Important role of nondiagnostic blood loss and blunted erythropoietic response in the anemia of medical intensive care patients

Reducing Blood Loss in a Burn Care Unit: A Review of Its Key Determinants

Patients with a major burn injury differ considerably from the typical critical ill and trauma population. Very often, burn patients suffer from anemia throughout their hospital stay. This is caused both by combination of persistent blood loss with decreased erythropoiesis. Therefore, burn patients do have major transfusion requirements. However, transfusion is not devoid of risks or costs. We hereby review the best surgical techniques and medical approaches, aiming to reduce blood loss in a burn patient and optimize red cell production, so that we can reduce the need of RBC transfusion. The implementation of a combination of surgical techniques aiming to reduce blood loss and medical care approaches to prevent anemia, rather than single attitudes, should be adopted in burn care. There is an urgent need for clear guidelines that can easily be accepted, applied, and spread across different burn units to methodically implement measures to reduce blood loss and transfusion needs, and ultimately improve burn patients' outcome and the health care financial status.

A Cohort Study in Intensive Care Units: Health Decisions Related to Blood Transfusion during the COVID-19 Pandemic

Critically ill polytrauma patients with hemorrhage require a rapid assessment to initiate hemostatic resuscitation in the shortest possible time with the activation of a massive transfusion or a critical hemorrhage management protocol. The hospital reality experienced during the COVID-19 pandemic in all countries was critical, as it was in Spain; according to the data published daily by the Ministry of Health on its website, during the period of this study, the occupancy rate of intensive care units (ICUs) by patients diagnosed with the novel coronavirus disease (COVID-19) rose to 23.09% in Spain, even reaching 45.23% at the end of January 2021. We aimed to analyze the changes observed during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic period regarding the effectiveness of Spanish ICUs in terms of mortality reduction. We present a cross-sectional study that compares two cohorts of patients admitted to ICUs across all autonomous communities of Spain with a diagnosis of polytrauma. Results: Only age was slightly higher at admission during the first wave of the pandemic (47.74 ± 18.65 vs. 41.42 ± 18.82 years, p = 0.014). The transfusion rate during the pandemic increased by 10.4% compared to the previous stage (p = 0.058). Regarding hemostatic components, the use of tranexamic acid increased from 1.8% to 10.7% and fibrinogen concentrates from 0.9% to 1.9%. In the case of prothrombin complex concentrates, although there was a slight increase in their use, there were no significant differences during the pandemic compared to the previous period. Conclusion: Mortality showed no difference before and during the pandemic, despite the observed change in the transfusion policy. In summary, the immediate and global implementation of patient blood management (PBM) based on clinical transfusion algorithms should be mandatory in all hospitals in our country.

Epidemiology of blood transfusion in the Spanish Critical Care Units: «Transfusion Day»

OBJECTIVE

To describe the transfusion practice in the ICUs in Spain, according to national and international recommendations (guidelines).

DESIGN

Prospective, cross-sectional, multi-centre study.

SCOPE

Data collection was carried out by means of a questionnaire sent electronically to the Heads of Service of 111 ICUs in Spain.

PARTICIPANTS

1,448 patients were included, aged 61.8 (SD 15.7) years, 66.2% male, with an SOFA of 4.7 ± 3.8 and average stay of 10.62 ± 17.49 days.

VARIABLES

Demographic and clinical variables of the patients were collected, as well as variables related to the transfusion act.

RESULTS

Of the 1,448 patients, 9.9% received al least one transfusion of any blood product, 3.7% fresh plasma, 3.9% platelets and 8.9% red blood cell concentrate, mainly by analytical criteria (36.2%). Hemoglobin had a mean of 7.8 g/dL (95% CI: 6-9-8.5) and 9.8 g/dL (95% CI: 8.5-11.2) before and after the transfusion, respectively, p < 0.001. The transfusion units had a mean of 2.5 ± 2.4 per patient. The most commonly used blood product was red blood cell concentrate (CH) (90.2%). Patients admitted for surgery had a higher transfusion rate (14.4%) than those admitted for medical pathology (8.9%) (p = 0.006). 5.4% (7/129) of patients who received CH died compared to 2.4% (31/1302) who did not (p = 0.04). Mortality of transfused patients was higher. The transfusion rate in most of hospitals was 5% to 20%, with 18 hospitals (16.21%) having transfusion rates between 20% and 50%. Hospitals with PBM programs and mass transfusion programs had a lower transfusion rate, although not statistically significant.

CONCLUSIONS

In this multicenter cross-sectional study, a transfusion prevalence of 9.9% was observed in Spanish Critical Care Units. The most frequent blood product transfused was red blood cells and the main reasons for transfusion were acute anemia with hemodynamic impact and analytical criteria. Mortality of transfused patients was higher.

Related Factors of Anemia in Critically Ill Patients: A Prospective Multicenter Study

Anemia is common in critically ill patients; almost 95% of patients admitted to intensive care units (ICUs) have hemoglobin levels below normal. Several causes may explain this phenomenon as well as the tendency to transfuse patients without adequate cause: due to a lack of adherence to protocols, lack of supervision, incomplete transfusion request forms, or a lack of knowledge about the indications, risks, and costs of transfusions. Daily sampling to monitor the coagulation parameters and the acid-base balance can aggravate anemia as the main iatrogenic factor in its production. We studied the association and importance of iatrogenic blood loss and other factors in the incidence of anemia in ICUs. We performed a prospective, observational, multicenter study in five Spanish hospitals. A total of 142 patients with a median age of 58 years (IQI: 48-69), 71.83% male and 28.17% female, were admitted to ICUs without a diagnosis of iatrogenic anemia. During their ICU stay, anemia appeared in 66.90% of the sample, 95 patients, (95% CI: 58.51-74.56%). Risk factors associated with the occurrence of iatrogenic anemia were arterial catheter insertion (72.63% vs. 46.81%, p-value = 0.003), venous catheter insertion (87.37% vs. 72.34%, p-value = 0.023), drainages (33.68% vs. 12. 77%, p-value = 0.038), and ICU stay, where the longer the stay, the higher the rate of iatrogenic anemia (p-value < 0.001). We concluded that there was a statistical significance in the production of iatrogenic anemia due to the daily sampling for laboratory monitoring and critical procedures in intensive care units. The implementation of patient blood management programs could address these issues.

Avoidable Blood Loss in Critical Care and Patient Blood Management: Scoping Review of Diagnostic Blood Loss

Background: Anemia remains one of the most common comorbidities in intensive care patients worldwide. The cause of anemia is often multifactorial and triggered by underlying disease, comorbidities, and iatrogenic factors, such as diagnostic phlebotomies. As anemia is associated with a worse outcome, especially in intensive care patients, unnecessary iatrogenic blood loss must be avoided. Therefore, this scoping review addresses the amount of blood loss during routine phlebotomies in adult (>17 years) intensive care patients and whether there are factors that need to be improved in terms of patient blood management (PBM). Methods: A systematic search of the Medline Database via PubMed was conducted according to PRISMA guidelines. The reported daily blood volume for diagnostics and other relevant information from eligible studies were charted. Results: A total of 2167 studies were identified in our search, of which 38 studies met the inclusion criteria (9 interventional studies and 29 observational studies). The majority of the studies were conducted in the US (37%) and Canada (13%). An increasing interest to reduce iatrogenic blood loss has been observed since 2015. Phlebotomized blood volume per patient per day was up to 377 mL. All interventional trials showed that the use of pediatric-sized blood collection tubes can significantly reduce the daily amount of blood drawn. Conclusion: Iatrogenic blood loss for diagnostic purposes contributes significantly to the development and exacerbation of hospital-acquired anemia. Therefore, a comprehensive PBM in intensive care is urgently needed to reduce avoidable blood loss, including blood-sparing techniques, regular advanced training, and small-volume blood collection tubes.

