Diverse immunological dysregulation, chronic inflammation, and impaired erythropoiesis in long COVID patients with chronic fatigue syndrome.

A substantial number of patients recovering from acute SARS-CoV-2 infection present serious lingering symptoms, often referred to as long COVID (LC). However, a subset of these patients exhibits the most debilitating symptoms characterized by ongoing myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS). We specifically identified and studied ME/CFS patients from two independent LC cohorts, at least 12 months post the onset of acute disease, and compared them to the recovered group (R). ME/CFS patients had relatively increased neutrophils and monocytes but reduced lymphocytes. Selective T cell exhaustion with reduced naïve but increased terminal effector T cells was observed in these patients. LC was associated with elevated levels of plasma pro-inflammatory cytokines, chemokines, Galectin-9 (Gal-9), and artemin (ARTN). A defined threshold of Gal-9 and ARTN concentrations had a strong association with LC. The expansion of immunosuppressive CD71+ erythroid cells (CECs) was noted. These cells may modulate the immune response and contribute to increased ARTN concentration, which correlated with pain and cognitive impairment. Serology revealed an elevation in a variety of autoantibodies in LC. Intriguingly, we found that the frequency of 2B4+CD160+ and TIM3+CD160+ CD8+ T cells completely separated LC patients from the R group. Our further analyses using a multiple regression model revealed that the elevated frequency/levels of CD4 terminal effector, ARTN, CEC, Gal-9, CD8 terminal effector, and MCP1 but lower frequency/levels of TGF-ß and MAIT cells can distinguish LC from the R group. Our findings provide a new paradigm in the pathogenesis of ME/CFS to identify strategies for its prevention and treatment.

The Role of Coinhibitory Receptors in B Cell Dysregulation in SARS-CoV-2-Infected Individuals with Severe Disease.

Severe SARS-CoV-2 infection is associated with significant immune dysregulation involving different immune cell subsets. In this study, when analyzing critically ill COVID-19 patients versus those with mild disease, we observed a significant reduction in total and memory B cell subsets but an increase in naive B cells. Moreover, B cells from COVID-19 patients displayed impaired effector functions, evidenced by diminished proliferative capacity, reduced cytokine, and Ab production. This functional impairment was accompanied by an increased apoptotic potential upon stimulation in B cells from severely ill COVID-19 patients. Our further studies revealed the expansion of B cells expressing coinhibitory molecules (PD-1, PD-L1, TIM-1, VISTA, CTLA-4, and Gal-9) in intensive care unit (ICU)-admitted patients but not in those with mild disease. The coinhibitory receptor expression was linked to altered IgA and IgG expression and increased the apoptotic capacity of B cells. Also, we found a reduced frequency of CD24hiCD38hi regulatory B cells with impaired IL-10 production. Our mechanistic studies revealed that the upregulation of PD-L1 was linked to elevated plasma IL-6 levels in COVID-19 patients. This implies a connection between the cytokine storm and altered B cell phenotype and function. Finally, our metabolomic analysis showed a significant reduction in tryptophan but elevation of kynurenine in ICU-admitted COVID-19 patients. We found that kynurenine promotes PD-L1 expression in B cells, correlating with increased IL-6R expression and STAT1/STAT3 activation. Our observations provide novel insights into the complex interplay of B cell dysregulation, implicating coinhibitory receptors, IL-6, and kynurenine in impaired B cell effector functions, potentially contributing to the pathogenesis of COVID-19.

Modelling the potential increase in eligible participants in clinical trials with inclusion of community intensive care unit patients in Alberta, Canada: a decision tree analysis.

PURPOSE: Critical care research in Canada is conducted primarily in academically affiliated intensive care units (ICUs) with established research infrastructure. Efforts are made to engage community hospital ICUs in research, although the impacts of their inclusion in clinical research have never been explicitly quantified. We therefore sought to determine the number of additional eligible patients that could be recruited into critical care trials and the change in time to study completion if community ICUs were included in clinical research. METHODS: We conducted a decision tree analysis using 2018 Alberta Health Services data. Patient demographics and clinical characteristics for all ICU patients were compared against eligibility criteria from ten landmark, randomized, multicentre critical care trials. Individual patients from academic and community ICUs were assessed for eligibility in each of the ten studies, and decision tree analysis models were built based on prior inclusion and exclusion criteria from those trials. RESULTS: The number of potentially eligible patients for the ten trials ranged from 2,082 to 10,157. Potentially eligible participants from community ICUs accounted for 40.0% of total potentially eligible participants. The recruitment of community ICU patients in trials would have increased potential enrolment by an average of 64.0%. The inclusion of community ICU patients was predicted to decrease time to trial completion by a mean of 14 months (43% reduction). CONCLUSION: Inclusion of community ICU patients in critical care research trials has the potential to substantially increase enrolment and decrease time to trial completion.

