Disaster management - preparation and planning for acute care facilities

PURPOSE OF REVIEW

Both human-derived and naturally-occurring disasters stress the surge capacity of health systems and acute care facilities. In this article, we review recent literature related to having a disaster plan, facility planning principles, institutional and team preparedness, the concept of surge capacity, simulation exercises and advantages and disadvantages of each.

RECENT FINDINGS

Evidence suggests that every institution should have a disaster plan and a dedicated team responsible for updating this plan. The disaster plan must be people-oriented and incorporate different perspectives and opinions so that all stakeholders feel included and can contribute to a joint response. Simulation exercises are fundamental for preparation so that the team functions seamlessly in uncommon times when disaster management transitions from a theoretical plan to one that is executed in real time. Notably, however, there are significantly different realities related to disaster management between countries and even within the same country or region. Unfortunately, key stakeholders such as hospital administration, board of directors and investors often do not believe they have any responsibility related to disaster management planning or response. Additionally, while a disaster plan often exists within an institution, it is frequently not well known or understood by many stakeholders. Communication, simple plans and well defined roles are some of the most important characteristics of a successful response. In extreme circumstances, adapting civilian facilities to manage high-volume warfare-related injuries may be adopted, but the consequences of this approach for routine healthcare within a system can be devastating.

SUMMARY

Disaster management requires careful planning with input from multiple stakeholders and a plan that is frequently updated with repeated preparation to ensure the team is ready when a disaster occurs. Close communication as well as clearly defined roles are critical to success when transitioning from preparation to activation and execution of a disaster response.

Parsimonious Waveform-derived Features consisting of Pulse Arrival Time and Heart Rate Variability Predicts the Onset of Septic Shock

Sepsis is a major public health emergency and one of the leading causes of morbidity and mortality in critically ill patients. For each hour treatment is delayed, shock-related mortality increases, so early diagnosis and intervention is of utmost importance. However, earlier recognition of shock requires active monitoring, which may be delayed due to subclinical manifestations of the disease at the early phase of onset. Machine learning systems can increase timely detection of shock onset by exploiting complex interactions among continuous physiological waveforms. We use a dataset consisting of high-resolution physiological waveforms from intensive care unit (ICU) of a tertiary hospital system. We investigate the use of mean arterial blood pressure (MAP), pulse arrival time (PAT), heart rate variability (HRV), and heart rate (HR) for the early prediction of shock onset. Using only five minutes of the aforementioned vital signals from 239 ICU patients, our developed models can accurately predict septic shock onset 6 to 36 hours prior to clinical recognition with area under the receiver operating characteristic (AUROC) of 0.84 and 0.8 respectively. This work lays foundations for a robust, efficient, accurate and early prediction of septic shock onset which may help clinicians in their decision-making processes. This study introduces machine learning models that provide fast and accurate predictions of septic shock onset times up to 36 hours in advance. BP, PAT and HR dynamics can independently predict septic shock onset with a look-back period of only 5 mins.

CD8+ T cells are necessary for improved sepsis survival induced by CD28 agonism in immunologically experienced mice

Introduction

A hallmark of T cell dysregulation during sepsis is the downregulation of costimulatory molecules. CD28 is one of T cell costimulatory molecules significantly altered on memory T cells during sepsis. We recently showed that treatment with a αCD28 agonist in septic immunologically experienced mice led to improved survival. Therefore, here we aimed to identify the cell subset(s) necessary for the survival benefit observed in the context of CD28 agonism, and to further investigate the mechanism by which CD28 agonism improves sepsis survival in immunologically experienced mice. Methods: Mice received specific pathogen inoculation to generate memory T cell populations similar in frequency to that of adult humans. Once these infections were cleared and the T cell response had transitioned to the memory phase, animals were rendered septic via cecal ligation and puncture in the presence or absence of an agonistic anti-CD28 mAb.

Results

Results demonstrated that CD8+ T cells, and not bulk CD4+ T cells or CD25+ regulatory T cells, were necessary for the survival benefit observed in CD28 agonist-treated septic immunologically experienced mice. Upon examination of these CD8+ T cells, we found that CD28 agonism in septic immunologically experienced mice was associated with an increase in Foxp3+ CD8+ T cells as compared to vehicle-treated controls. When CD8+ T cells were depleted in septic immunologically experienced mice in the setting of CD28 agonism, a significant increase in levels of inflammatory cytokines in the blood was observed.

Discussion

Taken together, these results indicate that CD28 agonism in immunologically experienced mice effectively suppresses inflammation via a CD8+-dependent mechanism to decrease mortality during sepsis.

OXIDATIVE study: A pilot prospective observational cohort study protocol examining the influence of peri-reperfusion hyperoxemia and immune dysregulation on early allograft dysfunction after orthotopic liver transplantation

Early allograft dysfunction (EAD) is a functional hepatic insufficiency within a week of orthotopic liver transplantation (OLT) and is associated with morbidity and mortality. The etiology of EAD is multifactorial and largely driven by ischemia reperfusion injury (IRI), a phenomenon characterized by oxygen scarcity followed by paradoxical oxidative stress and inflammation. With the expanded use of marginal allografts more susceptible to IRI, the incidence of EAD may be increasing. This necessitates an in-depth understanding of the innate molecular mechanisms underlying EAD and interventions to mitigate its impact. Our central hypothesis is peri-reperfusion hyperoxemia and immune dysregulation exacerbate IRI and increase the risk of EAD. We will perform a pilot prospective single-center observational cohort study of 40 patients. The aims are to determine (1) the association between peri-reperfusion hyperoxemia and EAD and (2) whether peri-reperfusion perturbed cytokine, protein, and hypoxia inducible factor-1 alpha (HIF-1α) levels correlate with EAD after OLT. Inclusion criteria include age ≥ 18 years, liver failure, and donation after brain or circulatory death. Exclusion criteria include living donor donation, repeat OLT within a week of transplantation, multiple organ transplantation, and pregnancy. Partial pressure of arterial oxygen (PaO2) as the study measure allows for the examination of oxygen exposure within the confines of existing variability in anesthesiologist-administered fraction of inspired oxygen (FiO2) and the inclusion of patients with intrapulmonary shunting. The Olthoff et al. definition of EAD is the primary outcome. Secondary outcomes include postoperative acute kidney injury, pulmonary and biliary complications, surgical wound dehiscence and infection, and mortality. The goal of this study protocol is to identify EAD contributors that could be targeted to attenuate its impact and improve OLT outcomes. If validated, peri-reperfusion hyperoxemia and immune perturbations could be targeted via FiO2 titration to a goal PaO2 and/or administration of an immunomodulatory agent by the anesthesiologist intraoperatively.

Claudin-2 upregulation enhances intestinal permeability, immune activation, dysbiosis, and mortality in sepsis

Intestinal epithelial expression of the tight junction protein claudin-2, which forms paracellular cation and water channels, is precisely regulated during development and in disease. Here, we show that small intestinal epithelial claudin-2 expression is selectively upregulated in septic patients. Similar changes occurred in septic mice, where claudin-2 upregulation coincided with increased flux across the paracellular pore pathway. In order to define the significance of these changes, sepsis was induced in claudin-2 knockout (KO) and wild-type (WT) mice. Sepsis-induced increases in pore pathway permeability were prevented by claudin-2 KO. Moreover, claudin-2 deletion reduced interleukin-17 production and T cell activation and limited intestinal damage. These effects were associated with reduced numbers of neutrophils, macrophages, dendritic cells, and bacteria within the peritoneal fluid of septic claudin-2 KO mice. Most strikingly, claudin-2 deletion dramatically enhanced survival in sepsis. Finally, the microbial changes induced by sepsis were less pathogenic in claudin-2 KO mice as survival of healthy WT mice injected with cecal slurry collected from WT mice 24 h after sepsis was far worse than that of healthy WT mice injected with cecal slurry collected from claudin-2 KO mice 24 h after sepsis. Claudin-2 upregulation and increased pore pathway permeability are, therefore, key intermediates that contribute to development of dysbiosis, intestinal damage, inflammation, ineffective pathogen control, and increased mortality in sepsis. The striking impact of claudin-2 deletion on progression of the lethal cascade activated during sepsis suggests that claudin-2 may be an attractive therapeutic target in septic patients.

