'Sepsis-related anemia' is absent at hospital presentation; a retrospective cohort analysis

Haemolysis index conundrum in a COVID-19 patient

In this study, we report a preanalytical challenge noted in our laboratory on plasma samples from a critically ill COVID-19 patient treated with hydroxychloroquine. This is significant because, in critically ill COVID-19 patients on hydroxychloroquine, plasma samples can have a high measured haemolysis index in the absence of haemolysis, with the impact on reporting the results for potassium and other analytes.

Hemoglobin, Ferritin, and Lactate Dehydrogenase as Predictive Markers for Neonatal Sepsis

(1) Background: This study evaluates the predictive effectiveness of biomarkers in diagnosing newborn sepsis. (2) Methods: This was a case-control study conducted on neonates hospitalized at the Clinical Hospital "Louis Turcanu", Timisoara, Romania, from October 2018 to July 2023. Using a vacutainer collection device, venous blood was collected at admission for complete blood tests, including ferritin, hemoglobin, LDH, and blood culture analysis. Neonates were divided into two groups: sepsis-positive and sepsis-negative. The outcome of interest was a diagnosis of sepsis. (3) Results: Data from 86 neonates, 51 of whom had been confirmed to have sepsis, were analyzed. This study found no significant difference in gestational age, infant weight, fetal growth restriction, or APGAR score between neonates with and without sepsis. However, there was a higher incidence of sepsis among neonates delivered via cesarean section. Neonatal patients with sepsis showed significantly higher levels of neonatal serum ferritin and LDH compared to those without sepsis. Ferritin and LDH biomarkers demonstrated excellent discriminatory capabilities in diagnosing neonatal sepsis. Logistic regression analysis revealed a significant association between elevated ferritin and LDH levels and the likelihood of neonatal sepsis, while anemia did not show a significant association. (4) Conclusions: LDH and ferritin concentrations are found to be predictive biomarkers for neonatal sepsis, indicating a potential role in detecting susceptible neonates and implementing prompt interventions to improve patient outcomes.

Exploring the relationship between hyperlactatemia and anemia

Hyperlactatemia and anemia commonly coexist and their crosstalk is a longstanding mystery with elusive mechanisms involved in physical activities, infections, cancers, and genetic disorders. For instance, hyperlactatemia leads to iron restriction by upregulating hepatic hepcidin expression. Increasing evidence also points to lactate as a crucial signaling molecule rather than merely a metabolic byproduct. Here, we discuss the mutual influence between anemia and hyperlactatemia. This opinion calls for a reconsideration of the multifaceted roles of lactate and lactylation in anemia and emphasizes the need to fill knowledge gaps, including the dose dependence of lactate's effects, its sources, and its subcellular localization.

Acute blood loss anemia in hospitalized patients is associated with adverse outcomes: An analysis of the Nationwide Inpatient Sample

BACKGROUND

Acute blood loss anemia is the most common form of anemia and often results from traumatic injuries or gastrointestinal bleeding. There are limited studies analyzing outcomes associated with acute blood loss anemia in hospitalized patients.

METHODS

The Nationwide Inpatient Sample (NIS) was analyzed from 2010 to 2014 (n = 133,809). The impact of acute blood loss anemia on in-hospital mortality, length of stay (LOS), healthcare cost, and disposition was determined using regression modeling adjusted for age, gender, race, and comorbidities.

RESULTS

Hospitalized patients with acute blood loss anemia had significantly higher healthcare cost (adj OR 1.04; 95% CI: 1.04-1.05), greater lengths of stay (adj OR 1.18; 95% CI: 1.17-1.18), and were less likely to be discharged home compared to the general medical population (adj OR 0.27; 95% CI: 0.26-0.28). Acute blood loss anemia was associated with increased risk for mortality in unadjusted models (unadj 1.16; 95% CI: 1.12-1.20) but not in adjusted models (adj OR 0.91; 95% CI: 0.88-0.94). When analyzing comorbidities, a "muscle loss phenotype" had the strongest association with mortality in patients with acute blood loss anemia (adj OR 4.48; 95% CI: 4.35-4.61). The top five primary diagnostic codes associated with acute blood loss anemia were long bone fractures, GI bleeds, cardiac repair, sepsis, and OB/Gyn related causes. Sepsis had the highest association with mortality (18%, adj OR 2.59; 95% CI: 2.34-2.86) in those with acute blood loss anemia.