RéSUMé: OBJECTIF: La recherche en soins intensifs au Canada est principalement réalisée dans des unités de soins intensifs affiliées à des centres universitaires jouissant d'infrastructures de recherche bien établies. Des efforts ont été déployés pour engager les unités de soins intensifs des hôpitaux communautaires en recherche, mais les impacts de leur participation à la recherche clinique n'ont jamais été explicitement quantifiés. Nous avons conséquemment cherché à déterminer le nombre de patient·es additionnel·les pouvant être recruté·es dans des études de soins critiques ainsi que la variation du temps nécessaire pour compléter les études si la patientèle issue d'unités de soins intensifs d'hôpitaux communautaires participait à la recherche clinique. MéTHODE: Une analyse par arbre de décision a été réalisée à partir de données provenant des Alberta Health Services pour l'année 2018. Les données démographiques et les caractéristiques cliniques de tou·tes les patient·es admis·es aux soins intensifs ont été comparées avec les critères d'éligibilité de dix importantes études multicentriques, randomisées, contrôlées en soins intensifs. Les patient·es des unités de soins intensifs universitaires et communautaires ont tou·tes été évalué·es pour leur éligibilité à chacune des dix études, et des modèles d'arbres décisionnels ont été construits en se basant sur les critères originaux d'inclusion et d'exclusion. RéSULTATS: Le nombre de personnes potentiellement éligibles pour les dix études s'est situé entre 2082 et 10 157. Les patient·es potentiellement admissibles en provenance d'unités de soins intensifs communautaires ont représenté 40,0 % de toutes les personnes potentiellement admissibles. Le recrutement de patient·es en provenance d'unités de soins intensifs communautaires aurait permis une hausse moyenne du recrutement potentiel de 64,0 %. L'inclusion de patient·es des unités de soins intensifs communautaires pourrait également réduire le temps nécessaire à la complétion des études de 14 mois en moyenne (réduction de 43 %). CONCLUSION: L'inclusion de patient·es en provenance d'unités de soins intensifs d'hôpitaux communautaires dans la recherche clinique en soins critiques a le potentiel d'augmenter substantiellement le recrutement et de diminuer le temps nécessaire à la complétion des études.

Randomized trial of the safety and efficacy of anti-SARS-CoV-2 mAb in the treatment of patients with nosocomial COVID-19 (CATCO-NOS).

Background: Patients with nosocomial acquisition of COVID-19 have poor outcomes but have not been included in therapeutic trials to date. Methods: A pragmatic open-label randomized controlled trial of anti-SARS-CoV-2 monoclonal antibodies (mAb) was performed in hospitalized patients with nosocomial COVID-19 infection in acute care hospitals spanning a provincial health care network. Participants within 5 days of first positive test or symptom onset were randomized to standard of care (SOC) plus a single dose intravenous mAb treatment (bamlanivimab or casirivimab/imdevimab) or SOC alone on a 2:1 basis. The primary study endpoint was the need for invasive mechanical ventilation (IMV) or inpatient mortality by day 60 after randomization. Results: Forty-six participants were enrolled from 13 hospitals between February 14 and October 8, 2021: 31 in the mAb and 15 in the SOC arm. IMV or inpatient mortality up to day 60 occurred in 4 (12.9%) participants in the mAb versus 3 in the SOC arm (20.0%), difference of -7.1% (95% CI -22.5 to 13.4, p = 0.67). The study was terminated early due to lack of equipoise as effectiveness of anti-viral therapies and mAb was published in similar high-risk patient populations. Conclusions: The trial was underpowered to detect meaningful differences given its early termination. The study does highlight the feasibility of undertaking trials in this patient population using a pragmatic approach allowing for trial participation and treatment access across a large health care network and may serve as a template for future designs.

