Blunted erythropoietic response to anemia in multiply traumatized patients

Serum levels of erythropoietin in patients with chronic obstructive pulmonary disease and anemia

The important association of erythropoietin (EPO) serum levels and chronic obstructive pulmonary disease (COPD) with anemia has been inadequately studied and remains a controversial issue. We aimed to shed light on this matter by comparing EPO levels in anemic and non-anemic COPD patients, along with a review of published literature. This cross-sectional study was conducted on COPD patients referred to the pulmonary clinic of Shahid Faghihi Hospital and Motahari clinic, Shiraz, Iran, for one year. We measured complete blood count, red blood cell indices, serum iron, TIBC and ferritin levels, serum EPO levels, and body mass index. Among 35 patients in this study, 28 males and 7 females were enrolled with a mean age of 54.57 ± 8.07 years. The average Forced expiratory volume in first second (FEV1) was 37.26 ± 7.33% and FEV1/FVC was 0.46 ± 0.12. Mean EPO levels were 30.29 ± 2.066 mU/mL. No statistically significant association was observed among erythropoietin levels and Hb, COPD severity, and age. There was no significant difference in EPO levels between anemic and non-anemic patients. EPO level, against the traditional expectation, didn't increase in COPD patients. EPO production also didn't compensate for the anemia of chronic disease which considers as a common comorbid disorder in these patients.

Patient Blood Management

Patient blood management is a highly successful and cost-effective concept that improves patient outcome by correction of anemia with hematinic medication and reduction of blood loss perioperatively by meticulous surgical techniques and individualized coagulation management.

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).

Pterins as Diagnostic Markers of Mechanical and Impact-Induced Trauma: A Systematic Review

We performed a systematic review of the literature to evaluate pterins as biomarkers of mechanical and impact-induced trauma. MEDLINE and Scopus were searched in March 2019. We included in vivo human studies that measured a pterin in response to mechanical or impact-induced trauma with no underlying prior disease or complication. We included 40 studies with a total of 3829 subjects. Seventy-seven percent of studies measured a significant increase in a pterin, primarily neopterin or total neopterin (neopterin + 7,8-dihydroneopterin). Fifty-one percent of studies measured an increase within 24 h of trauma, while 46% measured increases beyond 48 h. Pterins also showed promise as predictors of post-trauma complications such as sepsis, multi-organ failure and mortality. Exercise-induced trauma and traumatic brain injury caused an immediate increase in neopterin or total neopterin, while patients of multiple trauma had elevated pterin levels that remained above baseline for several days. Pterin concentration changes in response to surgery were variable with patients undergoing cardiac surgery having immediate and sustained pterin increases, while gastrectomy, liver resection or hysterectomy showed no change. This review provides systematic evidence that pterins, in particular neopterin and total neopterin, increase in response to multiple forms of mechanical or impact-induced trauma.

The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition

Background

Severe traumatic injury continues to present challenges to healthcare systems around the world, and post-traumatic bleeding remains a leading cause of potentially preventable death among injured patients. Now in its fifth edition, this document aims to provide guidance on the management of major bleeding and coagulopathy following traumatic injury and encourages adaptation of the guiding principles described here to individual institutional circumstances and resources.

Methods

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004, and the current author group included representatives of six relevant European professional societies. The group applied a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were re-examined and revised based on scientific evidence that has emerged since the previous edition and observed shifts in clinical practice. New recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated.

Results

Advances in our understanding of the pathophysiology of post-traumatic coagulopathy have supported improved management strategies, including evidence that early, individualised goal-directed treatment improves the outcome of severely injured patients. The overall organisation of the current guideline has been designed to reflect the clinical decision-making process along the patient pathway in an approximate temporal sequence. Recommendations are grouped behind the rationale for key decision points, which are patient- or problem-oriented rather than related to specific treatment modalities. While these recommendations provide guidance for the diagnosis and treatment of major bleeding and coagulopathy, emerging evidence supports the author group’s belief that the greatest outcome improvement can be achieved through education and the establishment of and adherence to local clinical management algorithms.

