Features of acute COVID-19 associated with post-acute sequelae of SARS-CoV-2 phenotypes: results from the IMPACC study.

Post-acute sequelae of SARS-CoV-2 (PASC) is a significant public health concern. We describe Patient Reported Outcomes (PROs) on 590 participants prospectively assessed from hospital admission for COVID-19 through one year after discharge. Modeling identified 4 PRO clusters based on reported deficits (minimal, physical, mental/cognitive, and multidomain), supporting heterogenous clinical presentations in PASC, with sub-phenotypes associated with female sex and distinctive comorbidities. During the acute phase of disease, a higher respiratory SARS-CoV-2 viral burden and lower Receptor Binding Domain and Spike antibody titers were associated with both the physical predominant and the multidomain deficit clusters. A lower frequency of circulating B lymphocytes by mass cytometry (CyTOF) was observed in the multidomain deficit cluster. Circulating fibroblast growth factor 21 (FGF21) was significantly elevated in the mental/cognitive predominant and the multidomain clusters. Future efforts to link PASC to acute anti-viral host responses may help to better target treatment and prevention of PASC.

Predicting high-intensity resuscitation needs in injured patients in the post-hemostasis phase of care following intervention.

BACKGROUND: Best resuscitation practices in the posthemostasis phase of care are poorly defined; this phase of care is characterized by a range of physiologic derangements and multiple therapeutic modalities used to address them. Using a cohort of injured patients who required an immediate intervention in the operating room or angiography suite following arrival to the emergency department, we sought to define high-intensity resuscitation (HIR) in this posthemostasis phase of care; we hypothesized that those who would require HIR could be identified, using only data available at intensive care unit (ICU) admission. METHODS: Clinical data were extracted for consecutive injured patients (2016-2019) admitted to the ICU following an immediate procedure in the operating room or angiography suite. High-intensity resuscitation thresholds were defined as the top decile of blood product (≥3 units) and/or crystalloid (≥4 L) use in the initial 12 hours of ICU care and/or vasoactive medication use between ICU hours 2 and 12. The primary outcome, HIR, was a composite of any of these modalities. Predictive modeling of HIR was performed using logistic regression with predictor variables selected using Least Absolute Shrinkage and Selection Operator (LASSO) estimation. Model was trained using 70% of the cohort and tested on the remaining 30%; model predictive ability was evaluated using area under receiver operator curves. RESULTS: Six hundred five patients were included. Patients were 79% male, young (median age, 39 years), severely injured (median Injury Severity Score, 26), and an approximately 3:2 ratio of blunt to penetrating mechanisms of injury. A total of 215 (36%) required HIR. Predictors selected by LASSO included: shock index, lactate, base deficit, hematocrit, and INR. The area under receiver operator curve for the LASSO-derived HIR prediction model was 0.82. CONCLUSION: Intensive care unit admission data can identify subsequent HIR in the posthemostasis phase of care. Use of this model may facilitate triage, nursing ratio determination, and resource allocation. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Adverse outcomes and an immunosuppressed endotype in septic patients with reduced IFN-γ ELISpot.

BACKGROUNDSepsis remains a major clinical challenge for which successful treatment requires greater precision in identifying patients at increased risk of adverse outcomes requiring different therapeutic approaches. Predicting clinical outcomes and immunological endotyping of septic patients generally relies on using blood protein or mRNA biomarkers, or static cell phenotyping. Here, we sought to determine whether functional immune responsiveness would yield improved precision.METHODSAn ex vivo whole-blood enzyme-linked immunosorbent spot (ELISpot) assay for cellular production of interferon γ (IFN-γ) was evaluated in 107 septic and 68 nonseptic patients from 5 academic health centers using blood samples collected on days 1, 4, and 7 following ICU admission.RESULTSCompared with 46 healthy participants, unstimulated and stimulated whole-blood IFN-γ expression was either increased or unchanged, respectively, in septic and nonseptic ICU patients. However, in septic patients who did not survive 180 days, stimulated whole-blood IFN-γ expression was significantly reduced on ICU days 1, 4, and 7 (all P < 0.05), due to both significant reductions in total number of IFN-γ-producing cells and amount of IFN-γ produced per cell (all P < 0.05). Importantly, IFN-γ total expression on days 1 and 4 after admission could discriminate 180-day mortality better than absolute lymphocyte count (ALC), IL-6, and procalcitonin. Septic patients with low IFN-γ expression were older and had lower ALCs and higher soluble PD-L1 and IL-10 concentrations, consistent with an immunosuppressed endotype.CONCLUSIONSA whole-blood IFN-γ ELISpot assay can both identify septic patients at increased risk of late mortality and identify immunosuppressed septic patients.TRIAL REGISTRYN/A.FUNDINGThis prospective, observational, multicenter clinical study was directly supported by National Institute of General Medical Sciences grant R01 GM-139046, including a supplement (R01 GM-139046-03S1) from 2022 to 2024.

