Erythropoietin response is blunted in critically ill 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.

Impact of anemia requiring transfusion or erythropoiesis-stimulating agents on new-onset cardiovascular events and mortality after continuous renal replacement therapy

Anemia is common in critically ill patients undergoing continuous renal replacement therapy (CRRT). We investigated the impact of anemia requiring red blood cell (RBC) transfusion or erythropoiesis-stimulating agents (ESAs) on patient outcomes after hospital discharge in critically ill patients with acute kidney injury (AKI) requiring CRRT. In this retrospective cohort study using the Health Insurance Review and Assessment database of South Korea, 10,923 adult patients who received CRRT for 3 days or more between 2010 and 2019 and discharged alive were included. Anemia was defined as the need for RBC transfusion or ESAs. Outcomes included cardiovascular events (CVEs) and all-cause mortality after discharge. The anemia group showed a tendency to be older with more females and had more comorbidities compared to the control group. Anemia was not associated with an increased risk of CVEs (adjusted hazard ratio [aHR]: 1.05; 95% confidence interval [CI]: 0.85-1.29), but was associated with an increased risk of all-cause mortality (aHR: 1.41; 95% CI 1.30-1.53). For critically ill patients with AKI requiring CRRT, anemia, defined as requirement for RBC transfusion or ESAs, may increase the long-term risk of all-cause mortality.

The Ratio of Red Blood Cell Distribution Width to Albumin as a Predictor for Rehospitalization Risk and Rehospitalization All-Cause Mortality in Middle-Aged and Elderly Survivors with Sepsis: An Ambispective ICU Cohort Study

Objective

To explore the relationship between red blood cell distribution width to albumin (RDW/ALB) ratio (RAR) and the risk of rehospitalization and rehospitalization all-cause mortality in middle-aged and elderly survivors with sepsis based on an ambispective longitudinal cohort from the Intensive Care Unit (ICU).

Methods

Between 2017 and 2022, 455 adults who survived the first-episode severe sepsis without recurrence for at least 3 months were included in this study. All participants were followed up every 4 weeks for 12 months. According to the tertiles of RAR, participants were divided into three groups: low-level (≤0.36, n = 152), moderate-level (0.37-0.44, n = 152), and high-level (≥0.45, n = 151). The relationship between RAR and the risk of rehospitalization and rehospitalization all-cause mortality was evaluated.

Results

Out of 455 participants, 156 experienced rehospitalization (34.3%), of which 44 (28.2%) died. Receiver operating characteristic (ROC) analysis showed that the RAR cut-off values for rehospitalization and rehospitalization all-cause mortality were 0.4251 and 0.4743, respectively. Multivariate Cox regression analysis indicated that the RAR was positively associated with rehospitalization (P = 0.011) and all-cause mortality (P = 0.006). Compared with the low-level, the high-level RAR presented a higher dose-dependent rehospitalization risk (P = 0.02) and rehospitalization all-cause mortality (P = 0.044). The stratified analysis displayed that compared to the low-level, with the RAR increasing by 1.0, the risk for rehospitalization increased 3.602-fold in aged <65 patients (P = 0.002) and 1.721-fold in female patients (P = 0.014). Kaplan-Meier survival analysis implied a significant positive association between the RAR and the cumulative incidence of rehospitalization and rehospitalization all-cause mortality (log-rank, all P < 0.001).

Conclusion

RAR has a reliable predictive value for the risk of rehospitalization and rehospitalization all-cause mortality in patients with sepsis. Consequently, monitoring RAR for at least 1 year after surviving sepsis in female patients aged <65 in clinical practice is critical.

Small-volume tubes to reduce anemia and transfusion (STRATUS): a pilot study

PURPOSE

Blood sampling for diagnostic testing causes blood loss. Small-volume tubes have the same cost, dimensions, and blood-draw techniques as standard-volume tubes, and are compatible with laboratory equipment; however, they are not commonly used. We sought to assess the feasibility of a stepped-wedge cluster trial to determine whether small-volume tubes reduce transfusion compared with standard-volume tubes in intensive care unit (ICU) patients.

METHODS

We conducted a prospective mixed-methods pilot study (before-after design) in one ICU with a six-week control period (standard-volume tubes) and a six-week intervention period (small-volume tubes). All patients admitted to the ICU were included. Feasibility was assessed as successful switch to small-volume tubes; adherence to tube size; sufficient volume for testing; user acceptance; barriers and facilitators to implementation; and 95% transfusion collection. We explored end-user acceptability using focus groups.

RESULTS

One hundred and sixty-five patients were included in the standard-volume and 204 in the small-volume periods. Transition to small-volume tubes was successful. Random audits showed 100% compliance. The proportion of samples with inadequate volume for testing was the same for both groups (both, 0.2%). Based on ten focus groups, small-volume tubes were acceptable with no barriers identified. Transfusion data collection was 100%. Median [interquartile range] estimated blood loss due to laboratory testing per patient per day in ICU was 11 [8-17] mL with standard-volume and 6 [4-8] mL with small-volume tubes.

CONCLUSION

Small-volume tubes can be implemented with acceptability to end-users and without barriers. They did not result in an increased frequency of inadequate samples. These results inform a trial to determine whether small-volume tubes reduce transfusion.

STUDY REGISTRATION

ClinicalTrials.gov (NCT03284944); registered 15 September 2017.

Erythropoietin-mediated IL-17 F attenuates sepsis-induced gut microbiota dysbiosis and barrier dysfunction

Septic gut damage is critical in the progression of sepsis and multiple organ failure, characterized by gut microbiota dysbiosis and epithelium deficiency in the gut barrier. Recent studies highlight the protective effects of Erythropoietin (EPO) on multiple organs. The present study found that EPO treatment significantly alleviated the survival rate, suppressed inflammatory responses, and ameliorated intestine damage in mice with sepsis. EPO treatment also reversed sepsis-induced gut microbiota dysbiosis. The protective role of EPO in the gut barrier and microbiota was impaired after EPOR knockout. Notably, we innovatively demonstrated that IL-17 F screened by transcriptome sequencing could ameliorate sepsis and septic gut damage including gut microbiota dysbiosis and barrier dysfunction, which was verified by IL-17 F-treated fecal microbiota transplantation (FMT) as well. Our findings highlight the protection effects of EPO-mediated IL-17 F in sepsis-induced gut damage by alleviating gut barrier dysfunction and restoring gut microbiota dysbiosis. EPO and IL-17 F may be potential therapeutic targets in septic patients.

The correlation of hemoglobin and 28-day mortality in septic patients: secondary data mining using the MIMIC-IV database

BACKGROUND

Previous studies found minimal evidence and raised controversy about the link between hemoglobin and 28-day mortality in sepsis patients. As a result, the purpose of this study was to examine the association between hemoglobin and 28-day death in sepsis patients by analyzing the Medical Intensive Care IV (MIMIC-IV) database from 2008 to 2019 at an advanced medical center in Boston, Massachusetts.

METHODS

We extracted 34,916 sepsis patients from the MIMIC-IV retrospective cohort database, using hemoglobin as the exposure variable and 28-day death as the outcome variable, and after adjusting for confounders (demographic indicators, Charlson co-morbidity index, SOFA score, vital signs, medication use status (glucocorticoids, vasoactive drugs, antibiotics, and immunoglobulins, etc.)), we investigated the independent effects of hemoglobin and 28-day risk of death by binary logistic regression as well as two-piecewise linear model, respectively.

RESULTS

Hemoglobin levels and 28-day mortality were shown to be non-linearly related.The inflection points were 104 g/L and 128 g/L, respectively. When HGB levels were between 41 and 104 g/L, there was a 10% decrease in the risk of 28-day mortality (OR: 0.90; 95% CI: 0.87 to 0.94, p-value = 0.0001). However, in the range of 104-128 g/L, we did not observe a significant association between hemoglobin and 28-day mortality (OR: 1.17; 95% CI: 1.00 to 1.35, P value = 0.0586). When HGB was in the range of 128-207 g/L, there was a 7% increase in the risk of 28-day mortality for every 1 unit increase in HGB (OR: 1.07; 95% CI: 1.01 to 1.15, P value = 0.0424).

