RBC storage and avoiding hyperkalemia from transfusions to neonates & infants

Multi-component cord blood banking: a proof-of-concept international exercise

BACKGROUND

Most public cord blood (CB) banks currently discard more than 80% of umbilical CB units not suitable for hemopoietic stem cell transplant due to low stem cell count. Although CB platelets, plasma, and red blood cells have been used for experimental allogeneic applications in wound healing, corneal ulcer treatment, and neonatal transfusion, no standard procedures for their preparation have been defined internationally.

MATERIALS AND METHODS

A network of 12 public CB banks in Spain, Italy, Greece, the UK, and Singapore developed a protocol to validate a procedure for the routine production of CB platelet concentrate (CB-PC), CB platelet-poor plasma (CB-PPP), and CB leukoreduced red blood cells (CB-LR-RBC) using locally available equipment and the commercial BioNest ABC and EF medical devices. CB units with >50 mL volume (excluding anticoagulant) and ≥150×109/L platelets were double centrifuged to obtain CB-PC, CB-PPP, and CB-RBC. The CB-RBC were diluted with saline-adenine-glucose-mannitol (SAGM), leukoreduced by filtration, stored at 2-6°C, and tested for hemolysis and potassium (K+) release over 15 days, with gamma irradiation performed on day 14. A set of acceptance criteria was pre-defined. This was for CB-PC: volume ≥5 mL and platelet count 800-1,200×109/L; for CB-PPP: platelet count <50×109/L; and for CB-LR-RBC: volume ≥20 mL, hematocrit 55-65%, residual leukocytes <0.2×106/unit, and hemolysis ≤0.8%.

RESULTS

Eight CB banks completed the validation exercise. Compliance with acceptance criteria was 99% for minimum volume and 86.1% for platelet count in CB-PC, and 90% for platelet count in CB-PPP. Compliance in CB-LR-RBC was 85.7% for minimum volume, 98.9% for residual leukocytes, and 90% for hematocrit. Compliance for hemolysis ≤0.8% decreased from 89.0 to 63.2% from day 0 to 15. K+ release increased from 3.0±1.8 to 25.0±7.0 mmol/L from day 0 to 15, respectively.

DISCUSSION

The MultiCord12 protocol was a useful tool to develop preliminary standardization of CB-PC, CB-PPP, and CB-LR-RBC.

The compound effect of irradiation and familial pseudohyperkalemia on potassium leak from red blood cells

BACKGROUND

Familial pseudohyperkalemia (FP) is a rare asymptomatic condition characterized by an increased rate of potassium leak from red blood cells (RBC) on refrigeration. Gamma irradiation compromises RBC membrane integrity and accelerates potassium leakage. Here, we compared the effect of irradiation, applied early or late in storage, on FP versus non-FP RBC.

STUDY DESIGN

Five FP and 10 non-FP individuals from the National Institute for Health Research Cambridge BioResource, UK, and three FP and six non-FP individuals identified by Australian Red Cross Lifeblood consented to the study. Blood was collected according to standard practice in each center, held overnight at 18-24°C, leucocyte-depleted, and processed into red cell concentrates (RCC) in Saline Adenine Glucose Mannitol. On Day 1, RCC were split equally into six Red Cell Splits (RCS). Two RCS remained non-irradiated, two were irradiated on Day 1 and two were irradiated on Day 14. RBCs were tested over cold storage for quality parameters.

RESULTS

As expected, non-irradiated FP RCS had significantly higher supernatant potassium levels than controls throughout 28 days of storage (p < .001). When irradiated early, FP RCS released potassium at similar rates to control. When irradiated late, FP RCS supernatants had higher initial post-irradiation potassium concentration than controls but were similar to controls by the end of storage (14 days post-irradiation). No other parameters studied showed a significant difference between FP and control.

DISCUSSION

FP does not increase the rate of potassium leak from irradiated RBCs. Irradiation may cause a membrane defect similar to that in FP RBCs.

Adverse transfusion reactions and what we can do

INTRODUCTION

Transfusions of blood and blood components have inherent risks and the ensuing adverse reactions. It is very important to understand the adverse reactions of blood transfusion comprehensively for ensuring the safety of any future transfusions.

AREAS COVERED

According to the time of onset, adverse reactions of blood transfusion are divided into immediate and delayed transfusion reactions. In acute transfusion reactions, timely identification and immediate cessation of transfusion is critical. Vigilance is required to distinguish delayed responses or reactions that present non-specific signs and symptoms. In this review, we present the progress of mechanism, clinical characteristics and management of commonly encountered transfusion reactions.

EXPERT OPINION

The incidence of many transfusion-related adverse events is decreasing, but threats to transfusion safety are always emerging. It is particularly important for clinicians and blood transfusion staff to recognize the causes, symptoms and treatment methods of adverse blood transfusion reactions to improve the safety. In the future, at-risk patients will be better identified and can benefit from more closely matched blood components.