Conclusions

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. If incorporated into local practice, these clinical practice guidelines have the potential to ensure a uniform standard of care across Europe and beyond and better outcomes for the severely bleeding trauma patient.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2347-3) contains supplementary material, which is available to authorized users.

Iron Metabolism: An Emerging Therapeutic Target in Critical Illness

This article is one of ten reviews selected from the Annual Update in Intensive Care and Emergency Medicine 2019. Other selected articles can be found online at https://www.biomedcentral.com/collections/annualupdate2019. Further information about the Annual Update in Intensive Care and Emergency Medicine is available from http://www.springer.com/series/8901.

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.

Pharmacotherapy in Acutely Anemic Jehovah’s Witnesses: An Evidence-Based Review

Objective: To determine the pharmacological treatment methods available to anemic Jehovah’s Witnesses (JW). Data Sources: MEDLINE and PubMed were searched from inception through February 2018 using the search terms Jehovah’s Witnesses, treatment, erythropoietin, hemoglobin-based oxygen carrier, Sanguinate, Hemopure, bleeding, and anemia. Study Selection and Data Extraction: All clinical trials, cohort studies, case-control studies, and observational trials involving pharmacotherapy in anemic JW patients were evaluated. Case reports and bibliographies were also analyzed for inclusion. Data Synthesis: Two studies involving the use of erythropoietin (EPO) and one study involving recombinant factor VIIa were included. Information was also included from other pharmacotherapeutic modalities that had case report data only. Current published evidence is limited with regard to evidence-based management of JW patients. High-dose EPO, intravenous iron supplementation, and hemostatic agents have demonstrated good clinical outcomes in case reports. EPO doses as high as 40 000 units daily have been advocated by some experts; however, pharmacokinetic studies do not support dose-dependent effects. Hemoglobin-based oxygen carriers (HBOCs) are currently not Food and Drug Administration approved. They are available through expanded access programs and may represent a lifesaving modality in the setting of severe anemia. Conclusions: There are currently not enough data to make definitive recommendations on the use of pharmacological agents to treat severe anemia in the JW population. Further evidence utilizing EPO and HBOCs will be beneficial to guide therapy.

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.

Children are not little adults: blood transfusion in children with burn injury

Blood transfusion in burns larger than 20% total body surface area (TBSA) are frequent due to operative procedures, blood sampling, and physiologic response to burn injury. Optimizing the use of blood transfusions requires an understanding of the physiology of burn injury, the risks and benefits of blood transfusion, and the indications for transfusion. Age also plays a role in determining blood transfusion requirements. Children in particular have a different physiology than adults, which needs to be considered prior to transfusing blood and blood products. This article describes the physiologic differences between children and adults in general and after burn injury and describes how these differences impact blood transfusion practices in children.

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.

The European guideline on management of major bleeding and coagulopathy following trauma: fourth edition

BACKGROUND

Severe trauma continues to represent a global public health issue and mortality and morbidity in trauma patients remains substantial. A number of initiatives have aimed to provide guidance on the management of trauma patients. This document focuses on the management of major bleeding and coagulopathy following trauma and encourages adaptation of the guiding principles to each local situation and implementation within each institution.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004 and included representatives of six relevant European professional societies. The group used a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were reconsidered and revised based on new scientific evidence and observed shifts in clinical practice; new recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated. This guideline represents the fourth edition of a document first published in 2007 and updated in 2010 and 2013.

RESULTS

The guideline now recommends that patients be transferred directly to an appropriate trauma treatment centre and encourages use of a restricted volume replacement strategy during initial resuscitation. Best-practice use of blood products during further resuscitation continues to evolve and should be guided by a goal-directed strategy. The identification and management of patients pre-treated with anticoagulant agents continues to pose a real challenge, despite accumulating experience and awareness. The present guideline should be viewed as an educational aid to improve and standardise the care of the bleeding trauma patients across Europe and beyond. This document may also serve as a basis for local implementation. Furthermore, local quality and safety management systems need to be established to specifically assess key measures of bleeding control and outcome.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. The implementation of locally adapted treatment algorithms should strive to achieve measureable improvements in patient outcome.