The Hematopoietic Stem/Progenitor Cell Response to Hemorrhage, Injury, and Sepsis: A Review of Pathophysiology

ABSTRACT

Hematopoietic stem/progenitor cells (HSPC) have both unique and common responses following hemorrhage, injury, and sepsis. HSPCs from different lineages have a distinctive response to these "stress" signals. Inflammation, via the production of inflammatory factors, including cytokines, hormones, and interferons, has been demonstrated to impact the differentiation and function of HSPCs. In response to injury, hemorrhagic shock, and sepsis, cellular phenotypic changes and altered function occur, demonstrating the rapid response and potential adaptability of bone marrow hematopoietic cells. In this review, we summarize the pathophysiology of emergency myelopoiesis and the role of myeloid-derived suppressor cells, impaired erythropoiesis, as well as the mobilization of HSPCs from the bone marrow. Finally, we discuss potential therapeutic options to optimize HSPC function after severe trauma or infection.

Red blood cell transfusion in animal models of acute brain injuries: a systematic review protocol

BACKGROUND

Anemia is common in neurocritically ill patients. Considering the limited clinical evidence in this population, preclinical data may provide some understanding of the potential impact of anemia and of red blood cell transfusion in these patients. We aim to estimate the association between different transfusion strategies and neurobehavioral outcome in animal models.

METHODS

We will conduct a systematic review of comparative studies of red blood cell transfusion strategies using animal models of traumatic brain injury, ischemic stroke or cerebral hemorrhage. We will search MEDLINE, EMBASE, and Web of Science databases for eligible studies from inception onwards. Two independent reviewers will perform study selection and data extraction. We will report our results in a descriptive synthesis focusing on characteristics of included studies, reported outcomes, risk of bias, and construct validity. Our primary outcome is the neurological function (neurobehavioral performance) and our secondary outcomes include mortality, infarct size, intracranial pressure, cerebral perfusion pressure, cerebral blood flow, and brain tissue oxygen tension. If appropriate, we will also perform a quantitative synthesis and pool results using random-effect models. Heterogeneity will be expressed with I² statistics. Subgroup analyses are planned according to animal model characteristics, co-interventions, and risks of bias.

DISCUSSION

Our study is aligned with the efforts to better understand the level of evidence on the impact of red blood cell transfusion strategies from preclinical studies in animal models of acute brain injury and the potential translation of information from the preclinical to the clinical research field.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018086662 .

Impact of treating iron deficiency, diagnosed according to hepcidin quantification, on outcomes after a prolonged ICU stay compared to standard care: a multicenter, randomized, single-blinded trial

BACKGROUND

Anemia is a significant problem in patients on ICU. Its commonest cause, iron deficiency (ID), is difficult to diagnose in the context of inflammation. Hepcidin is a new marker of ID. We aimed to assess whether hepcidin levels would accurately guide treatment of ID in critically ill anemic patients after a prolonged ICU stay and affect the post-ICU outcomes.

METHODS

In a controlled, single-blinded, multicenter study, anemic (WHO definition) critically ill patients with an ICU stay ≥ 5 days were randomized when discharge was expected to either intervention by hepcidin treatment protocol or control. In the intervention arm, patients were treated with intravenous iron (1 g of ferric carboxymaltose) when hepcidin was < 20 μg/l and with intravenous iron and erythropoietin for 20 ≤ hepcidin < 41 μg/l. Control patients were treated according to standard care (hepcidin quantification remained blinded). Primary endpoint was the number of days spent in hospital 90 days after ICU discharge (post-ICU LOS). Secondary endpoints were day 15 anemia, day 30 fatigue, day 90 mortality and 1-year survival.

RESULTS

Of 405 randomized patients, 399 were analyzed (201 in intervention and 198 in control arm). A total of 220 patients (55%) had ID at discharge (i.e., a hepcidin < 41 μg/l). Primary endpoint was not different (medians (IQR) post-ICU LOS 33(13;90) vs. 33(11;90) days for intervention and control, respectively, median difference - 1(- 3;1) days, p = 0.78). D90 mortality was significantly lower in intervention arm (16(8%) vs 33(16.6%) deaths, absolute risk difference - 8.7 (- 15.1 to - 2.3)%, p = 0.008, OR 95% IC, 0.46, 0.22-0.94, p = 0.035), and one-year survival was improved (p = 0.04).

CONCLUSION

Treatment of ID diagnosed according to hepcidin levels did not reduce the post-ICU LOS, but was associated with a significant reduction in D90 mortality and with improved 1-year survival in critically ill patients about to be discharged after a prolonged stay.

TRIAL REGISTRATION

www.clinicaltrial.gov NCT02276690 (October 28, 2014; retrospectively registered).

Reducing Blood Loss by Changing to Small Volume Tubes for Laboratory Testing

Objective

To reduce diagnostic blood loss by using small volume tubes for routine laboratory testing throughout the hospital, as blood loss from laboratory testing can be substantial for patients and may lead to hospital-acquired anemia.

Patients and Methods

Diagnostic blood loss was evaluated in hospitalized patients between April 1, 2017, and June 1, 2018. The preintervention, during intervention, and postintervention mean diagnostic blood loss per hospitalized patient was compared across the floors and for each type of tube for hematology, basic metabolic panel, and coagulation tests. Mean hemoglobin levels, blood transfusions per hospitalized patient, and percent redraws were also compared.

Results

The total volume of blood drawn for all the 3 tests decreased across each implementation phase; however, only patients admitted to the transplant and critical care (T/CC) units had increased hemoglobin levels. In addition, there was a significant reduction in transfusions across implementation phases. The incidence risk ratio for transfusion reduced even more in patients admitted to the T/CC units. Finally, there was no significant difference in the overall percent redraws across all the units.

Conclusion

The use of small volume tubes in exchange for standard sized tubes markedly decreased diagnostic blood loss by 25.7% in all the units and 22.9% in the T/CC units. Also, the number of transfusions decreased across units, with the greatest decrease in the T/CC units. An increase in mean hemoglobin levels was observed specifically in patients admitted to the T/CC units, with no corresponding change in percent redraws across all the units.

Epidemiology of blood transfusion in the Spanish Critical Care Units: «Transfusion Day»

OBJECTIVE

To describe the transfusion practice in the ICUs in Spain, according to national and international recommendations (guidelines).

