The transfusion dilemma – Weighing the known and newly proposed risks of blood transfusions against the uncertain benefits

Patient Blood Management as an Emerging Concept in Quality: The Role of Nurses

BACKGROUND

Transfusion of blood components has long been considered lifesaving therapy. While blood transfusion may be clinically indicated as a treatment option for some patients, the benefits of transfusion in asymptomatic, hemodynamically stable patients are questionable.

PROBLEM

Blood component transfusion is routinely used as a default therapy when not clinically indicated, increasing the risk of poor patient outcomes, adverse events, pressures on blood supply and availability, and increased health care costs.

APPROACH

Nurses have the responsibility to advocate for patients and reduce/avoid unnecessary blood transfusion through the implementation of patient blood management (PBM). The PBM paradigm includes treatment of anemia, minimizing blood loss and bleeding, optimization of coagulation, and employing true patient-centered decision making.

CONCLUSIONS

PBM should become the standard of care with the goal of improving health care quality and patient outcomes while using the multidisciplinary team for its implementation. As advocates for their patients, nurses can play a major role in the development, implementation, and promotion of PBM.

Measuring Mitochondrial Oxygen Tension during Red Blood Cell Transfusion in Chronic Anemia Patients: A Pilot Study

In light of the associated risks, the question has been raised whether the decision to give a blood transfusion should solely be based on the hemoglobin level. As mitochondria are the final destination of oxygen transport, mitochondrial parameters are suggested to be of added value. The aims of this pilot study were to investigate the effect of a red blood cell transfusion on mitochondrial oxygenation as measured by the COMET device in chronic anemia patients and to explore the clinical usability of the COMET monitor in blood transfusion treatments, especially the feasibility of performing measurements in an outpatient setting. To correct the effect of volume load on mitochondrial oxygenation, a red blood cell transfusion and a saline infusion were given in random order. In total, 21 patients were included, and this resulted in 31 observations. If patients participated twice, the order of infusion was reversed. In both the measurements wherein a blood transfusion was given first and wherein 500 mL of 0.9% saline was given first, the median mitochondrial oxygen tension decreased after red blood cell transfusion. The results of this study have strengthened the need for further research into the effect of blood transfusion tissue oxygenation and the potential role of mitochondrial parameters herein.

MicroRNAs as Quality Assessment Tool in Stored Packed Red Blood Cell in Blood Banks

Micro-ribonucleic acids are control gene expression in cells. They represent the changed cellular states that occur can be employed as biomarkers. Red blood cells alter biochemically and morphologically while they are being stored, which could be detrimental to transfusion. The effect of storage on the erythrocyte transcriptome is not mostly investigated. Because adult erythrocytes lack a nucleus, it has long been assumed that they lack deoxyribonucleic acid and ribonucleic acid. On the other hand, erythrocytes contain a diverse range of ribonucleic acids, of which micro-ribonucleic acids are key component. Changes in this micro-ribonucleic acid protect cells from death and adenine triphosphate depletion, and they are linked to specific storage lesions. As a result, changes in micro-ribonucleic acid in stored erythrocytes may be used as a marker to assess the quality and safety of stored erythrocytes. Therefore, this review ams to review the role of microRNA in stored packed red blood cells as quality indicator. Google Scholar, PubMed, Scopus, and Z-libraries are used for searching articles and books. The article included in this paper was written in the English language and had the full article. During long storage of RBCs, miR-16-2-3p, miR-1260a, miR-1260b, miR-4443, miR-4695-3p, miR-5100, let-7b, miR-16, miRNA-1246, MiR-31-5p, miR-203a, miR-654-3p, miR-769-3p, miR-4454, miR-451a and miR-125b- 5p are up regulated. However, miR-96, miR-150, miR-196a, miR-197, miR-381 and miR-1245a are down regulated after long storage of RBCs. The changes of this microRNAs are linked to red blood cell lesions. Therefore, micro-ribonucleic acids are the potential quality indicator in stored packed red blood cells in the blood bank. Particularly, micro-ribonucleic acid-96 is the most suitable biomarker for monitoring red blood cell quality in stored packed red blood units.

Biological investigations of transfusion reactions: contribution of symptom-based decisional algorithms

OBJECTIVES

While transfusion is a common and safe therapeutic procedure in health care facilities, transfusion reactions can occur, whether acute or delayed, mild or life-threatening. In face of these reactions, the biological analysis laboratory plays a central role in their diagnosis. The objective of this article is to develop decisional algorithms for laboratory tests to be performed according to the clinical symptoms developed by the patient during or after transfusion.