CONCLUSIONS

Acute blood loss anemia is associated with adverse outcomes in hospitalized patients.

Association between haemoglobin-to-red blood cell distribution width ratio at admission and all-cause mortality in adult patients with sepsis in an intensive care unit: a secondary analysis of the MIMIC-IV database

OBJECTIVE

The association between haemoglobin-to-red blood cell distribution width ratio (HRR) and all-cause mortality remains poorly understood. This study aimed to examine the influence of HRR at the time of admission mortality over 1 year and 30 days in patients with sepsis.

DESIGN

This was a secondary analysis.

SETTING

This study was conducted in intensive care units (ICUs).

PARTICIPANTS

Adult patients with sepsis were identified and included from an intensive care database based on eligibility criteria.

PRIMARY OUTCOME AND MEASURE

The primary outcome was the rate of death within 1 year. The secondary outcome was the death rate within 30 days.

RESULTS

A total of 4233 patients with sepsis who met the inclusion criteria were analysed, excluding those ineligible. These participants were divided into quartiles based on their HRR at admission. The overall mortality rates at 1 year and 30 days were 42.9% and 25.5%, respectively. A significant inverse association was observed between HRR quartiles and all-cause mortality (p<0.001). Pairwise comparisons using Kaplan-Meier analysis showed significant differences in 1-year mortality rates across the quartiles. However, no significant difference was detected in 30-day mortality between the Q3 and Q4 groups (p=0.222). Multivariate Cox regression analysis demonstrated that a higher HRR at ICU admission was independently associated with reduced mortality at 1 year (HR, 0.935; 95% CI 0.913 to 0.958; p<0.001) and 30 days (HR, 0.969; 95% CI 0.939 to 0.999; p=0.043). Furthermore, restricted cubic spline models indicated a non-linear relationship between HRR and mortality at both 1 year and 30 days (p<0.001 for both).

CONCLUSIONS

This retrospective analysis demonstrated that the HRR at the time of admission was a significant prognostic marker for long-term mortality in patients with sepsis.

Association between admission hemoglobin level and prognosis in sepsis patients based on a critical care database

This study aimed to explore the association between admission hemoglobin level and clinical outcomes in sepsis based on Medical Information Mart for Intensive Care IV(MIMIC-IV) database. It was a retrospective study. Sepsis patients in the database were included. Data extraction from MIMIC-IV was performed by PostgreSQL 9.6 software. Three different models including crude model (adjusted for none), model I (adjusted for gender and age) and model II (adjusted for all potential cofounders) were constructed. A generalized liner model and a smooth fitting curve for indicating the relationship between hemoglobin level and 30-day mortality were performed. 6249 septic patients with a 30.18% of 30-day mortality were included. With 1 g/dl increment in hemoglobin level, the values of odds ratio (OR) in crude model, model I and model II were 0.96 (95% confidential interval (CI) 0.94-0.99, P = 0.0023), 0.96 (95%CI 0.93-0.98, P = 0.0010) and 0.87 (95%CI 0.79-0.95, P = 0.0020), respectively. The smooth fitting curve indicated a non-linear relationship and the turning point was 7.2 g/dl. Compared the hemoglobin group < 7.2 g/dl, the risk of 30-day mortality significantly decreased by 32% in the hemoglobin group ≥ 7.2 g/dl (OR = 0.68, 95%CI 0.51-0.93, P = 0.0142). The non-linear relationship between admission hemoglobin level and 30-day mortality in sepsis was found. Hemoglobin supplementation might be beneficial for septic patients with hemoglobin level < 7.2 g/dl.