Impaired hematopoietic progenitor cells in trauma hemorrhagic shock

Hemorrhagic shock (HS) is the major cause of death during trauma. Mortality due to HS is about 50%. Dysfunction of hematopoietic progenitor cells (HPCs) has been observed during severe trauma and HS. HS induces the elevation of cytokines, granulocyte-colony stimulating factor (G-CSF), peripheral blood HPCs, and circulating catecholamines, and decreases the expression of erythropoietin receptor connected with suppression of HPCs. Impaired HPCs may lead to persistent anemia and risk of susceptibility to infection, sepsis, and MOF. There is a need to reactivate impaired HPCs during trauma hemorrhagic shock.

Chronic restraint stress after injury and shock is associated with persistent anemia despite prolonged elevation in erythropoietin levels

BACKGROUND

Following severe traumatic injury, critically ill patients have a prolonged hypercatacholamine state that is associated with bone marrow (BM) dysfunction and persistent anemia. However, current animal models of injury and shock result in a transient anemia. Daily restraint stress (chronic stress [CS]) has been shown to increase catecholamines. We hypothesize that adding CS following injury or injury and shock in rats will prolong the hypercatecholaminemia and prolong the initial anemia, despite elevated erythropoietin (EPO) levels.

METHODS

Male Sprague-Dawley rats (n = 6-8 per group) underwent lung contusion (LC) or combined LC/hemorrhagic shock (LCHS) followed by 6 days of CS. CS consisted of a 2-hour restraint period interrupted with repositioning and alarms every 30 minutes. At 7 days, urine was assessed for norepinephrine (NE) levels, blood for EPO and hemoglobin (Hgb), and BM for erythroid progenitor growth.

RESULTS

Animals undergoing LC or combined LCHS predictably recovered by Day 7; urine NE, EPO, and Hgb levels were normal. The addition of CS to LC and LCHS models was associated with a significant elevation in NE on Day 6. The addition of CS to LC led to a persistent 20% to 25% decrease in the growth of BM hematopoietic progenitor cells. These findings were further exaggerated when CS was added following LCHS, resulting in a 20%q to 40% reduction in BM erythroid progenitor colony growth and a 20% decrease in Hgb when compared with LCHS alone.

CONCLUSION

Exposing injured animals to CS results in prolonged elevation of NE and EPO, which is associated with worsening BM erythroid function and persistent anemia. Chronic restraint stress following injury and shock provides a clinically relevant model to further evaluate persistent injury-associated anemia seen in critically ill trauma patients. Furthermore, alleviating CS after severe injury is a potential therapeutic target to improve BM dysfunction and anemia.

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.

Pathophysiology of perioperative anaemia

Perioperative anaemia is a common clinical entity. It is usually due to combination of various mechanisms, including: pre-existing anaemia prior to surgery; anaemia due to impaired erythropoiesis, including alterations of metabolism of iron and erythropoietin (EPO); anaemia due to increased destruction of red blood cells (RBCs); and anaemia due to iatrogenic causes. Postoperatively, anaemia resembles anaemia of chronic disease and is probably related to the effects of inflammatory mediators released during and after surgery on the production and survival of RBCs. Pro-inflammatory cytokines, such as tumour necrosis factor, impair erythropoietin-dependent signalling and iron homeostasis. Iatrogenic causes, notably excessive phlebotomies, remain a major cause of perioperative anaemia. With increasing emphasis on restrictive blood transfusion strategies, understanding these mechanisms is important for the clinician.