DESIGN

Prospective, cross-sectional, multi-centre study.

SCOPE

Data collection was carried out by means of a questionnaire sent electronically to the Heads of Service of 111 ICUs in Spain.

PARTICIPANTS

1,448 patients were included, aged 61.8 (SD 15.7) years, 66.2% male, with an SOFA of 4.7±3.8 and average stay of 10.62±17.49 days.

VARIABLES

Demographic and clinical variables of the patients were collected, as well as variables related to the transfusion act.

RESULTS

Of the 1,448 patients, 9.9% received al least one transfusion of any blood product, 3.7% fresh plasma, 3.9% platelets and 8.9% red blood cell concentrate, mainly by analytical criteria (36.2%). Hemoglobin had a mean of 7.8g/dL (95% CI: 6-9-8.5) and 9.8g/dL (95% CI: 8.5-11.2) before and after the transfusion, respectively, p<0.001. The transfusion units had a mean of 2.5±2.4 per patient. The most commonly used blood product was red blood cell concentrate (90.2%). Patients admitted for surgery had a higher transfusion rate (14.4%) than those admitted for medical pathology (8.9%) (p=0.006). 5.4% (7/129) of patients who received red blood cell concentrate died compared to 2.4% (31/1302) who did not (p=0.04). Mortality of transfused patients was higher. The transfusion rate in most of hospitals was 5% to 20%, with 18 hospitals (16.21%) having transfusion rates between 20% and 50%. Hospitals with PBM programs and mass transfusion programs had a lower transfusion rate, although not statistically significant.

CONCLUSIONS

In this multicenter cross-sectional study, a transfusion prevalence of 9.9% was observed in Spanish critical care units. The most frequent blood product transfused was red blood cells and the main reasons for transfusion were acute anemia with hemodynamic impact and analytical criteria. Mortality of transfused patients was higher.

Pediatric size phlebotomy tubes and transfusions in adult critically ill patients: a pilot randomized controlled trial

Background

Transfusion of red blood cells (RBC) is common, can have adverse effects, and is a costly and limited resource. Interventions that reduce iatrogenic blood losses could reduce transfusions. The objectives of this pilot trial were to assess the feasibility (acceptability of the intervention and suitability of eligibility criteria) and potential effectiveness of pediatric size phlebotomy tubes in adult critically ill patients.

Methods

We conducted a pilot, randomized controlled trial in the medical intensive care unit (ICU) of a university-affiliated, tertiary care referral hospital from November 2017 to September 2018. A total of 200 patients with hemoglobin of at least 7 g/dL and without bleeding were randomized to pediatric or adult size phlebotomy tubes. Stratification was according to baseline hemoglobin (7-9.49 g/dL, 9.5-11.99 g/dL, and 12 g/dL or greater). Acceptability was measured via the number of blood test recollections and the number of patients that discontinued the use of pediatric tubes. The suitability of patient eligibility criteria was determined by identifying baseline characteristics associated with RBC transfusions. Potential effectiveness was estimated from the time to RBC transfusion or to hemoglobin level below 7 g/dL.

Results

The use of pediatric tubes was acceptable as patients experienced a low number of tests recollections (on average 1 every 57 days), and none of the participants discontinued their use. The baseline hemoglobin category was the only factor that appeared to be independently associated with RBC transfusions. A total of 6 patients (6%) in the pediatric tube group and 11 patients (11%) in the adult tube group (hazard ratio, 0.69; 95% CI, 0.25 to 1.9) received an RBC transfusion or reached hemoglobin below 7 g/dL. Almost all of these patients (16 of 17 participants) had baseline hemoglobin of 7-9.49 g/dL.

Conclusions

This pilot study suggests that pediatric phlebotomy tubes are acceptable to patients and can therefore be used in adult ICU patients. A future study should focus on patients with hemoglobin levels below 9.5 g/dL, as these patients have a high risk of transfusions. This intervention has the potential of being successful in selected patients. A definitive trial is warranted.

Trial registration

ClinicalTrials.gov, NCT03286465. Retrospectively registered on September 18, 2017.

Management and prevention of anemia (acute bleeding excluded) in adult critical care patients

OBJECTIVE

Anemia is very common in critical care patients, on admission (affecting about two thirds of patients), but also during and after their stay, due to repeated blood loss, the effects of inflammation on erythropoiesis, a decreased red blood cell life span, and haemodilution. Anemia is associated with severity of illness and length of stay.

METHODS

A committee composed of 16 experts from four scientific societies, SFAR, SRLF, SFTS and SFVTT, evaluated three fields: (1) anaemia prevention, (2) transfusion strategies and (3) non-transfusion treatment of anaemia. Population, Intervention, Comparison, and Outcome (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Analysis of the literature and formulation of recommendations were then conducted according to the GRADE® methodology.

RESULTS

The SFAR-SRLF guideline panel provided ten statements concerning the management of anemia in adult critical care patients. Acute haemorrhage and chronic anemia were excluded from the scope of these recommendations. After two rounds of discussion and various amendments, a strong consensus was reached for ten recommendations. Three of these recommendations had a high level of evidence (GRADE 1±) and four had a low level of evidence (GRADE 2±). No GRADE recommendation could be provided for two questions in the absence of strong consensus.

CONCLUSIONS

The experts reached a substantial consensus for several strong recommendations for optimal patient management. The experts recommended phlebotomy reduction strategies, restrictive red blood cell transfusion and a single-unit transfusion policy, the use of red blood cells regardless of storage time, treatment of anemic patients with erythropoietin, especially after trauma, in the absence of contraindications and avoidance of iron therapy (except in the context of erythropoietin therapy).

Management and prevention of anemia (acute bleeding excluded) in adult critical care patients

Objective

Anemia is very common in critical care patients, on admission (affecting about two-thirds of patients), but also during and after their stay, due to repeated blood loss, the effects of inflammation on erythropoiesis, a decreased red blood cell life span, and haemodilution. Anemia is associated with severity of illness and length of stay.

Methods

A committee composed of 16 experts from four scientific societies, SFAR, SRLF, SFTS and SFVTT, evaluated three fields: (1) anemia prevention, (2) transfusion strategies and (3) non-transfusion treatment of anemia. Population, Intervention, Comparison, and Outcome (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Analysis of the literature and formulation of recommendations were then conducted according to the GRADE^® methodology.

Results

The SFAR–SRLF guideline panel provided ten statements concerning the management of anemia in adult critical care patients. Acute haemorrhage and chronic anemia were excluded from the scope of these recommendations. After two rounds of discussion and various amendments, a strong consensus was reached for ten recommendations. Three of these recommendations had a high level of evidence (GRADE 1±) and four had a low level of evidence (GRADE 2±). No GRADE recommendation could be provided for two questions in the absence of strong consensus.

Conclusions

The experts reached a substantial consensus for several strong recommendations for optimal patient management. The experts recommended phlebotomy reduction strategies, restrictive red blood cell transfusion and a single-unit transfusion policy, the use of red blood cells regardless of storage time, treatment of anaemic patients with erythropoietin, especially after trauma, in the absence of contraindications and avoidance of iron therapy (except in the context of erythropoietin therapy).