Drinking recommended daily water significantly alters haemato-biochemical parameters in prospective blood donors; a one-center quasi-experimental study in a tropical setting

BACKGROUND

In sub-Saharan Africa, the prevailing high ambient temperatures should warrant increased daily water intake (DWI) to prevent haemo-concentration and its potential to confound patients' laboratory data.

AIM

To assess the impact that the recommended DWI has on the haemato-biochemical variables in a tropical setting.

MATERIALS AND METHODS

This quasi-experimental study recruited 101 apparently healthy individuals (18-60 years) in the Bawku municipality. DWI, anthropometrics, and haemato-biochemical variables were assessed at baseline. Participants were encouraged to increase their DWI to ≥4 L over a 30-day period; haemato-biochemical variables were re-evaluated. Total body water (TBW) was anthropometrically estimated.

RESULTS

The median post-treatment DWI significantly increased; consequently, anaemia cases increased by >20-fold (2.0 % vs 47.5 % post-treatment). RBC count, platelet count, WBC count, and median haemoglobin significantly decreased compared to baseline (p < 0.0001). Biochemically, median plasma osmolality (p < 0.0001), serum sodium (p < 0.0001), serum potassium (p = 0.0012) and random blood sugar (p = 0.0403) significantly decreased. Compared to baseline, significantly higher proportion of participants classified as thrombocytopenic (8.9 % vs 3.0 %), hyponatraemia (10.9 % vs 2.0 %), or normal osmolarity (77.2 % vs 20.8 %). There were differential bivariate correlations between pre- and post-treatment haemato-biochemical variables.

CONCLUSION

Sub-optimal DWI is a likely confounder in haemato-biochemical data interpretation in the tropics.

Exploring a global interpretation mechanism for deep learning networks when predicting sepsis

The purpose of this study is to identify additional clinical features for sepsis detection through the use of a novel mechanism for interpreting black-box machine learning models trained and to provide a suitable evaluation for the mechanism. We use the publicly available dataset from the 2019 PhysioNet Challenge. It has around 40,000 Intensive Care Unit (ICU) patients with 40 physiological variables. Using Long Short-Term Memory (LSTM) as the representative black-box machine learning model, we adapted the Multi-set Classifier to globally interpret the black-box model for concepts it learned about sepsis. To identify relevant features, the result is compared against: (i) features used by a computational sepsis expert, (ii) clinical features from clinical collaborators, (iii) academic features from literature, and (iv) significant features from statistical hypothesis testing. Random Forest was found to be the computational sepsis expert because it had high accuracies for solving both the detection and early detection, and a high degree of overlap with clinical and literature features. Using the proposed interpretation mechanism and the dataset, we identified 17 features that the LSTM used for sepsis classification, 11 of which overlaps with the top 20 features from the Random Forest model, 10 with academic features and 5 with clinical features. Clinical opinion suggests, 3 LSTM features have strong correlation with some clinical features that were not identified by the mechanism. We also found that age, chloride ion concentration, pH and oxygen saturation should be investigated further for connection with developing sepsis. Interpretation mechanisms can bolster the incorporation of state-of-the-art machine learning models into clinical decision support systems, and might help clinicians to address the issue of early sepsis detection. The promising results from this study warrants further investigation into creation of new and improvement of existing interpretation mechanisms for black-box models, and into clinical features that are currently not used in clinical assessment of sepsis.

A Decrease in Hb and Hypoproteinemia: Possible Predictors of Complications in Neonates with Late-Onset Sepsis in a Developing Country

Objective

The main purpose of our study was to determine the predictors of complications in neonates with late-onset sepsis (LOS).

Materials and methods

This was a retrospective cohort study conducted in a neonatal intensive care unit between June 2016 and February 2020. Neonates with LOS were enrolled in this study. According to whether complications were merged after LOS, neonates were divided into a complicated group and a noncomplicated group. The demographic data, perinatal conditions, blood cell count analysis, blood cultures, hypoproteinemia within 1 week after the onset of sepsis and treatment measures were compared between the groups.