Impact of erythropoietin on intensive care unit patients

Anemia is common in intensive care unit (ICU) patients. Red blood cell (RBC) transfusions are mainstays of their treatment and can be life-saving. Allogeneic blood components inherently bear risks of infection and immune reactions. Although these risks are rare in developed countries, recombinant human erythropoietin (rhEpo) and other erythropoiesis-stimulating agents (ESAs) have been considered alternative anti-anemia treatment options. As summarized herein, however, most of the clinical studies suggest that ESAs are not usually advisable in ICU patients unless approved indications exist (e.g., renal disease). First, ESAs act in a delayed way, inducing an increase in reticulocytes only after a lag of 3-4 days. Second, many critically ill patients present with ESA resistance as inflammatory mediators impair erythropoietic cell proliferation and iron availability. Third, the ESA doses used for treatment of ICU patients are very high. Fourth, ESAs are not legally approved for general use in ICU patients. Solely in distinct cases, such as Jehovah's Witnesses who refuse allogeneic blood transfusions due to religious beliefs, ESAs may be considered an exceptional therapy.

Simulation of repetitive diagnostic blood loss and onset of iatrogenic anemia in critical care patients with a mathematical model

Anemia is prevalent among critical care patients and is attributed to pathologic and iatrogenic processes and bleeding. The extent that diagnostic blood loss contributes to anemia among adult critical care patients is controversial and multi-factorial. The aim of this study is to describe an erythrokinetic model that integrates rates of phlebotomy, erythropoiesis and red cell senescence with patient characteristics to predict the onset of iatrogenic anemia in an objective manner. Using sex-specific parameters, the model predicts that adults with (average body weight and average blood volume), initial hemoglobin concentration at mid-reference interval, active erythropoiesis and losing 53 mL of blood per day by phlebotomy would require 40-70 days to reach 70 g/L of hemoglobin. To mimic critical care patients with low initial hemoglobin and suppressed erythropoiesis, the influence of daily blood loss and total blood volume was predicted. Simultaneous lack of erythropoiesis, initial hemoglobin concentrations at the lower limit of the reference interval (110 g/L), low body weight and increased phlebotomy accelerated onset of ~70 g/L hemoglobin transfusion threshold to 9-14 days. This computer simulation depicts the extent that adult critical care patients with anemia risk factors could benefit from conservative test ordering practices and subsequent reduced diagnostic phlebotomy.

Hepcidin in trauma: linking injury, inflammation, and anemia

BACKGROUND

Anemia is almost universal in trauma patients admitted to the intensive care unit (ICU). Hepcidin is a liver-derived peptide that is a negative regulator of iron stores. Hepcidin synthesis is suppressed by erythropoiesis and iron deficiency and upregulated by iron overload and inflammation. Hepcidin has been shown to have an important role in the anemia of chronic inflammatory diseases but has not been previously studied in the setting of trauma. We sought to define the link between traumatic injury, hepcidin, and inflammation.

METHODS

One hundred fifty trauma patients admitted to the ICU were prospectively enrolled in the study. Urine was collected at regular time points for hepcidin measurement. Serum for iron studies and measurement of those cytokines associated with acute inflammation was also collected.

RESULTS

The study population comprised 73% men. Mean age was 46 years, with a median Injury Severity Score (ISS) of 27. The mean lactate level was 2.9 mmol/L, and mean hemoglobin was 12.4 g/dL. More than 50% of patients were anemic on ICU admission, and nearly all were anemic by postinjury day 10. Urinary hepcidin levels were among the highest reported to date and had a rightward skew. Iron studies confirmed functional iron deficiency. Log hepcidin values were positively correlated with ISS and negatively correlated with admission Pao₂/FiO₂. Every increase in ISS by 10 was associated with a 40% increase in hepcidin. Initial hepcidin levels were positively correlated with duration of anemia.

CONCLUSIONS

Hepcidin levels rise to extremely high but variable levels after trauma and are positively correlated with injury severity measured by ISS and duration of anemia and negatively correlated with hypoxia. Hepcidin is likely a key factor in the impaired erythropoiesis seen in critically injured trauma patients.