CONCLUSION

In patients with sepsis, baseline hemoglobin was related to a U-shaped risk of 28-day death. When HGB was in the range of 12.8-20.7 g/dL, there was a 7% increase in the risk of 28-day mortality for every 1 unit increase in HGB.

Importance of assessing biomarkers and physiological parameters of anemia-induced tissue hypoxia in the perioperative period

Anemia is associated with increased risk of Acute Kidney Injury (AKI), stroke and mortality in perioperative patients. We sought to understand the mechanism(s) by assessing the integrative physiological responses to anemia (kidney, brain), the degrees of anemia-induced tissue hypoxia, and associated biomarkers and physiological parameters. Experimental measurements demonstrate a linear relationship between blood Oxygen Content (C_aO₂) and renal microvascular PO₂ (y = 0.30x + 6.9, r² = 0.75), demonstrating that renal hypoxia is proportional to the degree of anemia. This defines the kidney as a potential oxygen sensor during anemia. Further evidence of renal oxygen sensing is demonstrated by proportional increase in serum Erythropoietin (EPO) during anemia (y = 93.806*10^-0.02, r² = 0.82). This data implicates systemic EPO levels as a biomarker of anemia-induced renal tissue hypoxia. By contrast, cerebral Oxygen Delivery (DO₂) is defended by a profound proportional increase in Cerebral Blood Flow (CBF), minimizing tissue hypoxia in the brain, until more severe levels of anemia occur. We hypothesize that the kidney experiences profound early anemia-induced tissue hypoxia which contributes to adaptive mechanisms to preserve cerebral perfusion. At severe levels of anemia, renal hypoxia intensifies, and cerebral hypoxia occurs, possibly contributing to the mechanism(s) of AKI and stroke when adaptive mechanisms to preserve organ perfusion are overwhelmed. Clinical methods to detect renal tissue hypoxia (an early warning signal) and cerebral hypoxia (a later consequence of severe anemia) may inform clinical practice and support the assessment of clinical biomarkers (i.e., EPO) and physiological parameters (i.e., urinary PO₂) of anemia-induced tissue hypoxia. This information may direct targeted treatment strategies to prevent adverse outcomes associated with anemia.

Novel biomarker panel for the diagnosis and prognosis assessment of sepsis based on machine learning

Background: The authors investigated a panel of novel biomarkers for diagnosis and prognosis assessment of sepsis using machine learning (ML) methods. Methods: Hematological parameters, liver function indices and inflammatory marker levels of 332 subjects were retrospectively analyzed. Results: The authors constructed sepsis diagnosis models and identified the random forest (RF) model to be the most optimal. Compared with PCT (procalcitonin) and CRP (C-reactive protein), the RF model identified sepsis patients at an earlier stage. The sepsis group had a mortality rate of 36.3%, and the RF model had greater predictive ability for the 30-day mortality risk of sepsis patients. Conclusion: The RF model facilitated the identification of sepsis patients and showed greater accuracy in predicting the 30-day mortality risk of sepsis patients.

Red blood cell distribution width: A severity indicator in patients with COVID-19

Red blood cell distribution width (RDW) was frequently assessed in COVID-19 infection and reported to be associated with adverse outcomes. However, there was no consensus regarding the optimal cutoff value for RDW. Records of 98 patients with COVID-19 from the First People's Hospital of Jingzhou were reviewed. They were divided into two groups according to the cutoff value for RDW on admission by receiver operator characteristic curve analysis: ≤11.5% (n = 50) and >11.5% (n = 48). The association of RDW with the severity and outcomes of COVID-19 was analyzed. The receiver operating characteristic curve indicated that the RDW was a good discrimination factor for identifying COVID-19 severity (area under the curve = 0.728, 95% CI: 0.626-0.830, p < 0.001). Patients with RDW > 11.5% more frequently suffered from critical COVID-19 than those with RDW ≤ 11.5% (62.5% vs. 26.0%, p < 0.001). Multivariate logistic regression analysis showed RDW to be an independent predictor for critical illness due to COVID-19 (OR = 2.40, 95% CI: 1.27-4.55, p = 0.007). A similar result was obtained when we included RDW > 11.5% into another model instead of RDW as a continuous variable (OR = 5.41, 95% CI: 1.53-19.10, p = 0.009). RDW, as an inexpensive and routinely measured parameter, showed promise as a predictor for critical illness in patients with COVID-19 infection. RDW > 11.5% could be the optimal cutoff to discriminate critical COVID-19 infection.

Prediction of Outcome in Anemic Critically ill Patients in Intensive Care Unit: A Retrospective Observational Study

Objective: Anemia is a universal finding in critically-ill patients which add to the risk of poor outcomes. We aimed to evaluate the prevalence of anemic critically-ill patients and to detect predictors of outcome.   Methods: A retrospective study from 5-year data in the electronic medical record of the critical care department at Cairo University. All medical ICU patients that were admitted with or developed anemia during their ICU stay were included. All data of admission, ICU stay, and APACHE II were recorded and their association with the final outcome was determined.   Results: The study included 301 patients. Anemia was detected in 84.6% of patients. Blood transfusion was given to 61.8% of patients while not given to 38.2% and was not significantly associated with outcome. Non-survivors were 37.5%. Only DM, IHD and CKD were associated with poor outcome (P values 0.045, 0.026, 0.001 respectively). Need for MV or vasopressors was associated with poor outcome (P values 0.0001 for both). WBC, platelets at admission, and Hb at day 14 (P values 0.014, 0.002, 0.0001) respectively. The Multi-variate analysis detected these variables (need for MV, vasopressors, and Hb at the 14 th day ≤7.3 g/dl) could correctly detect outcome with sensitivity 91.6%, specificity 73.6%, PPV 76.7%, and NPV 90.3% and total accuracy 82.4%.   Conclusions: Anemia in critically-ill patients is common and associated with poor outcomes. Blood transfusion was not associated with a better outcome. Combination of MV need and vasopressors with persistent anemia at day 14 were the best predictors of poor outcomes.

Transcriptomic Changes Within Human Bone Marrow After Severe Trauma

BACKGROUND

Severe trauma is associated with severe systemic inflammation and neuroendocrine activation that is associated with erythroid progenitor growth suppression and refractory anemia. Although distinct transcriptional profiles have been detected in numerous tissue types after trauma, no study has yet characterized this within the bone marrow. This study sought to identify a unique bone marrow transcriptomic response following trauma.

METHODS

In a prospective observational cohort study, bone marrow was obtained from severely injured trauma patients with a hip or femur fracture (n = 52), elective hip replacement patients (n = 33), and healthy controls (n = 11). RNA was isolated from bone marrow using a Purelink RNA mini kit. Direct quantification of mRNA copies was performed by NanoString Technologies on a custom gene panel.

RESULTS

Trauma patients displayed an upregulation of genes encoding receptors known to have inhibitory downstream effects on erythropoiesis, including ferroportin, interleukin-6 (IL-6) receptor, transforming growth factor-beta (TGF-β) receptor, and IL-10, as well as genes involved in innate immunity including toll-like receptor 4 (TLR4)-mediated signaling factors. In contrast, hip replacement patients had downregulated transcription of IL-1β, IL-6, TGF-β, tumor necrosis factor alpha, and the HAMP gene with no change in TLR4-mediated signaling factors.

CONCLUSIONS

A unique transcriptomic response within the bone marrow was identified following severe trauma compared to elective hip replacement. These transcriptomic differences were related to the innate immune response as well as known inhibitors of erythropoiesis. Although confined to just one time point, this differential transcriptional response may be linked to refractory anemia and inflammation after injury.

Red cell distribution width is a predictor of all-cause mortality in hospitalized dogs

OBJECTIVE

To determine whether RBC distribution width (RDW) is associated with an increased odds of mortality in hospitalized dogs and cats.

DESIGN

Retrospective, single-center study; data collected from 2007 to 2017.

SETTING

University teaching hospital.

ANIMALS

Six thousand six hundred and sixty-one animals (5183 dogs and 1478 cats).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records were identified from animals presented to the emergency service and admitted to the ICU with a CBC and serum biochemistry performed on admission. Patients were stratified into quintiles based upon presenting RDW, and logistic regression modeling was performed to evaluate the relationship between RDW and in-hospital mortality. Canine patients with a presenting RDW in the upper fourth and fifth quintiles had an increased odds of all-cause in-hospital mortality (p < 0.0001). Specifically, dogs in the upper fifth quintile had a 2.1-fold greater odds of death compared to dogs in the first quintile, and dogs in the upper fourth quintile had a 1.9-fold greater odds of death compared to dogs in the first quintile. This relationship remained significant after adjusting for age, sex, key laboratory values excluding HCT, medical versus surgical disease, and diagnosis category. This relationship was no longer significant with the inclusion of HCT. No significant association was identified between presenting RDW and in-hospital mortality in cats.