Types and outcomes of cytopenia in critically ill patients

Cytopenia is common complication in critically ill patients. Aim: Incidence and pattern of different types of cytopenia as well as its impact on mortality and length of stay in critically ill patients were evaluated. Methods: Critically ill patients with any kind of cytopenia for more than 2 days were evaluated. Results: Anemia was the most common type of cytopenia in the patients (99.14%), followed by lymphocytopenia (32.17%), thrombocytopenia (27.82%), and leukopenia (19.13%). Mortality rate was significantly higher in patients with anemia (p < 0.0001), thrombocytopenia (p < 0.0001), leukopenia (p < 0.0001), neutropenia (p = 0.004), lymphopenia (p = 0.002) and pancytopenia (p < 0.0001). Higher duration of anemia, lymphopenia and thrombocytopenia were associated with longer intensive care unit stay (p < 0.0001, p < 0.0001 and p < 0.001, respectively). Conclusion: Among all assessed variables, incidence of thrombocytopenia could independently predict the mortality.

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).

Age of Red Cells for Transfusion and Outcomes in Critically Ill Patients: A Meta-Analysis

Objective

Whether the age of red blood cells (RBCs) affects mortality after transfusion in critically ill patients is controversial.

Methods

We searched MEDLINE, EMBASE, PubMed, Web of Science, and the Cochrane Library Central Register of Controlled Trials databases from inception to January 10, 2018 to identify systematic reviews or meta-analyses and published randomized controlled trials of the effects of fresh versus older blood transfusion on mortality of adults in the intensive care unit (ICU). There were no date restrictions, but the language was restricted to English. The primary outcome was mortality. Risk ratios (RR) and 95% confidence intervals (CI) were calculated.

Results

We included six trials that enrolled 8,467 critically ill patients and compared fresh RBC transfusion with current standard practice. There were no significant differences in 90-day mortality (RR 1.04, 95% CI 0.97, 1.12), 28/30-day mortality (RR 1.04, 95% CI 0.96, 1.13), in-hospital mortality (RR 1.06, 95% CI 0.94, 1.19), and in-ICU mortality (RR 1.11, 95% CI 0.97, 1.27) with fresh RBC transfusion compared with older blood transfusion.

Conclusions

The study concluded that age of red cells for transfusion did not affect the outcomes in critically ill patients.

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.

The Influence of a Blood Conserving Device on Anaemia in Intensive Care Patients

The contribution of iatrogenic blood loss through diagnostic testing to the anaemia of critical illness remains controversial. We measured the effect of an arterial line blood conservation device upon blood loss and anaemia in adult intensive care patients.

This randomized controlled trial of 160 patients in a major Intensive Care Unit (ICU) compared a blood conservation device (Venous Arterial Blood Management Protection Plus, VAMP Plus system, Baxter Healthcare) (VAMP group) to a standard arterial pressure line set attached to an arterial catheter (control group). The primary outcome measured was the change in haemoglobin concentration (Hb) during each patient's ICU admission and the volume of blood lost through diagnostic testing in ICU was also recorded.

Both groups of 80 patients were matched for age, gender, severity of illness (APACHE II), baseline Hb on entry and ICU length of stay. Both groups had a similar (median [range]) change in Hb during ICU admission (VAMP-7 [- 84 to+21] g/l; Control -4 [-67 to+40] g/l; P=0.33). The VAMP patients lost significantly less blood for diagnostic testing while in ICU (VAMP 63 [0 to 787] ml; Control 133 [7 to 1227] ml; P=0.001).

We conclude that the VAMP Plus system significantly reduced iatrogenic blood loss in critically ill patients, but this reduction did not affect the fall in Hb that accompanies critical illness.

Approach to an Anemic Critically Ill Patient

How to cite this article: Hegde A. Approach to an Anemic Critically Ill Patient. Indian J Crit Care Med 2019;23(Suppl 3):S178–S180.

Iron deficiency diagnosed using hepcidin on critical care discharge is an independent risk factor for death and poor quality of life at one year: an observational prospective study on 1161 patients

Background

Iron deficiency is difficult to diagnose in critically ill patients, but may be frequent and may impair recovery. Measurement of hepcidin could help in the diagnosis of iron deficiency. We aim to assess if iron deficiency diagnosed using hepcidin is associated with poorer outcome one year after an intensive care unit stay.

Methods

We used the prospective FROG-ICU, multicentre (n = 28 ICUs), observational cohort study of critically ill survivors followed up one year after intensive care unit discharge. Iron deficiency was defined as hepcidin < 20 ng/l, ferritin < 100 ng/l or soluble transferrin receptor (sTfR)/log(ferritin) > 0.8, measured in blood drawn at intensive care unit discharge. Main outcomes were one-year all-cause mortality and poor quality of life (defined as a Short Form 36 (SF-36) score below the median).

Results

Among the 2087 patients in the FROG-ICU cohort, 1570 were discharged alive and 1161 had a blood sample available at intensive care unit discharge and were included in the analysis. Using hepcidin, 429 (37%) patients had iron deficiency, compared to 72 (6%) using ferritin alone and 151 (13%) using the sTfR/log(ferritin) ratio. Iron deficiency diagnosed according to low hepcidin was an independent predictor of one-year mortality (OR 1.51 (1.10–2.08)) as was high sTfR/log ferritin ratio (OR = 1.95 (1.27–3.00)), but low ferritin was not. Severe ID, defined as hepcidin < 10 ng/l, was also an independent predictor of poor one-year physical recovery (1.58 (1.01–2.49)).

Conclusions

Iron deficiency, diagnosed using hepcidin, is very frequent at intensive care unit discharge and is associated with increased one-year mortality and poorer physical recovery. Whether iron treatment may improve these outcomes remains to be investigated.

Electronic supplementary material

The online version of this article (10.1186/s13054-018-2253-0) contains supplementary material, which is available to authorized users.

Changes in the hemoglobin level after one unit of packed red blood cell transfusion in Intensive Care Unit patients

Background:

Blood transfusion is essential in severely ill patients whose hemoglobin (Hb) levels are low, but there are some factors that inhibit optimal increase in Hb. The aim of this study was to evaluate the amount of increase in Hb levels after packed red blood cell (PRBC) transfusions in the Intensive Care Unit (ICU) patients and its related factors.

Materials and Methods:

This cross-sectional study included 124 patients admitted to the ICU, and needed PRBC transfusion. Demographic information, Hb on the 1^st day of admission, blood volume transfusions during the 7 days, and the 7^th day of admission Hb level were extracted from patients’ records.

Results:

The average initial Hb level of patients was reported as 6.17 ± 1.43 g/dl, and after administrating PRBC (4.23 ± 1.87 units during 7 days), the Hb level was 8.09 ± 1.66 g/dl after 7 days (mean difference was 1.91 ± 1.93, t = 11.06, P < 0.001). No significant differences were found between change in Hb level in the terms of age, gender, underlying illness, body mass index, hospitalization history, fever, and duration of hospitalization (P > 0.05). However, the mean increased Hb level in hospitalized patients with internal disorders was the lowest (0.25 g/dl, P = 0.002).