Historique: Les patients qui contractent une COVID-19 nosocomiale ont de mauvais résultats cliniques, mais n'ont pas fait partie des études thérapeutiques jusqu'à présent. Méthodologie: Les chercheurs ont mené une étude randomisée et contrôlée ouverte et pragmatique des anticorps monoclonaux (AcM) anti-SRAS-CoV-2 auprès de patients hospitalisés qui ont contracté une COVID-19 nosocomiale dans les hôpitaux de soins aigus d'un réseau de santé provincial. Dans les cinq jours suivant un premier test positif ou l'apparition des symptômes, les participants ont été divisés de manière randomisée entre la norme des soins (NdS) combinée à une monodose de traitement aux AcM par voie intraveineuse (bamlanivimab ou casirivimab-imdevimab) ou la NdS seule sur une base de deux pour un. Le critère d'évaluation primaire de l'étude était la ventilation mécanique invasive (VMI) ou la mortalité en milieu hospitalier le 60e jour après la randomisation. Résultats: Au total, 46 participants de 13 hôpitaux ont été inclus entre le 14 février et le 8 octobre 2021, soit 31 patients du volet des AcM et 15 du volet de la NdS. La VMI ou la mortalité en milieu hospitalier jusqu'au 60e jour a été observée chez quatre participants au volet des AcM (12,9 %) et trois participants du volet de la NdS (20,0 %), soit une différence de −7,1 % (IC à 95 %, −22,5 à 13,4, p = 0,67). L'étude a été interrompue précocement à cause de l'absence d'équilibre clinique, car des données sur l'efficacité des traitements antiviraux et des AcM ont été publiées au sujet de populations semblables de patients à haut risque. Conclusions: L'échantillon à l'étude était insuffisant pour déceler des différences significatives compte tenu de son interruption précoce. Cette recherche fait ressortir la faisabilité d'études auprès de cette population de patients au moyen d'une approche pragmatique pour y inclure des participants et accéder au traitement dans un vaste réseau de soins et pourrait servir de modèle pour concevoir d'autres études.

Routine history and physical examinations prior to cataract surgery are not beneficial.

OBJECTIVE: To determine the safety of a policy change eliminating the requirement for preoperative history and physical examination before cataract surgery. DESIGN: A retrospective population-based study. METHODS: Because preoperative history and physical examination were no longer required in Alberta after April 1, 2017, a retrospective review of provincial health claims data was conducted to determine the safety of removing this requirement. Data from Albertans who underwent cataract surgery and had a preoperative medical examination between April 2014 and March 2017 were compared with data from those who underwent surgery between April 2017 and May 2020 without one. The primary outcome was adverse medical events, defined as an emergency room visit, inpatient admission, or death within 30 days of cataract surgery. RESULTS: A total of 236,046 cataract surgeries were performed over the study period. The likelihood of a postoperative emergency room visit was higher (odds ratio [OR] = 1.04; 95% CI, 1.01-1.08) in the preoperative examination group (n = 112,806 eyes), occurring in 4.8% of patients, compared with 4.7% in the no preoperative examination group (n = 123,240 eyes; p = 0.03). Inpatient admissions also were more likely to occur in the preoperative examination group (OR = 1.26; 95% CI, 1.18-1.34) at 1.8% in comparison with 1.5% in the no preoperative examination group (p < 0.0001). The death rate in both groups was 0.09% (p = 0.992). CONCLUSIONS: The rate of postoperative emergency room visits and inpatient admissions within 30 days of cataract surgery was negligibly different, indicating that preoperative examinations, which have been traditionally performed to reduce postoperative morbidity and mortality, offer little value to patients.

Systemic corticosteroids for outpatient respiratory viral infections in lung transplant recipients.

INTRODUCTION: Respiratory viral infections (RVI) in lung transplant recipients (LTR) have variably been associated with rejection and chronic lung allograft dysfunction. Our center has used systemic corticosteroids to treat outpatient RVI in some cases, but evidence is limited. We reviewed all adult LTR diagnosed with outpatient RVI January 2017 to December 2019. The primary outcome was recovery of lung function (forced expiratory volume in 1 s [FEV1]) at next stable visit between 1 and 12 months postinfection, expressed as a ratio over stable preinfection FEV1 (FEV1 recovery ratio). METHODS: We identified 100 adult LTR with outpatient RVI diagnoses eligible for study, 36% of whom received corticosteroids. We modelled the adjusted association between corticosteroid use and FEV1 recovery ratio using linear regression. RESULTS: Steroid-treated patients had a lower FEV1 presentation ratio (0.92 vs. 1.04, p = .0070) and were more likely to have chronic lung allograft dysfunction at time of infection (25% vs. 5%, p = .0077). Mean FEV1 recovery ratio was 1.02 (SD 0.19) with no association with corticosteroid therapy via multivariable linear regression (p = .5888). CONCLUSIONS: Steroid treatment was not associated with FEV1 recovery. This suggests corticosteroids may not have a role in the management of RVI in this population.

Sequential multi-omics analysis identifies clinical phenotypes and predictive biomarkers for long COVID.

The post-acute sequelae of COVID-19 (PASC), also known as long COVID, is often associated with debilitating symptoms and adverse multisystem consequences. We obtain plasma samples from 117 individuals during and 6 months following their acute phase of infection to comprehensively profile and assess changes in cytokines, proteome, and metabolome. Network analysis reveals sustained inflammatory response, platelet degranulation, and cellular activation during convalescence accompanied by dysregulation in arginine biosynthesis, methionine metabolism, taurine metabolism, and tricarboxylic acid (TCA) cycle processes. Furthermore, we develop a prognostic model composed of 20 molecules involved in regulating T cell exhaustion and energy metabolism that can reliably predict adverse clinical outcomes following discharge from acute infection with 83% accuracy and an area under the curve (AUC) of 0.96. Our study reveals pertinent biological processes during convalescence that differ from acute infection, and it supports the development of specific therapies and biomarkers for patients suffering from long COVID.