Defining critical illness using immunological endotypes in patients with and without sepsis: a cohort study.

BACKGROUND: Sepsis is a heterogenous syndrome with limited therapeutic options. Identifying immunological endotypes through gene expression patterns in septic patients may lead to targeted interventions. We investigated whether patients admitted to a surgical intensive care unit (ICU) with sepsis and with high risk of mortality express similar endotypes to non-septic, but still critically ill patients using two multiplex transcriptomic metrics obtained both on admission to a surgical ICU and at set intervals. METHODS: We analyzed transcriptomic data from 522 patients in two single-site, prospective, observational cohorts admitted to surgical ICUs over a 5-year period ending in July 2020. Using an FDA-cleared analytical platform (nCounter FLEX®, NanoString, Inc.), we assessed a previously validated 29-messenger RNA transcriptomic classifier for likelihood of 30-day mortality (IMX-SEV-3) and a 33-messenger RNA transcriptomic endotype classifier. Clinical outcomes included all-cause mortality, development of chronic critical illness, and secondary infections. Univariate and multivariate analyses were performed to assess for true effect and confounding. RESULTS: Sepsis was associated with a significantly higher predicted and actual hospital mortality. At enrollment, the predominant endotype for both septic and non-septic patients was adaptive, though with significantly different distributions. Inflammopathic and coagulopathic septic patients, as well as inflammopathic non-septic patients, showed significantly higher frequencies of secondary infections compared to those with adaptive endotypes (p < 0.01). Endotypes changed during ICU hospitalization in 57.5% of patients. Patients who remained adaptive had overall better prognosis, while those who remained inflammopathic or coagulopathic had worse overall outcomes. For severity metrics, patients admitted with sepsis and a high predicted likelihood of mortality showed an inflammopathic (49.6%) endotype and had higher rates of cumulative adverse outcomes (67.4%). Patients at low mortality risk, whether septic or non-septic, almost uniformly presented with an adaptive endotype (100% and 93.4%, respectively). CONCLUSION: Critically ill surgical patients express different and evolving immunological endotypes depending upon both their sepsis status and severity of their clinical course. Future studies will elucidate whether endotyping critically ill, septic patients can identify individuals for targeted therapeutic interventions to improve patient management and outcomes.

Defining critical illness using immunological endotypes in patients with and without of sepsis: A cohort study.

Background: Sepsis is a heterogenous syndrome with limited therapeutic options. Identifying characteristic gene expression patterns, or endotypes, in septic patients may lead to targeted interventions. We investigated whether patients admitted to a surgical ICU with sepsis and with high risk of mortality express similar endotypes to non-septic, but still critically ill patients using two multiplex transcriptomic metrics obtained both on admission to a surgical intensive care unit (ICU) and at set intervals. Methods: We analyzed transcriptomic data from 522 patients in two single-site, prospective, observational cohorts admitted to surgical ICUs over a 5-year period ending in July 2020 . Using an FDA-cleared analytical platform (nCounter FLEX ® , NanoString, Inc.), we assessed a previously validated 29-messenger RNA transcriptomic classifier for likelihood of 30-day mortality (IMX-SEV-3) and a 33-messenger RNA transcriptomic endotype classifier. Clinical outcomes included all-cause (in-hospital, 30-, 90-day) mortality, development of chronic critical illness (CCI), and secondary infections. Univariate and multivariate analyses were performed to assess for true effect and confounding. Results: Sepsis was associated with a significantly higher predicted and actual hospital mortality. At enrollment, the predominant endotype for both septic and non-septic patients was adaptive , though with significantly different distributions. Inflammopathic and coagulopathic septic patients, as well as inflammopathic non-septic patients, showed significantly higher frequencies of secondary infections compared to those with adaptive endotypes (p<0.01). Endotypes changed during ICU hospitalization in 57.5% of patients. Patients who remained adaptive had overall better prognosis, while those who remained inflammopathic or coagulopathic had worse overall outcomes. For severity metrics, patients admitted with sepsis and a high predicted likelihood of mortality showed an inflammopathic (49.6%) endotype and had higher rates of cumulative adverse outcomes (67.4%). Patients at low mortality risk, whether septic or non-septic, almost uniformly presented with an adaptive endotype (100% and 93.4%, respectively). Conclusion : Critically ill surgical patients express different and evolving immunological endotypes depending upon both their sepsis status and severity of their clinical course. Future studies will elucidate whether endotyping critically ill, septic patients can identify individuals for targeted therapeutic interventions to improve patient management and outcomes.

