Transfusion – Whence and why

The potential mechanisms of extracellular vesicles in transfusion-related adverse reactions: Recent advances

Blood transfusion is an irreplaceable clinical treatment. Blood components are differentiated and stored according to specific guidelines. Storage temperatures and times vary depending on the blood component, but they all release extracellular vesicles (EVs) during storage. Although blood transfusions can be life-saving, they can also cause many adverse transfusion reactions, among which the effects of EVs are of increasing interest to researchers. EVs are submicron particles that vary in size, composition, and surface biomarkers, are encapsulated by a lipid bilayer, and are not capable of self-replication. EVs released by blood cells are important contributors to pathophysiologic states through proinflammatory, coagulant, and immunosuppressive effects, which in turn promote or inhibit the associated disease phenotype. Therefore, this review explores the potential mechanisms of hematopoietic-derived EVs in transfusion-associated adverse reactions and discusses the potential of the latest proteomics tools to be applied to the analysis of EVs in the field of transfusion medicine with a view to reducing the risk of blood transfusion.

Prevalence, incidence, risk factors and residual risk associated with viral infections among eligible Brazilian blood donors

Knowledge regarding the profile of eligible blood donors presenting positive results in laboratory screening is essential for reducing transfusion-transmitted human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV). Our study aimed to evaluate the prevalence, incidence, predictor variables and residual risk (RR) of HIV/HBV/HCV in blood bags donated in Minas Gerais, Brazil. This study analysed data retrieved from the records of a large blood bank relating to donations collected at multiple centres within the period 2012-2018, during which 1 991 120 blood bags were screened using immunoassays and nucleic acid tests (NATs). Multilevel modelling was used to investigate the association between sex, civil status and age group with HIV/HBV/HCV. RR was estimated from the incidence values (restricted to negative and positive tests within the study period) and window periods for infections. The prevalence in first time donors, incidence and RR of HCV (223.73 cases per 100 000; 54.84 per 100 000 persons-year and 1.6527 per 100 000, respectively) were higher than those of HIV (172.65 cases per 100 000; 28.25 per 100 000 persons-year and 0.8514 per 100 000) and HBV (168.17 cases per 100 000; 18.54 per 100 000 persons-year and 0.5588 per 100 000). The odds of acquiring infection were greater in male, single and older donors. Sixteen donors were identified as seronegative and NATs+ during the 7-year span of the study. Our study has clarified some spatiotemporal trends regarding HIV/HBV/HCV infections in donated blood in Brazil. The results will contribute to the formulation of directives addressed to high-risk donors.

Comparison of computerized provider order entry specific transfusion indications versus the use of "Other"

BACKGROUND

Computerized physician order entry (CPOE) systems are one way to reinforce evidence-based transfusion indications for blood products. The new CPOE system that was implemented at our institution allowed healthcare providers to select "Other" as an indication and provide reasons for transfusion outside of accepted guidelines.

STUDY DESIGN AND METHODS

Transfusion order records for packed red blood cells (RBCs), platelets, and fresh frozen plasma (FFP) from high product-ordering areas of Long Island Jewish Medical Center and Cohen's Children's Medical Center from April 2021, when the new CPOE system was implemented, to November 2021 were reviewed. The percentage of "Other" orders was determined and the reason for each "Other" order was reviewed to identify possible areas for education or valid indications not included in the institutionally recognized indications.

RESULTS

9.7% of RBC orders, 1.9% of platelet orders, and 18.2% of FFP orders were placed with "Other" as the indication for transfusion (χ² ₂  = 88.5; p < .001). Reasons for "Other" orders were varied, but notable reasons included indications already institutionally accepted such as, bleeding (15.7% of pediatric "Other" RBC orders), hold for OR (14.3% of pediatric and 15.8% of adult "Other" RBC orders), and novel reasons such as FFP for ACE-inhibitor associated angioedema (84.6% of adult "Other" FFP orders).

DISCUSSION

The findings from our study provide examples of potential difficulties hospitals may encounter when they implement a new computerized physician order entry system. Provider education may play an important role to reduce the number of "Other" orders placed for already recognized indications.