Using Trajectories of Bedside Vital Signs to Identify COVID-19 Subphenotypes

BACKGROUND

Trajectories of bedside vital signs have been used to identify sepsis subphenotypes with distinct outcomes and treatment responses. The objective of this study was to validate the vitals trajectory model in a multicenter cohort of patients hospitalized with COVID-19 and to evaluate the clinical characteristics and outcomes of the resulting subphenotypes.

RESEARCH QUESTION

Can the trajectory of routine bedside vital signs identify COVID-19 subphenotypes with distinct clinical characteristics and outcomes?

STUDY DESIGN AND METHODS

The study included adult patients admitted with COVID-19 to four academic hospitals in the Emory Healthcare system between March 1, 2020, and May 31, 2022. Using a validated group-based trajectory model, we classified patients into previously defined vital sign trajectories using oral temperature, heart rate, respiratory rate, and systolic and diastolic BP measured in the first 8 h of hospitalization. Clinical characteristics, biomarkers, and outcomes were compared between subphenotypes. Heterogeneity of treatment effect to tocilizumab was evaluated.

RESULTS

The 7,065 patients with hospitalized COVID-19 were classified into four subphenotypes: group A (n = 1,429, 20%)-high temperature, heart rate, respiratory rate, and hypotensive; group B (1,454, 21%)-high temperature, heart rate, respiratory rate, and hypertensive; group C (2,996, 42%)-low temperature, heart rate, respiratory rate, and normotensive; and group D (1,186, 17%)-low temperature, heart rate, respiratory rate, and hypotensive. Groups A and D had higher ORs of mechanical ventilation, vasopressors, and 30-day inpatient mortality (P < .001). On comparing patients receiving tocilizumab (n = 55) with those who met criteria for tocilizumab but were admitted before its use (n = 461), there was significant heterogeneity of treatment effect across subphenotypes in the association of tocilizumab with 30-day mortality (P = .001).

INTERPRETATION

By using bedside vital signs available in even low-resource settings, we found novel subphenotypes associated with distinct manifestations of COVID-19, which could lead to preemptive and targeted treatments.

TiME OUT: Time-specific machine-learning evaluation to optimize ultramassive transfusion

BACKGROUND

Ultramassive transfusion (UMT) is a resource-demanding intervention for trauma patients in hemorrhagic shock, and associated mortality rates remains high. Current research has been unable to identify a transfusion ceiling or point where UMT transitions from lifesaving to futility. Furthermore, little consideration has been given to how time-specific patient data points impact decisions with ongoing high-volume resuscitation. Therefore, this study sought to use time-specific machine learning modeling to predict mortality and identify parameters associated with survivability in trauma patients undergoing UMT.

METHODS

A retrospective review was conducted at a Level I trauma (2018-2021) and included trauma patients meeting criteria for UMT, defined as ≥20 red blood cell products within 24 hours of admission. Cross-sectional data were obtained from the blood bank and trauma registries, and time-specific data were obtained from the electronic medical record. Time-specific decision-tree models predicating mortality were generated and evaluated using area under the curve.

RESULTS

In the 180 patients included, mortality rate was 40.5% at 48 hours and 52.2% overall. The deceased received significantly more blood products with a median of 71.5 total units compared with 55.5 in the survivors ( p < 0.001) and significantly greater rates of packed red blood cells and fresh frozen plasma at each time interval. Time-specific decision-tree models predicted mortality with an accuracy as high as 81%. In the early time intervals, hemodynamic stability, undergoing an emergency department thoracotomy, and injury severity were most predictive of survival, while, in the later intervals, markers of adequate resuscitation such as arterial pH and lactate level became more prominent.

CONCLUSION

This study supports that the decision of "when to stop" in UMT resuscitation is not based exclusively on the number of units transfused but rather the complex integration of patient and time-specific data. Machine learning is an effective tool to investigate this concept, and further research is needed to refine and validate these time-specific decision-tree models.

LEVEL OF EVIDENCE

Prognostic and Epidemiological; Level IV.

Transforming the Future of Surgeon-Scientists

OBJECTIVE

To create a blueprint for surgical department leaders, academic institutions, and funding agencies to optimally support surgeon-scientists.

BACKGROUND

Scientific contributions by surgeons have been transformative across many medical disciplines. Surgeon-scientists provide a distinct approach and mindset toward key scientific questions. However, lack of institutional support, pressure for increased clinical productivity, and growing administrative burden are major challenges for the surgeon-scientist, as is the time-consuming nature of surgical training and practice.

METHODS

An American Surgical Association Research Sustainability Task Force was created to outline a blueprint for sustainable science in surgery. Leaders from top NIH-sponsored departments of surgery engaged in video and in-person meetings between January and April 2023. A strength, weakness, opportunities, threats analysis was performed, and workgroups focused on the roles of surgeons, the department and institutions, and funding agencies.

RESULTS

Taskforce recommendations: (1) SURGEONS: Growth mindset : identifying research focus, long-term planning, patience/tenacity, team science, collaborations with disparate experts; Skill set : align skills and research, fill critical skill gaps, develop team leadership skills; DEPARTMENT OF SURGERY (DOS): (2) MENTORSHIP: Chair : mentor-mentee matching/regular meetings/accountability, review of junior faculty progress, mentorship training requirement, recognition of mentorship (eg, relative value unit equivalent, awards; Mentor: dedicated time, relevant scientific expertise, extramural funding, experience and/or trained as mentor, trusted advisor; Mentee : enthusiastic/eager, proactive, open to feedback, clear about goals; (3) FINANCIAL SUSTAINABILITY: diversification of research portfolio, identification of matching funding sources, departmental resource awards (eg, T-/P-grants), leveraging of institutional resources, negotiation of formalized/formulaic funds flow investment from academic medical center toward science, philanthropy; (4) STRUCTURAL/STRATEGIC SUPPORT: Structural: grants administrative support, biostats/bioinformatics support, clinical trial and research support, regulatory support, shared departmental laboratory space/equipment; Strategic: hiring diverse surgeon-scientist/scientists faculty across DOS, strategic faculty retention/ recruitment, philanthropy, career development support, progress tracking, grant writing support, DOS-wide research meetings, regular DOS strategic research planning; (5) COMMUNITY AND CULTURE: Community: right mix of faculty, connection surgeon with broad scientific community; Culture: building research infrastructure, financial support for research, projecting importance of research (awards, grand rounds, shoutouts); (6) THE ROLE OF INSTITUTIONS: Foundation: research space co-location, flexible start-up packages, courses/mock study section, awards, diverse institutional mentorship teams; Nurture: institutional infrastructure, funding (eg, endowed chairs), promotion friendly toward surgeon-scientists, surgeon-scientists in institutional leadership positions; Expectations: RVU target relief, salary gap funding, competitive starting salaries, longitudinal salary strategy; (7) THE ROLE OF FUNDING AGENCIES: change surgeon research training paradigm, offer alternate awards to K-awards, increasing salary cap to reflect market reality, time extension for surgeon early-stage investigator status, surgeon representation on study section, focused award strategies for professional societies/foundations.

CONCLUSIONS

Authentic recommitment from surgeon leaders with intentional and ambitious actions from institutions, corporations, funders, and society is essential in order to reap the essential benefits of surgeon-scientists toward advancements of science.

Surviving Sepsis Campaign Research Priorities 2023

OBJECTIVES

To identify research priorities in the management, epidemiology, outcome, and pathophysiology of sepsis and septic shock.

