Transfusion recipient epidemiology and outcomes research: possibilities for the future

Study of the Frequency and Specificity of Red Cell Antibodies in Patients with Hemoglobinopathies

Patients with thalassemia and sickle cell disease (SCD) require blood transfusions as part of their supportive care. However, one of the most serious side effects of this treatment is the risk of red cell alloimmunization. The goal of this study was to assess the prevalence and Specificity of red cell alloimmunization in Egyptian thalassemia and sickle cell anaemia patients. This study included 200 multi transfused Egyptian patients, one hundred and forty patients with transfusion dependent thalassaemia and sixty patients with sickle cell anaemia, who were attending the Paediatric Children Hospital-Cairo University at the period from March 2019 to October 2019. Alloantibody identification was made by Diamed- ID microtyping system. In the studied groups both thalassemia and sickle patients, the prevalence of alloimmunization was 22/200 (11%) patients. The two most often alloantibodies were, antibodies against Kell antigen (37%) and against E antigen (30%). The prevalence of alloimmunization was more in females in comparison to males, but it did not reach statistical significance and patients with thalassemia major had higher alloimmunization rates than other studied groups but was not statistically significant. In the D negative patients in the research group, alloimmunization demonstrated a statistically significant difference (p = 0.01). Age, gender, age of transfusion onset and splenectomy were not contributing factors to the antibody presence in the group of patients being investigated. Before receiving blood transfusions, extended red blood cell phenotyping should be thought of as a crucial procedure for hemoglobinopathies patients who would likely have several transfusions. It is advised that haemoglobinopathies patients in Egypt be checked through phenotyping of RBC units for Kell and all Rh antigens to be phenotyped before starting transfusion in these patients which is also standard of care for these patients presently.

The effect of blood transfusion on sublingual microcirculation in critically ill patients: A scoping review

PURPOSE

To investigate the effects of red blood cell (RBC) transfusion on sublingual microcirculation in critically ill patients.

METHODS

Systematic strategy was conducted to search studies that measured sublingual microcirculation before and after transfusion in critically ill patients. This review was reported according to the Preferred Reporting Items for Systematic Review and Meta-Analyses Scoping Review Extension.

RESULTS

The literature search yielded 114 articles. A total of 11 studies met the inclusion criteria. Observational evidence showed diffusive capacity of the microcirculation significantly improved in intraoperative and anemic hematologic patients after transfusion, while the convective parameters significantly improved in traumatic patients. RBC transfusion improved both diffusive and convective microcirculatory parameters in hypovolemic hemorrhagic shock patients. Most of the studies enrolled septic patients showed no microcirculatory improvements after transfusion. The positive effects of the leukoreduction were insufficiently supported. The effects of the storage time of the RBCs were not conclusive. The majority of the evidence supported a negative correlation between baseline proportion of perfused vessels (PPV) and changes in PPV.

CONCLUSIONS

This scoping review has catalogued evidence that RBC transfusion differently improves sublingual microcirculation in different populations. The existing evidence is not sufficient to conclude the effects of the leukoreduction and storage time of RBCs.

The dielectric spectroscopy of human red blood cells during 37-day storage: β-dispersion parameterization

This study exploits dielectric spectroscopy to monitor the kinetics of red blood cells (RBC) storage lesions, focusing on those processes linked to cellular membrane interface known as β-dispersion. The dielectric response of RBC suspensions, exposed to blood-bank cold storage for 37 days, was studied using time-domain dielectric spectroscopy in the frequency range 500 kHz to 200 MHz. The measured dielectric processes are characterized by their dielectric strength (Δε) and their relaxation times (τ). Changes in the dielectric properties of the RBC suspensions, due to storage-related biophysical changes, were evaluated. For a quantitative characterization of RBC vitality, we characterized the shape of fresh and stored RBC and measured their deformability as expressed by their average elongation ratio, which was achieved under a shear stress of 3.0 Pa. During the second week of storage, an increment in the evolution of the relaxation times and in the dielectric permittivity strength of about 25% was observed. We propose that the characteristic increment of ATP, during the second and third weeks of storage, is responsible for the raise of the specific capacitance of cell membrane, which in turn explains the changes observed in the dielectric response when combined with the influence of the shape changes.