Bench to bedside: A role for erythropoietin in sepsis

Sepsis is the systemic inflammatory response to infection and can result in multiple organ dysfunction syndrome with associated high mortality, morbidity and health costs. Erythropoietin is a well-established treatment for the anaemia of renal failure due to its anti-apoptotic effects on red blood cells and their precursors. The extra-haemopoietic actions of erythropoietin include vasopressor, anti-apoptotic, cytoprotective and immunomodulating actions, all of which could prove beneficial in sepsis. Attenuation of organ dysfunction has been shown in several animal models and its vasopressor effects have been well characterised in laboratory and clinical settings. Clinical trials of erythropoietin in single organ disorders have suggested promising cytoprotective effects, and while no randomised trials have been performed in patients with sepsis, good quality data exist from studies on anaemia in critically ill patients, giving useful information of its pharmacokinetics and potential for harm. An observational cohort study examining the microvascular effects of erythropoietin is underway and the evidence would support further phase II and III clinical trials examining this molecule as an adjunctive treatment in sepsis.

[Is there still a role for recombinant erythropoietin in the management of anaemia of critical illness?]

There is a high prevalence of anaemia among patients admitted to the intensive care unit (ICU), and it may have a negative effect on patient's outcome. The most common treatment for anaemia in the ICU patient is allogeneic blood transfusion (ABT), yet it has been found to be a risk factor associated with an increased risk of morbidity and mortality in critical care patients. As a reduction of erythropoietin secretion and action is observed in most ICU patients, the administration of (rHuEPO) has emerged as a therapeutic option. Unfortunately, the results from different studies show that rHuEPO treatment results in a small reduction of ABT requirements when "restrictive" transfusion criteria are applied, which has only been supported by three of the studies. Yet this did not result in a decreased mortality rate, except for patients with a diagnosis on admission of trauma in two studies, even though one study reported a dose-dependent increase of thrombotic vascular events among patients without thromboprophylaxis. Altogether, clinical data suggest a role for rHuEPO in the treatment of anaemia in trauma patients, especially in those sustaining neurotrauma, whereas for non-trauma patients without an approved indication, rHuEPO administration is an expensive approach, does not seem to improve outcome, and might result in serious adverse effects. Consequently, more basic and clinical studies are required to ascertain which patients are more likely to benefit from these treatments, as well as to identify the optimal doses and administration schedules, and iron administration.

Anemia of critical illness

Anemia of critical illness, a commonly encountered clinical situation, is hematologically similar to that of chronic anemia, except that the onset is generally sudden. The etiology is usually multifactorial, occurring as a consequence of direct inhibitory effects of inflammatory cytokines, erythropoietin deficiency, blunted erythropoietic response, blood loss, nutritional deficiencies, and renal insufficiency. Although anemia is not well tolerated by critically ill patients, aggressive treatment of anemia can be just as detrimental as no treatment. Different types of anemia may coexist in a patient in the intensive care unit, making diagnosis and differentiation among these anemias complex, therefore requiring good diagnostic skills. Although several therapeutic options are available to treat anemia, critically ill patients often receive a transfusion, and yet, most recent studies indicate that blood transfusions in critically ill patients are associated with worse outcomes, including higher morbidity and mortality. These studies have generated interest in the administration of exogenous erythropoietin and iron therapy. Unfortunately, the accurate determination of iron status can be a rather difficult task, an undertaking that is made even more difficult by the presence of comorbid conditions that can affect the commonly used parameters for guiding iron therapy. The use of erythropoiesis-stimulating agents is rapidly gaining acceptance, although they also present potential problems of their own.

Anemia in the Critically Ill Patient

Anemia in critically ill patients has been described as an acute form of anemia of inflammatory disease and is characterized by a blunted erythropoietic response due in part to proinflammatory mediators. Management of anemia in critically ill patients is a complex issue and is best approached via a multiprofessional team regarding the use of allogenic blood, iron, nutritional therapy, and erythropoietic agents. Indiscriminant, ``routine'' red blood cell transfusions may not only be unnecessary, but may pose unnecessary risk to the intensive care unit patient. Most intensive care unit patients can tolerate lower hemoglobin/hematocrit concentrations than the typically accepted ``10/30 rule.'' Lower transfusion triggers with an overall transfusion strategy is warranted in the intensive care unit patient. The use of recombinant human erythropoietic agents may not be necessary with appropriate transfusion practices.