Immunological responses in SARS-CoV-2 and HIV co-infection versus SARS-CoV-2 mono-infection: case report of the interplay between SARS-CoV-2 and HIV.

BACKGROUND: There is an urgent need to understand the interplay between SARS-CoV-2 and HIV to inform risk-mitigation approaches for HIV-infected individuals. OBJECTIVES: We conclude that people living with HIV (PLWH) who are antiretroviral therapy (ART) naïve could be at a greater risk of morbidity or mortality once co-infected with SARS-CoV-2. METHODS: Here, we performed extensive immune phenotyping using flow cytometry. Moreover, to compare the range of values observed in the co-infected case, we have included a larger number of mono-infected cases with SARS-CoV-2. We also quantified soluble co-inhibitory/co-stimulatory molecules in the plasma of our patients. RESULTS: We noted a robust immune activation characterized by the expansion of CD8+ T cells expressing co-inhibitory/stimulatory molecules (e.g. PD-1, TIM-3, 2B4, TIGIT, CD39, and ICOS) and activation markers (CD38, CD71, and HLA-DR) in the co-infected case. We further found that neutrophilia was more pronounced at the expense of lymphopenia in the co-infected case. In particular, naïve and central memory CD8+ T cells were scarce as a result of switching to effector and effector memory in the co-infected case. CD8+ T cell effector functions such as cytokine production (e.g. TNF-α and IFN-γ) and cytolytic molecules expression (granzyme B and perforin) following anti-CD3/CD28 or the Spike peptide pool stimulation were more prominent in the co-infected case versus the mono-infected case. We also observed that SARS-CoV-2 alters T cell exhaustion commonly observed in PLWH. CONCLUSION: These findings imply that inadequate immune reconstitution and/or lack of access to ART could dysregulate immune response against SARS-CoV-2 infection, which can result in poor clinical outcomes in PLWH. Our study has implications for prioritizing PLWH in the vaccination program/access to ART in resource-constrained settings.

Analysis of SARS-CoV-2 isolates, namely the Wuhan strain, Delta variant, and Omicron variant, identifies differential immune profiles.

There is an urgent need to better understand the impact of different severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants on immune response and disease dynamics to facilitate better intervention strategies. Here, we show that SARS-CoV-2 variants differentially affect host immune responses. The magnitude and quantity of cytokines and chemokines were comparable in those infected with the Wuhan strain and the Delta variant. However, individuals infected with the Omicron variant had significantly lower levels of these mediators. We also found an elevation of plasma galectins (Gal-3, Gal-8, and Gal-9) in infected individuals, in particular, in those with the original strain. Soluble galectins exert a proinflammatory role in COVID-19 pathogenesis. This was illustrated by their correlation with the plasma levels of sCD14, sCD163, enhanced TNF-α/IL-6 secretion, and increased SARS-CoV-2 infectivity in vitro. Moreover, we observed enhanced CD4+ and CD8+ T cell activation in Wuhan strain-infected individuals. Surprisingly, there was a more pronounced T cell activation in those infected with the Omicron in comparison to the Delta variant. In line with T cell activation status, we observed a more pronounced expansion of T cells expressing different co-inhibitory receptors in patients infected with the Wuhan strain, followed by the Omicron and Delta variants. Individuals infected with the Wuhan strain or the Omicron variant had a similar pattern of plasma soluble immune checkpoints. Our results imply that a milder innate immune response might be beneficial and protective in those infected with the Omicron variant. Our results provide a novel insight into the differential impact of SARS-CoV-2 variants on host immunity. IMPORTANCE There is a need to better understand how different SARS-CoV-2 variants influence the immune system and disease dynamics to facilitate the development of better vaccines and therapies. We compared immune responses in 140 SARS-CoV-2-infected individuals with the Wuhan strain, the Delta variant, or the Omicron variant. All these patients were admitted to the intensive care unit and were SARS-CoV-2 vaccination naïve. We found that SARS-CoV-2 variants differentially affect the host immune response. This was done by measuring soluble biomarkers in their plasma and examining different immune cells. Overall, we found that the magnitude of cytokine storm in individuals infected with the Wuhan strain or the Delta variant was greater than in those infected with the Omicron variant. In light of enhanced cytokine release syndrome in individuals infected with the Wuhan strain or the Delta variant, we believe that a milder innate immune response might be beneficial and protective in those infected with the Omicron variant.

Systemic Nonsteroidal Anti-Inflammatories for Analgesia in Postoperative Critical Care Patients: A Systematic Review and Meta-Analysis of Randomized Control Trials.