Platelet function of whole blood after short-term cold storage: A prospective in vitro observational study

BACKGROUND

There is no standardized storage temperature of whole blood for acute normovolemic hemodilution (ANH).

STUDY DESIGN AND METHODS

We conducted a prospective observational study to examine the difference in platelet function between short-term whole blood storage at 4 and 22°C. Venous blood (40 ml) was collected from seven healthy subjects who gave prior written consent. The samples were divided into three groups: before storage (group Pre), cold (4°C) storage (group C), and room temperature (22°C) storage (group R). Groups C and R were tested after 6 h of blood storage. Platelet aggregability, platelet factor 4 (PF4), β-thromboglobulin (β-TG), P-selectin expression, pH, PO₂ , PCO₂ , glucose, lactate, blood count, and thromboelastography (TEG) parameters were measured. The percentage change in each parameter in groups C and R was calculated using the value in group Pre as a reference. These data were then compared between groups C and R using a Wilcoxon matched pairs test. p < 0.05 was considered to be statistically significant.

RESULTS

Compared with group R, group C showed significantly higher platelet aggregability with adenosine diphosphate (ADP) 2, 4, and 6 μM (all p = 0.016) and collagen 1 μg/ml (p = 0.047) stimulation, and significantly lower PF4 and β-TG elevation (both p = 0.031), glucose consumption (p = 0.031), and lactate production (p = 0.016). The ADP channel in TEG showed a significant increase in platelet aggregation rate in group C compared to group R.

DISCUSSION

Cold storage of whole blood in ANH may provide improved storage conditions for platelets and contribute to improved hemostasis compared to room temperature storage.

US Central Command Military Blood Utilization Practices 2011 to 2020

BACKGROUND

Military involvement in Afghanistan ended in 2021 and while low intensity troop engagements continue globally, casualty numbers are dwindling. To understand the clinical and operational connections between blood utilization and clinical paradigm shifts in resuscitation strategies, a review of blood product utilization and the changes in the last decade was conducted within the US Central Command area of responsibility (AOR). The intent of this review was to assess patterns of blood use during the last decade of the US's involvement in the most recent major conflicts in order to potentially inform future blood requirements.Study DesignBlood product and types transfused between Jan 1, 2011 and Dec 31, 2020 were acquired from the Medical Situational Awareness in Theater (MSAT) blood reports. All reported blood usage data in the US Central Command area of responsibility were queried.

RESULTS

Packed red blood cells and fresh frozen plasma usage showed no statistically significant change over time (τb = 0.24, p = 0.3252; τb = -0.47, p = .0603). Fresh and stored whole blood use increased overtime (τb = 0.69, p = 0.0056; τb = 0.83, p = 0.0015). A strong inverse relationship was found between SWB and FFP usage (r = -0.68, p = .0309) and LP and FFP usage (r = -0.65, p = 0.0407) over time.

CONCLUSION

Whole blood usage increased significantly over time with a preference for stored whole blood. Component therapy is anticipated to remain a critical element of resuscitation in the event of large-scale combat operations secondary to supply chain and longer storage times.

LEVEL OF EVIDENCE

Level III Therapeutic/Care Management.

Whole blood at the tip of the spear: A retrospective cohort analysis of warm fresh whole blood resuscitation versus component therapy in severely injured combat casualties

BACKGROUND

Death from uncontrolled hemorrhage occurs rapidly, particularly among combat casualties. The US military has used warm fresh whole blood during combat operations owing to clinical and operational exigencies, but published outcomes data are limited. We compared early mortality between casualties who received warm fresh whole blood versus no warm fresh whole blood.

METHODS

Casualties injured in Afghanistan from 2008 to 2014 who received ≥2 red blood cell containing units were reviewed using records from the Joint Trauma System Role 2 Database. The primary outcome was 6-hour mortality. Patients who received red blood cells solely from component therapy were categorized as the non-warm fresh whole blood group. Non- warm fresh whole blood patients were frequency-matched to warm fresh whole blood patients on identical strata by injury type, patient affiliation, tourniquet use, prehospital transfusion, and average hourly unit red blood cell transfusion rates, creating clinically unique strata. Multilevel mixed effects logistic regression adjusted for the matching, immortal time bias, and other covariates.