Conclusion:

The results of our study showed that the increased Hb level based on one unit of received PRBC was low, especially in patients with internal. Therefore, based on high frequency of anemia in ICU patients and relative complications, physicians should pay attention to factors affecting Hb levels after PRBC transfusion such as medical history.

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.

Economic Analysis of the Reduction of Blood Transfusions during Surgical Procedures While Continuous Hemoglobin Monitoring Is Used

Background: Two million transfusions are performed in Spain every year. These come at a high economic price for the health system, increasing the morbidity and mortality rates. The way of obtaining the hemoglobin concentration value is via invasive and intermittent methods, the results of which take time to obtain. The drawbacks of this method mean that some transfusions are unnecessary. New continuous noninvasive hemoglobin measurement technology can save unnecessary transfusions. Methods: A prospective study was carried out with a historical control of two homogeneous groups. The control group used the traditional hemoglobin measurement methodology. The experimental group used the new continuous hemoglobin measurement technology. The difference was analyzed by comparing the transfused units of the groups. The economic savings was calculated by multiplying the cost of a transfusion by the difference in units, taking into account measurement costs. Results: The percentage of patients needing a transfusion decreased by 7.4%, and the number of transfused units per patient by 12.56%. Economic savings per patient were €20.59. At the national level, savings were estimated to be 13,500 transfusions (€1.736 million). Conclusions: Constant monitoring of the hemoglobin level significantly reduces the need for blood transfusions. By using this new measurement technology, health care facilities can significantly reduce costs and improve care quality.

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.

Impact of iron deficiency diagnosis using hepcidin mass spectrometry dosage methods on hospital stay and costs after a prolonged ICU stay: Study protocol for a multicentre, randomised, single-blinded medico-economic trial

BACKGROUND

Iron deficiency (ID) is frequent but difficult to diagnose in critically ill patients. ID may be responsible for prolonged post-ICU hospital stays, since it results in fatigue, muscle weakness and anaemia. Hepcidin, the key iron metabolism hormone, may be a good marker of ID in these patients. The aim of this study is to determine whether using mass spectrometry hepcidin determination to diagnose (and treat) ID after prolonged ICU stays may reduce patients' subsequent hospital stays and costs in comparison with conventional (ferritin) methods.

METHODS

This is a randomised, controlled, single-blinded, multicentre medico-economic study. Hepcidin quantification will be performed in anaemic (WHO criteria) critically ill adults about to be discharged, after a stay ≥5days. In the intervention arm (hepcidin) results will be given to the ICU-physicians, and not in the control arm. ID Treatment will be recommended in intervention arm: IV iron when hepcidin is <20μg/L; IV iron+erythropoietin when hepcidin is between 20-41μg/L; in the control arm: IV iron when ferritin <300μg/L and Transferrin saturation <20%. The primary endpoint will be the number of days spent in hospital 90 days after ICU discharge and the direct hospital costs. Secondary endpoints will be anaemia and iron deficiency on D15, fatigue and the proportion of patients alive and at home on D30 and D90.

DISCUSSION

The results of this study will show whether diagnosing iron deficiency using MS hepcidin determination methods is liable to reduce patients' post-ICU hospital stay and costs, as well as their anaemia and fatigue.

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.

Epidemiology of RBC Transfusions in Patients With Severe Acute Kidney Injury: Analysis From the Randomized Evaluation of Normal Versus Augmented Level Study

OBJECTIVE

To assess the epidemiology and outcomes associated with RBC transfusion in patients with severe acute kidney injury requiring continuous renal replacement therapy.

DESIGN

Post hoc analysis of data from a multicenter, randomized, controlled trial.

SETTING

Thirty-five ICUs in Australia and New Zealand.

PATIENTS

Cohort of 1,465 patients enrolled in the Randomized Evaluation of Normal versus Augmented Level replacement therapy study.

INTERVENTIONS

Daily information on morning hemoglobin level and amount of RBC transfused were prospectively collected in the Randomized Evaluation of Normal versus Augmented Level study. We analyzed the epidemiology of such transfusions and their association with clinical outcomes.

MEASUREMENTS AND MAIN RESULTS

Overall, 977 patients(66.7%) received a total of 1,192 RBC units. By day 5, 785 of 977 transfused patients (80.4%) had received at least one RBC transfusion. Hemoglobin at randomization was lower in transfused than in nontransfused patients (94 vs 111 g/L; p < 0.001). Mean daily hemoglobin was 88 ± 7 and 99 ± 12 g/L in transfused and nontransfused patients. Among transfused patients, 228 (46.7%) had died by day 90 when compared with 426 (43.6%) of nontransfused patients (p = 0.27). Survivors received on average 316 ± 261 mL of RBC, whereas nonsurvivors received 302 ± 362 mL (p = 0.42). On multivariate Cox regression analysis, RBC transfusion was independently associated with lower 90-day mortality (hazard ratio, 0.55; 95% CI, 0.38-0.79). However, we found no independent association between RBC transfusions and mortality when the analyses were restricted to patients surviving at least 5 days (hazard ratio, 1.29; 95% CI, 0.90-1.85). We found no independent association between RBC transfusion and renal replacement therapy-free days, mechanical ventilator-free days, or length of stay in ICU or hospital.

CONCLUSIONS

In patients with severe acute kidney injury treated with continuous renal replacement therapy, we found no association of RBC transfusion with 90-day mortality or other patient-centered outcomes. The optimal hemoglobin threshold for RBC transfusion in such patients needs to be determined in future randomized controlled trials.

[Hospital-acquired anemia: Facts, consequences and prevention]

Hospital-acquired anemia is common, especially in the most critically ill patients. It may be associated with poor patient outcomes. It may result from increased blood loss, impaired red cell production or reduced red cell life span. Multiple associated factors may contribute simultaneously or sequentially to the decrease in hemoglobin level. Some of them are related to the underlying disease and others are iatrogenic. Clinicians should be aware of the importance and consequences of iatrogenic anemia caused by diagnostic blood sampling. Strategies and measures to minimize iatrogenic blood loss should be prioritized. They may reduce the risk of developing anemia and then red blood cells transfusion requirement.

Does IV Iron Induce Plasma Oxidative Stress in Critically Ill Patients? A Comparison With Healthy Volunteers

OBJECTIVE

To compare the oxidative stress induced by IV iron infusion in critically ill patients and in healthy volunteers.

DESIGN

Multicenter, interventional study.

SETTING

Two ICUs and one clinical research center.

SUBJECTS

Anemic critically ill patients treated with IV iron and healthy volunteers.

INTERVENTIONS

IV infusion of 100 mg of iron sucrose.