DESIGN

Shortly after publication of the most recent Surviving Sepsis Campaign Guidelines, the Surviving Sepsis Research Committee, a multiprofessional group of 16 international experts representing the European Society of Intensive Care Medicine and the Society of Critical Care Medicine, convened virtually and iteratively developed the article and recommendations, which represents an update from the 2018 Surviving Sepsis Campaign Research Priorities.

METHODS

Each task force member submitted five research questions on any sepsis-related subject. Committee members then independently ranked their top three priorities from the list generated. The highest rated clinical and basic science questions were developed into the current article.

RESULTS

A total of 81 questions were submitted. After merging similar questions, there were 34 clinical and ten basic science research questions submitted for voting. The five top clinical priorities were as follows: 1) what is the best strategy for screening and identification of patients with sepsis, and can predictive modeling assist in real-time recognition of sepsis? 2) what causes organ injury and dysfunction in sepsis, how should it be defined, and how can it be detected? 3) how should fluid resuscitation be individualized initially and beyond? 4) what is the best vasopressor approach for treating the different phases of septic shock? and 5) can a personalized/precision medicine approach identify optimal therapies to improve patient outcomes? The five top basic science priorities were as follows: 1) How can we improve animal models so that they more closely resemble sepsis in humans? 2) What outcome variables maximize correlations between human sepsis and animal models and are therefore most appropriate to use in both? 3) How does sepsis affect the brain, and how do sepsis-induced brain alterations contribute to organ dysfunction? How does sepsis affect interactions between neural, endocrine, and immune systems? 4) How does the microbiome affect sepsis pathobiology? 5) How do genetics and epigenetics influence the development of sepsis, the course of sepsis and the response to treatments for sepsis?

CONCLUSIONS

Knowledge advances in multiple clinical domains have been incorporated in progressive iterations of the Surviving Sepsis Campaign guidelines, allowing for evidence-based recommendations for short- and long-term management of sepsis. However, the strength of existing evidence is modest with significant knowledge gaps and mortality from sepsis remains high. The priorities identified represent a roadmap for research in sepsis and septic shock.

Cell death proteins in sepsis: key players and modern therapeutic approaches

Cell death proteins play a central role in host immune signaling during sepsis. These interconnected mechanisms trigger cell demise via apoptosis, necroptosis, and pyroptosis while also driving inflammatory signaling. Targeting cell death mediators with novel therapies may correct the dysregulated inflammation seen during sepsis and improve outcomes for septic patients.

CTLA-4 Checkpoint Inhibition Improves Sepsis Survival in Alcohol-Exposed Mice

Chronic alcohol use increases morbidity and mortality in the setting of sepsis. Both chronic alcohol use and sepsis are characterized by immune dysregulation, including overexpression of T cell coinhibitory molecules. We sought to characterize the role of CTLA-4 during sepsis in the setting of chronic alcohol exposure using a murine model of chronic alcohol ingestion followed by cecal ligation and puncture. Results indicated that CTLA-4 expression is increased on CD4+ T cells isolated from alcohol-drinking septic mice as compared with either alcohol-drinking sham controls or water-drinking septic mice. Moreover, checkpoint inhibition of CTLA-4 improved sepsis survival in alcohol-drinking septic mice, but not water-drinking septic mice. Interrogation of the T cell compartments in these animals following pharmacologic CTLA-4 blockade, as well as following conditional Ctla4 deletion in CD4+ T cells, revealed that CTLA-4 deficiency promoted the activation and proliferation of effector regulatory T cells and the generation of conventional effector memory CD4+ T cells. These data highlight an important role for CTLA-4 in mediating mortality during sepsis in the setting of chronic alcohol exposure and may inform future approaches to develop targeted therapies for this patient population.

A Novel Scoring System for Humane Endpoints in Mice with Cecal Ligation and Puncture-Induced Sepsis

Animal-based research is essential to the study of sepsis pathophysiology, diagnostics, and therapeutics. However, animal models of sepsis are often associated with high mortality because of the difficulty in predicting imminent death based on premortem assessment of the animals. The use of validated visual scoring would allow researchers to systematically identify humane endpoints but visual approaches require high interobserver agreement for accurate results. The objective of this study was to establish a scoring system for mice undergoing cecal ligation and puncture (CLP)-induced sepsis based on 3 visual parameters: respiratory status, activity and response to stimulus (ASR), and eye appearance, with scores ranging from 0 to 3. In the first study, we evaluated interobserver agreement. Veterinary and investigative staff assessed 283 mice with CLP and had substantial to near-perfect agreement for all 3 parameters as evaluated using weighted Cohen κ statistic. The second study assessed the ability of the scoring system and temperature to predict death. The scoring system and subcutaneous transpond- ers were used to monitor C57BL/6J mice (n = 80, male and female) until death or for 7 days after CLP. Results showed that the scoring system discriminates between surviving (n = 26) and nonsurviving (n = 54) septic mice. The scoring system was accurate in predicting death, with an AUC of 0.8997. The sensitivity and specificity of the ASR parameter were 96% and 92%, respectively, and for the eye parameter were 94% and 73%. A sum of the ASR and eye scores that was 5 or more was also predictive of death. Temperature was a quantitative predictor, with sensitivity and specificity of 93% and 92%, respectively. This scoring system refines the CLP model by allowing identification of humane endpoints and avoidance of spontaneous death.

Flow-Sizing Critical Care Resources

OBJECTIVES

To describe the factors affecting critical care capacity and how critical care organizations (CCOs) within academic centers in the U.S. flow-size critical care resources under normal operations, strain, and surge conditions.

DATA SOURCES

PubMed, federal agency and American Hospital Association reports, and previous CCO survey results were reviewed.

STUDY SELECTION

Studies and reports of critical care bed capacity and utilization within CCOs and in the United States were selected.

DATA EXTRACTION

The Academic Leaders in the Critical Care Medicine Task Force established regular conference calls to reach a consensus on the approach of CCOs to "flow-sizing" critical care services.

DATA SYNTHESIS

The approach of CCOs to "flow-sizing" critical care is outlined. The vertical (relation to institutional resources, e.g., space allocation, equipment, personnel redistribution) and horizontal (interdepartmental, e.g., emergency department, operating room, inpatient floors) integration of critical care delivery (ICUs, rapid response) for healthcare organizations and the methods by which CCOs flow-size critical care during normal operations, strain, and surge conditions are described. The advantages, barriers, and recommendations for the rapid and efficient scaling of critical care operations via a CCO structure are explained. Comprehensive guidance and resources for the development of "flow-sizing" capability by a CCO within a healthcare organization are provided.

CONCLUSIONS

We identified and summarized the fundamental principles affecting critical care capacity. The taskforce highlighted the advantages of the CCO governance model to achieve rapid and cost-effective "flow-sizing" of critical care services and provide recommendations and resources to facilitate this capability. The relevance of a comprehensive approach to "flow-sizing" has become particularly relevant in the wake of the latest COVID-19 pandemic. In light of the growing risks of another extreme epidemic, planning for adequate capacity to confront the next critical care crisis is urgent.

Intravenous vitamin C therapy in adult patients with sepsis: A rapid practice guideline

BACKGROUND

This Rapid Practice Guideline provides an evidence-based recommendation to address the question: in adults with sepsis or septic shock, should we recommend using or not using intravenous vitamin C therapy?

METHODS

The panel included 21 experts from 16 countries and used a strict policy for potential financial and intellectual conflicts of interest. Methodological support was provided by the Guidelines in Intensive Care, Development, and Evaluation (GUIDE) group. Based on an updated systematic review, and the grading of recommendations, assessment, development, and evaluation approach, we evaluated the certainty of evidence and developed recommendations using the evidence-to-decision framework. We conducted an electronic vote, requiring >80% agreement among the panel for a recommendation to be adopted.