CONCLUSIONS

Hospitalized dogs with higher RDW on presentation to the emergency service have greater odds of all-cause in-hospital mortality compared to dogs with a lower RDW. A similar association between RDW and mortality was not found in cats. Further studies are warranted to assess the usefulness of this biomarker for specific diseases in dogs and to better understand the mechanisms driving the association between increased RDW and mortality in canine patients.

Repurposing of High-Dose Erythropoietin as a Potential Drug Attenuates Sepsis in Preconditioning Renal Injury

Due to (i) the uremia-enhanced sepsis severity, (ii) the high prevalence of sepsis with pre-existing renal injury and (iii) the non-erythropoiesis immunomodulation of erythropoietin (EPO), EPO was tested in sepsis with pre-existing renal injury models with the retrospective exploration in patients. Then, EPO was subcutaneously administered in mice with (i) cecal ligation and puncture (CLP) after renal injury including 5/6 nephrectomy (5/6Nx-CLP) and bilateral nephrectomy (BiNx-CLP) or sham surgery (sham-CLP) and (ii) lipopolysaccharide (LPS) injection, along with testing in macrophages. In patients, the data of EPO administration and the disease characteristics in patients with sepsis-induced acute kidney injury (sepsis-AKI) were evaluated. As such, increased endogenous EPO was demonstrated in all sepsis models, including BiNx-CLP despite the reduced liver erythropoietin receptor (EPOR), using Western blot analysis and gene expression, in liver (partly through hepatocyte apoptosis). A high-dose EPO, but not a low-dose, attenuated sepsis in mouse models as determined by mortality and serum inflammatory cytokines. Furthermore, EPO attenuated inflammatory responses in LPS-activated macrophages as determined by supernatant cytokines and the expression of several inflammatory genes (iNOS, IL-1β, STAT3 and NFκB). In parallel, patients with sepsis-AKI who were treated with the high-dose EPO showed favorable outcomes, particularly the 29-day mortality rate. In conclusion, high-dose EPO attenuated sepsis with preconditioning renal injury in mice possibly through the macrophage anti-inflammatory effect, which might be beneficial in some patients.

Predictive value of red blood cell distribution width in septic shock patients with thrombocytopenia: A retrospective study using machine learning

Background

Sepsis‐associated thrombocytopenia (SAT) is common in critical patients and results in the elevation of mortality. Red cell distribution width (RDW) can reflect body response to inflammation and oxidative stress. We try to investigate the relationship between the RDW and the prognosis of patients with SAT through machine learning.

Methods

809 patients were retrospectively analyzed from the Medical Information Mart for Intensive Care III (MIMIC‐III) database. The eXtreme Gradient Boosting (XGBoost) and SHapley Additive exPlanations (SHAP) were used to analyze the impact of each feature. Logistic regression analysis, propensity score matching (PSM), receiver‐operating characteristics (ROC) curve analysis, and the Kaplan‐Meier method were used for data processing.

Results

The patients with thrombocytopenia had higher 28‐day mortality (48.2%). Machine learning indicated that RDW was the second most important in predicting 28‐day mortality. The RDW was significantly increased in non‐survivors by logistic regression and PSM. ROC curve shows that RDW has moderate predictive power for 28‐day mortality. The patients with RDW>16.05 exhibited higher mortality through Kaplan‐Meier analysis.

Conclusions

Interpretable machine learning can be applied in clinical research. Elevated RDW is not only common in patients with SAT but is also associated with a poor prognosis.

Haemoglobin Levels in Early Life among Infants with and without Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a proliferative retinal vascular disorder attributed to an ischaemic stimulus in preterm infants. Haemoglobin, the main component for oxygen transportation, may be implicated in ROP development. This retrospective study compared the mean weekly haemoglobin levels between infants with and without ROP over the first six weeks of life. Premature infants of less than 32 weeks gestational age and less than 1.5 kg birth weight were grouped into age and birth weight-matched ROP cases and controls. Weekly mean haemoglobin levels were documented. An independent t-test was used to analyze the difference in mean haemoglobin levels between infants with ROP and infants without ROP. Adjustment for confounders was performed using one-way analysis of covariance. There was a statistically significant difference in adjusted mean haemoglobin levels between the ROP and non-ROP group during the first week of life (p = 0.038). No significant intergroup differences were observed at the other weeks. Haemoglobin monitoring during the first week of postnatal life may be useful to guide ROP screening in premature infants.

Low serum erythropoietin levels are associated with fatal COVID-19 cases at 4,150 meters above sea level

Previous studies suggested that erythropoietin (EPO) may protect against severe COVID-19-induced injuries, ultimately preventing mortality. This hypothesis is based on the fact that, in addition to promoting the increase in red blood cells, EPO is an anti-inflammatory, anti-apoptotic and protective factor in several non-erythropoietic tissues. Furthermore, EPO promotes nitric oxide production in the hypoxic lung and stimulates ventilation by interacting with the respiratory centers of the brainstem. Given that EPO in the blood is increased at high-altitude, we evaluated the serum levels of EPO in critical patients with COVID-19 at “Hospital Agramont” in the city of El Alto (4150 masl) in Bolivia. A total of 16 patients, 15 men, one woman, with a mean age of 55.8 ± 8.49 years, admitted to the Intensive Care Unit were studied. All patients were permanent residents of El Alto, with no travel history below 3000 masl for at least one year. Blood samples were collected upon admission to the ICU. Serum EPO concentration was assessed using an ELISA kit, and a standard technique determined hemoglobin concentration. Only half of the observed patients survived the disease. Remarkably, fatal cases showed 2.5 times lower serum EPO than survivors (2.78 ± 0.8643 mU/mL vs 7.06 ± 2.713 mU/mL; p = 0.0096), and 1.24 times lower hemoglobin levels (13.96 ± 2.56 g/dL vs 17.41 ± 1.61 g/dL; p = 0.0159). While the number of cases evaluated in this work is low, our findings strongly warrant further investigation of EPO levels in COVID-19 patients at high and low altitudes. Our results also support the hypothesis that exogenous EPO administration could help critically ill COVID-19 patients overcome the disease.

Tackling the unknowns in understanding and management of hospital acquired anemia

Hospital acquired anemia (HAA) has been a recognized entity for nearly 50 years. Despite multiple hypotheses, a mechanistic understanding is lacking, and targeted interventions have not yet yielded significantly impactful results. Known risk factors include advanced age, multiple co-morbidities, low bone marrow reserve, admission to the intensive care unit, and frequent phlebotomy. However, confounding variables in many studies continues to complicate the identification of additional risk factors. Improved understanding of iron metabolism, erythropoiesis, and the erythroid iron restriction response in the last few decades, as well as the recent demonstration of poor outcomes correlating with increased transfusion have refocused attention on HAA. While retrospective database studies provide ample correlative data between 1) HAA and poor outcomes; 2) reduction of phlebotomy volume and decrease in transfusion requirement; and 3) over-transfusion and increased mortality, no causal link between reduced phlebotomy volume, decreased rates of HAA, and improved mortality or other relevant outcomes have been definitely established. Here, we review the current state of knowledge and provide a summary of potential directions to understand and mitigate HAA. There are at present no clear guidelines on whether and when to evaluate hospitalized patients for underlying causes of anemia. We thus provide a guide for clinicians in general practice toward identifying patients at the highest risk for HAA, decreasing blood loss through phlebotomy to the greatest degree feasible, and evaluating and treating reversible causes of anemia in a targeted population.

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.

Persistent inflammation and anemia among critically ill septic patients

BACKGROUND

Associations among inflammatory cytokines, erythropoietin (EPO), and anemia in critically ill septic patients remain unclear. This study tested the hypothesis that elevated inflammatory cytokines and decreased EPO would be associated with iron-restricted anemia while accounting for operative blood loss, phlebotomy blood loss, and red blood cell (RBC) transfusion volume.