Defining Posttraumatic Sepsis for Population-Level Research.

Importance: Multiple classification methods are used to identify sepsis from existing data. In the trauma population, it is unknown how administrative methods compare with clinical criteria for sepsis classification. Objectives: To characterize the agreement between 3 approaches to sepsis classification among critically ill patients with trauma and compare the sepsis-associated risk of adverse outcomes when each method was used to define sepsis. Design, Setting, and Participants: This retrospective cohort study used data collected between January 1, 2012, and December 31, 2020, from patients aged 16 years or older with traumatic injury, admitted to the intensive care unit of a single-institution level 1 trauma center and requiring invasive mechanical ventilation for at least 3 days. Statistical analysis was conducted from August 1, 2021, to March 31, 2022. Exposure: Hospital-acquired sepsis, as classified by 3 methods: a novel automated clinical method based on data from the electronic health record, the National Trauma Data Bank (NTDB), and explicit and implicit medical billing codes. Main Outcomes and Measures: The primary outcomes were chronic critical illness and in-hospital mortality. Secondary outcomes included number of days in an intensive care unit, number of days receiving mechanical ventilation, discharge to a skilled nursing or long-term care facility, and discharge to home without assistance. Results: Of 3194 patients meeting inclusion criteria, the median age was 49 years (IQR, 31-64 years), 2380 (74%) were male, and 2826 (88%) sustained severe blunt injury (median Injury Severity Score, 29 [IQR, 21-38]). Sepsis was identified in 747 patients (23%) meeting automated clinical criteria, 118 (4%) meeting NTDB criteria, and 529 (17%) using medical billing codes. The Light κ value for 3-way agreement was 0.16 (95% CI, 0.14-0.19). The adjusted relative risk of chronic critical illness was 9.9 (95% CI, 8.0-12.3) for sepsis identified by automated clinical criteria, 5.0 (95% CI, 3.4-7.3) for sepsis identified by the NTDB, and 4.5 (95% CI, 3.6-5.6) for sepsis identified using medical billing codes. The adjusted relative risk for in-hospital mortality was 1.3 (95% CI, 1.0-1.6) for sepsis identified by automated clinical criteria, 2.7 (95% CI, 1.7-4.3) for sepsis identified by the NTDB, and 1.0 (95% CI, 0.7-1.2) for sepsis identified using medical billing codes. Conclusions and Relevance: In this cohort study of critically ill patients with trauma, administrative methods misclassified sepsis and underestimated the incidence and severity of sepsis compared with an automated clinical method using data from the electronic health record. This study suggests that an automated approach to sepsis classification consistent with Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) clinical criteria is feasible and may improve existing approaches to health services and population-based research in this population.

PREHOSPITAL CRYSTALLOID RESUSCITATION: PRACTICE VARIATION AND ASSOCIATIONS WITH CLINICAL OUTCOMES.

ABSTRACT: Introduction: Although resuscitation guidelines for injured patients favor blood products, crystalloid resuscitation remains a mainstay in prehospital care. Our understanding of contemporary prehospital crystalloid (PHC) practices and their relationship with clinical outcomes is limited. Methods: The Pragmatic, Randomized Optimal Platelet and Plasma Ratios trial data set was used for this investigation. We sought to identify factors associated with PHC volume variation and hypothesized that higher PHC volume is associated with worse coagulopathy and a higher risk of acute respiratory distress syndrome (ARDS) but a lower risk of acute kidney injury (AKI). Subjects were divided into groups that received <1,000 mL PHC (PHC<1,000) and ≥1,000 mL PHC (PHC≥1,000); initial laboratory values and outcomes (ARDS and AKI risk) were summarized with medians and interquartile ranges or percentages and compared using Wilcoxon rank-sum tests and chi-square tests. The primary outcome was ARDS risk. Multivariable regression was used to characterize the association of each 500 mL aliquot of PHC with initial laboratory values and clinical outcomes. Results: PHC volume among study subjects (n = 680) varied (median, 0.3 L; interquartile range, 0-0.9 L) with weak associations demonstrated among prehospital hemodynamics, intubation, Glasgow Coma Score, and Injury Severity Score (0.008 ≤ R2 ≤ 0.09); prehospital time and enrollment site explained more variation in PHC volume with R2 values of 0.2 and 0.54, respectively. Compared with PHC<1,000, PHC≥1,000 had higher INR, PT, PTT, and base deficit and lower hematocrit and platelets. The proportion of ARDS in the PHC≥1,000 group was higher than PHC<1,000 (21% vs. 12%, P < 0.01), whereas the rate of AKI was similar between groups (23% vs. 23%, P = 0.9). In regression analyses, each 500 mL of PHC was associated with increased INR and PTT, and decreased hematocrit and platelet count (P < 0.05). Each 500 mL of PHC was associated with increased ARDS risk and decreased AKI risk (P < 0.05). Conclusion: PHC administration correlates poorly with prehospital hemodynamics and injury characteristics. Increased PHC volume is associated with greater anemia, coagulopathy, and increased risk of ARDS, although it may be protective against AKI.