MEASUREMENTS AND MAIN RESULTS

Thirty-eight anemic patients (hemoglobin, median [interquartile range] = 8.4 g/dL [7.7-9.2]) (men, 25 [66%]; aged 68 yr [48-77]; Simplified Acute Physiology Score II, 48.5 [39-59]) and 39 healthy volunteers (men, 18 [46%]; aged 42.1 yr [29-50]) were included. Blood samples were drawn before (H0) and 2, 6, and 24 hours (H2, H6, and H24) after a 60-minute iron infusion for the determination of nontransferrin bound iron, markers of lipid peroxidation-8α-isoprostanes, protein oxidation-advanced oxidized protein product, and glutathione reduced/oxidized. Iron infusion had no effect on hemodynamic parameter in patients and volunteers. At baseline, patients had much higher interleukin-6, C-reactive protein, and hepcidin levels. 8α-isoprostanes was also higher in patients at baseline (8.5 pmol/L [6.5-12.9] vs 4.6 pmol/L [3.5-5.5]), but the area under the curve above baseline from H0 to H6 was not different (p = 0.38). Neither was it for advanced oxidized protein product and nontransferrin bound iron. The area under the curve above baseline from H0 to H6 (glutathione reduced/oxidized) was lower in volunteers (p = 0.009). Eight patients had a second set of dosages (after the fourth iron infusion), showing higher increase in 8α-isoprostanes.

CONCLUSIONS

In our observation, IV iron infusion does not induce more nontransferrin bound iron, lipid, or protein oxidation in patients compared with volunteers, despite higher inflammation, oxidative stress, and hepcidin levels and lower antioxidant at baseline. In contrary, iron induces a greater decrease in antioxidant, compatible with higher oxidative stress in volunteers than in critically ill patients.

Reliability of blood test results in samples obtained using a 2-mL discard volume from the proximal lumen of a triple-lumen central venous catheter in the critically ill patient

BACKGROUND

Intensive care patients require a high frequency of blood testing, which results in a significant amount of blood loss. When blood is obtained from a central venous catheter (CVC), a large volume is usually discarded to obtain an unaltered sample for testing.

AIM

To determine the reliability of complete blood test results in blood samples obtained from the proximal lumen of a triple-lumen CVC using a 2-mL discard volume DESIGN: Observational study with the prospective collection of data METHODS: The subjects enrolled were all patients with a subclavian triple-lumen CVC, older than 17 years and consecutively admitted to intensive care over a 2-year period. In each of the 54 participants, one blood sample was drawn from the proximal lumen of the catheter, discarding 1·61 mL of blood plus 0·39 mL of catheter deadspace (2 mL) and without interrupting infusion in the middle and distal lumens. A second sample was then obtained by direct venous puncture. The reliability of blood test results was determined by comparing sets of variables recorded for the two sampling methods through intraclass correlation coefficients in the Bland-Altman method.

RESULTS

Inter-method reliability for the variables examined was excellent, >0·75; range (0·868-0·998). Mean differences between the two sample types for the variables most often determined in critically ill patients were leukocytes: 0·200 × 10³ /µL, 95% confidence interval (CI) (0·025 to 0·375); erythrocytes: 0·045 × 10⁶ /uL, 95% CI (-0·003 to 0·094); sodium: 0·074 mEq/L, 95% CI (-0·369 to 0·517); potassium: -0·002mEq/L, 95% CI (-0·065 to 0·061) and glucose: 2·426 mg/dL, 95% CI (0·498-4·354).

CONCLUSIONS

The sampling method proposed minimizes blood loss while offering reliable blood test results.

RELEVANCE TO CLINICAL PRACTICE

The main benefit of the method proposed is reduced blood loss, improving the care of a critically ill patient.

A Simple "Blood-Saving Bundle" Reduces Diagnostic Blood Loss and the Transfusion Rate in Mechanically Ventilated Patients

Introduction

Aim of this study was to reduce blood loss caused by diagnostic blood sampling and to minimize the development of anemia in a high-risk group of mechanically ventilated medical intensive care patients. We therefore implemented a “blood-saving bundle” (BSB) combining a closed-loop arterial blood sampling system, smaller sampling tubes, reduced frequency of blood drawings, and reduced sample numbers.

Methods

The study included all patients from our medical ICU who were ventilated for more than 72 hours. Exclusion criteria were: acute or chronic anemia on admission, bleeding episode(s) during the ICU stay, or end-of-life therapy. The BSB was introduced in 2009 with training and educational support. Patients treated in 2008, before the introduction of the BSB, served as a control group (n = 41, 617 observation days), and were compared with patients treated in 2010 after the introduction of the BSB (BSB group, n = 50, 559 observation days). Primary endpoints were blood loss per day, and development of anemia. Secondary endpoints were numbers of blood transfusions, number of days on mechanical ventilation, and length of the ICU stay.

Results

Mean blood loss per ICU day was decreased from 43.3 ml (95% CI: 41.2 to 45.3 ml) in the controls to 15.0 ml (14.3 to 15.7 ml) in the BSB group (P < 0.001). The introduction of a closed-loop arterial blood sampling system was the major contributor to this effect. Mean hemoglobin concentrations showed no significant differences in both groups during the ICU stay. Hemoglobin values <9 g/dl, however, were recorded in 21.2% of observation days in the controls versus 15.4% in the BSB group (P = 0.01). Units of transfused red blood cells per 100 observation days decreased from 7 to 2.3 (P < 0.001). The mean number of ventilation days was 7.1 days (6.1 to 8.3 days) in the controls and 7.5 days (6.6 to 8.5 days) in the BSB group (P = NS). In total, patients in the BSB group stayed in ICU for a mean of 9.9 days (8.6 to 11.3 days), compared to a mean ICU stay of 13.0 days (10.9 to 15.4 days) in the control group (P = 0.014). Due to the longitudinal study design, however, we cannot exclude uncontrolled confounders affecting the transfusion frequency and mean ICU stay.

Conclusion

Our BSB could be easily implemented and was able to reduce diagnostic blood loss.

Sepsis-Induced Acute Kidney Injury

Acute kidney injury (AKI) is a serious yet potentially reversible complication of sepsis. Several molecular mechanisms involved in the development of septic AKI have been identified. These mechanisms may be important targets in the development of future therapies. This review highlights the role of the innate immune response to sepsis and its downstream effects on kidney structure and function with special reference to the adaptive cellular response and glomerular hemodynamic changes. In addition, current evidence surrounding the management of patients with septic AKI is summarized. Finally, potential novel therapies for septic AKI are presented.

Association of red blood cell transfusion and in-hospital mortality in patients admitted to the intensive care unit: a systematic review and meta-analysis

INTRODUCTION

Previous research has debated whether red blood cell (RBC) transfusion is associated with decreased or increased mortality in patients admitted to the intensive care unit (ICU). We conducted a systematic review and meta-analysis to assess the relationship of RBC transfusion with in-hospital mortality in ICU patients.

METHODS

We carried out a literature search on Medline (1950 through May 2013), Web of Science (1986 through May 2013) and Embase (1980 through May 2013). We included all prospective and retrospective studies on the association between RBC transfusion and in-hospital mortality in ICU patients. The relative risk for the overall pooled effects was estimated by random effects model. Sensitivity analyses were conducted to assess potential bias.