METHODS

Prospective observational cohort study of 42 critically ill septic patients was conducted. Hemoglobin (Hb) at sepsis onset and hospital discharge were used to calculate ΔHb. Operative blood loss, phlebotomy blood loss, and RBC transfusion volume were used to calculate adjusted ΔHb (AdjΔHb) assuming that 300 mL RBC is equal to 1 g/dL Hb. Patients with AdjΔHb of greater than 0 (positive AdjΔHb, n = 18) were compared with patients with AdjΔHb of less than or equal to 0 (negative AdjΔHb, n = 24).

RESULTS

Plasma tumor necrosis factor α, granulocyte colony-stimulating factor, interleukin (IL)-6, IL-8, EPO, erythrocyte mean corpuscular volume, and serum transferrin receptor were measured on days 0, 1, 4, 7, and 14. Patients with negative AdjΔHb had significantly higher day 14 levels of IL-6 (37.4 vs. 15.2 pg/mL, p < 0.05), IL-8 (39.1 vs. 18.2 pg/mL, p = 0.01), and granulocyte colony-stimulating factor (101.3 vs. 60.5 pg/mL, p = 0.01), but not EPO. On linear regression analysis, lower AdjΔHb was associated with higher day 14 levels of IL-6 (r = 0.22, p < 0.01), IL-8 (r = 0.10, p = 0.04), stromal cell-derived factor 1 (r = 0.14, p = 0.02), and tumor necrosis factor α (r = 0.13, p = 0.02), but not EPO. Patients with negative AdjΔHb had significantly lower mean corpuscular volume on days 4 (89.6 vs. 93.2 fL/cell, p = 0.04), 7 (92.3 vs. 94.9 fL/cell, p = 0.04), and 14 (92.1 vs. 96.0 fL/cell, p = 0.03) but similar serum transferrin receptor levels.

CONCLUSION

Persistent elevation of inflammatory cytokines was associated with iron-restricted anemia among critically ill septic patients, occurring in the absence of systemic iron deficiency, independent of endogenous EPO.

LEVEL OF EVIDENCE

Prognostic study, level II.

Perioperative blood transfusion is associated with an increased risk for post-surgical infection following pancreaticoduodenectomy

BACKGROUND/PURPOSE

Perioperative blood transfusion is common after pancreaticoduodenectomy (PD) and may predispose patients to infectious complications. The purpose of this study is to examine the association between perioperative blood transfusion and the development of post-surgical infection after PD.

METHODS

Patients who underwent PD from 2014 to 2015 were identified in the NSQIP pancreas-specific database. Logistic regression analysis was used to compute adjusted odds ratios (aOR) to identify an independent association between perioperative red blood cell transfusion (within 72 h of surgery) and the development of post-operative infection after 72 h.

RESULTS

A total of 6869 patients underwent PD during this time period. Of these, 1372 (20.0%) patients received a perioperative blood transfusion. Patients receiving transfusion had a higher rate of post-operative infection (34.7% vs 26.5%, p < 0.001). After adjusting for significant covariates, perioperative transfusion was independently associated the subsequent development of any post-operative infection (aOR 1.41 [1.23-1.62], p < 0.001), including pneumonia (aOR 2.01 [1.48-2.74], p < 0.001), sepsis (aOR 1.62 [1.29-2.04], p < 0.001), and septic shock (aOR 1.92 [1.38-2.68], p < 0.001).

CONCLUSION

There is a strong independent association between perioperative blood transfusion and the development of subsequent post-operative infection following PD.

The Postinjury Inflammatory State and the Bone Marrow Response to Anemia

RATIONALE

The pathophysiology of persistent injury-associated anemia is incompletely understood, and human data are sparse.

OBJECTIVES

To characterize persistent injury-associated anemia among critically ill trauma patients with the hypothesis that severe trauma would be associated with neuroendocrine activation, erythropoietin dysfunction, iron dysregulation, and decreased erythropoiesis.

METHODS

A translational prospective observational cohort study comparing severely injured, blunt trauma patients who had operative fixation of a hip or femur fracture (n = 17) with elective hip repair patients (n = 22). Bone marrow and plasma obtained at the index operation were assessed for circulating catecholamines, systemic inflammation, erythropoietin, iron trafficking pathways, and erythroid progenitor growth. Bone marrow was also obtained from healthy donors from a commercial source (n = 8).

MEASUREMENTS AND MAIN RESULTS

During admission, trauma patients had a median of 625 ml operative blood loss and 5 units of red blood cell transfusions, and Hb decreased from 10.5 to 9.3 g/dl. Compared with hip repair, trauma patients had higher median plasma norepinephrine (21.9 vs. 8.9 ng/ml) and hepcidin (56.3 vs. 12.2 ng/ml) concentrations (both P < 0.05). Bone marrow erythropoietin and erythropoietin receptor expression were significantly increased among patients undergoing hip repair (23% and 14% increases, respectively; both P < 0.05), but not in trauma patients (3% and 5% increases, respectively), compared with healthy control subjects. Trauma patients had lower bone marrow transferrin receptor expression than did hip repair patients (57% decrease; P < 0.05). Erythroid progenitor growth was decreased in trauma patients (39.0 colonies per plate; P < 0.05) compared with those with hip repair (57.0 colonies per plate; P < 0.05 compared with healthy control subjects) and healthy control subjects (66.5 colonies per plate).

CONCLUSIONS

Severe blunt trauma was associated with neuroendocrine activation, erythropoietin dysfunction, iron dysregulation, erythroid progenitor growth suppression, and persistent injury-associated anemia. Clinical trial registered with www.clinicaltrials.gov (NCT 02577731).

Inflammatory anemia-associated parameters are related to 28-day mortality in patients with sepsis admitted to the ICU: a preliminary observational study

Background

Anemia is one of the most common complications of sepsis. Sepsis-related anemia is associated mainly with inflammation. We aimed to observe the changes in the inflammatory anemia-associated parameters of patients with sepsis in the early stage of intensive care unit (ICU) admission and to evaluate their association with 28-day mortality.

Methods

A total of 198 patients with sepsis were divided into survivor (n = 110) and non-survivor (n = 88) groups on the basis of 28-day survival. Healthy volunteers (n = 20) were enrolled as a control group. Plasma levels of iron, ferritin, erythropoietin (EPO), soluble transferrin receptor (sTfR), hepcidin, interleukin-6 (IL-6), hemoglobin and the red blood cell distribution width (RDW) were measured on days 1, 3 and 7 of ICU admission. Clinical data and laboratory findings were collected, and the Sequential Organ Failure Assessment (SOFA) score was calculated.

Results

Patients with sepsis showed significant decreases in hemoglobin, plasma iron and sTfR/log ferritin and significant increases in plasma EPO, sTfR, hepcidin, ferritin and IL-6 on days 1, 3 and 7 of ICU admission compared with healthy volunteers. Hemoglobin was correlated negatively with plasma IL-6 and hepcidin. In patients with sepsis, non-survivors had significantly lower plasma iron, EPO and sTfR/log ferritin, but higher plasma hepcidin, ferritin and IL-6 than survivors on days 1, 3 and 7 of ICU admission. Plasma EPO, hepcidin, ferritin, IL-6, sTfR/log ferritin, the RDW and SOFA score were associated significantly with 28-day mortality but to a varying extent. In particular, in predicting 28-day mortality, plasma hepcidin had an area under the receiver operating curve of 0.808 and 87.3% specificity, which was the highest among the inflammatory anemia-associated parameters tested.

Conclusions

Inflammatory anemia-associated parameters changed significantly in patients with sepsis in the first week of ICU admission. Plasma EPO, hepcidin, ferritin, IL-6, sTfR/log ferritin, the RDW and SOFA score were associated significantly with 28-day mortality. Plasma hepcidin might have a superior predictive value, with high specificity, compared with other inflammatory anemia-associated parameters for 28-day mortality of sepsis patients in the ICU.

Electronic supplementary material

The online version of this article (10.1186/s13613-019-0542-7) contains supplementary material, which is available to authorized users.