METHODS

Based on the information collected by reviewing the literature and the procedures used in our hospital, we then developed biological investigation algorithms according to the symptoms presented by the patient, rather than the presumed reaction.

RESULTS AND CONCLUSION

We have developed symptom-based algorithms for acute transfusion reactions management that streamline laboratory testing and simplify the differential diagnosis.

Factors Associated with Rebound Pain After Patient-controlled Epidural Analgesia in Patients Undergoing Major Abdominal Surgery: A Retrospective Study

OBJECTIVES

Although patient-controlled epidural analgesia (PCEA) is an effective form of regional analgesia for abdominal surgery, some patients experience significant rebound pain after the discontinuation of PCEA. However, risk factors for rebound pain associated with PCEA in major abdominal surgery remain unknown. This study evaluated the incidence of rebound pain related to PCEA and explored potential associated risk factors.

METHODS

We performed a retrospective review of 236 patients using PCEA following hepatobiliary and pancreas surgery between 2018 and 2020 in a tertiary hospital in South Korea. Rebound pain was defined as an increase from well-controlled pain (numeric rating scale <4) during epidural analgesia to severe pain (numeric rating scale ≥7) within 24 hours of discontinuation of PCEA. Logistic regression analysis was performed to determine the factors associated with rebound pain.

RESULTS

A total of 236 patients were included in this study. Patients were categorized into the non-rebound pain group (170 patients; 72%) and the rebound pain group (66 patients; 28%). Multivariable logistic regression analysis revealed that preoperative prognostic nutritional index (PNI) below 45 (odds ratio [OR]=2.080, 95% confidential interval [CI]=1.061-4.079, P=0.033) and intraoperative transfusion (OR=4.190, 95% CI=1.436-12.226, P=0.009) were independently associated with rebound pain after PCEA discontinuation.

DISCUSSION

Rebound pain after PCEA occurred in approximately 30% of patients who underwent major abdominal surgery, resulting in insufficient postoperative pain management. Preoperative low PNI and intraoperative transfusion may be associated with rebound pain after PCEA discontinuation.

Making patient blood management the new norm(al) as experienced by implementors in diverse countries

BACKGROUND

Patient blood management (PBM) describes a set of evidence-based practices to optimize medical and surgical patient outcomes by clinically managing and preserving a patient's own blood. This concepts aims to detect and treat anemia, minimize the risk for blood loss and the need for blood replacement for each patient through a coordinated multidisciplinary care process. In combination with blood loss, anemia is the main driver for transfusion and all three are independent risk factors for adverse outcomes including morbidity and mortality. Evidence demonstrates that PBM significantly improves outcomes and safety while reducing cost by macroeconomic magnitudes. Despite its huge potential to improve healthcare systems, PBM is not yet adopted broadly. The aim of this study is to analyze the collective experiences of a diverse group of PBM implementors across countries reflecting different healthcare contexts and to use these experiences to develop a guidance for initiating and orchestrating PBM implementation for stakeholders from diverse professional backgrounds.

METHODS

Semi-structured interviews were conducted with 1-4 PBM implementors from 12 countries in Asia, Latin America, Australia, Central and Eastern Europe, the Middle East, and Africa. Responses reflecting the drivers, barriers, measures, and stakeholders regarding the implementation of PBM were summarized per country and underwent qualitative content analysis. Clustering the resulting implementation measures by levels of intervention for PBM implementation informed a PBM implementation framework.

RESULTS

A set of PBM implementation measures were extracted from the interviews with the implementors. Most of these measures relate to one of six levels of implementation including government, healthcare providers, funding, research, training/education, and patients/public. Essential cross-level measures are multi-stakeholder communication and collaboration.

CONCLUSION

The implementation matrix resulting from this research helps to decompose the complexity of PBM implementation into concrete measures on each implementation level. It provides guidance for diverse stakeholders to design, initiate and develop strategies and plans to make PBM a national standard of care, thus closing current practice gaps and matching this unmet public health need.