RESULTS

At longest follow-up, 90 days, intravenous vitamin C probably does not substantially impact (relative risk 1.05, 95% confidence interval [CI] 0.94 to 1.17; absolute risk difference 1.8%, 95% CI -2.2 to 6.2; 6 trials, n = 2148, moderate certainty). Effects of vitamin C on mortality at earlier timepoints was of low or very low certainty due to risk of bias of the included studies and significant heterogeneity between study results. Few adverse events were reported with the use of vitamin C. The panel did not identify any major differences in other outcomes, including duration of mechanical ventilation, ventilator free days, hospital or intensive care unit length of stay, acute kidney injury, need for renal replacement therapy. Vitamin C may result in a slight reduction in duration of vasopressor support (MD -18.9 h, 95% CI -26.5 to -11.4; 21 trials, n = 2661, low certainty); but may not reduce sequential organ failure assessment scores (MD -0.69, 95% CI -1.55 to 0.71; 24 trials, n = 4002, low certainty). The panel judged the undesirable consequences of using IV vitamin C to probably outweigh the desirable consequences, and therefore issued a conditional recommendation against using IV vitamin C therapy in sepsis.

CONCLUSIONS

The panel suggests against use of intravenous vitamin C in adult patients with sepsis, beyond that of standard nutritional supplementation. Small and single center trials on this topic should be discouraged.

Uncertainty-Aware Convolutional Neural Network for Identifying Bilateral Opacities on Chest X-rays: A Tool to Aid Diagnosis of Acute Respiratory Distress Syndrome

Acute Respiratory Distress Syndrome (ARDS) is a severe lung injury with high mortality, primarily characterized by bilateral pulmonary opacities on chest radiographs and hypoxemia. In this work, we trained a convolutional neural network (CNN) model that can reliably identify bilateral opacities on routine chest X-ray images of critically ill patients. We propose this model as a tool to generate predictive alerts for possible ARDS cases, enabling early diagnosis. Our team created a unique dataset of 7800 single-view chest-X-ray images labeled for the presence of bilateral or unilateral pulmonary opacities, or 'equivocal' images, by three blinded clinicians. We used a novel training technique that enables the CNN to explicitly predict the 'equivocal' class using an uncertainty-aware label smoothing loss. We achieved an Area under the Receiver Operating Characteristic Curve (AUROC) of 0.82 (95% CI: 0.80, 0.85), a precision of 0.75 (95% CI: 0.73, 0.78), and a sensitivity of 0.76 (95% CI: 0.73, 0.78) on the internal test set while achieving an (AUROC) of 0.84 (95% CI: 0.81, 0.86), a precision of 0.73 (95% CI: 0.63, 0.69), and a sensitivity of 0.73 (95% CI: 0.70, 0.75) on an external validation set. Further, our results show that this approach improves the model calibration and diagnostic odds ratio of the hypothesized alert tool, making it ideal for clinical decision support systems.

CHRONIC ETHANOL USE WORSENS GUT PERMEABILITY AND ALTERS TIGHT JUNCTION EXPRESSION IN A MURINE SEPSIS MODEL

ABSTRACT

Alcohol use disorder is associated with increased mortality in septic patients. Murine studies demonstrate that ethanol/sepsis is associated with changes in gut integrity. This study examined intestinal permeability after ethanol/sepsis and investigated mechanisms responsible for alterations in barrier function. Mice were randomized to drink either 20% ethanol or water for 12 weeks and then were subjected to either sham laparotomy or cecal ligation and puncture (CLP). Intestinal permeability was disproportionately increased in ethanol/septic mice via the pore, leak, and unrestricted pathways. Consistent with increased permeability in the leak pathway, jejunal myosin light chain (MLC) kinase (MLCK) expression and the ratio of phospho-MLC to total MLC were both increased in ethanol/CLP. Gut permeability was altered in MLCK -/- mice in water/CLP; however, permeability was not different between WT and MLCK -/- mice in ethanol/CLP. Similarly, jejunal IL-1β levels were decreased while systemic IL-6 levels were increased in MLCK -/- mice in water/CLP but no differences were identified in ethanol/CLP. While we have previously shown that mortality is improved in MLCK -/- mice after water/CLP, mortality was significantly worse in MLCK -/- mice after ethanol/CLP. Consistent with an increase in the pore pathway, claudin 4 levels were also selectively decreased in ethanol/CLP WT mice. Furthermore, mRNA expression of jejunal TNF and IFN-γ were both significantly increased in ethanol/CLP. The frequency of CD4 + cells expressing TNF and IL-17A and the frequency of CD8 + cells expressing IFN-γ in Peyer's Patches were also increased in ethanol/CLP. Thus, there is an ethanol-specific worsening of gut barrier function after CLP that impacts all pathways of intestinal permeability, mediated, in part, via changes to the tight junction. Differences in the host response in the setting of chronic alcohol use may play a role in future precision medicine approaches toward the treatment of sepsis.

Cancer and sepsis

Sepsis is one of the leading causes of death worldwide. While mortality is high regardless of inciting infection or comorbidities, mortality in patients with cancer and sepsis is significantly higher than mortality in patients with sepsis without cancer. Cancer patients are also significantly more likely to develop sepsis than the general population. The mechanisms underlying increased mortality in cancer and sepsis patients are multifactorial. Cancer treatment alters the host immune response and can increase susceptibility to infection. Preclinical data also suggests that cancer, in and of itself, increases mortality from sepsis with dysregulation of the adaptive immune system playing a key role. Further, preclinical data demonstrate that sepsis can alter subsequent tumor growth while tumoral immunity impacts survival from sepsis. Checkpoint inhibition is a well-accepted treatment for many types of cancer, and there is increasing evidence suggesting this may be a useful strategy in sepsis as well. However, preclinical studies of checkpoint inhibition in cancer and sepsis demonstrate results that could not have been predicted by examining either variable in isolation. As sepsis management transitions from a 'one size fits all' model to a more individualized approach, understanding the mechanistic impact of cancer on outcomes from sepsis represents an important strategy towards delivering on the promise of precision medicine in the intensive care unit.

Comparison of time series clustering methods for identifying novel subphenotypes of patients with infection

OBJECTIVE

Severe infection can lead to organ dysfunction and sepsis. Identifying subphenotypes of infected patients is essential for personalized management. It is unknown how different time series clustering algorithms compare in identifying these subphenotypes.

MATERIALS AND METHODS

Patients with suspected infection admitted between 2014 and 2019 to 4 hospitals in Emory healthcare were included, split into separate training and validation cohorts. Dynamic time warping (DTW) was applied to vital signs from the first 8 h of hospitalization, and hierarchical clustering (DTW-HC) and partition around medoids (DTW-PAM) were used to cluster patients into subphenotypes. DTW-HC, DTW-PAM, and a previously published group-based trajectory model (GBTM) were evaluated for agreement in subphenotype clusters, trajectory patterns, and subphenotype associations with clinical outcomes and treatment responses.

RESULTS

There were 12 473 patients in training and 8256 patients in validation cohorts. DTW-HC, DTW-PAM, and GBTM models resulted in 4 consistent vitals trajectory patterns with significant agreement in clustering (71-80% agreement, P < .001): group A was hyperthermic, tachycardic, tachypneic, and hypotensive. Group B was hyperthermic, tachycardic, tachypneic, and hypertensive. Groups C and D had lower temperatures, heart rates, and respiratory rates, with group C normotensive and group D hypotensive. Group A had higher odds ratio of 30-day inpatient mortality (P < .01) and group D had significant mortality benefit from balanced crystalloids compared to saline (P < .01) in all 3 models.

DISCUSSION

DTW- and GBTM-based clustering algorithms applied to vital signs in infected patients identified consistent subphenotypes with distinct clinical outcomes and treatment responses.

CONCLUSION

Time series clustering with distinct computational approaches demonstrate similar performance and significant agreement in the resulting subphenotypes.