While opioids are part of usual care for analgesia in the ICU, there are concerns regarding excess use. This is a systematic review of nonsteroidal anti-inflammatory drugs (NSAIDs) use in postoperative critical care adult patients. DATA SOURCES: We searched Medical Literature Analysis and Retrieval System Online, Excerpta Medica database, Cumulative Index to Nursing and Allied Health Literature, Cochrane Library, trial registries, Google Scholar, and relevant systematic reviews through March 2023. STUDY SELECTION: Titles, abstracts, and full texts were reviewed independently and induplicate by two investigators to identify eligible studies. We included randomized control trials (RCTs) that compared NSAIDs alone or as an adjunct to opioids for systemic analgesia. The primary outcome was opioid utilization. DATA EXTRACTION: In duplicate, investigators independently extracted study characteristics, patient demographics, intervention details, and outcomes of interest using predefined abstraction forms. Statistical analyses were conducted using Review Manager software Version 5.4. (The Cochrane Collaboration, Copenhagen, Denmark). DATA SYNTHESIS: We included 15 RCTs (n = 1,621 patients) for admission to the ICU for postoperative management after elective procedures. Adjunctive NSAID therapy to opioids reduced 24-hour oral morphine equivalent consumption by 21.4 mg (95% CI, 11.8-31.0 mg reduction; high certainty) and probably reduced pain scores (measured by Visual Analog Scale) by 6.1 mm (95% CI, 12.2 decrease to 0.1 increase; moderate certainty). Adjunctive NSAID therapy probably had no impact on the duration of mechanical ventilation (1.6 hr reduction; 95% CI, 0.4 hr to 2.7 reduction; moderate certainty) and may have no impact on ICU length of stay (2.1 hr reduction; 95% CI, 6.1 hr reduction to 2.0 hr increase; low certainty). Variability in reporting adverse outcomes (e.g., gastrointestinal bleeding, acute kidney injury) precluded their meta-analysis. CONCLUSIONS: In postoperative critical care adult patients, systemic NSAIDs reduced opioid use and probably reduced pain scores. However, the evidence is uncertain for the duration of mechanical ventilation or ICU length of stay. Further research is required to characterize the prevalence of NSAID-related adverse outcomes.

Antimicrobial stewardship, procalcitonin testing, and rapid blood-culture identification to optimize sepsis care in critically ill adult patients: A quality improvement initiative.

We examined the effect of an antimicrobial stewardship program (ASP), procalcitonin testing and rapid blood-culture identification on hospital mortality in a prospective quality improvement project in critically ill septic adults. Secondarily, we have reported antimicrobial guideline concordance, acceptance of ASP interventions, and antimicrobial and health-resource utilization.

Definitions, rates and associated mortality of ICU-acquired pneumonia: A multicenter cohort study.

INTRODUCTION: We aimed to analyze intensive care unit (ICU)-acquired pneumonia according to 7 definitions, estimating associated hospital mortality. METHODS: This cohort study was nested within an international randomized trial, evaluating the effect of probiotics on ICU-acquired pneumonia in 2650 mechanically ventilated adults. Each clinically suspected pneumonia was adjudicated by two physicians blinded to allocation and center. The primary outcome was ventilator-associated pneumonia (VAP) informed by ventilation for ≥2 days, new, progressive or persistent infiltrate plus 2 of: temperature > 38 °C or < 36 °C; leukopenia (<3 × 10(Fernando et al., 20206)/L) or leukocytosis (>10 × 10(Fernando et al., 20206)/L); and purulent sputum. We also used 6 other definitions estimating the risk of hospital mortality. RESULTS: The frequency of ICU-acquired pneumonia varied by definition: the trial primary outcome VAP (21.6%), Clinical Pulmonary Infection Score (CPIS) (24.9%), American College Chest Physicians (ACCP) (25.0%), International Sepsis Forum (ISF) (24.4%), Reducing Oxidative Stress Study (REDOXS) (17.6%), Centers for Disease Control (CDC) (7.8%), and invasively microbiologically confirmed (1.9%). The trial primary outcome VAP (HR 1.31 [1.08, 1.60]), ISF (HR 1.32 [1.09,1.60]), CPIS (HR 1.30 [1.08,1.58]) and ACCP definitions (HR 1.22 [1.00,1.47]) were associated with hospital mortality. CONCLUSIONS: Rates of ICU-acquired pneumonia vary by definition and are associated with differential increased risk of death.

Clostridioides difficile infection in mechanically ventilated critically ill patients: A nested cohort study.