Patient Blood Management: transfusion appropriateness in the post-operative period

BACKGROUND

Within the context of Patient Blood Management (PBM) policy for the peri-operative period, the transfusion medicine unit of our institution adopted a series of strategies to support and enhance red blood cell (RBC) transfusion best practices. This study aimed to evaluate the appropriateness of RBC transfusion therapy in the post-operative period, before and after starting a multifactorial PBM policy.

MATERIALS AND METHODS

A 2-phase observational study was conducted on patients who underwent major surgery. The study was designed as follows: 3 months of preliminary audit, followed by multifactorial PBM policy, and a final audit. The policy comprised seminars, teaching lessons, periodic consultations and the insertion of Points of Care. RBC transfusion appropriateness was evaluated in both audits.

RESULTS

The preliminary audit, performed on 168 patients, showed that 37.7% of the patients were appropriately transfused. The final audit, performed on 205 patients, indicated a significant increase of RBC transfusion appropriateness to 65.4%.

DISCUSSION

In our experience, our multifactorial PBM policy improved the RBC transfusion appropriateness in the post-operative period. We believe that our multifactorial PBM policy, which comprises the insertion of Points of Care, supported the healthcare workers in the transfusion decision-making process. This enhancement of transfusion appropriateness implies clinical and managerial advantages, such as reduced transfusion-related risks, optimisation of health care resources, and reduction in costs.

Incompatible erythrocyte transfusion with lipopolysaccharide induces acute lung injury in a novel rat model

Acute transfusion reactions can manifest in many forms including acute hemolytic transfusion reaction, allergic reaction and transfusion-related acute lung injury. We previously developed an acute hemolytic transfusion reaction rat model mediated by transfusion of incompatible human erythrocytes against which rats have preexisting antibodies resulting in classical complement pathway mediated intravascular hemolysis. In this study, the acute hemolytic transfusion reaction model was adapted to yield an acute lung injury phenotype. Adolescent male Wistar rats were primed in the presence or absence of lipopolysaccharide followed by transfusion of incompatible erythrocytes. Blood was collected at various time points during the course of the experiment to determine complement C5a levels and free DNA in isolated plasma. At 4 hours, blood and lung tissue were recovered and assayed for complete blood count and histological acute lung injury, respectively. Compared to sham animals or animals receiving increasing amounts of incompatible erythrocytes (equivalent to a 15–45% transfusion) in the absence of lipopolysaccharide, lungs of animals receiving lipopolysaccharide and a 30% erythrocyte transfusion showed dramatic alveolar wall thickening due to neutrophil infiltration. C5a levels were significantly elevated in these animals indicating that complement activation contributes to lung damage. Additionally, these animals demonstrated a significant increase of free DNA in the blood over time suggestive of neutrophil extracellular trap formation previously associated with transfusion-related acute lung injury in humans and mice. This novel ‘two-hit’ model utilizing incompatible erythrocyte transfusion in the presence of lipopolysaccharide yields a robust acute lung injury phenotype.

Modifiable risk factors for patients undergoing lung cancer surgery and their optimization: a review

Enhanced recovery after surgery (ERAS) programs include a variety of pre-, intra- and post-operative interventions that seek to decrease the stress response to surgery and facilitate the recovery of surgical patients. There are a number of patient factors that may increase the risk of postoperative complications (POC) after lung cancer surgery and delay recovery. Some of these factors may be amenable to optimization preoperatively and potentially decrease the incidence of these complications. We have chosen to discuss the incidence and complications associated with factors we felt were both relatively common and significant contributors to POCs. For each of these factors we discuss potential avenues for optimization and the evidence for the resulting decrease in complications.

Assessment of the knowledge and perceptions of Brazilian medical residents on transfusion medicine

Background

Medical education has a major social impact because it ultimately influences the quality and safety of the health service offered to the population. Several studies have acknowledged the relationship between medical knowledge on transfusion medicine and the proper use of this therapy. The rational use of blood has become a worldwide concern. In this context, the aim of the present study was to evaluate medical residents' knowledge on transfusion medicine in hospitals located in Rio de Janeiro, Brazil, and their training during their medical education.

Methods

One hundred and six residents from eight medical specialties of four hospitals participated. A questionnaire developed by the Biomedical Excellence for Safer Transfusion (BEST) group was applied to evaluate the participants' medical knowledge. Another questionnaire was also applied to evaluate participant profiles regarding frequency of transfusion prescriptions, self-perceived knowledge and relevance of the subject.