Erythropoietin in Critical Illness and Trauma

Erythropoietin (EPO) is a 34kD pleiotropic cytokine that was first identified as being essential for red blood cell (RBC) production. It is now recognized however that EPO is produced by many tissues. It plays a key role in the modulation of the response to injury, inflammation, and tissue hypoxia via the inhibition of apoptosis. Large clinical trials in the critically ill failed to demonstrate a role for EPO as an RBC transfusion sparing agent; however, improved clinical outcomes, attributable to EPO role in tissue protection are observed in critically ill trauma patients. Further research to confirm or refute these observations is required.

Recombinant Human Erythropoietin in Severe Anaemia: Issues of Dosing and Duration

The majority of Jehovah's Witnesses refuse blood product transfusion, even when it can be lifesaving. Treatment with recombinant human erythropoietin (RHuEPO) is a valuable adjunct in Jehovah's Witness patients undergoing surgery. A number of additional strategies, including acute normovolaemic haemodilution, intra-operative blood salvage and reinfusion, iron and folate supplementation are also utilized to avoid blood transfusion. Critically ill patients have blunted erythropoietin production and decreased endogenous iron availability. This case report reviews the treatment of anaemia in critically ill Jehovah's Witness patients after surgery and discusses the potential need for higher RHuEPO dosing strategies and longer duration of therapy.

Red cell distribution width at hospital discharge and out-of hospital outcomes in critically ill non-cardiac vascular surgery patients

Objective

Red cell distribution width (RDW) is associated with mortality and bloodstream infection risk in the critically ill. In vascular surgery patients surviving critical care it is not known if RDW can predict subsequent risk of all-cause mortality following hospital discharge. We hypothesized that an increase in RDW at hospital discharge in vascular surgery patients who received critical care would be associated with increased mortality following hospital discharge.

Design, setting, and participants

We performed a two-center observational cohort study of critically ill non-cardiac vascular surgery patients surviving admission 18 years or older treated between November, 1997, and December 2012 in Boston, Massachusetts.

Exposures

RDW measured within 24 hours of hospital discharge and categorized a priori as ≤13.3%, 13.3–14.0%, 14.0–14.7%, 14.7–15.8%, >15.8%.

Main outcomes and measures

The primary outcome was all cause mortality in the 90 days following hospital discharge.

Results

The cohort included 4,715 patients (male 58%; white 83%; mean age 62.9 years). 90 and 365-day post discharge mortality was 7.5% and 14.4% respectively. In the cohort, 47.3% were discharged to a care facility and 14.8% of patients were readmitted within 30 days. After adjustment for age, gender, race, Deyo-Charlson comorbidity Index, patient type, acute organ failures, prior vascular surgery and vascular surgery category, patients with a discharge RDW 14.7–15.8% or >15.8% have an adjusted OR of 90-day post discharge mortality of 2.52 (95%CI, 1.29–4.90; P = 0.007) or 5.13 (95%CI, 2.70–9.75; P <0.001) relative to patients with a discharge RDW ≤13.3%. The adjusted odds of 30-day readmission in the RDW >15.8% group was 1.52 (95%CI, 1.12–2.07; P = 0.007) relative to patients with a discharge RDW ≤13.3%. Similar adjusted discharge RDW-outcome associations are present at 365 days following hospital discharge and for discharge to a care facility.

Conclusions

In critically ill vascular surgery patients who survive hospitalization, an elevated RDW at hospital discharge is a strong predictor of subsequent mortality, hospital readmission and placement in a care facility. Patients with elevated RDW are at high risk for adverse out of hospital outcomes and may benefit from closer post discharge follow-up and higher intensity rehabilitation.

Relationship between Anaemia, Haemolysis, Inflammation and Haem Oxygenase-1 at Admission with Sepsis: a pilot study

Upregulation of haem oxygenase-1 (HO-1), due to haemolysis and/or inflammation, can lead to impaired immune function. Anaemia is common among sepsis patients, but the consequences of sepsis-associated anaemia are poorly understood. Here, our objective was to determine the prevalence and extent of anaemia, haemolysis, inflammation, and HO-1 induction after early hospital admission. We hypothesised that inflammation- or infection-induced haemolysis contributes to sepsis-associated anaemia and that this will lead to expression of HO-1. In this study, plasma obtained from seventy adult patients within 12 hours of admission to intensive care due to sepsis were analysed for anaemia, haemolysis and inflammatory markers by ELISA and microbead array. The majority (82.6%) of patients were anaemic with evidence of haemolysis (raised haem, haptoglobin, haemopexin, and HO-1 concentrations). Interestingly, concentrations of both haemoglobin and IL-10 were moderately positively correlated with HO-1 concentration (Hb: r = 0.32, p = 0.007; IL-10 r = 0.39, p = 0.0008) whereas HO-1 concentration was weakly negatively correlated with haemopexin (r = −0.23, p = 0.055). Anaemia, while common, was not associated with HO-1 concentration. After adjusting for confounding, HO-1 induction appears to be associated primarily with IL-10 concentration rather than haemolysis. Disease severity at diagnosis was correlated with early plasma IL-10 (r = 0.35, p = 0.003) and HO-1 (r = 0.24, p = 0.048) concentrations. Notably, admission levels of haem, HO-1, and IL-10 were indicators of survival.

Anaemia and transfusion triggers in critically ill patients - What we have learnt thus far

Anaemia is a common finding in critically ill patients, the cause of which is multi-factorial including: sepsis, haemolysis (and disseminated intravascular coagulation), iatrogenic blood loss secondary to laboratory sampling, post-operative anaemia, bone marrow suppression/failure, decreased production of erythropoietin, anaemia secondary to drugs/toxins, overt or occult blood loss, functional iron deficiency, poor nutrition and haemodilution. Anaemia is associated with deleterious outcomes including increased risk of cardiac-related morbidity and mortality and decrease in oxygen-carrying capacity in the face of increased metabolic demands. There is a growing body of evidence, which demonstrates that packed red blood cell transfusions are associated with poorer outcomes. Clinicians therefore need to weigh the potential benefit of treating anaemia against the desire to avoid unnecessary transfusions. We explored current literature regarding transfusion triggers and morbidity and mortality associated with packed red blood cell transfusions transfusion, concentrating on studies that have been conducted in critical care patients. In addition, we reflected on trials which considered the viability of iron transfusion and erythropoietin in critically unwell patients.

Is There a Role for Hematopoietic Growth Factors During Sepsis?

Sepsis is a complex syndrome characterized by simultaneous activation of pro- and anti-inflammatory processes. After an inflammatory phase, patients present signs of immunosuppression and possibly persistent inflammation. Hematopoietic growth factors (HGFs) are glycoproteins that cause immune cells to mature and/or proliferate. HGFs also have a profound effect on cell functions and behavior. HGFs play crucial role in sepsis pathophysiology and were tested in several clinical trials without success to date. This review summarizes the role played by HGFs during sepsis and their potential therapeutic role in the Management of sepsis-related immune disturbances.

Red cell distribution width predicts out of hospital outcomes in critically ill emergency general surgery patients

Introduction

Red cell distribution width (RDW) is associated with mortality and bloodstream infection risk in critically ill patients. We hypothesized that an increase in RDW at hospital discharge in critically ill patients who received emergency general surgery (EGS) would be associated with increased mortality after hospital discharge.

Methods

We performed a two-center observational study of patients treated in medical and surgical intensive care units. We studied 1567 patients, who received critical care between 1998 and 2012 who underwent EGS and survived hospitalization. The exposure of interest was RDW within 24 hours of hospital discharge and categorized a priori in quintiles as ≤13.3%, 13.3% to 14.0%, 14.0% to 14.7%, 14.7% to 15.8%, 15.8% to 17.0% and >17.0%. The primary outcome was 90-day all-cause mortality. Adjusted ORs were estimated by multivariable logistic regression models with inclusion of covariate terms for age, race, gender, Deyo-Charlson Index, sepsis and number of organs with acute failure.

Results

The cohort patients were 51.4% male and 23.2% non-white. 23.9% had sepsis and the mean age was 58 years. 90-day postdischarge mortality was 6.8%. Patients with a discharge RDW 15.8% to 17.0% or RDW >17.0% have an adjusted OR of 90-day postdischarge mortality of 3.64 (95% CI 1.04 to 12.68; p=0.043) or 4.58 (95% CI 1.32 to 15.93; p=0.02), respectively, relative to patients with a discharge RDW ≤13.3%. Further, patients with a discharge RDW ≥15.8 have an adjusted OR of 30-day hospital readmission of 2.12 (95% CI 1.17 to 3.83; p=0.013) relative to patients with a discharge RDW ≤13.3%.