Predictors of Blood Transfusion for Endoscopic Assisted Craniosynostosis Surgery

ABSTRACT

Blood loss is a main cause of morbidity after craniofacial procedures. The purpose of this study is to identify the incidence and predictors for transfusion of blood products in the endoscopic assisted strip craniectomy population. Data was prospectively collected from a single-center multi-surgeon cohort of 78 consecutive patients who underwent endoscopic assisted strip craniectomy for craniosynostosis between July 2013 and December 2020. The authors reviewed patient and treatment characteristics and outcomes. Of the 78 patients, 26 patients were transfused yielding an overall rate of transfusion of 33%. The most common fused suture was sagittal (n = 42, 54%) followed by metopic (n = 15, 19%), multiple (n = 10, 13%), coronal (n = 7, 9%) and finally lambdoid (n = 4, 5%). On univariate analysis, patients' weight in the transfusion cohort were significantly lower than those who did not receive a transfusion (5.6 ± 1.1 versus 6.5 ± 1.1 kg, P = 0.0008). The transfusion group also had significantly lower preoperative hemoglobin compared to the non-transfusion group (10.6 versus 11.1, P = .049). Eleven percent patients admitted to step-down received a transfusion, whereas 39% of patients admitted to the pediatric intensive care unit received a transfusion (P = 0.042). On multivariate analysis, only higher patient weight (operating room [OR] 0.305 [0.134, 0.693], P = 0.005) was protective against a transfusion, whereas colloid volume (OR 1.018 [1.003, 1.033], P = 0.019) predicted the need for a transfusion. Our results demonstrate that endoscopic craniosynostosis cases carry a moderate risk of transfusion. Individuals with lower weight and those that receive colloid volume are also at elevated risk.

Guideline development for prevention of transfusion-associated graft-versus-host disease: reduction of indications for irradiated blood components after prestorage leukodepletion of blood components

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare, commonly fatal complication of transfusion preventable by irradiation of blood units. The revision of the Dutch transfusion guideline addressed the question whether irradiation is still necessary if blood components are prestorage leukodepleted. We searched for published cases of TA-GVHD following transfusion of prestorage leukodepleted blood and through contacting haemovigilance systems. Six presumed cases were found, dating from 1998 to 2013. Four out of six patients had received one or more non-irradiated units despite recognised indications for irradiated blood components. In the countries providing information, over 50 million prestorage leukodepleted, non-irradiated, non-pathogen-reduced cellular components were transfused in a 10-year period. Potential benefits of lifting indications for irradiation were considered. These include reduced irradiation costs (€ 1.5 million annually in the Netherlands) and less donor exposure for neonates. Findings were presented in an invitational expert meeting. Recommendations linked to human leukocyte antigen similarity between donor and recipient or intra-uterine transfusion were left unchanged. Indications linked to long-lasting deep T-cell suppression were defined with durations of 6 or 12 months after end of treatment (e.g. autologous or allogeneic stem cell transplantation). Need for continued alertness to TA-GVHD and haemovigilance reporting of erroneous non-irradiated transfusions was emphasised.

Familial pseudohyperkalemia induces significantly higher levels of extracellular potassium in early storage of red cell concentrates without affecting other standard measures of quality: A case control and allele frequency study

BACKGROUND

Familial pseudohyperkalemia (FP) is characterized by an increased rate of potassium leakage in refrigerated red cells and is associated with the minor allele of the single nucleotide polymorphism rs148211042 (R723Q) in the ABCB6 gene. The study aims were to obtain the minor allele frequencies of ABCB6 variants and to measure supernatant potassium accumulation, and other red cell storage parameters, in red cell concentrates (RCC) from carriers of variant rs148211042 under standard blood bank conditions.

STUDY DESIGN

Whole blood units were collected from 6 FP individuals and 11 controls and processed into RCC in additive solution. RCC were sampled and tested over cold storage for full blood count, extracellular potassium, glucose, lactate, microvesicle release, deformability, hemolysis, pH, adenosine triphosphate, and 2,3-diphosphoglycerate.

RESULTS

Screening of genotyped cohorts identified that variant rs148211042 is present in 1 in 394 British citizens of European ancestry. FP RCC had significantly higher supernatant potassium at all time points from day 3 onwards (p < .001) and higher mean cell volume (p = .032) than controls. The initial rate of potassium release was higher in FP RCC; supernatant potassium reached 46.0 (23.8-57.6) mmol/L (mean [range]) by day 5, increasing to 68.9 (58.8-73.7) mmol/L by day 35. Other quality parameters were not significantly different between FP RCC and controls.

CONCLUSION

These data suggest that if a blood donor has FP, reducing the RCC shelf-life to 5 days may be insufficient to reduce the risk of hyperkalemia in clinical scenarios such as neonatal large volume transfusion.