Results

The mean number of correct answers to the questionnaire on knowledge about transfusion practices was 43.5% (range: 15-80%). A relationship between training during medical residency and the obtained result was observed (p-value = 0.0007). Most residents (73%) did not receive training in transfusion medicine during their graduation or residency and 93% would like to receive additional training.

Conclusion

A clear deficit in the knowledge of transfusion medicine was verified, indicating the need for change in the teaching of this specialty. This result is similar to some developed countries.

Transfusion Medicine and Molecular Genetic Methods

Transfusion procedures are always complicated by potential genetic mismatching between donor and recipient. Compatibility is determined by several major antigens, such as the ABO and Rhesus blood groups. Matching for other blood groups (Kell, Kidd, Duffy, and MNS), human platelet antigens, and human leukocyte antigens (HLAs) also contributes toward the successful transfusion outcomes, especially in multitransfused or highly immunized patients. All these antigens of tissue identity are highly polymorphic and thus present great challenges for finding suitable donors for transfusion patients. The ABO blood group and HLA markers are also the determinants of transplant compatibility, and mismatched antigens will cause graft rejection or graft-versus-host disease. Thus, a single and comprehensive registry covering all of the significant transfusion and transplantation antigens is expected to become an important tool in providing an efficient service capable of delivering safe blood and quickly locating matching organs/stem cells. This review article is intended as an accessible guide for physicians who care for transfusion-dependent patients. In particular, it serves to introduce the new molecular screening methods together with the biology of these systems, which underlies the tests.

Five-year trends in perioperative red blood cell transfusion from index cases in five surgical specialties: 2011 to 2015

BACKGROUND

Red blood cell (RBC) transfusion can be life-saving; however, the risks of RBC transfusion have been increasingly recognized, and current guidelines recommend restrictive transfusion in most patients. We hypothesized that RBC transfusions are decreasing in surgical patients.

STUDY DESIGN AND METHODS

A retrospective review of the National Surgical Quality Improvement Program database was performed from 2011 to 2015. Index cases in five surgical specialties were studied: neurosurgery, thoracic surgery, gynecologic surgery, orthopedic surgery, and vascular surgery. Patient characteristics, preoperative laboratory values, and surgery details were compared between years. The study's primary outcome was perioperative RBC transfusion, which was compared over the 5-year period for each specialty. Secondary outcomes were myocardial infarction and renal failure after surgery. In addition, trends in RBC transfusion between low-risk and high-risk patients and between emergency and elective surgery were examined.

RESULTS

RBC transfusion decreased in all surgical specialties except for thoracic and gynecologic surgery. RBC transfusion decreased substantially in orthopedic surgery, falling from 22.4% in 2011 to 6.3% in 2015 (p ≤ 0.0001). High-risk patients had greater reductions in the receipt of RBC transfusion than low-risk patients, and there were no increases in myocardial infarction or renal failure after surgery in any specialty.

CONCLUSION

RBC transfusion appears to be decreasing across multiple surgical specialties, with no apparent increase in myocardial infarctions or renal failure. This likely represents an important improvement in patient care. Continued efforts are needed to develop patient blood management programs and further reduce RBC transfusion.

Enhancing uniformity and overall quality of red cell concentrate with anaerobic storage

BACKGROUND

Recent research focused on understanding stored red blood cell (RBC) quality has demonstrated high variability in measures of RBC function and health across units. Studies have historically linked this high variability to variations in processing, storage method, and age. More recently, a large number of studies have focused on differences in donor demographics, donor iron sufficiency, and genetic predisposition of the donor to poor storage, particularly through mechanisms of accelerated oxidative damage. A study was undertaken to evaluate a potential additional source of unit to unit variation in stored RBC: the role of variable percent oxygen saturation (%SO₂) levels on blood quality parameters during storage.

MATERIALS AND METHODS

%SO₂ data from 492 LR-RBC/AS-3 units used for internal and external collaborative research was included in the analysis. Whole blood units were processed into red blood cells, AS-3 added, leucocyte reduced, in compliance with American Association of Blood Banks guidelines. LR-RBC/AS-3 products were subsequently analysed for %SO₂ levels within 3-24 hours of phlebotomy using a co-oximeter. Separately, to evaluate the impact of pre-storage as well as increasing levels of %SO₂ during storage, a pool-and-split study was performed. Four units of LR-RBC/AS-3 were split 6 ways; "as is" (control), hyperoxygenated to more than 90%, and four levels of pre-storage %SO₂. The units were periodically sampled up to 42 days and analysed for %SO₂, pCO₂, methaemoglobin, ATP, 2,3-BPG as well as with the metabolomics workflow.