Conclusions

In EGS patients requiring critical care who survive hospitalization, an elevated RDW at the time of discharge is a robust predictor of all-cause patient mortality and hospital readmission after discharge.

Level of evidence

Level II, prognostic retrospective study.

Extracellular HMGB1 as a therapeutic target in inflammatory diseases

INTRODUCTION

High-mobility group box 1 (HMGB1) is a ubiquitous nuclear protein that promotes inflammation when released extracellularly after cellular activation, stress, damage or death. HMGB1 operates as one of the most intriguing molecules in inflammatory disorders via recently elucidated signal and molecular transport mechanisms. Treatments based on antagonists specifically targeting extracellular HMGB1 have generated encouraging results in a wide number of experimental models of infectious and sterile inflammation. Clinical studies are still to come. Areas covered: We here summarize recent advances regarding pathways for extracellular HMGB1 release, receptor usage, and functional consequences of post-translational modifications. The review also addresses results of preclinical HMGB1-targeted therapy studies in multiple inflammatory conditions and outlines the current status of emerging clinical HMGB1-specific antagonists. Expert opinion: Blocking excessive amounts of extracellular HMGB1, particularly the disulfide isoform, offers an attractive clinical opportunity to ameliorate systemic inflammatory diseases. Therapeutic interventions to regulate intracellular HMGB1 biology must still await a deeper understanding of intracellular HMGB1 functions. Future work is needed to create more robust assays to evaluate functional bioactivity of HMGB1 antagonists. Forthcoming clinical studies would also greatly benefit from a development of antibody-based assays to quantify HMGB1 redox isoforms, presently assessed by mass spectrometry methods.

Effects of red blood cell storage time on transfused patients in the ICU-protocol for a systematic review

BACKGROUND

Patients in the intensive care unit (ICU) are often anaemic due to blood loss, impaired red blood cell (RBC) production and increased RBC destruction. In some studies, more than half of the patients were treated with RBC transfusion. During storage, the RBC and the storage medium undergo changes, which lead to impaired transportation and delivery of oxygen and may also promote an inflammatory response. Divergent results on the clinical consequences of storage have been reported in both observational studies and randomised trials. Therefore, we aim to gather and review the present evidence to assess the effects of shorter vs. longer storage time of transfused RBCs for ICU patients.

METHODS

We will conduct a systematic review with meta-analyses and trial sequential analyses of randomised clinical trials, and also include results of severe adverse events from large observational studies. Participants will be adult patients admitted to an ICU and treated with shorter vs. longer stored RBC units. We will systematically search the Cochrane Library, MEDLINE, Embase, BIOSIS, CINAHL and Science Citation Index for relevant literature, and we will follow the recommendation by the Cochrane Collaboration and the Preferred Reporting Items for Systemtic Review and Meta-Analysis (PRISMA)-statement. We will assess the risk of bias and random errors, and we will use the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach to evaluate the overall quality of evidence.

CONCLUSION

We need a high-quality systematic review to summarise the clinical consequences of RBC storage time among ICU patients.

Harms of off-label erythropoiesis-stimulating agents for critically ill people

BACKGROUND

Anaemia is a common problem experienced by critically-ill people. Treatment with erythropoiesis-stimulating agents (ESAs) has been used as a pharmacologic strategy when the blunted response of endogenous erythropoietin has been reported in critically-ill people. The use of ESAs becomes more important where adverse clinical outcomes of transfusing blood products is a limitation. However, this indication for ESAs is not licensed by regulatory authorities and is called off-label use. Recent studies concern the harm of ESAs in a critical care setting.

OBJECTIVES

To focus on harms in assessing the effects of erythropoiesis-stimulating agents (ESAs), alone or in combination, compared with placebo, no treatment or a different active treatment regimen when administered off-label to critically-ill people.

SEARCH METHODS

We conducted a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO via OvidSP, CINAHL, all evidence-based medicine (EBM) reviews including IPA and SCI-Expanded, Conference Proceedings Citation Index- Science, BIOSIS Previews and TOXLINE up to February 2017. We also searched trials registries, checked reference lists of relevant studies and tracked their citations by using SciVerse Scopus.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) and controlled observational studies, which compared scheduled systemic administration of ESAs versus other effective interventions, placebo or no treatment in critically-ill people.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and evaluated the eligibility of retrieved records, extracted data and assessed the risks of bias and quality of the included studies. We resolved differences in opinion by consensus or by involving a third review author. We assessed the evidence using GRADE and created a 'Summary of findings' table. We used fixed-effect or random-effects models, depending on the heterogeneity between studies. We fitted three-level hierarchical Bayesian models to calculate overall treatment effect estimates.

MAIN RESULTS

Of the 27,865 records identified, 39 clinical trials and 14 observational studies, including a total of 945,240 participants, were eligible for inclusion. Five studies are awaiting classification. Overall, we found 114 adverse events in 33 studies (30 RCTs and three observational studies), and mortality was reported in 41 studies (32 RCTs and nine observational studies). Most studies were at low to moderate risk of bias for harms outcomes. However, overall harm assessment and reporting were of moderate to low quality in the RCTs, and of low quality in the observational studies. We downgraded the GRADE quality of evidence for venous thromboembolism and mortality to very low and low, respectively, because of risk of bias, high inconsistency, imprecision and limitations of study design.It is unclear whether there is an increase in the risk of any adverse events (Bayesian risk ratio (RR) 1.05, 95% confidence interval (CI) 0.93 to 1.21; 3099 participants; 9 studies; low-quality evidence) or venous thromboembolism (Bayesian RR 1.04, 95% CI 0.70 to 1.41; 18,917 participants; 18 studies; very low-quality evidence).There was a decreased risk of mortality with off-label use of ESAs in critically-ill people (Bayesian RR 0.76, 95% CI 0.61 to 0.92; 930,470 participants; 34 studies; low-quality evidence).

AUTHORS' CONCLUSIONS

Low quality of evidence suggests that off-label use of ESAs may reduce mortality in a critical care setting. There was a lack of high-quality evidence about the harm of ESAs in critically-ill people. The information for biosimilar ESAs is less conclusive. Most studies neither evaluated ESAs' harm as a primary outcome nor predefined adverse events. Any further studies of ESA should address the quality of evaluating, recording and reporting of adverse events.

Characterization of erythropoietin and hepcidin in the regulation of persistent injury-associated anemia

BACKGROUND

The cause of persistent injury-associated anemia is multifactorial and includes acute blood loss, an altered erythropoietin (EPO) response, dysregulation of iron homeostasis, and impaired erythropoiesis in the setting of chronic inflammation/stress. Hepcidin plays a key role in iron homeostasis and is regulated by anemia and inflammation. Erythropoietin is a main regulator of erythropoiesis induced by hypoxia. A unique rodent model of combined lung injury (LC)/hemorrhagic shock (HS) (LCHS)/chronic restraint stress (CS) was used to produce persistent injury-associated anemia to further investigate the roles of EPO, hepcidin, iron, ferritin, and the expression of EPO receptors (EPOr).

METHODS

Male Sprague-Dawley rats were randomly assigned into one of the four groups of rodent models: naive, CS alone, combined LCHS, or LCHS/CS. Plasma was used to evaluate levels of EPO, hepcidin, iron, and ferritin. RNA was isolated from bone marrow and lung tissue to evaluate expression of EPOr. Comparisons between models were performed by t tests followed by one-way analysis of variance.

RESULTS

After 7 days, only LCHS/CS was associated with persistent anemia despite significant elevation of plasma EPO. Combined LCHS and LCHS/CS led to a persistent decrease in EPOr expression in bone marrow on Day 7. The LCHS/CS significantly decreased plasma hepcidin levels by 75% on Day 1 and 84% on Day 7 compared to LCHS alone. Hepcidin plasma levels are inversely proportional to EPO plasma levels (Pearson R = -0.362, p < 0.05).

CONCLUSION

Tissue injury, hemorrhagic shock, and stress stimulate and maintain high levels of plasma EPO while hepcidin levels are decreased. In addition, bone marrow EPOr and plasma iron availability are significantly reduced following LCHS/CS. The combined deficit of reduced iron availability and reduced bone marrow EPOr expression may play a key role in the ineffective EPO response associated with persistent injury-associated anemia.