INTRODUCTION: Clostridioides difficile infection (CDI) is a serious complication of critical illness. The objective of the study was to determine its incidence, prevalence, timing, severity, predictors, and outcomes. METHODS: We performed a prospective nested cohort study of CDI within a randomized trial comparing Lactobacillus rhamnosus GG to placebo. We adjudicated cases of CDI using standardized definitions, assessed timing (pre-ICU, in ICU, post-ICU) and severity. We analyzed risk factors and outcomes. RESULTS: Of 2650 patients, 86 were diagnosed with CDI during 90,833 hospital-days (0.95/1000 hospital-days); CDI prevalence was 3.2%. CDI incidence varied in timing; 0.3% patients had CDI pre-ICU, 2.2% in the ICU; an 0.8% developed CDI post-ICU. Relapse or recurrence of CDI was documented in 9.3% patients. Infections were mild/moderate in severity. Complications included septic shock (26.7%), organ failure (16.3%), and toxic megacolon requiring colectomy (1.2%). No risk factors for CDI were identified. CDI was not associated with hospital mortality. The duration of hospital stay was longer for those who had CDI compared those who did not, CONCLUSION: CDI was uncommon, severity was mild to moderate and not associated with mortality however CDI was associated with a longer hospital stay.

Midodrine therapy for vasopressor dependent shock in the intensive care unit: a protocol for a systematic review and meta-analysis.

INTRODUCTION: Intensive care unit (ICU) lengths of stay are modified by ongoing need for haemodynamic support in critically ill patients. This is most commonly provided by intravenous vasopressor therapy. Midodrine has been used as an oral agent for haemodynamic support in patients with orthostatic hypotension or cirrhosis. However, its efficacy in treating shock in the ICU, particularly for patients weaning from intravenous vasopressors, remains uncertain. The objective of this systematic review is to determine the efficacy of midodrine in vasopressor dependent shock. METHODS AND ANALYSIS: We will search Ovid MEDLINE, Ovid Embase, CINAHL and Cochrane Library for observational trials and randomised controlled trials evaluating midodrine in critically ill patients from inception to 21 April 2022. We will also review unpublished data and relevant conference abstracts. Outcomes will include ICU length of stay, duration of intravenous vasopressor support, ICU mortality, hospital mortality, hospital length of stay and rates of ICU readmission. Data will be analysed in aggregate, where appropriate. We will evaluate risk of bias using the modified Cochrane tool and certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluations methodology. We will perform trial sequential analysis for the outcome of ICU length of stay. ETHICS AND DISSEMINATION: Ethics approval is not required as primary data will not be collected. Findings of this review will be disseminated through peer-related publication and will inform future clinical trials. PROSPERO REGISTRATION NUMBER: CRD42021260375.

Differential effects of age, sex and dexamethasone therapy on ACE2/TMPRSS2 expression and susceptibility to SARS-CoV-2 infection.

ACE2 and TMPRSS2 are crucial for SARS-CoV-2 entry into the cell. Although ACE2 facilitates viral entry, its loss leads to promoting the devastating clinical symptoms of COVID-19 disease. Thus, enhanced ACE2/TMPRSS2 expression is likely to increase predisposition of target cells to SARS-CoV-2 infection. However, little evidence existed about the biological kinetics of these two enzymes and whether dexamethasone treatment modulates their expression. Here, we show that the expression of ACE2 at the protein and mRNA levels was significantly higher in the lung and heart tissues of neonatal compared to adult mice. However, the expression of TMPRSS2 was developmentally regulated. Our results may introduce a novel concept for the reduced susceptibility of the young to SARS-CoV-2 infection. Moreover, ACE2 expression but not TMPRSS2 was upregulated in adult female lungs compared to their male counterparts. Interestingly, the ACE2 and TMPRSS2 expressions were upregulated by dexamethasone treatment in the lung and heart tissues in both neonatal and adult mice. Furthermore, our findings provide a novel mechanism for the observed differential therapeutic effects of dexamethasone in COVID-19 patients. As such, dexamethasone exhibits different therapeutic effects depending on the disease stage. This was supported by increased ACE2/TMPRSS2 expression and subsequently enhanced infection of normal human bronchial epithelial cells (NHBE) and Vero E6 cells with SARS-CoV-2 once pre-treated with dexamethasone. Therefore, our results suggest that individuals who take dexamethasone for other clinical conditions may become more prone to SARS-CoV-2 infection.

Cost-effectiveness of remdesivir plus usual care versus usual care alone for hospitalized patients with COVID-19: an economic evaluation as part of the Canadian Treatments for COVID-19 (CATCO) randomized clinical trial.