RESULTS

The measured mean %SO₂ in LR-RBC/AS-3 within 24 hours of collection was 45.9±17.5% with (32.7-61.0 IQR). %SO₂ in all products increased to approximately 95-100% in three weeks. Measured blood quality parameters including ATP, % haemolysis, methaemoglobin, oxidised lipids, and GSH/GSSG indicated suppressed cellular metabolism and increased red cell degradation in response to higher %SO₂ levels.

DISCUSSION

The surprisingly high variability in starting %SO₂ levels, coupled with negative impacts of high oxygen saturation on red blood cell quality indicates that oxygen levels may be an important and under-appreciated source of unit-to-unit variability in RBC quality.

Pressure Infusion Cuff and Blood Warmer during Massive Transfusion: An Experimental Study About Hemolysis and Hypothermia

Background

Blood warmers were developed to reduce the risk of hypothermia associated with the infusion of cold blood products. During massive transfusion, these devices are used with compression sleeve, which induce a major stress to red blood cells. In this setting, the combination of blood warmer and compression sleeve could generate hemolysis and harm the patient. We conducted this study to compare the impact of different pressure rates on the hemolysis of packed red blood cells and on the outlet temperature when a blood warmer set at 41.5°C is used.

Methods

Pressure rates tested were 150 and 300 mmHg. Ten packed red blood cells units were provided by Héma-Québec and each unit was sequentially tested.

Results

We found no increase in hemolysis either at 150 or 300 mmHg. By cons, we found that the blood warmer was not effective at warming the red blood cells at the specified temperature. At 150 mmHg, the outlet temperature reached 37.1°C and at 300 mmHg, the temperature was 33.7°C.

Conclusion

To use a blood warmer set at 41.5°C in conjunction with a compression sleeve at 150 or 300 mmHg does not generate hemolysis. At 300 mmHg a blood warmer set at 41.5°C does not totally avoid a risk of hypothermia.

Smoking is Associated with Increased Blood Loss and Transfusion Use After Lumbar Spinal Surgery

BACKGROUND

Little is known about the association between smoking and intraoperative blood loss and perioperative transfusion use in patients undergoing spinal surgery. However, we found that although many of the common complications and deleterious effects of smoking on surgical patients had been well documented, the aspect of blood loss seemingly had been overlooked despite data reported in nonorthopaedic sources to suggest a possible connection.

QUESTIONS/PURPOSES

We asked: (1) Is smoking associated with increased estimated blood loss during surgery in patients undergoing lumbar spine surgery? (2) Is smoking associated with increased perioperative transfusion usage?

METHODS

Between 2005 and 2009, 581 lumbar decompression procedures (with or without fusion) were performed at one academic spine center. Of those, 559 (96%) had sufficient chart documentation to categorize patients by smoking status, necessary intra- and postoperative data to allow analysis with respect to bleeding and transfusion-related endpoints, and who did not meet exclusion criteria. Exclusion criteria included: patients whose smoking status did not fit in our two categories, patients with underlying coagulopathy, patients receiving anticoagulants (including aspirin and platelet inhibitors), history of hepatic disease, history of platelet disorder or other blood dyscrasias, and patient or family history of any other known bleeding disorder. Smoking history in packs per day was obtained for all subjects. We defined someone as a smoker if the patient reported smoking up until the day of their surgical procedure; nonsmokers were patients who quit smoking at least 6 weeks before surgery or had no history of smoking. We used a binomial grouping for whether patients did or did not receive a transfusion perioperatively. Age, sex, number of levels of discectomies, number of levels decompressed, number of levels fused, and use of instrumentation were recorded. The same approaches were used for transfusions in all patients regardless of smoking history; decisions were made in consultation between the surgeon and the anesthesia team. Absolute indications for transfusion postoperatively were: a hemoglobin less than 7 g/dL, continued symptoms of dizziness, tachycardia, decreased exertional tolerance, or hypotension that failed to respond to fluid resuscitation. Multiple linear regression analyses correcting for the above variables were performed to determine associations with intraoperative blood loss, while logistic regression was used to analyze perioperative transfusion use.