Chronic Critical Illness in Patients With Sepsis is Associated With Persistent Anemia, Inflammation, and Impaired Functional Outcomes.

INTRODUCTION: Survivors of sepsis will progress towards rapid recovery (RAP) or enter a state of persistent organ dysfunction and chronic critical illness (CCI). Independently, anemia is known to be a significant factor in functional recovery of hospitalized patients. This study aims to analyze long-term hemoglobin levels and functional outcomes following RAP and CCI. METHODS: A prospective, cohort study was performed in septic patients who were stratified into RAP (N = 54) with ICU length of stay < 14 days or CCI (N = 63) with ICU length of stay > 14 days. CBC and plasma inflammatory markers were measured on the day of enrollment, weekly until day 42, then at 3 and 6 months. Functional outcomes using Zubrod scale, gait speed test, and total short physical performance battery (SPPB) were assessed at 3, 6, and 12 months. RESULTS: Mean age was 59 years (range: 20-83) and 62% were male. Hemoglobin was significantly decreased at 3 and 6 months in CCI compared to RAP (8.9* and 9.2* vs 10.4 and 11.1 g/dL), despite receiving significantly more red blood cell transfusions. CCI patients had persistent elevation of CRP, IL-6 and TNF-α. CCI patients had worse functional outcome with a significantly higher Zubrod score, and lower SPPB, and gait speed score at 3, 6, and 12 months. CONCLUSION: Despite receiving more pRBC transfusions, CCI patients had a persistent anemia that was associated with chronic systemic inflammation and poor functional outcomes six months following sepsis. Alleviating prolonged inflammation could improve persistent anemia and functional outcomes in CCI patients.

Phenotypes of disease severity in a cohort of hospitalized COVID-19 patients: Results from the IMPACC study.

BACKGROUND: Better understanding of the association between characteristics of patients hospitalized with coronavirus disease 2019 (COVID-19) and outcome is needed to further improve upon patient management. METHODS: Immunophenotyping Assessment in a COVID-19 Cohort (IMPACC) is a prospective, observational study of 1164 patients from 20 hospitals across the United States. Disease severity was assessed using a 7-point ordinal scale based on degree of respiratory illness. Patients were prospectively surveyed for 1 year after discharge for post-acute sequalae of COVID-19 (PASC) through quarterly surveys. Demographics, comorbidities, radiographic findings, clinical laboratory values, SARS-CoV-2 PCR and serology were captured over a 28-day period. Multivariable logistic regression was performed. FINDINGS: The median age was 59 years (interquartile range [IQR] 20); 711 (61%) were men; overall mortality was 14%, and 228 (20%) required invasive mechanical ventilation. Unsupervised clustering of ordinal score over time revealed distinct disease course trajectories. Risk factors associated with prolonged hospitalization or death by day 28 included age ≥ 65 years (odds ratio [OR], 2.01; 95% CI 1.28-3.17), Hispanic ethnicity (OR, 1.71; 95% CI 1.13-2.57), elevated baseline creatinine (OR 2.80; 95% CI 1.63- 4.80) or troponin (OR 1.89; 95% 1.03-3.47), baseline lymphopenia (OR 2.19; 95% CI 1.61-2.97), presence of infiltrate by chest imaging (OR 3.16; 95% CI 1.96-5.10), and high SARS-CoV2 viral load (OR 1.53; 95% CI 1.17-2.00). Fatal cases had the lowest ratio of SARS-CoV-2 antibody to viral load levels compared to other trajectories over time (p=0.001). 589 survivors (51%) completed at least one survey at follow-up with 305 (52%) having at least one symptom consistent with PASC, most commonly dyspnea (56% among symptomatic patients). Female sex was the only associated risk factor for PASC. INTERPRETATION: Integration of PCR cycle threshold, and antibody values with demographics, comorbidities, and laboratory/radiographic findings identified risk factors for 28-day outcome severity, though only female sex was associated with PASC. Longitudinal clinical phenotyping offers important insights, and provides a framework for immunophenotyping for acute and long COVID-19. FUNDING: NIH.