MYOSIN LIGHT CHAIN KINASE DELETION WORSENS LUNG PERMEABILITY AND INCREASES MORTALITY IN PNEUMONIA-INDUCED SEPSIS

ABSTRACT

Increased epithelial permeability in sepsis is mediated via disruptions in tight junctions, which are closely associated with the perijunctional actin-myosin ring. Genetic deletion of myosin light chain kinase (MLCK) reverses sepsis-induced intestinal hyperpermeability and improves survival in a murine model of intra-abdominal sepsis. In an attempt to determine the generalizability of these findings, this study measured the impact of MLCK deletion on survival and potential associated mechanisms following pneumonia-induced sepsis. MLCK -/- and wild-type mice underwent intratracheal injection of Pseudomonas aeruginosa . Unexpectedly, survival was significantly worse in MLCK -/- mice than wild-type mice. This was associated with increased permeability to Evans blue dye in bronchoalveolar lavage fluid but not in tissue homogenate, suggesting increased alveolar epithelial leak. In addition, bacterial burden was increased in bronchoalveolar lavage fluid. Cytokine array using whole-lung homogenate demonstrated increases in multiple proinflammatory and anti-inflammatory cytokines in knockout mice. These local pulmonary changes were associated with systemic inflammation with increased serum levels of IL-6 and IL-10 and a marked increase in bacteremia in MLCK -/- mice. Increased numbers of both bulk and memory CD4 + T cells were identified in the spleens of knockout mice, with increased early and late activation. These results demonstrate that genetic deletion of MLCK unexpectedly increases mortality in pulmonary sepsis, associated with worsened alveolar epithelial leak and both local and systemic inflammation. This suggests that caution is required in targeting MLCK for therapeutic gain in sepsis.

Gut Microbiome in Sepsis

Abstract The gut has been hypothesized to be the "motor" of multiple organ dysfunction in sepsis. Although there are multiple ways in which the gut can drive systemic inflammation, increasing evidence suggests that the intestinal microbiome plays a more substantial role than previously appreciated. An English language literature review was performed to summarize the current knowledge of sepsis-induced gut microbiome dysbiosis. Conversion of a normal microbiome to a pathobiome in the setting of sepsis is associated with worsened mortality. Changes in microbiome composition and diversity signal the intestinal epithelium and immune system resulting in increased intestinal permeability and a dysregulated immune response to sepsis. Clinical approaches to return to microbiome homeostasis may be theoretically possible through a variety of methods including probiotics, prebiotics, fecal microbial transplant, and selective decontamination of the digestive tract. However, more research is required to determine the efficacy (if any) of targeting the microbiome for therapeutic gain. The gut microbiome rapidly loses diversity with emergence of virulent bacteria in sepsis. Restoring normal commensal bacterial diversity through various therapies may be an avenue to improve sepsis mortality.

Impact of chronic alcohol exposure on conventional and regulatory murine T cell subsets

Introduction

Chronic alcohol use poses significant negative consequences to public health and, among its many biologic effects, is associated with significant T cell dysregulation within the adaptive immune system that has yet to be fully characterized. Novel, automated strategies for high dimensional flow cytometric analysis of the immune system are rapidly improving researchers' ability to detect and characterize rare cell types.

Methods

Using a murine model of chronic alcohol ingestion in conjunction with viSNE and CITRUS analysis tools, we performed a machine-driven, exploratory analysis comparing rare splenic subpopulations within the conventional CD4+, regulatory CD4+ and CD8+ T cell compartments between alcohol- and water-fed animals.

Results

While there were no differences in the absolute numbers of bulk CD3+ T cells, bulk CD4+ T cells, bulk CD8+ T cells, Foxp3- CD4+ conventional T cells (Tconv) or Foxp3+ CD4+ regulatory T cells (Treg), we identified populations of naïve Helios+ CD4+Tconv and naïve CD103+ CD8+ splenic T cells that were decreased in chronically alcohol exposed mice versus water-fed controls. In addition, we identified increased CD69+ Treg and decreased CD103+ effector regulatory T cell (eTreg) subsets in conjunction with increased frequency of a population that may represent a transitional phenotype between central regulatory T cell (cTreg) and eTreg.

Discussion

These data provide further resolution into the character of decreased naïve T cell populations known to be present in alcohol exposed mice, as well as describe alterations in effector regulatory T cell phenotypes associated with the pathogenesis of chronic alcohol-induced immune dysfunction.

The RIPK3 Scaffold Regulates Lung Inflammation During Pseudomonas Aeruginosa Pneumonia

RIPK3 (receptor-interacting protein kinase 3) activity triggers cell death via necroptosis, whereas scaffold function supports protein binding and cytokine production. To determine if RIPK3 kinase or scaffold domains mediate pathology during Pseudomonas aeruginosa infection, control mice and those with deletion or mutation of RIPK3 and associated signaling partners were subjected to Pseudomonas pneumonia and followed for survival or killed for biologic assays. Murine immune cells were studied in vitro for Pseudomonas-induced cytokine production and cell death, and RIPK3 binding interactions were blocked with the viral inhibitor M45. Human tissue effects were assayed by infecting airway epithelial cells with Pseudomonas and measuring cytokine production after siRNA inhibition of RIPK3. Deletion of RIPK3 reduced inflammation and decreased animal mortality after Pseudomonas pneumonia. RIPK3 kinase inactivation did neither. In cell culture, RIPK3 was dispensable for cell killing by Pseudomonas and instead drove cytokine production that required the RIPK3 scaffold domain but not kinase activity. Blocking the RIP homotypic interaction motif (RHIM) with M45 reduced the inflammatory response to infection in vitro. Similarly, siRNA knockdown of RIPK3 decreased infection-triggered inflammation in human airway epithelial cells. Thus, the RIPK3 scaffold drives deleterious pulmonary inflammation and mortality in a relevant clinical model of Pseudomonas pneumonia. This process is distinct from kinase-mediated necroptosis, requiring only the RIPK3 RHIM. Inhibition of RHIM signaling is a potential strategy to reduce lung inflammation during infection.

Surgical Science and the Evolution of Critical Care Medicine

Surgical science has driven innovation and inquiry across adult and pediatric disciplines that provide critical care regardless of location. Surgically originated but broadly applicable knowledge has been globally shared within the pages Critical Care Medicine over the last 50 years.

The Sequential Organ Failure Assessment (SOFA) Score: has the time come for an update?

The Sequential Organ Failure Assessment (SOFA) score was developed more than 25 years ago to provide a simple method of assessing and monitoring organ dysfunction in critically ill patients. Changes in clinical practice over the last few decades, with new interventions and a greater focus on non-invasive monitoring systems, mean it is time to update the SOFA score. As a first step in this process, we propose some possible new variables that could be included in a SOFA 2.0. By so doing, we hope to stimulate debate and discussion to move toward a new, properly validated score that will be fit for modern practice.

Bioenergetic Crisis in ICU-Acquired Weakness Gene Signatures Was Associated With Sepsis-Related Mortality: A Brief Report

To investigate the relationship between ICU-acquired weakness (ICUAW) signatures and sepsis-related mortality using gene expression from the blood within 24 hours of sepsis onset.

DESIGN

Observational study using differential gene expression analysis.

SETTING

Publicly available gene expression profile GSE54514, single-center medical and surgical ICU.

PATIENTS

Patients with primary bacteremia- and respiratory-triggered sepsis including 8 nonsurvivors and 13 survivors who were 18 years old and older and admitted to ICU.

MEASUREMENTS AND MAIN RESULTS

Among validated 526 ICUAW gene signatures, differential gene expression analysis controlling for age identified 38 significantly expressed genes between nonsurvivors and survivors. Functional enrichment analysis of differentially expressed ICUAW genes identified impaired cadherin binding, sarcomere formation, and energy metabolism among nonsurvivors.

CONCLUSIONS

Our findings demonstrated a biological association between sepsis-related mortality and ICUAW signatures in the early phase of sepsis. Defects in energy metabolism and muscle fiber formation were associated with sepsis-related mortality.

Development and validation of novel sepsis subphenotypes using trajectories of vital signs

PURPOSE

Sepsis is a heterogeneous syndrome and identification of sub-phenotypes is essential. This study used trajectories of vital signs to develop and validate sub-phenotypes and investigated the interaction of sub-phenotypes with treatment using randomized controlled trial data.