RESULTS

After controlling for potentially relevant confounding variables noted earlier, we found smokers had increased estimated blood loss compared with nonsmokers (mean, 328 mL more for each pack per day smoked; 95% CI, 249-407 mL; p < 0.001). We also found that again correcting for confounders, smokers had increased perioperative transfusion use compared with nonsmokers (odds ratio, 13.8; 95% CI, 4.59-42.52).

CONCLUSIONS

Smoking is associated with increased estimated surgical blood loss and transfusion use in patients undergoing lumbar spine surgery. Patients who smoke should be counseled regarding these risks and on smoking cessation before undergoing lumbar surgery.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice

Background

The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme.

Methods

Studies were selected with particular attention being paid to meta‐analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English‐language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature.

Results

This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations.

Conclusions

Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS ^®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi‐institutional prospective and adequately powered randomized trials.

Novel method to leukoreduce murine blood for transfusion: how to reduce animal usage

BACKGROUND

Basic research on the pathomechanisms of transfusion-related adverse events depends on murine transfusion models, in which leukoreduction (LR) is a prevalent standard. The commonly used neonatal LR filter (LRF) is associated with considerable animal numbers. A more efficient method would help support the guiding principles of "replacement, reduction, refinement" (3Rs).

STUDY DESIGN AND METHODS

Blood from C57BL/6 and C57BL/6-Tg(UBC-GFP)30Scha/J mice was leukoreduced using (1) a neonatal LRF, (2) a syringe LRF, or (3) CD45 microbeads. Product quality was assessed according to US Food and Drug Administration (FDA) standards. White blood cell numbers were analyzed by flow cytometry; hemoglobin concentrations and hematocrit were measured and in vivo posttransfusion recoveries were determined after 2 weeks of storage.

RESULTS

Using the neonatal filter, a LR of 99.56% was achieved with wastage of 12.4 mL in comparison to 99.68% and 1-mL hold-up volume with the syringe filter and 99.11 ± 0.24% LR and 0.1-mL wastage using microbeads. All techniques achieved FDA quality standards, apart from posttransfusion recovery rate, which was only reached by the microbeads-based technique.

CONCLUSION

LR with CD45 microbeads not only reduces animal usage but also provides a more efficacious method regarding posttransfusion red blood cell recovery and, hence, provides a promising alternative to commonly used methods.

Respiratory Dysfunction Associated With RBC Transfusion in Critically Ill Children: A Prospective Cohort Study

OBJECTIVE

Respiratory complications associated with RBC transfusions may be underestimated in PICUs because current definitions exclude patients with preexisting respiratory dysfunction. This study aims to determine the prevalence and characterize the risk factors and outcomes of new or progressive respiratory dysfunction observed after RBC transfusion in critically ill children.

DESIGN

Prospective cohort study of all children admitted over a 1-year period.

SETTING

A multidisciplinary PICU in a tertiary pediatric university hospital.

PATIENTS

Patients who received a RBC transfusion while in PICU.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Two independent adjudicators established the diagnosis of respiratory dysfunction. A respiratory dysfunction associated with transfusion was considered new if it appeared after the first RBC transfusion in PICU. A progressive respiratory dysfunction associated with transfusion was diagnosed if the respiratory dysfunction was present before the transfusion and the PaO2/FIO2 or the SpO2/FIO2 ratio dropped by at least 20% thereafter. Among 842 children admitted into the PICU, 136 received at least one RBC transfusion and were analyzed. Fifty-eight cases of respiratory dysfunction associated with transfusion (43% of transfused patients) were detected, including nine new respiratory dysfunction associated with transfusion (7%) and 49 progressive respiratory dysfunction associated with transfusion (36%). Higher severity of illness, multiple organ dysfunction syndrome prior to transfusion, and volume (mL/kg) of RBC transfusion were independently associated with respiratory dysfunction associated with transfusion. A dose-response relationship was observed between transfusion volume (mL/kg) and the prevalence of respiratory dysfunction associated with transfusion. Patients with respiratory dysfunction associated with transfusion had more progressive multiple organ dysfunction and less ventilation-free and PICU-free days at day 28.

CONCLUSIONS

Development of respiratory dysfunction associated with transfusion is frequent in PICU and occurs mainly in patients with prior respiratory dysfunction, who would not be identified using current definitions for transfusion-associated complications. A cause-effect relationship cannot be confirmed. However, the high prevalence and the serious adverse outcomes associated with respiratory dysfunction associated with transfusion suggest that this complication should be further studied.