Results

A total of 87 neonates with LOS were enrolled in this study. Significant differences were observed between the complicated and noncomplicated groups with regard to hemoglobin (Hb), a decrease in Hb, hypoproteinemia and red blood cell transfusions (P < 0.05). Further comparison found that neonates with LOS who had moderate or severe anemia at the time of sepsis onset were more likely to have complications than those with mild or no anemia. The results of binomial stepwise logistic regression suggested that a decrease in Hb (OR=0.045, P=0.025 < 0.05) and hypoproteinemia (OR=0.266, P=0.007 < 0.05) were independent predictors of complications in neonates with LOS. A receiver operating characteristic analysis showed that the area under the curve was 0.807 for a decrease in Hb.

Conclusion

A decrease in Hb and hypoproteinemia were independent predictors of complications and may help to predict the occurrence of complications in neonates with LOS in the early stage.

Factors associated with in-hospital mortality in adult sepsis with Escherichia coli infection

Background

Escherichia coli (E. coli) is an important pathogen in sepsis. This study aimed to explore the factors which were associated with in-hospital mortality in adult sepsis with E. coli infection based on a public database.

Methods

All sepsis patients with E. coli infection in MIMIC-III were included in this study. Clinical characteristics between the survivor and non-survivor groups were analyzed. Factors associated with in-hospital mortality were identified by multivariate logistic regression.

Results

A total of 199 patients were eventually included and divided into two groups: a survivor group (n = 167) and a non-survivor group (n = 32). RDW and HCT were identified as the factors with clinical outcomes. The area under the ROC curve (AUC) were 0.633 and 0.579, respectively. When combined RDW and HCT for predicting in-hospital mortality, the AUC was 0.772, which was significantly superior to SOFA and APACHEII scores.

Conclusion

RDW and HCT were identified as factors associated with in-hospital mortality in adult sepsis patients with E. coli infection. Our findings will be of help in early and effective evaluation of clinical outcomes in those patients.

CD71+ Erythroid Cell Expansion in Adult Sepsis: Potential Causes and Role in Prognosis and Nosocomial Infection Prediction

Background

Immune suppression contributes to nosocomial infections (NIs) and poor prognosis in sepsis. Recent studies revealed that CD71⁺ erythroid cells had unappreciated immunosuppressive functions. This study aimed to investigate the values of CD71⁺ erythroid cells (CECs) in predicting NIs and prognosis among adult septic patients. The potential factors associated with the expansion of CECs were also explored.

Methods

In total, 112 septic patients and 32 critically ill controls were enrolled. The frequencies of CD71⁺ cells, CD71⁺CD235a⁺ cells, and CD45⁺ CECs were measured by flow cytometry. The associations between CECs and NIs and 30-day mortality were assessed by ROC curve analysis and Cox and competing-risk regression models. Factors associated with the frequency of CECs were identified by linear regression analysis.

Results

The percentage of CD71⁺ cells, CECs, and CD45⁺ CECs were higher in septic patients than critically ill controls. In septic patients, the percentages of CD71⁺ cells, CECs, and CD45⁺ CECs were associated with NI development, while CD71⁺ cells and CECs were independently associated with 30-day mortality. Linear regression analysis showed that the levels of interleukin (IL)-6 and interferon (IFN)-γ were positively associated with the frequencies of CD71⁺ cells, CECs, and CD45⁺ CECs, while IL-10 was negatively associated with them. Additionally, the levels of red blood cells (RBCs) were negatively associated with the percentage of CD45⁺ CECs.

Conclusions

CECs were expanded in sepsis and can serve as independent predictors of the development of NI and 30-day mortality. Low levels of RBCs and high levels of IL-6 and IFN-γ may contribute to the expansion of CECs in sepsis.