Evaluation of a Multivalent Transcriptomic Metric for Diagnosing Surgical Sepsis and Estimating Mortality Among Critically Ill Patients.

Importance: Rapid and accurate discrimination of sepsis and its potential severity currently require multiple assays with slow processing times that are often inconclusive in discerning sepsis from sterile inflammation. Objective: To analyze a whole-blood, multivalent, host-messenger RNA expression metric for estimating the likelihood of bacterial infection and 30-day mortality and compare performance of the metric with that of other diagnostic and prognostic biomarkers and clinical parameters. Design, Setting, and Participants: This prospective diagnostic and prognostic study was performed in the surgical intensive care unit (ICU) of a single, academic health science center. The analysis included 200 critically ill adult patients admitted with suspected sepsis (cohort A) or those at high risk for developing sepsis (cohort B) between July 1, 2020, and July 30, 2021. Exposures: Whole-blood sample measurements of a custom 29-messenger RNA transcriptomic metric classifier for likelihood of bacterial infection (IMX-BVN-3) or 30-day mortality (severity) (IMX-SEV-3) in a clinical-diagnostic laboratory setting using an analysis platform (510[k]-cleared nCounter FLEX; NanoString, Inc), compared with measurement of procalcitonin and interleukin 6 (IL-6) plasma levels, and maximum 24-hour sequential organ failure assessment (SOFA) scores. Main Outcomes and Measures: Estimated sepsis and 30-day mortality performance. Results: Among the 200 patients included (124 men [62.0%] and 76 women [38.0%]; median age, 62.5 [IQR, 47.0-72.0] years), the IMX-BVN-3 bacterial infection classifier had an area under the receiver operating characteristics curve (AUROC) of 0.84 (95% CI, 0.77-0.90) for discriminating bacterial infection at ICU admission, similar to procalcitonin (0.85 [95% CI, 0.79-0.90]; P = .79) and significantly better than IL-6 (0.67 [95% CI, 0.58-0.75]; P < .001). For estimating 30-day mortality, the IMX-SEV-3 metric had an AUROC of 0.81 (95% CI, 0.66-0.95), which was significantly better than IL-6 levels (0.57 [95% CI, 0.37-0.77]; P = .006), marginally better than procalcitonin levels (0.65 [95% CI, 0.50-0.79]; P = .06), and similar to the SOFA score (0.76 [95% CI, 0.62-0.91]; P = .48). Combining IMX-BVN-3 and IMX-SEV-3 with procalcitonin or IL-6 levels or SOFA scores did not significantly improve performance. Among patients with sepsis, IMX-BVN-3 scores decreased over time, reflecting the resolution of sepsis. In 11 individuals at high risk (cohort B) who subsequently developed sepsis during their hospital course, IMX-BVN-3 bacterial infection scores did not decline over time and peaked on the day of documented infection. Conclusions and Relevance: In this diagnostic and prognostic study, a novel, multivalent, transcriptomic metric accurately estimated the presence of bacterial infection and risk for 30-day mortality in patients admitted to a surgical ICU. The performance of this single transcriptomic metric was equivalent to or better than multiple alternative diagnostic and prognostic metrics when measured at admission and provided additional information when measured over time.

Sex differences associate with late microbiome alterations after murine surgical sepsis.