Transfusion of Blood and Blood Products

In transfusion medicine, several blood products can be prepared and used as replacement therapy; however, four of these products are more commonly used in general practice: RBCs, fresh frozen plasma (FFP), platelets and cryoprecipitate. RBC transfusions are mainly administered to improve tissue oxygenation in cases of anaemia or acute blood loss due to trauma or surgery. FFP, platelets and cryoprecipitate are used for the prevention and treatment of bleeding.

Perioperative blood management

Perioperative anaemia and allogenic blood transfusion (ABT) are known to increase the risk of adverse clinical outcomes. The quality, cost and availability of blood components are also major limitations with regard to ABT. Perioperative patient blood management (PBM) strategies should be aimed at minimizing and improving utilization of blood components. The goals of PBM are adequate preoperative evaluation and optimization of haemoglobin and bleeding parameters, techniques to minimize blood loss, blood conservation technologies and use of transfusion guidelines with targeted therapy. Attention to these details can help in cost reduction and improved patient outcome.

Peptide inhibitor of complement c1, a novel suppressor of classical pathway activation: mechanistic studies and clinical potential

The classical pathway of complement plays multiple physiological roles including modulating immunological effectors initiated by adaptive immune responses and an essential homeostatic role in the clearance of damaged self-antigens. However, dysregulated classical pathway activation is associated with antibody-initiated, inflammatory diseases processes like cold agglutinin disease, acute intravascular hemolytic transfusion reaction (AIHTR), and acute/hyperacute transplantation rejection. To date, only one putative classical pathway inhibitor, C1 esterase inhibitor (C1-INH), is currently commercially available and its only approved indication is for replacement treatment in hereditary angioedema, which is predominantly a kinin pathway disease. Given the variety of disease conditions in which the classical pathway is implicated, development of therapeutics that specifically inhibits complement initiation represents a major unmet medical need. Our laboratory has identified a peptide that specifically inhibits the classical and lectin pathways of complement. In vitro studies have demonstrated that these peptide inhibitors of complement C1 (PIC1) bind to the collagen-like region of the initiator molecule of the classical pathway, C1q. PIC1 binding to C1q blocks activation of the associated serine proteases (C1s–C1r–C1r–C1s) and subsequent downstream complement activation. Rational design optimization of PIC1 has resulted in the generation of a highly potent derivative of 15 amino acids. PIC1 inhibits classical pathway mediated complement activation in ABO incompatibility in vitro and inhibiting classical pathway activation in vivo in rats. This review will focus on the pre-clinical development of PIC1 and discuss its potential as a therapeutic in antibody-mediated classical pathway disease, specifically AIHTR.

Complement inhibition significantly decreases red blood cell lysis in a rat model of acute intravascular hemolysis

BACKGROUND

Prevention of acute hemolytic transfusion reactions is a worldwide concern. The objective of this study was to develop a simple rat model of complement-mediated acute intravascular hemolysis.

STUDY DESIGN AND METHODS

Human AB red blood cells (RBCs) were incubated with complement-sufficient or complement-deficient Wistar rat serum (WRS) in the presence and absence of human RBC antibody in vitro to elucidate the mechanism of hemolysis. To study the role of complement in acute intravascular hemolysis in vivo, Wistar rats were treated either with or without cobra venom factor (CVF) to deplete complement activity. Human AB RBCs were then injected into both groups of rats, followed by serial blood draws up to 2 hours. Venous blood clearance and lysis of transfused RBCs at each time point were measured by flow cytometry and spectrophotometry. RBC sequestration was determined in the liver, spleen, and kidney by immunohistochemistry.

RESULTS

In vitro incubation of human RBCs with WRS demonstrated that RBC lysis was mediated via the classical complement pathway and that hemolysis was antibody dependent. Transfusion of human RBCs into rats showed significantly less hemolysis in the CVF group versus untreated group. RBC sequestration in the spleen and liver 2 hours posttransfusion were not quantitatively different between the two groups.

CONCLUSIONS

Given the much higher degree of similarity for rat and human complement compared to mice, this simple rat model is ideal for testing novel inhibitors of classical pathway activation for the prevention and treatment of acute intravascular hemolysis.