Hemodynamic Functionality of Transfused Red Blood Cells in the Microcirculation of Blood Recipients

The primary goal of red blood cell (RBC) transfusion is to supply oxygen to tissues and organs. However, due to a growing number of studies that have reported negative transfusion outcomes, including reduced blood perfusion, there is rising concern about the risks in blood transfusion. RBC are characterized by unique flow-affecting properties, specifically adherence to blood vessel wall endothelium, cell deformability, and self-aggregability, which define their hemodynamic functionality (HF), namely their potential to affect blood circulation. The role of the HF of RBC in blood circulation, particularly the microcirculation, has been documented in numerous studies with animal models. These studies indicate that the HF of transfused RBC (TRBC) plays an important role in the transfusion outcome. However, studies with animal models must be interpreted with reservations, as animal physiology may not reflect human physiology. To test this concept in humans, we have directly examined the effect of the HF of TRBC, as expressed by their deformability and adherence to vascular endothelium, on the transfusion-induced effect on the skin blood flow and hemoglobin increment in β-thalassemia major patients. The results demonstrated, for the first time in humans, that the TRBC HF is a potent effector of the transfusion outcome, expressed by the transfusion-induced increase in the recipients' hemoglobin level, and the change in the skin blood flow, indicating a link between the microcirculation and the survival of TRBC in the recipients' vascular system. The implication of these findings for blood transfusion practice and to vascular function in blood recipients is discussed.

Dielectric Response of Cytoplasmic Water and Its Connection to the Vitality of Human Red Blood Cells. II. The Influence of Storage

Maintaining an appropriate inventory of packaged blood products is a critical part of modern medicine. Consequently, the assessment of red blood cell (RBC) functionality is instrumental for the monitoring of the quality of stored RBC (sRBC) in the blood bank. We present a comprehensive study of sRBC lesion kinetics in SAGM (saline, adenine, glucose, mannitol) solution, using microwave dielectric spectroscopy (0.5-50 GHz) and cell deformability. As part of the research, we have isolated the microwave dielectric response of cytoplasmic water in sRBC. The extracted dielectric parameters are sensitive to the age of the cells and, in particular, to the critical moment of transition from discocyte to echinocyte. From the analysis of the dielectric relaxation as a function of storage-duration, we postulate that the behavior is rooted in the delicate interplay between bound and bulk water in the cellular interior. In particular, the microwave dielectric response reflects the moment when the continuous diffusion of oxygen to the cell and the oxygenation of hemoglobin affects the role played by water in the maintenance of cell integrity. These results open a possible new avenue for the noninvasive inspection of stored red blood cells, permitting a true inventory system for the modern blood bank.

One size will never fit all: the future of research in pediatric transfusion medicine

There is concern at the National Heart, Lung, and Blood Institute (NHLBI) and among transfusion medicine specialists regarding the small number of investigators and studies in the field of pediatric transfusion medicine (PTM). Accordingly, the objective of this article is to provide a snapshot of the clinical and translational PTM research considered to be of high priority by pediatricians, neonatologists, and transfusion medicine specialists. Included is a targeted review of three research areas of importance: (i) transfusion strategies, (ii) short- and long-term clinical consequences, and (iii) transfusion-transmitted infectious diseases. The recommendations by PTM and transfusion medicine specialists represent opportunities and innovative strategies to execute translational research, observational studies, and clinical trials of high relevance to PTM. With the explosion of new biomedical knowledge and increasingly sophisticated methodologies over the past decade, this is an exciting time to consider transfusion medicine as a paradigm for addressing questions related to fields such as cell biology, immunology, neurodevelopment, outcomes research, and many others. Increased awareness of PTM as an important, fertile field and the promotion of accompanying opportunities will help establish PTM as a viable career option and advance basic and clinical investigation to improve the health and wellbeing of children.

Transfusion practice varies widely in cardiac surgery: Results from a national registry

OBJECTIVES

Evidence is accumulating of adverse outcomes associated with transfusion of blood components. If there are differences in perioperative transfusion rates in cardiac surgery, and what hospital factors may contribute, requires further investigation.