METHODS

All patients with suspected infection admitted to four academic hospitals in Emory Healthcare between 2014-2017 (training cohort) and 2018-2019 (validation cohort) were included. Group-based trajectory modeling was applied to vital signs from the first 8 h of hospitalization to develop and validate vitals trajectory sub-phenotypes. The associations between sub-phenotypes and outcomes were evaluated in patients with sepsis. The interaction between sub-phenotype and treatment with balanced crystalloids versus saline was tested in a secondary analysis of SMART (Isotonic Solutions and Major Adverse Renal Events Trial).

RESULTS

There were 12,473 patients with suspected infection in training and 8256 patients in validation cohorts, and 4 vitals trajectory sub-phenotypes were found. Group A (N = 3483, 28%) were hyperthermic, tachycardic, tachypneic, and hypotensive. Group B (N = 1578, 13%) were hyperthermic, tachycardic, tachypneic (not as pronounced as Group A) and hypertensive. Groups C (N = 4044, 32%) and D (N = 3368, 27%) had lower temperatures, heart rates, and respiratory rates, with Group C normotensive and Group D hypotensive. In the 6,919 patients with sepsis, Groups A and B were younger while Groups C and D were older. Group A had the lowest prevalence of congestive heart failure, hypertension, diabetes mellitus, and chronic kidney disease, while Group B had the highest prevalence. Groups A and D had the highest vasopressor use (p < 0.001 for all analyses above). In logistic regression, 30-day mortality was significantly higher in Groups A and D (p < 0.001 and p = 0.03, respectively). In the SMART trial, sub-phenotype significantly modified treatment effect (p = 0.03). Group D had significantly lower odds of mortality with balanced crystalloids compared to saline (odds ratio (OR) 0.39, 95% confidence interval (CI) 0.23-0.67, p < 0.001).

CONCLUSION

Sepsis sub-phenotypes based on vital sign trajectory were consistent across cohorts, had distinct outcomes, and different responses to treatment with balanced crystalloids versus saline.

SWEAT ICU-An Observational Study of Physician Workload and the Association of Physician Outcomes in Academic ICUs

The optimal staffing model for physicians in the ICU is unknown. Patient-to-intensivist ratios may offer a simple measure of workload and be associated with patient mortality and physician burnout. To evaluate the association of physician workload, as measured by the patient-to-intensivist ratio, with physician burnout and patient mortality.

DESIGN

Cross-sectional observational study.

SETTING

Fourteen academic centers in the United States from August 2020 to July 2021.

SUBJECTS

We enrolled ICU physicians and collected data on adult ICU patients under the physician's care on the single physician-selected study day for each physician.

MEASUREMENTS and MAIN RESULTS

The primary exposure was workload (self-reported number of patients' physician was responsible for) modeled as high (>14 patients) and low (≤14 patients). The primary outcome was burnout, measured by the Well-Being Index. The secondary outcome measure was 28-day patient mortality. We calculated odds ratio for burnout and patient outcomes using a multivariable logistic regression model and a binomial mixed effects model, respectively. We enrolled 122 physicians from 62 ICUs. The median patient-to-intensivist ratio was 12 (interquartile range, 10-14), and the overall prevalence of burnout was 26.4% (n = 32). Intensivist workload was not independently associated with burnout (adjusted odds ratio, 0.74; 95% CI, 0.24-2.23). Of 1,322 patients, 679 (52%) were discharged alive from the hospital, 257 (19%) remained hospitalized, and 347 (26%) were deceased by day 28; 28-day outcomes were unknown for 39 of patients (3%). Intensivist workload was not independently associated with 28-day patient mortality (adjusted odds ratio, 1.33; 95% CI, 0.92-1.91).

CONCLUSIONS

In our cohort, approximately one in four physicians experienced burnout on the study day. There was no relationship be- tween workload as measured by patient-to-intensivist ratio and burnout. Factors other than the number of patients may be important drivers of burnout among ICU physicians.

Junctional adhesion molecule-A deletion increases phagocytosis and improves survival in a murine model of sepsis

Expression of the tight junction–associated protein junctional adhesion molecule-A (JAM-A) is increased in sepsis, although the significance of this is unknown. Here, we show that septic JAM-A ^–/– mice have increased gut permeability, yet paradoxically have decreased bacteremia and systemic TNF and IL-1β expression. Survival is improved in JAM-A^–/– mice. However, intestine-specific JAM-A^–/– deletion does not alter mortality, suggesting that the mortality benefit conferred in mice lacking JAM-A is independent of the intestine. Septic JAM-A^–/– mice have increased numbers of splenic CD44^hiCD4⁺ T cells, decreased frequency of TNF⁺CD4⁺ cells, and elevated frequency of IL-2⁺CD4⁺ cells. Septic JAM-A^–/– mice have increased numbers of B cells in mesenteric lymph nodes with elevated serum IgA and intraepithelial lymphocyte IgA production. JAM-A^–/– × RAG^–/– mice have improved survival compared with RAG^–/– mice and identical mortality as WT mice. Gut neutrophil infiltration and neutrophil phagocytosis are increased in JAM-A^–/– mice, while septic JAM-A^–/– mice depleted of neutrophils lose their survival advantage. Therefore, increased bacterial clearance via neutrophils and an altered systemic inflammatory response with increased opsonizing IgA produced through the adaptive immune system results in improved survival in septic JAM-A^–/– mice. JAM-A may be a therapeutic target in sepsis via immune mechanisms not related to its role in permeability.

The microbiome restrains melanoma bone growth by promoting intestinal NK and Th1 cell homing to bone

Bone metastases are frequent complications of malignant melanoma leading to reduced quality of life and significant morbidity. Regulation of immune cells by the gut microbiome influences cancer progression, but the role of the microbiome in tumor growth in bone is unknown. Using intracardiac or intratibial injections of B16-F10 melanoma cells into mice, we showed that gut microbiome depletion by broad-spectrum antibiotics accelerated intraosseous tumor growth and osteolysis. Microbiome depletion blunted melanoma-induced expansion of intestinal NK cells and Th1 cells and their migration from the gut to tumor-bearing bones. Demonstrating the functional relevance of immune cell trafficking from the gut to the bone marrow (BM) in bone metastasis, blockade of S1P-mediated intestinal egress of NK and Th1 cells, or inhibition of their CXCR3/CXCL9-mediated influx into the BM, prevented the expansion of BM NK and Th1 cells and accelerated tumor growth and osteolysis. Using a mouse model, this study revealed mechanisms of microbiota-mediated gut-bone crosstalk that are relevant to the immunological restraint of melanoma metastasis and tumor growth in bone. Microbiome modifications induced by antibiotics might have negative clinical consequences in patients with melanoma.

Trends in ICU Mortality From Coronavirus Disease 2019: A Tale of Three Surges

OBJECTIVES

To determine the association between time period of hospitalization and hospital mortality among critically ill adults with coronavirus disease 2019.

DESIGN

Observational cohort study from March 6, 2020, to January 31, 2021.

SETTING

ICUs at four hospitals within an academic health center network in Atlanta, GA.

PATIENTS

Adults greater than or equal to 18 years with coronavirus disease 2019 admitted to an ICU during the study period (i.e., Surge 1: March to April, Lull 1: May to June, Surge 2: July to August, Lull 2: September to November, Surge 3: December to January).

MEASUREMENTS AND MAIN RESULTS

Among 1,686 patients with coronavirus disease 2019 admitted to an ICU during the study period, all-cause hospital mortality was 29.7%. Mortality differed significantly over time: 28.7% in Surge 1, 21.3% in Lull 1, 25.2% in Surge 2, 30.2% in Lull 2, 34.7% in Surge 3 (p = 0.007). Mortality was significantly associated with 1) preexisting risk factors (older age, race, ethnicity, lower body mass index, higher Elixhauser Comorbidity Index, admission from a nursing home); 2) clinical status at ICU admission (higher Sequential Organ Failure Assessment score, higher d-dimer, higher C-reactive protein); and 3) ICU interventions (receipt of mechanical ventilation, vasopressors, renal replacement therapy, inhaled vasodilators). After adjusting for baseline and clinical variables, there was a significantly increased risk of mortality associated with admission during Lull 2 (relative risk, 1.37 [95% CI = 1.03-1.81]) and Surge 3 (relative risk, 1.35 [95% CI = 1.04-1.77]) as compared to Surge 1.