Anemia of Inflammation in Critically Ill Patients

Anemia is seen frequently in critically ill patients and has several etiologies. This article reviews the causes with an emphasis on the effects of inflammation, examines the risks and benefits of current therapies, and discusses novel treatment options.

Impaired erythropoiesis after haemorrhagic shock in mice is associated with erythroid progenitor apoptosis in vivo

OBJECTIVE

Multiply traumatised patients often suffer from blood loss and from subsequent therapy-resistant anaemia, possibly mediated by apoptosis, necrosis, or humoral factors. Therefore, the underlying mechanisms were investigated in bone marrow (BM) and peripheral blood in a murine resuscitated haemorrhagic shock (HS) model.

METHODS

In healthy male mice, pressure-controlled HS was induced for 60 min. The BM was analysed for Annexin-V, 7-amino-actinomycin D, apoptotic enzymes (caspases-3/7, -8, and -9), expression of death receptors (CD120a, CD95), mitochondrial proteins (Bax, Bcl-2, Bcl-x), as well as erythropoietin (EPO) receptor (EPO-R). Blood cell count, peripheral EPO, and tumour necrosis factor-alpha response were additionally monitored.

RESULTS

Twenty-four and 72 h after HS, EPO and EPO-R were strongly up-regulated in peripheral blood and BM, respectively. Decreasing numbers of erythroid progenitors in BM after HS correlated with significant apoptotic changes confirmed by increased caspases-3/7, -8, -9 activity in total BM, death receptor CD95 and CD120a expression on erythroid progenitors, and down-regulated mitochondrial Bcl-2 expression in total BM. Erythroid progenitors in peripheral blood were found to be increased after 72 h.

CONCLUSION

Despite the massive EPO response and up-regulation of EPO-R, BM erythroblasts (EBs) decreased. This could be due to deficient maturation of erythroid progenitors. Furthermore, the increased intrinsic and extrinsic apoptosis activation suggests programmed death of erythroid progenitors. We propose that both apoptosis and negatively regulated erythropoiesis contribute to BM dysfunction, while erythroid progenitor egress plays an additional role.

[Prevalence and treatment of anemia in critically ill patients]

Anemia is a common condition among medical and surgical patients admitted to the intensive care unit (ICU) and generally has a multifactorial origin. In order to avoid the deleterious effects of anemia, 40% of ICU patients receive allogenic blood transfusion (ABT). This figure increases up to 70% if the ICU stay is longer than 7 days. However, ABT is associated with a dose-dependent increase in morbidity and mortality. In contrast, the administration of exogenous erythropoietin plus iron supplements, especially iv iron, improves anemia and reduces ABT requirements, although it does not reduce mortality. To ascertain whether treatment of anemia in the critically ill with exogenous erythropoietin and iron might improve outcomes and to optimize drug administration schedules and dosage, further studies with sufficient statistical power and adequate follow-up are warranted.

Neurobiology confirms psychopathology. On the antagonism of psychosis and obsessive-compulsive syndromes

BACKGROUND

Psychopathological concepts of the 19th and early 20th century postulated an antagonism between psychotic and obsessive-compulsive disorders, assuming obsessions and compulsions to have protective effects on psychotic disintegration. Although both disorders have been subject to intense multimodal research, their pathogeneses are yet to be fully understood.

METHODS

Here, we discuss recent neurobiological findings pointing towards opposite directions which are strongly reminiscent of the historical psychopathological antagonism.

RESULTS

Obsessive-compulsive syndromes (OCS) are efficiently treated with serotonergic substances, while on the other hand modern antipsychotic drugs exert antiserotonergic effects. Especially these atypical antipsychotic substances, however, were found to involve the risk of inducing second-onset OCS. Dopamine antagonists are potent antipsychotic substances, whereas the partial dopamine agonist aripiprazole has been associated with an antiobsessive potency. Within the glutamatergic system, reduced NMDA-dependent glutamatergic neurotransmission is discussed to be one major pathomechanism of psychotic disorders, whilst NMDA antagonists have proven to be effective in improving treatment-resistant OCS. While neurogenetic findings seem to separate the populations in heterogeneous samples, detailed neuroimaging studies suggest that both disorders affect similar neurocircuits in different manners.