METHODS

Analysis of 42,743 adult patients who underwent 43,482 procedures from 2005 to 2011 at 25 Australian hospitals, according to the Australian and New Zealand Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database. Multiple logistic regression examined associations of patient and hospital characteristics with transfusion of ≥1 red blood cell (RBC) unit; platelet (PLT), fresh frozen plasma (FFP), and cryoprecipitate (CRYO) doses; and ≥5 RBC units, from surgery until hospital discharge.

RESULTS

Procedures included 24,222 (55%) isolated coronary artery bypass grafts, 7299 (17%) isolated valve, 4714 (11%) coronary artery bypass graft and valve, and 7247 (17%) other procedures. After adjustment for various patient and procedure characteristics, transfusion rates varied across hospitals for ≥1 RBC unit from 22% to 67%, ≥5 RBC units from 5% to 25%, ≥1 PLT dose from 11% to 39%, ≥1 FFP dose from 11% to 48% and ≥1 CRYO dose from 1% to 20%. Hospital characteristics, including state or territory, private versus public, and teaching versus nonteaching, were not associated with variation in transfusion rates.

CONCLUSIONS

Variation in transfusion of all components and large volume RBC was identified, even after adjustment for patient and procedural factors known to influence transfusion, and this was not explained by hospital characteristics.

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.

Ideal donors, imperfect results in sickle cell disease

In this issue of Blood, Chou et al report findings from an observational study of alloimmunization in patients with sickle cell disease (SCD) receiving blood transfusions from ethnically matched donors.

Challenges of alloimmunization in patients with haemoglobinopathies

Red blood cell (RBC) transfusions can be life-sustaining in chronic inherited anaemias, such as thalassaemia, and the indications for blood transfusions in patients with sickle cell disease continue to expand. Complications of transfusions, such as allosensitization, can create significant medical challenges in the management of patients with haemoglobinopathies. This review summarizes key findings from the medical literature related to alloimmunization in haemoglobinopathies and examines potential measures to mitigate these risks. Areas where future studies are needed are also addressed.

Indications and complications of transfusions in sickle cell disease

Red cell transfusion remains an important part of the management of acute and chronic complications in SCD. The ongoing and emerging uses of transfusions in SCD may have significant benefits; however, the potential complications of transfusions also deserve careful consideration. In this report we review current indications for transfusions, transfusion complications, modifications of transfusion practices to mitigate risk, and potential considerations to improve transfusion outcomes.

Blood products and the phases of perianesthesia care-reviewing the implications

Perianesthesia nurses often provide care for patients who have received blood products. Over the years, great advances in the safety and technology around blood products have occurred, yet transfusions are not without risk. Because 50% of blood transfusions are administered in the surgical setting, the perianesthesia nurse must know the indications and potential adverse reactions. The perianesthesia nurse has an important role in supporting appropriate use of blood products, which can be a scarce resource at times. By knowing indications, benefits, and risks of transfusion, the nurse can better advocate for the patient's needs. Additionally, with this knowledge, the nurse is able to support patient education and ensure that consent obtained is informed in nature. In this article, the commonly used blood products, potential adverse reactions, and methods to reduce transfusion errors are being reviewed. Ideally, nurses should be provided a periodic review on blood products and transfusion safety to maintain knowledge, competency, and an acceptable comfort level overall. Ongoing education can be an effective means to expand knowledge of the health care provider and improve patient safety and outcomes.

Insufficient nitric oxide bioavailability: a hypothesis to explain adverse effects of red blood cell transfusion

While transfusion of red blood cells (RBCs) is effective at preventing morbidity and mortality in anemic patients, studies have indicated that some RBC components have functional defects ("RBC storage lesions") that may actually cause adverse events when transfused. For example, in some studies patients transfused with RBCs stored more than 14 days have had statistically worse outcomes than those receiving "fresher" RBC units. Recipient-specific factors may also contribute to the occurrence of these adverse events. Unfortunately, these events have been difficult to investigate because up to now they have existed primarily as "statistical occurrences" of increased morbidity and mortality in large data sets. There are currently no clinical or laboratory methods to detect or study them in individual transfusion recipients. We propose a unifying hypothesis, centered on insufficient nitric oxide bioavailability (INOBA), to explain the increased morbidity and mortality observed in some patients after RBC transfusion. In this model, variables associated with RBC units (storage time; 2,3-diphosphoglycerate acid concentration) and transfusion recipients (endothelial dysfunction) collectively lead to changes in nitric oxide (NO) levels in vascular beds. Under certain circumstances, these variables are "aligned" such that NO concentrations are markedly reduced, leading to vasoconstriction, decreased local blood flow, and insufficient O(2) delivery to end organs. Under these circumstances, the likelihood of morbidity and mortality escalates. If the key tenets of the INOBA hypothesis are confirmed, it may lead to improved transfusion methods including altered RBC storage and/or processing conditions, novel transfusion recipient screening methods, and improved RBC-recipient matching.