CONCLUSIONS

Despite increased experience and evidence-based treatments, the risk of death for patients admitted to the ICU with coronavirus disease 2019 was highest during the fall and winter of 2020. Reasons for this increased mortality are not clear.

Altered Heart Rate Variability Early in ICU Admission Differentiates Critically Ill Coronavirus Disease 2019 and All-Cause Sepsis Patients

IMPORTANCE

Altered heart rate variability has been associated with autonomic dysfunction in a number of disease profiles, in this work we elucidate differences in the biomarker among patients with all-cause sepsis and coronavirus disease 2019.

OBJECTIVES

To measure heart rate variability metrics in critically ill coronavirus disease 2019 patients with comparison to all-cause critically ill sepsis patients.

DESIGN SETTING AND PARTICIPANTS

Retrospective analysis of coronavirus disease 2019 patients admitted to an ICU for at least 24 hours at any of Emory Healthcare ICUs between March 2020 and April 2020 up to 5 days of ICU stay. The comparison group was a cohort of all-cause sepsis patients prior to coronavirus disease 2019 pandemic.

MAIN OUTCOMES AND MEASURES

Continuous waveforms were captured from the patient monitor. The electrocardiogram was then analyzed for each patient over a 300 seconds observational window that was shifted by 30 seconds in each iteration from admission till discharge. A total of 23 heart rate variability metrics were extracted in each iteration. We use the Kruskal-Wallis and Steel-Dwass tests (p < 0.05) for statistical analysis and interpretations of heart rate variability multiple measures.

RESULTS

A total of 141 critically ill coronavirus disease 2019 patients met inclusion criteria, who were compared with 208 patients with all-cause sepsis. Three nonlinear markers, including the ratio of standard deviation derived from the Poincaré plot, sample entropy, and approximate entropy and four linear features, including mode of beat-to-beat interval, acceleration capacity, deceleration capacity, and the proportion of consecutive RR intervals that differ by more than 50 ms, were all statistically significant (p < 0.05) between the coronavirus disease 2019 and all-cause sepsis cohorts. The three nonlinear features and acceleration capacity, deceleration capacity, and beat-to-beat interval (mode) were statistically significant (p < 0.05) when comparing pairwise analysis among the combinations of survivors and nonsurvivors between the coronavirus disease 2019 and sepsis cohorts. Temporal analysis of the main markers showed low variability across the 5 days of analysis compared with sepsis patients.

CONCLUSIONS AND RELEVANCE

In this descriptive statistical study, heart rate variability measures were found to be statistically different across critically ill patients infected with severe acute respiratory syndrome coronavirus 2 and distinct from bacterial sepsis.

Membrane Permeant Inhibitor of Myosin Light Chain Kinase Worsens Survival in Murine Polymicrobial Sepsis

ABSTRACT

Sepsis-induced intestinal hyperpermeability is mediated by disruption of the epithelial tight junction, which is closely associated with the peri-junctional actin-myosin ring. Genetic deletion of myosin light chain kinase (MLCK) reverses intestinal hyperpermeability and improves survival in a murine model of intra-abdominal sepsis. In an attempt to determine whether these findings could be translated using a more clinically relevant strategy, this study aimed to determine if pharmacologic inhibition of MLCK using the membrane permeant inhibitor of MLCK (PIK) improved gut barrier function and survival following sepsis. C57BL/6 mice underwent cecal ligation and puncture to induce sepsis and were then randomized to receive either PIK or vehicle. Unexpectedly, PIK significantly worsened 7-day survival following sepsis (24% vs. 62%). The three pathways of intestinal permeability were then interrogated by orally gavaging septic mice with creatinine (6Å), FD-4 (28Å), and rhodamine70 (120Å) and assaying their appearance in the bloodstream. PIK led to increased permeability in the leak pathway with higher levels of FD-4 in the bloodstream compared to septic mice given vehicle. In contrast, no differences were detected in the pore or unrestricted pathways of permeability. Examination of jejunal tight junctions for potential mechanisms underlying increased leak permeability revealed that mice that received PIK had increased phosphorylated MLC without alterations in occludin, ZO-1, or JAM-A. PIK administration was not associated with significant differences in systemic or peritoneal bacterial burden, cytokines, splenic or Peyer's Patches immune cells or intestinal integrity. These results demonstrate that pharmacologic inhibition of MLCK unexpectedly increases mortality, associated with worsened intestinal permeability through the leak pathway, and suggest caution is required in targeting the gut barrier as a potential therapy in sepsis.

Developing Treatment Guidelines During a Pandemic Health Crisis: Lessons Learned From COVID-19

The development of the National Institutes of Health (NIH) COVID-19 Treatment Guidelines began in March 2020 in response to a request from the White House Coronavirus Task Force. Within 4 days of the request, the NIH COVID-19 Treatment Guidelines Panel was established and the first meeting took place (virtually-as did subsequent meetings). The Panel comprises 57 individuals representing 6 governmental agencies, 11 professional societies, and 33 medical centers, plus 2 community members, who have worked together to create and frequently update the guidelines on the basis of evidence from the most recent clinical studies available. The initial version of the guidelines was completed within 2 weeks and posted online on 21 April 2020. Initially, sparse evidence was available to guide COVID-19 treatment recommendations. However, treatment data rapidly accrued based on results from clinical studies that used various study designs and evaluated different therapeutic agents and approaches. Data have continued to evolve at a rapid pace, leading to 24 revisions and updates of the guidelines in the first year. This process has provided important lessons for responding to an unprecedented public health emergency: Providers and stakeholders are eager to access credible, current treatment guidelines; governmental agencies, professional societies, and health care leaders can work together effectively and expeditiously; panelists from various disciplines, including biostatistics, are important for quickly developing well-informed recommendations; well-powered randomized clinical trials continue to provide the most compelling evidence to guide treatment recommendations; treatment recommendations need to be developed in a confidential setting free from external pressures; development of a user-friendly, web-based format for communicating with health care providers requires substantial administrative support; and frequent updates are necessary as clinical evidence rapidly emerges.

Integrated evaluation of lung disease in single animals

During infectious disease, pathogen load drives inflammation and immune response that together contribute to tissue injury often resulting in organ dysfunction. Pulmonary failure in SARS-CoV2-infected hospitalized COVID-19 patients is one such prominent example. Intervention strategies require characterization of the host-pathogen interaction by accurately assessing all of the above-mentioned disease parameters. To study infection in intact mammals, mice are often used as essential genetic models. Due to humane concerns, there is a constant unmet demand to develop studies that reduce the number of mice utilized while generating objective data. Here, we describe an integrated method of evaluating lung inflammation in mice infected with Pseudomonas aeruginosa or murine gammaherpesvirus (MHV)-68. This method conserves animal resources while permitting evaluation of disease mechanisms in both infection settings. Lungs from a single euthanized mouse were used for two purposes-biological assays to determine inflammation and infection load, as well as histology to evaluate tissue architecture. For this concurrent assessment of multiple parameters from a single euthanized mouse, we limit in-situ formalin fixation to the right lung of the cadaver. The unfixed left lung is collected immediately and divided into several segments for biological assays including determination of pathogen titer, assessment of infection-driven cytokine levels and appearance of cell death markers. In situ fixed right lung was then processed for histological determination of tissue injury and confirmation of infection-driven cell death patterns. This method reduces overall animal use and minimizes inter-animal variability that results from sacrificing different animals for different types of assays. The technique can be applied to any lung disease study in mice or other mammals.