Trial Registration

ChiCTR, ChiCTR1900024887. Registered 2 August 2019, http://www.chictr.org.cn/showproj.aspx?proj=38645

Erythrocyte degradation, metabolism, secretion, and communication with immune cells in the blood during sepsis: A review

Sepsis is a health issue that affects millions of people worldwide. It was assumed that erythrocytes were affected by sepsis. However, in recent years, a number of studies have shown that erythrocytes affect sepsis as well. When a pathogen invades the human body, it infects the blood and organs, causing infection and sepsis-related symptoms. Pathogens change the internal environment, increasing the levels of reactive oxygen species, influencing erythrocyte morphology, and causing erythrocyte death, i.e., eryptosis. Characteristics of eryptosis include cell shrinkage, membrane blebbing, and surface exposure of phosphatidylserine (PS). Eryptotic erythrocytes increase immune cell proliferation, and through PS, attract macrophages that remove the infected erythrocytes. Erythrocyte-degraded hemoglobin derivatives and heme deteriorate infection; however, they could also be metabolized to a series of derivatives. The result that erythrocytes play an anti-infection role during sepsis provides new perspectives for treatment. This review focuses on erythrocytes during pathogenic infection and sepsis.

Sepsis: Evidence-based pathogenesis and treatment

Sepsis can develop during the body’s response to a critical illness leading to multiple organ failure, irreversible shock, and death. Sepsis has been vexing health care providers for centuries due to its insidious onset, generalized metabolic dysfunction, and lack of specific therapy. A common factor underlying sepsis is the characteristic hypermetabolic response as the body ramps up every physiological system in its fight against the underlying critical illness. A hypermetabolic response requires supraphysiological amounts of energy, which is mostly supplied via oxidative phosphorylation generated ATP. A by-product of oxidative phosphorylation is hydrogen peroxide (H₂O₂), a toxic, membrane-permeable oxidizing agent that is produced in far greater amounts during a hypermetabolic state. Continued production of mitochondrial H₂O₂ can overwhelm cellular reductive (antioxidant) capacity leading to a build-up within cells and eventual diffusion into the bloodstream. H₂O₂ is a metabolic poison that can inhibit enzyme systems leading to organ failure, microangiopathic dysfunction, and irreversible septic shock. The toxic effects of H₂O₂ mirror the clinical and laboratory abnormalities observed in sepsis, and toxic levels of blood H₂O₂ have been reported in patients with septic shock. This review provides evidence to support a causal role for H₂O₂ in the pathogenesis of sepsis, and an evidence-based therapeutic intervention to reduce H₂O₂ levels in the body and restore redox homeostasis, which is necessary for normal organ function and vascular responsiveness.

Association of fluid balance with mortality in sepsis is modified by admission hemoglobin levels: A large database study

Purpose

Sepsis involves a dysregulated inflammatory response to infection that leads to organ dysfunction. Early fluid resuscitation has been advocated by the Surviving Sepsis Campaign guidelines. However, recent studies have shown that a positive fluid balance is associated with increased mortality in septic patients. We investigated if haemoglobin levels on admission to the intensive care unit (ICU) could modify the association of fluid balance with mortality in patients with sepsis. We hypothesized that with increasing fluid balance, patients with moderate anemia (hemoglobin 7-10g/dL) would have poorer outcomes compared to those without moderate anemia (hemoglobin >10g/dL).

Materials and methods

This retrospective study utilized the Medical Information Mart for Intensive Care-III (MIMIC-III) database. Patients with sepsis, as identified by the International Classification of Diseases, 9th, Clinical Modification codes, were studied. Patients were stratified into those with and without moderate anemia at ICU admission. We investigated the influence of fluid balance measured within 24 hours of ICU admission on 28-day mortality for both patient groups using multivariable logistic regression models. Subgroup and sensitivity analyses were conducted.

Results

8,132 patients (median age 68.6 years, interquartile range 55.1–79.8 years; 52.8% female) were included. Increasing fluid balance (in L) was associated with a significantly decreased risk of 28-day mortality in patients without moderate anemia (OR 0.91, 95%CI 0.84–0.97, p = 0.005, at 6-hour). Conversely, increasing fluid balance was associated with a significantly increased risk of 28-day mortality in patients with moderate anemia (OR 1.05, 95% CI 1.01–1.1, p = 0.022, at 24-hour). Interaction analyses showed that mortality was highest when haemoglobin decreased in patients with moderate anemia who had the most positive fluid balance. Multiple subgroups and sensitivity analyses yielded consistent results.