BACKGROUND: Sepsis-induced gut microbiome alterations contribute to sepsis-related morbidity and mortality. Given evidence for improved postsepsis outcomes in females compared with males, we hypothesized that female mice maintain microbiota resilience versus males. METHODS: Mixed-sex C57BL/6 mice underwent cecal ligation and puncture (CLP) with antibiotics, saline resuscitation, and daily chronic stress and were compared with naive (nonsepsis/no antibiotics) controls. For this work, the results of young (3-5 months) and old (18-22 months) adult mice were analyzed by sex, independent and dependent of age. Mice were sacrificed at days 7 and 14, and 16S rRNA gene sequencing was performed on fecal bacterial DNA. α and ß diversity were determined by Shannon index and Bray-Curtis with principal coordinate analysis, respectively. False discovery rate (FDR) correction was implemented to account for potential housing effect. RESULTS: In control mice, there was no difference in α or ß diversity between male and female mice (FDR, 0.76 and 0.99, respectively). However, male mice that underwent CLP with daily chronic stress had a decrease in microbiota α diversity at 7 days post-CLP (Shannon FDR, 0.005), which was sustained at 14 days post-CLP (Shannon FDR, 0.001), compared with baseline. In addition, male mice maintained differences in ß diversity even at day 14 compared with controls (FDR, <0.0001). In contrast, female mice had a decreased microbiota α diversity (Shannon FDR, 0.03) and ß diversity (FDR, 0.02) 7 days post-CLP but recovered their α and ß diversity by post-CLP day 14 (Shannon FDR, 0.5, and FDR, 0.02, respectively). Further analysis of females revealed that only young female mice were not different (ß diversity) post-CLP day 14 to controls. CONCLUSION: Although sepsis-induced perturbations of the intestinal microbiota occur initially in both male and female C57BL/6 mice, females demonstrate different microbiota by day 14. This may be seen primarily in younger females. This difference in recovery may play a role in outcome differences between sexes after sepsis.

Transcriptomic Changes Within Human Bone Marrow After Severe Trauma.

BACKGROUND: Severe trauma is associated with severe systemic inflammation and neuroendocrine activation that is associated with erythroid progenitor growth suppression and refractory anemia. Although distinct transcriptional profiles have been detected in numerous tissue types after trauma, no study has yet characterized this within the bone marrow. This study sought to identify a unique bone marrow transcriptomic response following trauma. METHODS: In a prospective observational cohort study, bone marrow was obtained from severely injured trauma patients with a hip or femur fracture (n = 52), elective hip replacement patients (n = 33), and healthy controls (n = 11). RNA was isolated from bone marrow using a Purelink RNA mini kit. Direct quantification of mRNA copies was performed by NanoString Technologies on a custom gene panel. RESULTS: Trauma patients displayed an upregulation of genes encoding receptors known to have inhibitory downstream effects on erythropoiesis, including ferroportin, interleukin-6 (IL-6) receptor, transforming growth factor-beta (TGF-ß) receptor, and IL-10, as well as genes involved in innate immunity including toll-like receptor 4 (TLR4)-mediated signaling factors. In contrast, hip replacement patients had downregulated transcription of IL-1ß, IL-6, TGF-ß, tumor necrosis factor alpha, and the HAMP gene with no change in TLR4-mediated signaling factors. CONCLUSIONS: A unique transcriptomic response within the bone marrow was identified following severe trauma compared to elective hip replacement. These transcriptomic differences were related to the innate immune response as well as known inhibitors of erythropoiesis. Although confined to just one time point, this differential transcriptional response may be linked to refractory anemia and inflammation after injury.

Nonocclusive mesenteric ischemia: A rare but lethal complication of enteral nutrition in critically ill patients.

BACKGROUND: The American Society for Parenteral and Enteral Nutrition (ASPEN)/ Society of Critical Care Medicine and the European Society for Clinical Nutrition and Metabolism guidelines recognize that critically ill patients receiving stable, low doses of vasopressors have experienced the advantages of early initiation of enteral nutrition (EN). However, clinical questions remained unanswered including vasopressor combinations associated with complications, the advent of other therapies during hypotensive states, as well as the volume and content of EN that might contribute to the development of a nonocclusive mesenteric ischemia (NOMI). PRESENTATION: A 68-year old male with a history of hypertension, hyperlipidemia, atrial fibrillation, coronary artery disease with two-vessel bypass grafting, and peripheral vascular disease underwent subtotal excision of an infected right axillofemoral-femoral bypass graft. Postoperatively, EN was held because of hemodynamic instability and postsurgical complications. A fiber-free, high-protein, and low-residue formula was started at 10 ml/h while the patient was receiving stable doses of midodrine, norepinephrine, and vasopressin. Despite advancement of tube-feed rates to goal, nasogastric output never exceeded 300 ml. Computerized tomography of the abdomen showed diffuse bowel distention with pneumatosis, concerning for bowel ischemia. No surgical interventions were pursued, and the patient died. CONCLUSIONS: Our patient developed NOMI postoperatively while receiving EN. Further studies addressing EN route, trophic vs full EN, recommended formula, the safety of vasoactive agents, the addition of fiber to EN, and continuous venovenous hemodiafiltration in relation to NOMI are needed, as there continues to be clinical controversy regarding these topics.

Older Adults Demonstrate Biomarker Evidence of the Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) After Sepsis.