BACKGROUND: The role of remdesivir in the treatment of hospitalized patients with COVID-19 remains ill-defined. We conducted a cost-effectiveness analysis alongside the Canadian Treatments for COVID-19 (CATCO) open-label, randomized clinical trial evaluating remdesivir. METHODS: Patients with COVID-19 in Canadian hospitals from Aug. 14, 2020, to Apr. 1, 2021, were randomly assigned to receive remdesivir plus usual care versus usual care alone. Taking a public health care payer's perspective, we collected in-hospital outcomes and health care resource utilization alongside estimated unit costs in 2020 Canadian dollars over a time horizon from randomization to hospital discharge or death. Data from 1281 adults admitted to 52 hospitals in 6 Canadian provinces were analyzed. RESULTS: The total mean cost per patient was $37 918 (standard deviation [SD] $42 413; 95% confidence interval [CI] $34 617 to $41 220) for patients randomly assigned to the remdesivir group and $38 026 (SD $46 021; 95% CI $34 480 to $41 573) for patients receiving usual care (incremental cost -$108 [95% CI -$4953 to $4737], p > 0.9). The difference in proportions of in-hospital deaths between remdesivir and usual care groups was -3.9% (18.7% v. 22.6%, 95% CI -8.3% to 1.0%, p = 0.09). The difference in proportions of incident invasive mechanical ventilation events between groups was -7.0% (8.0% v. 15.0%, 95% CI -10.6% to -3.4%, p = 0.006), whereas the difference in proportions of total mechanical ventilation events between groups was -5.7% (16.4% v. 22.1%, 95% CI -10.0% to -1.4%, p = 0.01). Remdesivir was the dominant intervention (but only marginally less costly, with mildly lower mortality) with an incalculable incremental cost effectiveness ratio; we report results of incremental costs and incremental effects separately. For willingness-to-pay thresholds of $0, $20 000, $50 000 and $100 000 per death averted, a strategy using remdesivir was cost-effective in 60%, 67%, 74% and 79% of simulations, respectively. The remdesivir costs were the fifth highest cost driver, offset by shorter lengths of stay and less mechanical ventilation. INTERPRETATION: From a health care payer perspective, treating patients hospitalized with COVID-19 with remdesivir and usual care appears to be preferrable to treating with usual care alone, albeit with marginal incremental cost and small clinical effects. The added cost of remdesivir was offset by shorter lengths of stay in the intensive care unit and less need for ventilation. STUDY REGISTRATION: ClinicalTrials. gov, no. NCT04330690.

Hyperammonemia syndrome post-lung transplantation: Case series and systematic review of literature.

BACKGROUND: Hyperammonemia syndrome (HS) is a rare post-transplant complication associated with high morbidity and mortality. Its incidence appears to be higher in lung transplant recipients and its pathophysiology is not well understood. In addition to underlying metabolic abnormalities, it is postulated that HS may be associated with Ureaplasma or Mycoplasma spp. lung infections. Management of this condition is not standardized and may include preemptive antimicrobials, renal replacement, nitrogen scavenging, and bowel decontamination therapies, as well as dietary modifications. METHODS: In this case series, we describe seven HS cases, five of whom had metabolic deficiencies ruled out. In addition, a literature review was performed by searching PubMed following PRISMA-P guidelines. Articles containing the terms "hyperammonemia" and "lung" were reviewed from 1 January 1997 to 31 October 2021. RESULTS: All HS cases described in our center had positive airway samples for Mycoplasmataceae, neurologic abnormalities and high ammonia levels post-transplant. Mortality in our group (57%) was similar to that published in previous cases. The literature review supported that HS is an early complication post-transplant, associated with Ureaplasma spp. and Mycoplasma hominis infections and of worse prognosis in patients presenting cerebral edema and seizures. CONCLUSION: This review highlights the need for rapid testing for Ureaplasma spp. and M. hominis after lung transplant, as well as the necessity for future studies to explore potential therapies that may improve outcomes in these patients.

Differential Impact of SARS-CoV-2 Isolates, Namely, the Wuhan Strain, Delta, and Omicron Variants on Erythropoiesis.

SARS-CoV-2 variants exhibit different viral transmissibility and disease severity. However, their impact on erythropoiesis has not been investigated. Here, we show SARS-CoV-2 variants differentially affect erythropoiesis. This is illustrated by the abundance of CD71+ erythroid cells (CECs) in the blood circulation of COVID-19 patients infected with the original Wuhan strain followed by the Delta and Omicron variants. We observed the CD45+CECs are the dominant subpopulation of CECs expressing the receptor, ACE2, and coreceptor, TMPRSS2, and thus, can be targeted by SARS-CoV-2. Also, we found CECs exhibit immunosuppressive properties, specifically CD45+CECs are the dominant immunosuppressive cells and via reactive oxygen species (ROS) and arginase I expression can impair CD8+ T cell functions. In agreement, we observed CECs suppress CD8+ T cell effector (e.g., Granzyme B expression and degranulation capacity [CD107]), which was partially but significantly reversed with l-arginine supplementation. In light of the enriched frequency of CECs, in particular, CD45+CECs in patients infected with the original (Wuhan) strain, we believe this strain has a more prominent impact on hematopoiesis compared with the Delta and Omicron variants. Therefore, our study provides an important insight into the differential impact of SARS-CoV-2 variants on erythropoiesis in COVID-19 patients. IMPORTANCE Silent hypoxia has been the hallmark of SARS-CoV-2 infection. Red blood cells (RBCs) work as gas cargo delivering oxygen to different tissues. However, their immature counterparts reside in the bone marrow and normally absent in the blood circulation. We show SARS-CoV-2 infection is associated with the emergence of immature RBCs so called CD71+ erythroid cells (CECs) in the blood. In particular, we found these cells were more prevalent in the blood of those infected with the SARS-CoV-2 original strain (Wuhan) followed by the Delta and Omicron variants. This suggests SARS-CoV-2 directly or indirectly impacts RBC production. In agreement, we observed immature RBCs express the receptor (ACE2) and coreceptor (TMPRSS2) for SARS-CoV-2. CECs suppress T cells functions (e.g., Granzyme B and degranulation capacity) in vitro. Therefore, our study provides a novel insight into the differential impact of SARS-CoV-2 variants on erythropoiesis and subsequently the hypoxia commonly observed in COVID-19 patients.