Conclusions

In septic patients admitted to ICU, admission hemoglobin levels modified the association between fluid balance and mortality and are an important consideration for future fluid therapy trials.

A significant decrease in hemoglobin concentrations may predict occurrence of necrotizing enterocolitis in preterm infants with late-onset sepsis

OBJECTIVE

This study aimed to examine the clinical value of a decrease in hemoglobin concentration (HC) after the onset of sepsis for predicting occurrence of necrotizing enterocolitis (NEC) in preterm infants with late-onset sepsis.

METHODS

We performed a retrospective cohort study between January 2015 and January 2020. Premature neonates (gestational age <37 weeks) with late-onset sepsis (age >3 days) were enrolled. According to the degree of reduction in HC, neonates were divided into the non-decrease group, mild decrease group, and severe decrease group. Demographic data, perinatal conditions, blood cell count analysis, blood culture, and treatment measures were compared.

RESULTS

Eighty premature infants with sepsis were studied. The mortality rate and incidence of NEC were significantly higher in the severe decrease group than in the non-decrease and mild decrease groups. Significant differences were observed in the decrease in HC, red blood cell transfusion, and ventilator application between the NEC and non-NEC groups. A significant decrease in HC was an independent risk factor for NEC in preterm infants with sepsis.

CONCLUSION

A significant decrease in HC is an independent risk factor for NEC and may predict the occurrence of NEC in preterm infants with sepsis.

Etiology of lactic acidosis in malaria

Lactic acidosis and hyperlactatemia are common metabolic disturbances in patients with severe malaria. Lactic acidosis causes physiological adverse effects, which can aggravate the outcome of malaria. Despite its clear association with mortality in malaria patients, the etiology of lactic acidosis is not completely understood. In this review, the possible contributors to lactic acidosis and hyperlactatemia in patients with malaria are discussed. Both increased lactate production and impaired lactate clearance may play a role in the pathogenesis of lactic acidosis. The increased lactate production is caused by several factors, including the metabolism of intraerythrocytic Plasmodium parasites, aerobic glycolysis by activated immune cells, and an increase in anaerobic glycolysis in hypoxic cells and tissues as a consequence of parasite sequestration and anemia. Impaired hepatic and renal lactate clearance, caused by underlying liver and kidney disease, might further aggravate hyperlactatemia. Multiple factors thus participate in the etiology of lactic acidosis in malaria, and further investigations are required to fully understand their relative contributions and the consequences of this major metabolic disturbance.

A Point-Based Risk Calculator Predicting Mortality in Patients That Developed Postoperative Sepsis

Background:

Predicting the mortality from post-operative sepsis remains a continuing problem. We built a statistical model using national data to predict mortality in patients who developed post-operative sepsis.

Methods:

This is a retrospective study using the American College of Surgeons National Quality Surgical Improvement Program database, in which we gathered data from adult patients between 2011 and 2016 who experienced postoperative sepsis. We designed a predictive model using multivariable logistic regression on a training set and validated the model on a separate test set.

Results:

There were 128,325 patients included in the final dataset, in which 18,499 (14.4%) died within 30-days of surgery. The model consisted of 10 covariates: American Society of Anesthesiologists Physical Status classification score, preoperative sepsis, age, chronic obstructive pulmonary disease, postoperative myocardial infarction, postoperative stroke, postoperative acute renal failure, transfusion requirement, and infection type. A point-based risk calculator was developed, which had an area under the receiver operating characteristics curve of 0.819 (95% confidence interval 0.814-0.823).

Conclusion:

Although further work is needed to confirm and validate our model on external datasets, our scoring system provides a novel way to measure mortality in septic post-operative patients.