Hemoglobin Threshold for Blood Transfusion in a Pediatric Intensive Care Unit

OBJECTIVE

To evaluate the hemoglobin threshold for red cell transfusion in children admitted to a pediatric intensive care unit (PICU).

METHODS

Retrospective chart review study. Tertiary care PICU. Critically ill pediatric patients requiring blood transfusion. No intervention.

RESULTS

We analyzed the charts of all children between 1 month and 21 years of age who received packed red blood cell (PRBC) transfusions during a 2-year period. The target patients were identified from our blood bank database. For analysis, the patients were subdivided into four groups: acute blood loss (postsurgically, trauma, or acute gastrointestinal bleeding from other causes), hematologic (hematologic malignancies, bone marrow suppression, hemolytic anemia, or sickle cell disease), unstable (FiO₂ > 0.6 and/or on inotropic support), and stable groups. We also compared the pre-transfusion hemoglobin threshold in all unstable patients with that of all stable patients. A total of 571 transfusion episodes in 284 patients were analyzed. 28% (n = 160) of transfusions were administered to patients in the acute blood loss group, 36% (n = 206) to hematologic patients, 17% (n = 99) to unstable patients, and 18% (n = 106) to stable patients. The mean pre-transfusion hemoglobin (± SD) in all children as well as in the acute blood loss, hematologic, unstable and stable groups was 7.3 ± 1.20, 7.83 ± 1.32, 6.97 ± 1.31, 7.96 ± 1.37, 7.31 ± 1.09 g/dl, respectively. The transfusion threshold for acute blood loss and unstable groups was higher compared to hematologic and stable groups (p < 0.001; ANOVA with multiple comparisons). The mean pre-transfusion hemoglobin threshold for stable and unstable patients among all groups was 7.3 ± 1.3 and 7.9 ± 1.3 (p < 0.0001), respectively. The observed mortality rate was higher among children who received transfusion compared to other children admitted to PICU.

CONCLUSION

The hemoglobin threshold for transfusion varied according to clinical conditions. Overall, the hemoglobin threshold for transfusion was 7.3 ± 1.20 g/dl.

HMGB1 Mediates Anemia of Inflammation in Murine Sepsis Survivors

Patients surviving sepsis develop anemia, but the molecular mechanism is unknown. Here we observed that mice surviving polymicrobial gram-negative sepsis develop hypochromic, microcytic anemia with reticulocytosis. The bone marrow of sepsis survivors accumulates polychromatophilic and orthochromatic erythroblasts. Compensatory extramedullary erythropoiesis in the spleen is defective during terminal differentiation. Circulating tumor necrosis factor (TNF) and interleukin (IL)-6 are elevated for 5 d after the onset of sepsis, and serum high-mobility group box 1 (HMGB1) levels are increased from d 7 until at least d 28. Administration of recombinant HMGB1 to healthy mice mediates anemia with extramedullary erythropoiesis and significantly elevated reticulocyte counts. Moreover, administration of anti-HMGB1 monoclonal antibodies after sepsis significantly ameliorates the development of anemia (hematocrit 48.5 ± 9.0% versus 37.4 ± 6.1%, p < 0.01; hemoglobin 14.0 ± 1.7 versus 11.7 ± 1.2 g/dL, p < 0.01). Together, these results indicate that HMGB1 mediates anemia by interfering with erythropoiesis, suggesting a potential therapeutic strategy for anemia in sepsis.

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

BACKGROUND

Anemia is a common feature during sepsis that occurs due to iatrogenic blood loss, depression of serum iron levels and erythropoietin production, and a decreased lifespan of erythrocytes. However, these mechanisms are unlikely to play a role in anemia at the start of sepsis. Moreover, sequestration of fluids, renal failure and increase of intravascular space may additionally influence the change in hemoglobin concentration during intravenous fluid administration in the acute phase of sepsis.

METHODS

In this retrospective study, patients who were admitted acutely to the Intensive Care Unit (ICU) were included. Patients who fulfilled the international criteria for severe sepsis or septic shock were included in the sepsis group (S-group). The remaining patients were allocated to the control group (C-group). Laboratory data from blood samples taken at first presentation to the hospital and at admission to the ICU, the amount of intravenous fluid administration and length of stay in the emergency department were collected and tested for significant differences between groups.

RESULTS

The difference in hemoglobin concentration between the S-group (n = 296) and C-group (n = 320) at first presentation in hospital was not significant (8.8 ± 1.2 versus 8.9 ± 1.2 mmol/l, respectively, p = 0.07). The reduction in hemoglobin concentration from the first presentation at the emergency department to ICU admission was significantly greater in the S-group compared to the C-group (1 [0.5-1.7] versus 0.5 [0.1-1.1] mmol/l, (p < 0.001)). Spearman rho correlation coefficients between the reduction in hemoglobin concentration and the amount of intravenous fluids administered or the creatinine level in the emergency department were significant (0.3 and 0.4, respectively, p < 0.001). In a multivariate regression analysis, creatinine, the amount of fluid administration and the presence of sepsis remained independently associated.

CONCLUSIONS

Prior to in-hospital intravenous fluid administration, there is no significant difference in hemoglobin concentration between acute septic patients and acutely ill controls. Within several hours after hospital admission, there is a significant reduction in hemoglobin concentration, not only associated with the amount of intravenous fluids administered and the creatinine level, but also independently with sepsis itself.

Transfusion-free management of gastrointestinal bleeding: the experience of a bloodless institute

GOALS

The Institute for Patient Blood Management and Bloodless Medicine at the Englewood Hospital has considerable experience in managing patients with gastrointestinal bleeding who do not accept blood-derived products. We present our data and experience over the last 8 years in managing such patients.

BACKGROUND

There is paucity of data on management and outcomes of gastrointestinal bleeding in patients who do not accept blood-derived products.

STUDY

We performed a retrospective study of patients from 2003 to 2011 presenting with gastrointestinal bleeding who do not accept blood-derived products. Inclusion criteria were either overt bleeding with a presenting hemoglobin (Hb) of <12 g/dL or a decrease in Hb of >1.5 g/dL.

RESULTS

Ninety-six patients who met the inclusion criteria were included. Forty-one upper and 48 lower gastrointestinal bleeding sources were identified. Mean Hb was 8.8 g/dL and mean nadir was 6.9 g/dL. Among 37 patients (80.5%) with Hb ≤6.0 g/dL, 30 (81%) survived. Four of 7 patients (57%) with a Hb <3 g/dL survived. The overall mortality rate was 10.4%. In unadjusted logistic regression models, age [1.06 (1.01-1.12 y)], admission to ICU [6.37(1.27-31.9)], and anticoagulation use [6.95 (1.57-30.6)] were associated with increased mortality. Initial Hb [0.68 (0.51-0.92)] and nadir Hb [0.48 (0.29-0.78)] inversely predicted mortality.

CONCLUSIONS

These results suggest that transfusion-free management of gastrointestinal hemorrhage can be effective with mortality comparable with the general population accepting medically indicated transfusion. Management of these patients is challenging and requires a dedicated multidisciplinary team approach knowledgeable in techniques of blood conservation.

Red cell distribution width as a potential index to assess the severity of hepatitis B virus-related liver diseases

AIM

To investigate the association between red cell distribution width (RDW) and the severity of hepatitis B virus (HBV)-related liver diseases.

METHODS

Sixty-nine patients with chronic hepatitis B (CHB) and 61 patients with HBV-related liver cirrhosis were enrolled in the present study. Forty-one healthy individuals were included as controls. Hematological parameters, hepatitis B e-antigen (HBeAg) status, HBV DNA levels and liver biochemistry were analyzed. Child-Pugh scores and Model for End-Stage Liver Disease (MELD) scores of the patients with HBV-related liver cirrhosis were calculated.

RESULTS

The RDW was significantly higher in patients with HBV-related liver cirrhosis as compared with CHB patients and healthy controls. RDW was slightly higher in CHB patients as compared with healthy controls. An increasing correlation of RDW with Child-Pugh grades was found. RDW was positively correlated with Child-Pugh scores and MELD scores. In patients with HBV-related liver cirrhosis, RDW was also positively correlated with total bilirubin and negatively correlated with hemoglobin and serum albumin concentration. However, no significant difference was found between HBeAg positive and negative patients and no significant correlation between RDW and HBV DNA levels was found.