The Surviving Sepsis Campaign: research priorities for the administration, epidemiology, scoring and identification of sepsis

Objective

To identify priorities for administrative, epidemiologic and diagnostic research in sepsis.

Design

As a follow-up to a previous consensus statement about sepsis research, members of the Surviving Sepsis Campaign Research Committee, representing the European Society of Intensive Care Medicine and the Society of Critical Care Medicine addressed six questions regarding care delivery, epidemiology, organ dysfunction, screening, identification of septic shock, and information that can predict outcomes in sepsis.

Methods

Six questions from the Scoring/Identification and Administration sections of the original Research Priorities publication were explored in greater detail to better examine the knowledge gaps and rationales for questions that were previously identified through a consensus process.

Results

The document provides a framework for priorities in research to address the following questions: (1) What is the optimal model of delivering sepsis care?; (2) What is the epidemiology of sepsis susceptibility and response to treatment?; (3) What information identifies organ dysfunction?; (4) How can we screen for sepsis in various settings?; (5) How do we identify septic shock?; and (6) What in-hospital clinical information is associated with important outcomes in patients with sepsis?

Conclusions

There is substantial knowledge of sepsis epidemiology and ways to identify and treat sepsis patients, but many gaps remain. Areas of uncertainty identified in this manuscript can help prioritize initiatives to improve an understanding of individual patient and demographic heterogeneity with sepsis and septic shock, biomarkers and accurate patient identification, organ dysfunction, and ways to improve sepsis care.

Temporal Differential Expression of Physiomarkers Predicts Sepsis in Critically Ill Adults

BACKGROUND

Sepsis is a life-threatening condition with high mortality rates. Early detection and treatment are critical to improving outcomes. Our primary objective was to develop artificial intelligence capable of predicting sepsis earlier using a minimal set of streaming physiological data in real time.

METHODS AND FINDINGS

A total of 29,552 adult patients were admitted to the intensive care unit across five regional hospitals in Memphis, Tenn, over 18 months from January 2017 to July 2018. From these, 5,958 patients were selected after filtering for continuous (minute-by-minute) physiological data availability. A total of 617 (10.4%) patients were identified as sepsis cases, using the Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) criteria. Physiomarkers, a set of signal processing features, were derived from five physiological data streams including heart rate, respiratory rate, and blood pressure (systolic, diastolic, and mean), captured every minute from the bedside monitors. A support vector machine classifier was used for classification. The model accurately predicted sepsis up to a mean and 95% confidence interval of 17.4 ± 0.22 h before sepsis onset, with an average test accuracy of 83.0% (average sensitivity, specificity, and area under the receiver operating characteristics curve of 0.757, 0.902, and 0.781, respectively).

CONCLUSIONS

This study demonstrates that salient physiomarkers derived from continuous bedside monitoring are temporally and differentially expressed in septic patients. Using this information, minimalistic artificial intelligence models can be developed to predict sepsis earlier in critically ill patients.

TIGIT modulates sepsis-induced immune dysregulation in mice with preexisting malignancy

TIGIT is a recently identified coinhibitory receptor that is upregulated in the setting of cancer and functionally contributes to the impairment of antitumor immunity. However, its role during sepsis is unknown. Because patients with cancer are 10 times more likely to die of sepsis than previously healthy (PH) patients with sepsis, we interrogated the role of TIGIT during sepsis in the context of preexistent malignancy. PH mice or cancer (CA) mice inoculated with lung carcinoma cells were made septic by cecal ligation and puncture (CLP). We found that sepsis induced TIGIT upregulation predominantly on Tregs and NK cells in both PH and CA mice. Anti-TIGIT Ab improved the 7-d survival of CA septic mice but not PH mice after CLP. Treatment of CA septic animals but not PH septic animals with anti-TIGIT mAb significantly reversed sepsis-induced loss of CD4+ T cells, CD8+ T cells, Foxp3+ Treg, and CD19+ B cells in the spleen, which was the result of decreased caspase-3+ apoptotic cells. In sum, we found that anti-TIGIT Ab reversed sepsis-induced T cell apoptosis in CA septic mice and led to a significant survival benefit, suggesting its use as a potential immunotherapy to improve outcomes in septic patients with cancer.

Breaking the bond between tetranectin and HMGB1 in sepsis

The interaction between tetranectin and high-mobility group box-1 protein may be manipulated via monoclonal antibodies to improve survival in sepsis (Chen et al. same issue).

Temperature Trajectory Subphenotypes Correlate With Immune Responses in Patients With Sepsis

OBJECTIVES

We recently found that distinct body temperature trajectories of infected patients correlated with survival. Understanding the relationship between the temperature trajectories and the host immune response to infection could allow us to immunophenotype patients at the bedside using temperature. The objective was to identify whether temperature trajectories have consistent associations with specific cytokine responses in two distinct cohorts of infected patients.

DESIGN

Prospective observational study.

SETTING

Large academic medical center between 2013 and 2019.

SUBJECTS

Two cohorts of infected patients: 1) patients in the ICU with septic shock and 2) hospitalized patients with Staphylococcus aureus bacteremia.

INTERVENTIONS

Clinical data (including body temperature) and plasma cytokine concentrations were measured. Patients were classified into four temperature trajectory subphenotypes using their temperature measurements in the first 72 hours from the onset of infection. Log-transformed cytokine levels were standardized to the mean and compared with the subphenotypes in both cohorts.

MEASUREMENTS AND MAIN RESULTS

The cohorts consisted of 120 patients with septic shock (cohort 1) and 88 patients with S. aureus bacteremia (cohort 2). Patients from both cohorts were classified into one of four previously validated temperature subphenotypes: "hyperthermic, slow resolvers" (n = 19 cohort 1; n = 13 cohort 2), "hyperthermic, fast resolvers" (n = 18 C1; n = 24 C2), "normothermic" (n = 54 C1; n = 31 C2), and "hypothermic" (n = 29 C1; n = 20 C2). Both "hyperthermic, slow resolvers" and "hyperthermic, fast resolvers" had high levels of G-CSF, CCL2, and interleukin-10 compared with the "hypothermic" group when controlling for cohort and timing of cytokine measurement (p < 0.05). In contrast to the "hyperthermic, slow resolvers," the "hyperthermic, fast resolvers" showed significant decreases in the levels of several cytokines over a 24-hour period, including interleukin-1RA, interleukin-6, interleukin-8, G-CSF, and M-CSF (p < 0.001).

CONCLUSIONS

Temperature trajectory subphenotypes are associated with consistent cytokine profiles in two distinct cohorts of infected patients. These subphenotypes could play a role in the bedside identification of cytokine profiles in patients with sepsis.

Tumor-Specific T Cells Exacerbate Mortality and Immune Dysregulation during Sepsis

Sepsis induces significant immune dysregulation characterized by lymphocyte apoptosis and alterations in the cytokine milieu. Because cancer patients exhibit a 10-fold greater risk of developing sepsis compared with the general population, we aimed to understand how pre-existing malignancy alters sepsis-induced immune dysregulation. To address this question, we assessed the impact of tumor-specific CD8⁺ T cells on the immune response in a mouse model of cecal ligation and puncture (CLP)-induced sepsis. Tumor-bearing animals containing Thy1.1⁺ tumor-specific CD8⁺ T cells were subjected to CLP, and groups of animals received anti-Thy1.1 mAb to deplete tumor-specific CD8⁺ T cells or isotype control. Results indicated that depleting tumor-specific T cells significantly improved mortality from sepsis. The presence of tumor-specific CD8⁺ T cells resulted in increased expression of the 2B4 coinhibitory receptor and increased apoptosis of endogenous CD8⁺ T cells. Moreover, tumor-specific T cells were not reduced in number in the tumors during sepsis but did exhibit impaired IFN-γ production in the tumor, tumor draining lymph node, and spleen 24 h after CLP. Our research provides novel insight into the mechanisms by which pre-existing malignancy contributes to increased mortality during sepsis.