Bacterial Lipopolysaccharides Suppress Erythroblastic Islands and Erythropoiesis in the Bone Marrow in an Extrinsic and G- CSF-, IL-1-, and TNF-Independent Manner

Anemia of inflammation (AI) is the second most prevalent anemia after iron deficiency anemia and results in persistent low blood erythrocytes and hemoglobin, fatigue, weakness, and early death. Anemia of inflammation is common in people with chronic inflammation, chronic infections, or sepsis. Although several studies have reported the effect of inflammation on stress erythropoiesis and iron homeostasis, the mechanisms by which inflammation suppresses erythropoiesis in the bone marrow (BM), where differentiation and maturation of erythroid cells from hematopoietic stem cells (HSCs) occurs, have not been extensively studied. Here we show that in a mouse model of acute sepsis, bacterial lipopolysaccharides (LPS) suppress medullary erythroblastic islands (EBIs) and erythropoiesis in a TLR-4- and MyD88-dependent manner with concomitant mobilization of HSCs. LPS suppressive effect on erythropoiesis is indirect as erythroid progenitors and erythroblasts do not express TLR-4 whereas EBI macrophages do. Using cytokine receptor gene knock-out mice LPS-induced mobilization of HSCs is G-CSF-dependent whereas LPS-induced suppression of medullary erythropoiesis does not require G- CSF-, IL- 1-, or TNF-mediated signaling. Therefore suppression of medullary erythropoiesis and mobilization of HSCs in response to LPS are mechanistically distinct. Our findings also suggest that EBI macrophages in the BM may sense innate immune stimuli in response to acute inflammation or infections to rapidly convert to a pro-inflammatory function at the expense of their erythropoietic function.

Anemia measurements to distinguish between viral and bacterial infections in the emergency department

The clinical diagnosis of acute infections in the emergency department is a challenging task due to the similarity in symptom presentation between virally and bacterially infected individuals, while the use of routine laboratory tests for pathogen identification is often time-consuming and may contain contaminants. We investigated the ability of various anemia-related parameters, including hemoglobin, red cell distribution width (RDW), and iron, to differentiate between viral and bacterial infection in a retrospective study of 3883 patients admitted to the emergency department with a confirmed viral (n = 1238) or bacterial (n = 2645) infection based on either laboratory tests or microbiological cultures. The ratio between hemoglobin to RDW was found to be significant in distinguishing between virally and bacterially infected patients and outperformed other anemia measurements. Moreover, the predictive value of the ratio was high even in patients presenting with low C-reactive protein values (< 21 mg/L). We followed the dynamics of hemoglobin, RDW, and the ratio between them up to 72 h post emergency department admission, and observed a consistent discrepancy between virally and bacterially infected patients over time. Additional analysis demonstrated higher levels of ferritin and lower levels of iron in bacterially infected compared with virally infected patients. The anemia measurements were associated with length of hospital stay, where all higher levels, except for RDW, corresponded to a shorter hospitalization period. We highlighted the importance of various anemia measurements as an additional host-biomarker to discern virally from bacterially infected patients.

An attention based deep learning model of clinical events in the intensive care unit

This study trained long short-term memory (LSTM) recurrent neural networks (RNNs) incorporating an attention mechanism to predict daily sepsis, myocardial infarction (MI), and vancomycin antibiotic administration over two week patient ICU courses in the MIMIC-III dataset. These models achieved next-day predictive AUC of 0.876 for sepsis, 0.823 for MI, and 0.833 for vancomycin administration. Attention maps built from these models highlighted those times when input variables most influenced predictions and could provide a degree of interpretability to clinicians. These models appeared to attend to variables that were proxies for clinician decision-making, demonstrating a challenge of using flexible deep learning approaches trained with EHR data to build clinical decision support. While continued development and refinement is needed, we believe that such models could one day prove useful in reducing information overload for ICU physicians by providing needed clinical decision support for a variety of clinically important tasks.

