in a 1:1 ratio to usual care (which commonly consists of minimal exercise and under-achievement of guideline-recommended caloric and protein intake goals) versus a combined intravenous amino acid supplementation and in-bed cycle ergometery exercise intervention. We hypothesise that this novel combined intervention will (1) improve physical functioning at hospital discharge; (2) reduce muscle wasting with improved amino acid metabolism and protein synthesis in-hospital and (3) improve patient-reported outcomes and healthcare resource utilisation at 6 months after enrolment. Key cointerventions will be standardised. In-hospital outcome assessments will be conducted at baseline, ICU discharge and hospital discharge. An intent-to-treat analysis will be used to analyse all data with additional per-protocol analyses.Ethics and disseminationThe trial received ethics approval at each institution and enrolment has begun. These results will inform both clinical practice and future research in the area. We plan to disseminate trial results in peer-reviewed journals, at national and international conferences, and via nutritional and rehabilitation-focused electronic education and knowledge translation platforms.Trial registration numberNCT03021902; Pre-results.

Although we remain at a relatively early stage in our understanding of obesity’s effects on acute respiratory distress syndrome (ARDS), mounting data suggest that a complex and as of yet incompletely understood interaction exists. Clinical studies examining the effects of obesity suggest that a rising body mass index (BMI) is associated with an increased risk for the development of ARDS and other organ failures, as might be predicted from the baseline systemic proinflammatory state that accompanies obesity. Interestingly, however, substantial evidence also indicates that subsequent mortality from ARDS and from critical illness, in general, is in fact lower in obese patients. Although some controversy has accompanied these latter findings, additional studies carefully adjusting for potentially confounding diagnostic artifacts and process of care effects have confirmed this association. The expanding clinical and animal model data available suggest that, although the obesity-associated increase in risk for the development of ARDS may reflect inflammatory and biomechanical “priming” of the lung for this disease, the witnessed obesity-associated survival advantage may in part be driven by an attenuation of the inflammatory milieu in such patients with established ARDS.