RESULTS

The meta-analysis included 28,797 participants from 18 studies. The pooled relative risk for transfused versus nontransfused ICU patients was 1.431 (95% CI, 1.105 to 1.854). In sensitivity analyses, the pooled relative risk was 1.211 (95% CI, 0.975 to 1.505) if excluding studies without adjustment for confounders, 1.178 (95% CI, 0.937 to 1.481) if excluding studies with relative high risk of bias, and 0.901 (95% CI, 0.622 to 1.305) if excluding studies without reporting hazard ratio (HR) or relative risk (RR) as an effect size measure. Subgroup analyses revealed increased risks in studies enrolling patients from all ICU admissions (RR 1.513, 95%CI 1.123 to 2.039), studies without reporting information on leukoreduction (RR 1.851, 95%CI 1.229 to 2.786), studies reporting unadjusted effect estimates (RR 3.933, 95%CI 2.107 to 7.343), and studies using odds ratio as an effect measure (RR 1.465, 95%CI 1.049 to 2.045). Meta-regression analyses showed that RBC transfusion could decrease risk of mortality in older patients (slope coefficient -0.0417, 95%CI -0.0680 to -0.0154).

CONCLUSIONS

There is lack of strong evidence to support the notion that ICU patients who receive RBC transfusion have an increased risk of in-hospital death. In studies adjusted for confounders, we found that RBC transfusion does not increase the risk of in-hospital mortality in ICU patients. Type of patient, information on leukoreduction, statistical method, mean age of patient enrolled and publication year of the article may account for the disagreement between previous studies.

Prevalence of iron deficiency on ICU discharge and its relation with fatigue: a multicenter prospective study

INTRODUCTION

Prevalence of iron deficiency (ID) at intensive care (ICU) admission is around 25 to 40%. Blood losses are important during ICU stay, leading to iron losses, but prevalence of ID at ICU discharge is unknown. ID has been associated with fatigue and muscular weakness, and may thus impair post-ICU rehabilitation. This study assessed ID prevalence at ICU discharge, day 28 (D28) and six months (M6) after and its relation with fatigue.

METHODS

We conducted this prospective, multicenter observational study at four University hospitals ICUs. Anemic (hemoglobin (Hb) less than 13 g/dL in male and less than 12 g/dL in female) critically ill adult patients hospitalized for at least five days had an iron profile taken at discharge, D28 and M6. ID was defined as ferritin less than 100 ng/L or less than 300 ng/L together with a transferrin saturation less than 20%. Fatigue was assessed by numerical scale and the Multidimensional Fatigue Inventory-20 questionnaire at D28 and M6 and muscular weakness by a hand grip test at ICU discharge.

RESULTS

Among 107 patients (men 77%, median (IQR) age 63 (48 to 73) years) who had a complete iron profile at ICU discharge, 9 (8.4%) had ID. At ICU discharge, their hemoglobin concentration (9.5 (87.7 to 10.3) versus 10.2 (92.2 to 11.7) g/dL, P =0.09), hand grip strength (52.5 (30 to 65) versus 49.5 (15.5 to 67.7)% of normal value, P =0.61) and visual analog scale fatigue scale (57 (40 to 80) versus 60 (47.5 to 80)/100, P =0.82) were not different from non-ID patients. At D28 (n =80 patients) and M6 (n =78 patients), ID prevalence increased (to 25 and 35% respectively) while anemia prevalence decreased (from 100% to 80 and 25% respectively, P <0.0001). ID was associated with increased fatigue at D28, after adjustment for main confounding factors, including anemia (regression coefficient (95%CI), 3.19 (0.74 to 5.64), P =0.012). At M6, this association disappeared.

CONCLUSIONS

The prevalence of ID increases from 8% at discharge to 35% six months after prolonged ICU stay (more than five days). ID was associated with increased fatigue, independently of anemia, at D28.

Variation in diagnostic testing in ICUs: a comparison of teaching and nonteaching hospitals in a regional system

OBJECTIVES

To explore variation in the use of diagnostic testing in ICUs, with emphasis on differences between teaching and nonteaching ICUs.

DESIGN

Retrospective review of a prospective clinical ICU database.

SETTING

Five teaching and four nonteaching ICUs in Winnipeg, Canada, during 2006-2010.

PATIENTS

All adults admitted to the nine ICUs during the study period were eligible. After excluding subgroups restricted to teaching ICUs, inter-ICU transfers, prior ICU admission within 90 days, ICU length of stay less than 12 hours, and missing death dates, 10,262 patients were evaluated.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Our primary outcome variable (TotalTesting) was the cumulative number of nine common laboratory tests, three radiologic tests, and electrocardiograms performed in each ICU. We used multivariable median regression to identify factors associated with TotalTesting, including length of stay, demographics, admission details, type and severity of acute illness, and specific medical interventions. We estimated the predictive power of variables as the decline in pseudo-R2 (a goodness-of-fit measure for median regression) when omitting those variables from the model. Median (interquartile range) TotalTesting was 27 (18-49) in teaching ICUs and 20 (13-36) in nonteaching units. With multivariable adjustment, median TotalTesting was 7.1 higher (95% CI, 6.6-7.7) in teaching ICUs. The most influential variable was length of stay, accounting for almost half of the variation. ICU teaching status was the second most important factor, greater than the degree of physiologic derangement and details of medical management.

CONCLUSIONS

After adjustment for confounding variables, patients in teaching ICUs had slightly but significantly more diagnostic tests done than those in nonteaching ICUs. In addition to increasing costs, prior studies have shown that excessive testing can cause harm in various ways and does not improve outcomes. Interventions to reduce testing should be directed to all caregivers with responsibility for ordering diagnostic tests, in both teaching and nonteaching institutions.

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.

Timing of blood transfusion in relation to ICU admission-a single centre audit

There is growing concern that blood transfusion may be associated with adverse outcomes in critically ill patients. Timing of transfusion in relation to intensive care unit (ICU) stay may be important in designing and understanding transfusion studies. The objective of this study was to determine the timing of red blood cell transfusion in relation to admission to an Australian ICU and to describe associations with transfusion requirements. We undertook a retrospective, observational, single-centre cohort study of all patients admitted to the ICU at The Northern Hospital, Melbourne, Australia, between 1 January and 31 December 2008 in order to measure the timing of transfusion in relation to ICU admission and the demographic and outcome data of the cohort. 674 individual hospital admissions were analysed. Overall, 28% (188/674) of patients admitted to ICU received a red cell transfusion during their hospital stay. A total of 55 (28.5%) patients were transfused either before and/or after ICU discharge but never in the ICU. Thirty-five percent (258/741) of red cell units were transfused outside the ICU. The median number of red cell units transfused was three units per patient (interquartile range 1 to 5). There was no difference between transfused and non-transfused groups in either crude mortality or severity-adjusted mortality. In approximately one-third of ICU patients in our study transfusions occurred before admission to, and/or after discharge from, the ICU. This has implications for designing and interpreting transfusion studies in the ICU and requires confirmation in a multi-centre study.

RBC transfusion practices among critically ill patients: has evidence changed practice?

OBJECTIVE

Increasing evidence, including publication of the Transfusion Requirements in Critical Care trial in 1999, supports a lower hemoglobin threshold for RBC transfusion in ICU patients. However, little is known regarding the influence of this evidence on clinical practice over time in a large population-based cohort.