Anaemia requiring red blood cell transfusion is associated with unfavourable 90-day survival in surgical patients with sepsis

Objective

The mortality associated with sepsis remains unacceptably high, despite modern high-quality intensive care. Based on the results from previous studies, anaemia and its management in patients with sepsis appear to impact outcomes; however, the transfusion policy is still being debated, and the ideal approach may be extremely specific to the individual. This study aimed to investigate the long-term impact of anaemia requiring red blood cell (RBC) transfusion on mortality and disease severity in patients with sepsis. We studied a general surgical intensive care unit (ICU) population, excluding cardiac surgery patients. 435 patients were enrolled in this observational study between 2012 and 2016.

Results

Patients who received RBC transfusion between 28 days before and 28 days after the development of sepsis (n = 302) exhibited a significantly higher 90-day mortality rate (34.1% vs 19.6%; P = 0.004, Kaplan–Meier analysis). This association remained significant after adjusting for confounders in the multivariate Cox regression analysis (hazard ratio 1.68; 95% confidence interval 1.03–2.73; P = 0.035). Patients who received transfusions also showed significantly higher morbidity scores, such as SOFA scores, and ICU lengths of stay compared to patients without transfusions (n = 133). Our results indicate that anaemia and RBC transfusion are associated with unfavourable outcomes in patients with sepsis.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3988-z) contains supplementary material, which is available to authorized users.

Haemoglobin concentration and volume of intravenous fluids in septic shock in the ARISE trial

BACKGROUND

Intravenous fluids may contribute to lower haemoglobin levels in patients with septic shock. We sought to determine the relationship between the changes in haemoglobin concentration and the volume of intravenous fluids administered during resuscitation from septic shock.

METHODS

We performed a retrospective cohort study of patients enrolled in the Australasian Resuscitation in Sepsis Evaluation (ARISE) trial who were not transfused red blood cells (N = 1275). We determined the relationship between haemoglobin concentration, its change over time and volume of intravenous fluids administered over 6, 24 and 72 h using univariate and multivariate analysis.

RESULTS

Median (IQR) haemoglobin concentration at baseline was 133 (118-146) g/L and decreased to 115 (102-127) g/L within the first 6 h of resuscitation (P < 0.001), 110 (99-122) g/L after 24 h, and 109 (97-121) g/L after 72 h. At the corresponding time points, the cumulative volume of intravenous fluid administered was 1.3 (0.7-2.2) L, 2.9 (1.8-4.3) L and 4.6 (2.7-7.1) L. Haemoglobin concentration and its change from baseline had an independent but weak association with intravenous fluid volume at each time point (R² < 20%, P < 0.001). After adjusting for covariates, each litre of intravenous fluid administered was associated with a change in haemoglobin concentration of - 1.0 g/L (95% CI -1.5 to -0.6, P < 0.001) at 24 h and - 1.3 g/L (- 1.6 to - 0.9, P < 0.001) at 72 h.

CONCLUSIONS

Haemoglobin concentration decreases during resuscitation from septic shock, and has a significant but weak association with the volume of intravenous fluids administered.

Sphingosine-1-Phosphate: A Potential Biomarker and Therapeutic Target for Endothelial Dysfunction and Sepsis?

Sepsis is an acute life-threatening multiple organ failure caused by a dysregulated host response to infection. Endothelial dysfunction, particularly barrier disruption leading to increased vascular permeability, edema, and insufficient tissue oxygenation, is critical to sepsis pathogenesis. Sphingosine-1-phosphate (S1P) is a signaling lipid that regulates important pathophysiological processes including vascular endothelial cell permeability, inflammation, and coagulation. It is present at high concentrations in blood and lymph and at very low concentrations in tissues due to the activity of the S1P-degrading enzyme S1P-lyase in tissue cells. Recently, four preclinical observational studies determined S1P levels in serum or plasma of sepsis patients, and all found reduced S1P levels associated with the disease. Based on these findings, this review summarizes S1P-regulated processes pertaining to endothelial functions, discusses the possible use of S1P as a marker and possibilities how to manipulate S1P levels and S1P receptor activation to restore endothelial integrity, dampens the inflammatory host response, and improves organ function in sepsis.