Many, but not all, outcome studies support exclusion of female plasma from the blood supply

Transfusion-related acute lung injury (TRALI) has been identified as the most common cause of transfusion-related death. Although extensive literature supports restrictions on female-donor plasma to reduce antibody-mediated TRALI, only a few outcome studies have assessed for effects of this change, and some, but not all, have endorsed the policy. A recent report even suggests poorer outcomes in cardiac surgery patients with a shift to male-donor-only plasma, raising concerns that TRALI alone, whether catastrophic or more survivable, is insufficient compared with broader measures, such as short-term mortality or long-term survival, as an end point to assess for overall improvements in patient care.

Hospital blood bank information systems accurately reflect patient transfusion: results of a validation study

BACKGROUND

Hospital transfusion laboratories collect information regarding blood transfusion and some registries gather clinical outcomes data without transfusion information, providing an opportunity to integrate these two sources to explore effects of transfusion on clinical outcomes. However, the use of laboratory information system (LIS) data for this purpose has not been validated previously.

STUDY DESIGN AND METHODS

Validation of LIS data against individual patient records was undertaken at two major centers. Data regarding all transfusion episodes were analyzed over seven 24-hour periods.

RESULTS

Data regarding 596 units were captured including 399 red blood cell (RBC), 95 platelet (PLT), 72 plasma, and 30 cryoprecipitate units. They were issued to: inpatient 221 (37.1%), intensive care 109 (18.3%), outpatient 95 (15.9%), operating theater 45 (7.6%), emergency department 27 (4.5%), and unrecorded 99 (16.6%). All products recorded by LIS as issued were documented as transfused to intended patients. Median time from issue to transfusion initiation could be calculated for 535 (89.8%) components: RBCs 16 minutes (95% confidence interval [CI], 15-18 min; interquartile range [IQR], 7-30 min), PLTs 20 minutes (95% CI, 15-22 min; IQR, 10-37 min), fresh-frozen plasma 33 minutes (95% CI, 14-83 min; IQR, 11-134 min), and cryoprecipitate 3 minutes (95% CI, -10 to 42 min; IQR, -15 to 116 min).

CONCLUSIONS

Across a range of blood component types and destinations comparison of LIS data with clinical records demonstrated concordance. The difference between LIS timing data and patient clinical records reflects expected time to transport, check, and prepare transfusion but does not affect the validity of linkage for most research purposes. Linkage of clinical registries with LIS data can therefore provide robust information regarding individual patient transfusion. This enables analysis of joint data sets to determine the impact of transfusion on clinical outcomes.

The relationship of plasma transfusion from female and male donors with outcome after cardiac surgery

OBJECTIVE

Pulmonary dysfunction is common in transfused patients recovering from heart surgery. Plasma transfusion from female donors has been linked with rare catastrophic lung injury, but its relationship with outcome after cardiac surgery is poorly understood. We examined whether plasma donor gender is related to postcardiac surgery pulmonary dysfunction and death or prolonged hospitalization.

METHODS

In this retrospective case-control study, cardiac surgery candidates who received plasma perioperatively from only female donors were compared with male-only recipients who were matched for the number of units transfused and surgery date.

RESULTS

In a dataset of 2157 recipients, there were no blood bank-reported complications, but escalating plasma transfusion was associated with increased 30-day mortality (odds ratio, 1.52 per unit; P = .0001). From the 1069 recipients receiving plasma exclusively from female or male donors, 390 matched pairs were identified. Recipients of female compared with male donor plasma had a lower incidence of pulmonary dysfunction (5.9% vs 10.8%; P = .01) and death or hospitalization more than 10 days (9% vs 16.4%; P = .002) but similar long-term survivals.