DESIGN

Retrospective population-based cohort study.

SETTING

Thirty-five Maryland hospitals.

PATIENTS

Seventy-three thousand three hundred eighty-five nonsurgical adults with an ICU stay greater than 1 day between 1994 and 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The unadjusted odds of patients receiving an RBC transfusion increased from 7.9% during the pre-Transfusion Requirements in Critical Care baseline period (1994-1998) to 14.7% during the post-Transfusion Requirements in Critical Care period (1999-2007). A logistic regression model, including 40 relevant patient and hospital characteristics, compared the annual trend in the adjusted odds of RBC transfusion during the pre- versus post-Transfusion Requirements in Critical Care periods. During the pre-Transfusion Requirements in Critical Care period, the trend in the adjusted odds of RBC transfusion did not differ between hospitals averaging>200 annual ICU discharges and hospitals averaging≤200 annual ICU discharges (odds ratio, 1.07 [95% CI, 1.01-1.13] annually and 1.03 [95% CI, 0.99-1.07] annually, respectively; p=0.401). However, during the post-Transfusion Requirements in Critical Care period, the adjusted odds of RBC transfusion decreased over time in higher ICU volume hospitals (odds ratio, 0.96 [95% CI, 0.93-0.98] annually) but continued to increase in lower ICU volume hospitals (odds ratio, 1.10 [95% CI, 1.08-1.13] annually), p<0.001.

CONCLUSIONS

In this population-based cohort of ICU patients, the unadjusted odds of RBC transfusion increased in both higher and lower ICU volume hospitals both before and after Transfusion Requirements in Critical Care publication. After adjusting for relevant characteristics, the odds continued to increase in lower ICU volume hospitals in the post-Transfusion Requirements in Critical Care period, but it decreased in higher ICU volume hospitals. This suggests that evidence supporting restrictive RBC transfusion thresholds may not be uniformly translated into practice in different hospital settings.

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.

Blood conservation devices in critical care: a narrative review

Anaemia is associated with inferior outcomes in critically ill patients. It is difficult to prevent and is treated commonly with the transfusion of packed red cells. However, transfusion to augment oxygen delivery has not been shown to consistently offer a survival advantage when the haemoglobin concentration exceeds 7 g/dL. Several studies point to inferior outcomes when patients are transfused. Observational studies have confirmed that critically ill patients have frequent blood draws as part of their routine daily care. Cumulatively large volumes of blood are frequently taken, which contribute significantly towards the development of anaemia. Reducing iatrogenic blood loss may reduce the risk of developing anaemia and possibly the need for transfusion. Blood conservation devices may help to achieve this goal. The integration of blood conservation devices into routine care has been relatively slow in critical care. This review summarises the current evidence base and confirms that blood conservation devices do reduce the volume of iatrogenic blood loss. In the most recent studies, these devices have been shown to reduce transfusion requirements even in those intensive care units that follow a restrictive transfusion strategy.

Serum Soluble-Fas, Inflammation, and Anemia in Acute Kidney Injury

Anemia is a common feature in critically ill patients. Serum soluble-Fas (sFas) levels are associated with anemia in chronic kidney disease. It is possible that sFas levels are also associated with anemia in acute kidney injury (AKI) patients. The study aims to investigate the relationship between serum levels of sFas, erythropoietin (Epo), inflammatory cytokines, and hemoglobin (Hb) concentration in critically ill patients with AKI. We studied 72 critically ill patients with AKI (AKI group; n = 53) or without AKI (non-AKI group; n = 19), and 18 healthy volunteers. Serum sFas, Epo, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, IL-10, iron status, and Hb concentration were analyzed in all groups. We also investigated the correlation between these variables in the AKI group. Critically ill patients (AKI and non-AKI groups) had higher serum levels of Epo than healthy volunteers. Hb concentration was lower in the AKI group than in the other groups. Serum sFas, IL-6, TNF-α, and ferritin levels were higher in the AKI group. Hb concentration correlated negatively with serum IL-6 (r = -0.37, P = 0.008), sFas (r = -0.35, P = 0.01), and Epo (r = -0.27, P = 0.04), while serum sFas correlated positively with iron levels (r = 0.36, P = 0.008) and IL-6 (r = 0.28, P = 0.04) in the AKI group. In multivariate analysis, after adjusting for markers of inflammation and iron stores, only serum sFas levels (P = 0.03) correlated negatively with Hb concentration in the AKI group. Serum Epo and inflammatory cytokine levels are elevated in critically ill patients with or without AKI. Serum levels of sFas are elevated and independently associated with anemia in critically ill patients with AKI.

Critically ill and septic patient: is red blood cell transfusion adding to the Domino Effect?

Sepsis is a major cause of patient morbidity and mortality. Many critically ill patients are septic, and red blood cell transfusion is often part of their treatment plan. Studies have shown that red blood cell transfusion is associated with a dose-dependent increase in patient morbidity and mortality. Although red blood cells are transfused to increase the recipient's oxygen-carrying capacity, there are new and emerging data to support that red blood cell transfusion may potentially decrease perfusion and oxygen delivery to the microcirculation, particularly when older red blood cells are transfused. In addition, there are similar effects in the pathophysiology of sepsis that may overlap with the changes that occur with storage of red blood cells. This article will discuss recent literature addressing red cell transfusion in critically ill and septic patients and discuss general guidelines for red cell transfusion in this patient population. This article will also discuss the epidemiology and pathophysiology of sepsis and relate how storage and transfusion of red cells may potentially contribute to changes observed in a septic patient.

Update in critical care for the nephrologist: transfusion in nonhemorrhaging critically ill patients

A growing number of guidelines and recommendations advocate a restrictive transfusion strategy. Strong evidence exists that a hemoglobin threshold of less than 7 g/dL conserves resources and may improve outcomes in critically ill patients and that platelet counts greater than 10,000/μL are well tolerated. Patients with coronary artery disease can be safely managed with a restrictive transfusion strategy, utilizing a hemoglobin threshold of less than 7 or 8 g/dL; a threshold of less than 8 g/dL can be applied to patients with acute coronary syndromes. In the absence of coagulopathy with bleeding or high risk for bleeding, plasma transfusion should be withheld. Complications from transfusion are significant and previously under-recognized immunologic complications pose a more serious threat than infections. Erythropoietin and iron administration do not reduce transfusion needs in the critically ill. Interventions to reduce blood loss and educate clinicians are successful in reducing transfusion requirements.

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.

Anemia and blood transfusions in critically ill patients

Anemia is common in critically ill patients. As a consequence packed red blood cell (PRBC) transfusions are frequent in the critically ill. Over the past two decades a growing body of literature has emerged, linking PRBC transfusion to infections, immunosuppression, organ dysfunction, and a higher mortality rate. However, despite growing evidence that risk of PRBC transfusion outweighs its benefit, significant numbers of critically ill patients still receive PRBC transfusion during their intensive care unit (ICU) stay. In this paper, we summarize the current literature concerning the impact of anemia on outcomes in critically ill patients and the potential complications of PRBC transfusions.