CONCLUSION

The RDW was elevated in CHB patients and patients with HBV-related liver cirrhosis and was positively correlated with the severity of HBV-related liver cirrhosis. RDW is a potential index to assess the severity of HBV-related liver diseases.

Serum soluble-Fas is a predictor of red blood cell transfusion in critically ill patients

Objective:

To investigate the relation between the need for red blood cell transfusion and serum levels of soluble-Fas, erythropoietin and inflammatory cytokines in critically ill patients with and without acute kidney injury.

Methods:

We studied critically ill patients with acute kidney injury (n=30) and without acute kidney injury (n=13), end-stage renal disease patients on hemodialysis (n=25) and healthy subjects (n=21). Serum levels of soluble-Fas, erythropoietin, interleukin 6, interleukin 10, iron status, hemoglobin and hematocrit concentration were analyzed in all groups. The association between these variables in critically ill patients was investigated.

Results:

Critically ill patients (acute kidney injury and non-acute kidney injury patients) had higher serum levels of erythropoietin than the other groups. Hemoglobin concentration was lower in the acute kidney injury patients than in other groups. Serum soluble-Fas levels were higher in acute kidney injury and end-stage renal disease patients. Critically ill patients requiring red blood cell transfusions had higher serum levels of soluble-Fas (5,906±2,047 and 1,920±1,060; p<0.001), interleukin 6 (518±537 and 255+502; p=0.02) and interleukin 10 (35.8±30.7 and 18.5±10.9; p=0.02), better iron status and higher mortality rates in the first 28 days in intensive care unit. Serum soluble-Fas levels were independently associated with the number of red blood cell units transfused (p=0.02). Serum soluble-Fas behaved as an independent predictor of the need for red blood cell transfusion in critically ill patients (p=0.01).

Conclusions:

Serum soluble-Fas level is an independent predictor of the need for red blood cell transfusion in critically ill patients with or without acute kidney injury. Further studies are warranted to reconfirm this finding.

The association of red cell distribution width at hospital discharge and out-of-hospital mortality following critical illness*

OBJECTIVES

Red cell distribution width is associated with mortality and bloodstream infection risk in the critically ill. In hospitalized patients with critical illness, it is not known if red cell distribution width can predict subsequent risk of all-cause mortality following hospital discharge. We hypothesized that an increase in red cell distribution width at hospital discharge in patients who survived to discharge following critical care would be associated with increased postdischarge mortality.

DESIGN

Two-center observational cohort study

SETTING

: All medical and surgical ICUs at the Brigham and Women's Hospital and Massachusetts General Hospital.

PATIENTS

We studied 43,212 patients, who were 18 years old or older and received critical care between 1997 and 2007 and survived hospitalization.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The exposure of interest was red cell distribution width within 24 hours of hospital discharge and categorized a priori in quintiles as less than or equal to 13.3%, 13.3-14.0%, 14.0-14.7%, 14.7-15.8%, and more than 15.8%. The primary outcome was all-cause mortality in the 30 days following hospital discharge. Secondary outcomes included 90-day and 365-day mortality following hospital discharge. Mortality was determined using the U.S. Social Security Administration Death Master File, and 365-day follow-up was present in all cohort patients. Adjusted odds ratios were estimated by multivariable logistic regression models with inclusion of covariate terms thought to plausibly interact with both red cell distribution width and mortality. Adjustment included age, race, gender, Deyo-Charlson Index, patient type (medical vs surgical), sepsis, and number of organs with acute failure. In patients who received critical care and survived hospitalization, the discharge red cell distribution width was a robust predictor of all-cause mortality and remained so following multivariable adjustment. Patients with a discharge red cell distribution width of 14.0-14.7%, 14.7-15.8%, and more than 15.8% have an odds ratio for mortality in the 30 days following hospital discharge of 2.86 (95% CI, 2.25-3.62), 4.57 (95% CI, 3.66-5.72), and 8.80 (95% CI, 7.15-10.83), respectively, all relative to patients with a discharge red cell distribution width less than or equal to 13.3%. Following multivariable adjustment, patients with a discharge red cell distribution width of 14.0-14.7%, 14.7-15.8%, and more than 15.8% have an odds ratio for mortality in the 30 days following hospital discharge of 1.63 (95% CI, 1.27-2.07), 2.36 (95% CI, 1.87-2.97), and 4.18 (95% CI, 3.36-5.20), respectively, all relative to patients with a discharge red cell distribution width less than or equal to 13.3%. Similar significant robust associations post multivariable adjustments are seen with death by days 90 and 365 postdischarge. Estimating the receiver-operating characteristic area under the curve shows that discharge red cell distribution width has moderate discriminative power for mortality 30 days following hospital discharge (area under the curve = 0.70; SE 0.006; 95% CI, 0.69-0.71; p < 0.0001).

CONCLUSION

In patients treated with critical care who survive hospitalization, an elevated red cell distribution width at the time of discharge is a robust predictor of subsequent all-cause patient mortality. Increased discharge red cell distribution width likely reflects the presence of proinflammatory state, oxidative stress, arterial underfilling, or a combination, thereof which may explain the observed impact on patient survival following discharge. Elevated red cell distribution width at hospital discharge may identify ICU survivors who are at risk for adverse outcomes following hospital discharge.

Anaemia secondary to critical illness: an unexplained phenomenon

Almost all patients suffering critical illness become anaemic during their time in intensive care. The cause of this anaemia and its management has been a topic of debate in critical care medicine for the last two decades. Packed red cell transfusion has an associated cost and morbidity such that decreasing the number of units transfused would be of great benefit. Our understanding of the aetiology and importance of this anaemia is improving with recent and ongoing work to establish the cause, effect and best treatment options. This review aims to describe the current literature whilst suggesting that the nature of the anaemia should be considered with reference to the time point in critical illness. Finally, we suggest that using haemoglobin concentration as a measure of oxygen-carrying capacity has limitations and that ways of measuring haemoglobin mass should be explored.

The impact of low hemoglobin levels and transfusion on critical care patients with severe ischemic stroke: STroke: RelevAnt Impact of HemoGlobin, Hematocrit and Transfusion (STRAIGHT)--an observational study

PURPOSE

Optimal management of hemoglobin (Hb) and red blood cell transfusion (RBCT) in neurologic intensive care unit (NICU) patients has not been determined yet. Here we aimed to investigate the impact of anemia and transfusion activity in patients who had acute ischemic stroke.

MATERIALS AND METHODS

A retrospective analysis of clinical, laboratory, and outcome data of patients with severe acute ischemic stroke treated on our NICU between 2004 and 2011 was performed.

RESULTS

Of 109 patients, 97.2% developed anemia and 33% received RBCT. Significant correlations were found between NICU length of stay (NICU LOS) and lowest (nadir) Hb (correlation coefficient, -0.42, P < .001), Hb decrease (0.52, P < .001), nadir hematocrit (Hct; -0.43, P < .001), and Hct decrease (0.51, P < .001). Duration of mechanical ventilation (MV) was strongly associated with both nadir Hb (-0.41, P < .001) and decrease (0.42, P < .001) and nadir Hct (-0.43, P < .001) and decrease (0.40, P < .001). Red blood cell transfusion correlated with NICU LOS (0.33, P < .001) and with duration of MV (0.40, P < .001). None of these hematologic parameters correlated with in-hospital mortality or 90-day outcome. The linear regression model showed number of RBCT (0.29, P = .008), nadir Hb (-0.18, P = .049), Hb decrease (0.33, P < .001), nadir Hct (-0.18, P = .03), and Hct decrease (0.29, P < .001) to be independent predictors of NICU LOS. Duration of MV was also independently predicted by number of RBC transfusions (0.29, P < .001), nadir Hb (-0.20, P = .02), Hb decrease (0.25, P = .002), nadir Hct (-0.21, P = .015), and Hct decrease (0.26, P < .001).

CONCLUSIONS

Low and further decreasing Hb and Hct levels as well as RBCT activity are associated with prolonged NICU stay and duration of MV but not with mortality or long-term outcome. Our findings do not justify using a more aggressive transfusion practice at present.