RESULTS

The 1,105 study patients (221 warm fresh whole blood, 884 non-warm fresh whole blood) were classified into 29 unique clinical strata. The adjusted odds ratio of 6-hour mortality was 0.27 (95% confidence interval 0.13-0.58) for the warm fresh whole blood versus non-warm fresh whole blood group. The reduction in mortality increased in magnitude (odds ratio = 0.15, P = .024) among the subgroup of 422 patients with complete data allowing adjustment for seven additional covariates. There was a dose-dependent effect of warm fresh whole blood, with patients receiving higher warm fresh whole blood dose (>33% of red blood cell-containing units) having significantly lower mortality versus the non-warm fresh whole blood group.

CONCLUSION

Warm fresh whole blood resuscitation was associated with a significant reduction in 6-hour mortality versus non-warm fresh whole blood in combat casualties, with a dose-dependent effect. These findings support warm fresh whole blood use for hemorrhage control as well as expanded study in military and civilian trauma settings.

Prescription of red cell concentrates by emergency physicians

OBJECTIVE

To evaluate the adequacy of the prescription of red cell concentrates by emergency physicians.

METHODS

A cross-sectional study based on the survey of transfusion requests records completed by emergency physicians, from May/2018 to April/2019, in an emergency hospital. Adequacy in the indication, volume, and subtype (filtered, irradiated, and washed) of prescribed erythrocytes were evaluated. To compare the qualitative data, we used the χ2 test. The significance level adopted was 5%.

RESULTS

One thousand and twenty-two transfusions were evaluated. The indication, volume, and subtypes were correct in 72.7%, 45.9%, and 81.6% respectively. Transfusion in symptomatic patients presented superior adequacy when compared to asymptomatic individuals with significant statistical difference (indication: 79,6% vs 67.2%, p <0.001; Volume: 63.5% vs 31.7%, p <0.001; subtype: 85.3% vs 78.7%, p 0.006). Among clinical situations, there were more errors in sepsis (39.7%) and pneumonia (36.3%). More than half of the prescriptions presented excessive volume, raising the risk of circulatory overload, observing that the mean age was 60.6 years. The specific analysis of the prescribed subtypes showed adequacy of 17.9% in the filtered, 1.7% in the irradiated, and none in the washed. Thirty transfusions should have been filtered, but the prescriber did not request the subtype.

CONCLUSION

One hypothesis for the observed inaccuracies is inadequate medical training on the subject, both in undergraduate and medical residency, associated with a lack of continuing education on transfusion protocols. The transfusion Committee received the results of this study with a proposal for continuing education measures on transfusion hemotherapy.

Estimation of the number of blood donors during the COVID-19 incubation period across China and analysis of prevention and control measures for blood transfusion transmission

BACKGROUND

The aim of this study was to estimate the number of blood donors during the COVID‐19 incubation period across China.

STUDY DESIGN AND METHODS

In this study, we developed a predictive model to estimate the number of blood donors during the COVID‐19 incubation period among 34 provincial regions in China. Our main assumption was that blood donors of all ages in different regions have a stable blood donation intention and the same infection risk.

RESULTS

First, we estimated the number of blood donors during the COVID‐19 incubation period in Wuhan city, Hubei Province, and China, from December 31, 2019 to March 17, 2020. Second, we compared the number of blood donors during the COVID‐19 incubation period in all provinces across China. In addition, we found that if all RBCs, plasma, and cryoprecipitation were stored in isolation until the 14th day, the potential risk of SARS‐CoV‐2 transmission through blood transfusion was reduced by at least 65.77% after the blood donor safely passed the COVID‐19 incubation period. Moreover, if the detection of SARS‐CoV‐2 RNA was carried out on all platelets, the potential risk would be reduced by 77.48%.

CONCLUSIONS

Although the risk is low, with the rapid spread of the COVID‐19 and the appearance of alarmingly high infectivity and a high fatality rate, appropriate measures should be taken by health departments to ensure the safety of clinical blood.