CONCLUSIONS

With regard to these findings, future research on schizo-obsessive syndromes will have to be multimodal, integrating psychopathology, neuropsychology, functional imaging, neurogenetics and psychopharmacology. Prospective trials involving these methods might be able to elucidate the dysbalances of neurotransmission and to locate the neuroanatomical and neuropsychological correlates. In particular, this might contribute to defining schizophrenic patients at risk for developing second-onset OCS and to evaluating new treatment strategies in patients suffering from both psychosis and OCS.

Erythropoiesis in multiply injured patients

Posttraumatic anemia in multiply injured patients is caused by hemorrhage, reduced red blood cell survival, and impaired erythropoiesis. Trauma-induced hyperinflammation causes impaired bone-marrow function by means of blunted erythropoietin (EPO) response, reduced iron availability, suppression and egress of erythroid progenitor cells. To treat posttraumatic anemia in severely injured patients, symptomatic therapy by blood transfusion is not sufficient. Furthermore, EPO, iron, and the use of red cell substitutes should be considered. The posttraumatic systemic inflammatory response syndrome (SIRS) induces posttraumatic anemia. Thus, a worsening of SIRS by a "second-hit" through blood transfusion ought to be avoided.

Molecular and clinical aspects of iron homeostasis: From anemia to hemochromatosis

The discovery in recent years of a plethora of new genes whose products are implicated in iron homeostasis has led to rapid expansion of our knowledge in the field of iron metabolism and its underlying complex regulation in both health and disease. Abnormalities of iron metabolism are among the most common disorders encountered in practical medicine and may have significant negative impact on physical condition and life expectancy. Basic insights into the principles of iron homeostasis and the pathophysiological and clinical consequences of iron overload, iron deficiency and misdistribution are thus of crucial importance in modern medicine. This review summarizes our current understanding of human iron metabolism and focuses on the clinically relevant features of hereditary and secondary hemochromatosis, iron deficiency anemia, anemia of chronic disease and anemia of critical illness. The interconnections between iron metabolism and immunity are also addressed, in as much as they may affect the risk and course of infections and malignancies.

What is new in cytokine research related to trauma/critical care

Cytokines are low molecular weight proteins whose production can be modified by various insults. They have the potential to modify cellular responses to these insults. Recent years have seen a plethora of research in cytokine biology in trauma and critical care.

Blood Transfusion is Associated with Infection and Increased Resource Utilization in Combat Casualties

Combat casualty care has made significant advances in recent years, including administration of blood products in far-forward locations. However, recent studies have shown blood transfusion to be a significant risk factor for infection and increased resource utilization in critically injured patients. We therefore sought to investigate the incidence of blood transfusion and its association with infection and resource utilization in combat casualties. Prospective data were collected and retrospectively reviewed on 210 critically injured patients admitted to the USNS Comfort over a 7-week period during the 2003 assault phase of Operation Iraqi Freedom. Patients were stratified by age, gender, and injury severity score (ISS). Multivariate regression analyses were used to assess blood transfusion and hematocrit (HCT) as independent risk factors for infection and intensive care unit (ICU) admission controlling for age, gender, and ISS. The study cohort had a mean age of 30 ± 2 years, a mean ISS of 14 ± 3, 84 per cent were male, and 88 per cent sustained penetrating trauma. Blood transfusion was required in 44 per cent (n = 93) of the study cohort. Transfused patients had a higher ISS (18 ± 4 vs. 10 ± 3, P < 0.01), a higher pulse rate (105 ± 4 vs. 93 ± 3, P < 0.0001), and a lower admission HCT (27 ± 1 vs. 33 ± 2, P < 0.0001) compared with patients not transfused. Patients receiving blood transfusion had an increased infection rate (69% vs. 18%, P < 0.0001), ICU admission rate (52% vs. 21%, P < 0.0001), and ICU length of stay (6.7 ± 2.1 days vs. 1.4 ± 0.5 days, P < 0.0001) compared with nontransfused patients. However, there was no significant difference in mortality between transfused and nontransfused patients. Multivariate binomial regression analysis identified blood transfusion and HCT as independent risk factors for infection (P < 0.01) and blood transfusion as an independent risk factor for ICU admission (P < 0.05). Combat casualties have a high incidence of blood transfusion. Blood transfusion is an independent risk factor for infection and increased resource utilization. Therefore, consideration should be given to the use of alternative blood substitutes and recombinant human erythropoietin in the treatment and management of combat casualties.