BACKGROUND: Hospital deaths after sepsis have decreased substantially and most young adult survivors rapidly recover (RAP). However, many older survivors develop chronic critical illness (CCI) with poor long-term outcomes. The etiology of CCI is multifactorial and the relative importance remains unclear. Sepsis is caused by a dysregulated immune response and biomarkers reflecting a persistent inflammation, immunosuppression, and catabolism syndrome (PICS) have been observed in CCI after sepsis. Therefore, the purpose of this study was to compare serial PICS biomarkers in (i) older (vs young) adults and (ii) older CCI (vs older RAP) patients to gain insight into underlying pathobiology of CCI in older adults. METHOD: Prospective longitudinal study with young (≤45 years) and older (≥65 years) septic adults, who were characterized by (i) baseline predisposition, (ii) hospital outcomes, (iii) serial Sequential Organ Failure Assessment (SOFA) organ dysfunction scores over 14 days, (iv) Zubrod Performance status at 3-, 6-, and 12-month follow-up, and (v) mortality over 12 months, was conducted. Serial blood samples over 14 days were analyzed for selected biomarkers reflecting PICS. RESULTS: Compared to the young, more older adults developed CCI (20% vs 42%) and had markedly worse serial SOFA scores, performance status, and mortality over 12 months. Additionally, older (vs young) and older CCI (vs older RAP) patients had more persistent aberrations in biomarkers reflecting inflammation, immunosuppression, stress metabolism, lack of anabolism, and antiangiogenesis over 14 days after sepsis. CONCLUSION: Older (vs young) and older CCI (vs older RAP) patient subgroups demonstrate early biomarker evidence of the underlying pathobiology of PICS.

Estimated vs measured energy expenditure in ventilated surgical-trauma critically ill patients.

BACKGROUND: The American and European guidelines recommend measuring resting energy expenditure (REE) using indirect calorimetry (IC). Predictive equations (PEs) are used to estimate REE, but there is limited evidence for their use in critically ill patients. The aim of this study is to evaluate the degree of agreement and accuracy between IC-measured REE (REE-IC) and 10 different PEs in mechanically ventilated critically ill patients with surgical trauma who met their estimated energy requirement. METHODS: REE-IC was retrospectively compared with REE-PE by 10 PEs. The degree of agreement between REE-PE and REE-IC was analyzed by the Bland-Altman test (BAt) and the concordance correlation coefficient (CCC). The accuracy was calculated by the percentage of patients whose REE-PE values differ by up to ±10% in relation to REE-IC. All analyses were stratified by gender and body mass index (BMI; <25 vs ≥25). RESULTS: We analyzed 104 patients and the closest estimate to REE-IC was the modified Harris-Benedict equation (mHB) by the BAt with a mean difference of 49.2 overall (61.6 for males, 28.5 for females, 67.5 for BMI <25, and 42.5 for BMI ≥25). The overall CCC between the REE-IC and mHB was 0.652 (0.560 for males, 0.496 for females, 0.570 for BMI <25, and 0.598 for BMI ≥25). The mHB equation was the most accurate with an overall accuracy of 44.2%. CONCLUSION: The effectiveness of PEs for estimating the REE of mechanically ventilated surgical-trauma critically ill patients is limited. [Correction added on 17 February 2022, after first online publication: The word "with" was deleted before "is limited" in the preceding sentence.] Nonetheless, of the 10 equations examined, the closest to REE-IC was the mHB equation.

Ineffective Erythropoietin Response to Anemia in Sepsis.

Background: To determine whether degree of anemia at sepsis onset is predictive of inflammatory cytokine trajectory, erythropoietin response, and recovery. Patients and Methods: Critically ill patients with sepsis were stratified into three groups based on initial hemoglobin (Hgb): Hgb <8 g/dL (severe); 8-10 g/dL (moderate); and >10 g/dL (mild). Granulocyte colony stimulating factor (G-CSF), interferon (IFN)-γ, tumor necrosis factor (TNF)-α, C-reactive protein (CRP), erythropoietin (EPO), and Zubrod scores were measured serially. Results: Thirty-four percent had severe anemia (Hgb, 7.2 ± 0.7g/dL), 35% had moderate anemia (Hgb, 9.1 ± 0.6g/dL), and 31% had mild anemia (Hgb, 11.3 ± 1.1g/dL). All groups experienced persistently high EPO levels without resolution of anemia. IFN-γ and CRP was persistently elevated in all groups. At three, six, and 12 months, the severe anemia group had higher Zubrod scores. Conclusions: Degree of anemia at sepsis onset was not associated with a difference in proinflammatory cytokine trajectory but was associated with a worse functional outcome. Despite initial elevated EPO levels, it did not correlate with resolution of anemia.