Intraoperative cell salvage: A technology built upon the failures, fads and fashions of blood transfusion

Transfusion, as we know it today, developed into a very sophisticated treatment modality as a result of centuries of experimentation. Intraoperative cell salvage is a transfusion technique where autologous blood lost during surgery is reinfused. The success of this process relies on specialised equipment and techniques to collect, process, anticoagulate filter and reinfuse blood. Through a literature review, we collected information about the early origins of specific techniques relevant to intraoperative cell salvage: the ability to collect lost blood, to prevent collected blood from clotting, to remove debris through processing and other harmful aspects through filtering, the benefits of autologous blood transfusion, reinfusion and traditional concerns and contraindications. A culmination of knowledge specific to each of these techniques over centuries provides the background to the safe intraoperative cell salvage technique used today. In addition, we aimed to identify the reasons why specific equipment and techniques developed, why practice changed and what is still unknown. This article reviews relevant allogeneic transfusion and autotransfusion history, starting in Roman times, and includes landmark events through the centuries.

Red blood cell transfusion policy: a critical literature review

The issue of the most appropriate red blood cell transfusion policy has been addressed by a number of randomised controlled trials, conducted over the last decades, comparing the effects on patients' outcome of restrictive blood transfusion strategies (transfusing when the haemoglobin concentration is less than 7 g/dL to 8 g/dL) vs more liberal ones (transfusing when the haemoglobin concentration is less than 9 g/dL to 10 g/dL) in a variety of clinical settings. In parallel, various systematic reviews and meta-analyses have tried to perform pooled analyses of the data from these randomised controlled trials and their results have been utilised by scientific societies to provide recommendations and guidelines on red blood cell transfusion thresholds. All these aspects will be critically discussed in this narrative review.

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.

Perioperative red blood cell transfusion in orofacial surgery

In the field of orofacial surgery, a red blood cell transfusion (RBCT) is occasionally required during double jaw and oral cancer surgery. However, the question remains whether the effect of RBCT during the perioperative period is beneficial or harmful. The answer to this question remains challenging. In the field of orofacial surgery, transfusion is performed for the purpose of oxygen transfer to hypoxic tissues and plasma volume expansion when there is bleeding. However, there are various risks, such as infectious complications (viral and bacterial), transfusion-related acute lung injury, ABO and non-ABO associated hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions, transfusion associated graft-versus-host disease, transfusion associated circulatory overload, and hypersensitivity transfusion reaction including anaphylaxis and transfusion-related immune-modulation. Many studies and guidelines have suggested RBCT is considered when hemoglobin levels recorded are 7 g/dL for general patients and 8-9 g/dL for patients with cardiovascular disease or hemodynamically unstable patients. However, RBCT is occasionally an essential treatment during surgeries and it is often required in emergency cases. We need to comprehensively consider postoperative bleeding, different clinical situations, the level of intra- and postoperative patient monitoring, and various problems that may arise from a transfusion, in the perspective of patient safety. Since orofacial surgery has an especially high risk of bleeding due to the complex structures involved and the extensive vascular distribution, measures to prevent bleeding should be taken and the conditions for a transfusion should be optimized and appropriate in order to promote patient safety.

Maintaining a Safe Blood Supply in an Era of Emerging Pathogens

Coming shortly after outbreaks of dengue and chikungunya virus in related locations, the recent outbreak of Zika virus in the southern part of the western hemisphere is yet another reminder that infectious pathogens continue to emerge rapidly and can adversely affect public health, including the safety of the blood supply. In response to Zika virus, public health measures that rely largely on donor deferral and sourcing of blood from non-outbreak areas until a blood donor screening test becomes available have been implemented to address the safety of the blood supply in the United States. However, a more universal approach to ensuring blood safety in the setting of rapidly emerging infectious diseases is needed.

[Norman Bethune (1890-1939), an involved doctor, icon of the blood transfusion history]

Norman Bethune was born in 1890, in Gravenhurst (Ontario, Canada). Thereafter a strong surgical training, he implied in thoracic surgery and fight against tuberculosis. His political opinions led him to join the Republicans in the Spanish Civil War. He played an important part in the development of blood transfusion on the battlefield. Then he joined China with communist troops and therein developed surgical units and accelerated training for health personal. He died of septicemia in 1939.