Alternatives to blood product transfusion in the critically ill: erythropoietin

OBJECTIVE

To present information regarding the use of recombinant human erythropoietin (rHuEPO) to treat anemia in intensive care unit (ICU) patients

MAIN RESULTS

Anemia is common in critically ill patients. Approximately 95% of patients have subnormal hemoglobin (Hb) values by day 3 of their ICU stay. ICU-associated anemia often requires replacement of red blood cells (RBCs) via transfusion. Recent surveys of ICU practice document that approximately 50% of ICU patients receive RBC transfusions. ICU-associated anemia is largely the result of the cumulative effects of blood loss and decreased RBC production. Blood loss in critically ill patients may be overt, occult, or due to phlebotomy. Decreased RBC production is the other major factor influencing the development of anemia. Decreased RBC production is due to the combined effects of abnormal iron metabolism, inappropriately low erythropoietin production, diminished response to erythropoietin, and direct suppression of RBC production. Inflammatory mediators play a pivotal role in the pathogenesis of decreased RBC production. Clinical trials have shown that, compared with nontreated subjects, rHuEPO-treated ICU patients will have increased serum erythropoietin concentrations, increased reticulocyte counts, and increased hemoglobin and hematocrit values and require fewer RBC transfusions. These clinical trials have not detected significant differences in outcomes in association with rHuEPO, however.

CONCLUSIONS

rHuEPO can be used to increase hemoglobin and hematocrit values and decrease the number of RBC transfusions in ICU patients. Further investigation is necessary to identify the appropriate target population of ICU patients for treatment, to clarify the appropriate dosing schedule, and to ascertain whether such therapy has a positive impact on outcomes.

The impact of a hypercatecholamine state on erythropoiesis following severe injury and the role of IL-6

BACKGROUND

Severe traumatic injury can lead to hemorrhagic shock-induced bone marrow (BM) dysfunction resulting in persistent anemia. The hypercatacholamine state that accompanies severe injury has been shown to impact the growth of erythroid progenitors. IL-6 has a role both in the acute phase response of trauma and has been implicated in the development of anemia. The aim of this study was to investigate the severity of a hyper-adrenergic stimulus on pluripotent progenitors (GEMM-CFU) as well as erythroid progenitors (BFU-E and CFU-E) and the potential regulatory role of IL-6.

METHODS

Normal human BM mononuclear cells were isolated and erythropoiesis was assessed by the growth of GEMM-CFU, BFU-E and CFU-E in the presence of adrenergic agonists, norepinephrine (NE) and epinephrine (EPI), at increasing concentrations. Similarly, normal BM stroma cells were grown to confluence then incubated with NE and EPI. Supernatant was harvested and IL-6 levels were determined using ELISA.

RESULTS

Under physiologic conditions (10(-7) M), NE and EPI increase BFU-E and CFU-E growth (374% and 177% versus 100% control). At severe stress levels (10(-3) M), NE and EPI completely inhibited BFU-E and CFU-E growth (5% and 4% versus 100% control). GEMM-CFU growth was increased by NE and not EPI at 10(-7) M. The presence of NE and EPI increased IL-6 levels in a dose-dependent fashion.

CONCLUSIONS

The proliferative effect of adrenergic agonists at physiologic levels on normal erythropoiesis begins early during erythroid differentiation. At severe stress levels, BFU-E and CFU-E growth is inhibited. The erythropoietic dysfunction and resultant anemia seen following severe injury may be due to the presence of a severe hypercatecholamine state and may be mediated by IL-6.