LIBERATE: a study protocol for midodrine for the early liberation from vasopressor support in the intensive care unit (LIBERATE): protocol for a randomized controlled trial.

BACKGROUND: Intravenous (IV) vasopressors to support hemodynamics are a primary indication for intensive care unit (ICU) admission. Utilization of oral vasopressor therapy may offer an alternative to IV vasopressor therapy in the ICU, thus decreasing the need for ICU admission. Oral vasopressors, such as midodrine, have been used for hemodynamic support in non-critically ill patients, but their evaluation in critically ill patients to potentially spare IV vasopressor therapy has been limited. METHODS: The LIBERATE study will be a multicenter, parallel-group, blinded, randomized placebo-controlled trial. It will recruit adult (i.e., age ≥ 18 years) critically ill patients receiving stable or decreasing doses of IV vasopressors. Eligible patients will be randomized to receive either midodrine 10 mg administered enterally every 8 h or placebo until 24 h post-discontinuation of IV vasopressors. The primary outcome will be ICU length of stay. Secondary outcomes include all-cause mortality at 90 days, hospital length of stay, length of IV vasopressor support, re-initiation of IV vasopressors, rates of ICU readmission, and occurrence of AEs. Health economic outcomes including ICU, hospital and healthcare costs, and cost-effectiveness will be evaluated. Pre-planned subgroup analyses include age, sex, frailty, severity of illness, etiology of shock, and comorbid conditions. DISCUSSION: LIBERATE will rigorously evaluate the effect of oral midodrine on duration of ICU stay and IV vasopressor support in critically ill patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT05058612 . Registered on September 28, 2021.

Defining COVID-19-associated pulmonary aspergillosis: systematic review and meta-analysis.

BACKGROUND: Pulmonary aspergillosis may complicate coronavirus disease 2019 (COVID-19) and contribute to excess mortality in intensive care unit (ICU) patients. The disease is poorly understood, in part due to discordant definitions across studies. OBJECTIVES: We sought to review the prevalence, diagnosis, treatment, and outcomes of COVID-19-associated pulmonary aspergillosis (CAPA) and compare research definitions. DATA SOURCES: PubMed, Embase, Web of Science, and MedRxiv were searched from inception to October 12, 2021. STUDY ELIGIBILITY CRITERIA: ICU cohort studies and CAPA case series including ≥3 patients were included. PARTICIPANTS: Adult patients in ICUs with COVID-19. INTERVENTIONS: Patients were reclassified according to four research definitions. We assessed risk of bias with an adaptation of the Joanna Briggs Institute cohort checklist tool for systematic reviews. METHODS: We calculated CAPA prevalence using the Freeman-Tukey random effects method. Correlations between definitions were assessed with Spearman's rank test. Associations between antifungals and outcome were assessed with random effects meta-analysis. RESULTS: Fifty-one studies were included. Among 3297 COVID-19 patients in ICU cohort studies, 313 were diagnosed with CAPA (prevalence 10%; 95% CI 8%-13%). Two hundred seventy-seven patients had patient-level data allowing reclassification. Definitions had limited correlation with one another (ρ = 0.268-0.447; p < 0.001), with the exception of Koehler and Verweij (ρ = 0.893; p < 0.001); 33.9% of patients reported to have CAPA did not fulfill any research definitions. Patients were diagnosed after a median of 8 days (interquartile range 5-14) in ICUs. Tracheobronchitis occurred in 3% of patients examined with bronchoscopy. The mortality rate was high (59.2%). Applying CAPA research definitions did not strengthen the association between mould-active antifungals and survival. CONCLUSIONS: The reported prevalence of CAPA is significant but may be exaggerated by nonstandard definitions.