CONCLUSIONS

Escalating plasma transfusion was associated with 30-day mortality, but female donor plasma recipients had less pulmonary dysfunction and fewer poor outcomes compared with male-only recipients. Although our retrospective study findings neither support nor refute a strategic policy to exclude female donor plasma to reduce catastrophic transfusion-related acute lung injury, they raise concern that such a policy may have unanticipated effects on outcome in patients undergoing cardiac surgery and highlight a need for additional studies in this and other patient groups.

Red blood cell transfusion practices in acute lung injury: what do patient factors contribute?

OBJECTIVE

To describe red blood cell (RBC) transfusion practices and evaluate the association between patient-related factors and pretransfusion hemoglobin concentration in acute lung injury (ALI).

DESIGN

Secondary analysis of prospectively collected data.

SETTING

Nine intensive care units (ICUs) in three teaching hospitals in Baltimore, MD.

PATIENTS

Two hundred forty-nine consecutive patients with ALI requiring mechanical ventilation.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Simple and multiple linear regression analyses were used to evaluate the association between the nadir hemoglobin concentration on the day of initial RBC transfusion and 20 patient-level demographic, clinical and ICU treatment factors as well as ICU type. Of 249 patients with ALI, 47% received an RBC transfusion in the ICU without evidence of active hemorrhage or acute cardiac ischemia. The mean (sd) nadir hemoglobin on the day of first transfusion was 7.7 (1.1) g/dL with 67%, 36%, 15%, and 5% of patients transfused at >7, >8, >9, and >10 g/dL, respectively. Transfused patients received a mean (sd) of 5 (6) RBC units from ALI diagnosis to ICU discharge. Prehospital use of iron or erythropoietin and platelet transfusion in the ICU were independently associated with lower pretransfusion hemoglobin concentrations. No patient factors were associated with higher hemoglobin concentrations. Admission to a surgical (vs. medical) ICU was independently associated with a 0.6 g/dL (95% confidence interval 0.1-1.1 g/dL) higher pretransfusion hemoglobin.

CONCLUSIONS

Patients with ALI commonly receive RBC transfusions in the ICU. The pretransfusion hemoglobin observed in our study was lower than earlier studies, but a restrictive strategy was not universally adopted. Patient factors do not explain the gap between clinical trial evidence and routine transfusion practices. Future studies should further explore ICU- and physician-related factors as a source of variability in transfusion practice.

Noninfectious serious hazards of transfusion

As infectious complications from blood transfusion have decreased because of improved donor questionnaires and sophisticated infectious disease blood screening, noninfectious serious hazards of transfusion (NISHOTs) have emerged as the most common complications of transfusion. The category of NISHOTs is very broad, including everything from well-described and categorized transfusion reactions (hemolytic, febrile, septic, and allergic/urticarial/anaphylactic) to lesser known complications. These include mistransfusion, transfusion-related acute lung injury, transfusion-associated circulatory overload, posttransfusion purpura, transfusion-associated graft versus host disease, microchimerism, transfusion-related immunomodulation, alloimmunization, metabolic derangements, coagulopathic complications of massive transfusion, complications from red cell storage lesions, complications from over or undertransfusion, and iron overload. In recent years, NISHOTs have attracted more attention than ever before, both in the lay press and in the scientific community. As the list of potential complications from blood transfusion grows, investigators have focused on the morbidity and mortality of liberal versus restrictive red blood cell transfusion, as well as the potential dangers of transfusing "older" versus "younger" blood. In this article, we review NISHOTs, focusing on the most recent concerns and literature.

Pediatric transfusion medicine: development of a critical mass

Many significant events have occurred in the recent past that beg a broad audience to address the question "What is pediatric transfusion medicine?" Herein, we list some of these events and their relevance below and attempt to provide an answer for this question. Indeed, several issues regarding the subspecialty of pediatric transfusion medicine (PTM) are particularly timely, and it appears that a critical mass, or a nidus capable of becoming a critical mass, is developing in PTM.