Overlapping but Disparate Inflammatory and Immunosuppressive Responses to SARS-CoV-2 and Bacterial Sepsis: An Immunological Time Course Analysis.

Both severe SARS-CoV-2 infections and bacterial sepsis exhibit an immunological dyscrasia and propensity for secondary infections. The nature of the immunological dyscrasias for these differing etiologies and their time course remain unclear. In this study, thirty hospitalized patients with SARS-CoV-2 infection were compared with ten critically ill patients with bacterial sepsis over 21 days, as well as ten healthy control subjects. Blood was sampled between days 1 and 21 after admission for targeted plasma biomarker analysis, cellular phenotyping, and leukocyte functional analysis via enzyme-linked immunospot assay. We found that circulating inflammatory markers were significantly higher early after bacterial sepsis compared with SARS-CoV-2. Both cohorts exhibited profound immune suppression through 21 days (suppressed HLA-DR expression, reduced mononuclear cell IFN-gamma production), and expanded numbers of myeloid-derived suppressor cells (MDSCs). In addition, MDSC expansion and ex vivo production of IFN-gamma and TNF-alpha were resolving over time in bacterial sepsis, whereas in SARS-CoV-2, immunosuppression and inflammation were accelerating. Despite less severe initial physiologic derangement, SARS-CoV-2 patients had similar incidence of secondary infections (23% vs 30%) as bacterial sepsis patients. Finally, COVID patients who developed secondary bacterial infections exhibited profound immunosuppression evident by elevated sPD-L1 and depressed HLA-DR. Although both bacterial sepsis and SARS-CoV-2 are associated with inflammation and immune suppression, their immune dyscrasia temporal patterns and clinical outcomes are different. SARS-CoV-2 patients had less severe early inflammation and organ dysfunction but had persistent inflammation and immunosuppression and suffered worse clinical outcomes, especially when SARS-CoV-2 infection was followed by secondary bacterial infection.

A Transcriptomic Severity Metric That Predicts Clinical Outcomes in Critically Ill Surgical Sepsis Patients.

OBJECTIVES: Clinically deployable methods for the rapid and accurate prediction of sepsis severity that could elicit a meaningful change in clinical practice are currently lacking. We evaluated a whole-blood, multiplex host-messenger RNA expression metric, Inflammatix-Severity-2, for identifying septic, hospitalized patients' likelihood of 30-day mortality, development of chronic critical illness, discharge disposition, and/or secondary infections. DESIGN: Retrospective, validation cohort analysis. SETTING: Single, academic health center ICU. PATIENTS: Three hundred thirty-five critically ill adult surgical patients with sepsis. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Whole blood was collected in PAXgene Blood RNA collection tubes at 24 hours after sepsis diagnosis and analyzed using a custom 29-messenger RNA classifier (Inflammatix-Severity-2) in a Clinical Laboratory Improvement Amendments certified diagnostic laboratory using the NanoString FLEX platform. Among patients meeting Sepsis-3 criteria, the Inflammatix-Severity-2 severity score was significantly better (p < 0.05) at predicting secondary infections (area under the receiver operating curve 0.71) and adverse clinical outcomes (area under the receiver operating curve 0.75) than C-reactive protein, absolute lymphocyte counts, total WBC count, age, and Charlson comorbidity index (and better, albeit nonsignificantly, than interleukin-6 and Acute Physiology and Chronic Health Evaluation II). Using multivariate logistic regression analysis, only combining the Charlson comorbidity index (area under the receiver operating curve 0.80) or Acute Physiology and Chronic Health Evaluation II (area under the receiver operating curve 0.81) with Inflammatix-Severity-2 significantly improved prediction of adverse clinical outcomes, and combining with the Charlson comorbidity index for predicting 30-day mortality (area under the receiver operating curve 0.79). CONCLUSIONS: The Inflammatix-Severity-2 severity score was superior at predicting secondary infections and overall adverse clinical outcomes compared with other common metrics. Combining a rapidly measured transcriptomic metric with clinical or physiologic indices offers the potential to optimize risk-based resource utilization and patient management adjustments that may improve outcomes in surgical sepsis. Hospitalized patients who are septic and present with an elevated IMX-SEV2 severity score and preexisting comorbidities may be ideal candidates for clinical interventions aimed at reducing the risk of secondary infections and adverse clinical outcomes.