Transfusion-associated hyperkalemia in pediatric population: Prevalence, risk factors, survival, infusion rate, and RBC unit features

BACKGROUND

Hyperkalemia is a rare life-threatening complication of red blood cell (RBC) transfusion. Stored RBCs leak intracellular potassium (K+) into the supernatant; irradiation potentiates the K+ leak. As the characteristics of patients and implicated RBCs have not been studied systematically, a multicenter study of transfusion-associated hyperkalemia (TAH) in the pediatric population was conducted through the AABB Pediatric Transfusion Medicine Subsection.

STUDY DESIGN

The medical records of patients <18 years old were retrospectively queried for hyperkalemia occurrence during or ≤12 h after the completion of RBC transfusion in a 1-year period. Collected data included patient demographics, diagnosis, medical history, timing of hyperkalemia and transfusion, mortality, and RBC unit characteristics.

RESULTS/FINDINGS

A total of 3777 patients received 19,649 RBC units during the study period in four facilities. TAH was found in 35 patients (0.93%) in 37 occurrences. The patient median age and weight were 1.28 years and 9.80 kg, respectively. All patients had multiple serious comorbidities. There were 79 RBC units transfused in the TAH events; 62% were irradiated, and the median age of the units was 10 days. The median total RBC volume transfused ≤12 h before TAH was 24% of patient estimated total blood volume, and the median infusion rate (IR) was19.6 ml/kg/h. Mortality rate within 1 day after the TAH event was 20%.

CONCLUSIONS

The prevalence of TAH in children was low; however, the 1-day mortality rate was 20%. Patients with multiple comorbidities may be at higher risk for TAH. The IR was higher for patients who had TAH than the IR threshold for safe transfusion.

Transfusion-Associated Hyperkalemic Cardiac Arrest in Neonatal, Infant, and Pediatric Patients

Red blood cell (RBC) transfusions are a life-saving intervention, with nearly 14 million RBC units transfused in the United States each year. However, the safety and efficacy of this procedure can be influenced by variations in the collection, processing, and administration of RBCs. Procedures or manipulations that increase potassium (K⁺) levels in stored blood products can also predispose patients to hyperkalemia and transfusion-associated hyperkalemic cardiac arrest (TAHCA). In this mini review, we aimed to provide a brief overview of blood storage, the red cell storage lesion, and variables that increase extracellular [K⁺]. We also summarize cases of TAHCA and identify potential mitigation strategies. Hyperkalemia and cardiac arrhythmias can occur in pediatric patients when RBCs are transfused quickly, delivered directly to the heart without time for electrolyte equilibration, or accumulate extracellular K⁺ due to storage time or irradiation. Advances in blood banking have improved the availability and quality of RBCs, yet, some patient populations are sensitive to transfusion-associated hyperkalemia. Future research studies should further investigate potential mitigation strategies to reduce the risk of TAHCA, which may include using fresh RBCs, reducing storage time after irradiation, transfusing at slower rates, implementing manipulations that wash or remove excess extracellular K⁺, and implementing restrictive transfusion strategies.

Pediatric Hemovigilance and Adverse Transfusion Reactions

Some types of transfusion reactions occur more frequently in the pediatric than the adult population. Allergic reactions are the most common, followed by nonhemolytic transfusion reactions; male children seem most susceptible to such reactions. Platelets are often implicated and pulmonary reactions are understudied in children. Clinical sequelae in neonates, such as bronchopulmonary dysplasia/chronic lung disease and intraventricular hemorrhage, have received increasing attention in relation to transfusion. There is a need to better understand the pathophysiology of transfusion reactions in neonatal and pediatric populations so preventive strategies can be undertaken. There is also a need for robust hemovigilance systems.

Neonatal red blood cell transfusion

Transfusions are more common in premature infants with approximately 40% of low birth weight infants and up to 90% of extremely low birth weight infants requiring red blood cell transfusion. Although red blood cell transfusion can be life-saving in these preterm infants, it has been associated with higher rates of complications including necrotizing enterocolitis, bronchopulmonary dysplasia, retinopathy of prematurity and possibly abnormal neurodevelopment. The main objective of this review is to assess current red blood cell transfusion practices in the neonatal intensive care unit, to summarize available neonatal transfusion guidelines published in different countries and to emphasize the wide variation in transfusion thresholds that exists for red blood cell transfusion. This review also addresses certain issues specific to red blood cell processing for the neonatal population including storage time, irradiation, cytomegalovirus (CMV) prevention strategies and patient blood management. Future research avenues are proposed to better define optimal transfusion practice in neonatal intensive care units.

Double-filtered leukoreduction as a method for risk reduction of transfusion-associated graft-versus-host disease

Background

Transfusion-associated graft-versus-host disease (TA-GvHD) is caused by leukocytes, specifically T cells within a transfused blood product. Currently, the prevention of transfusion-associated graft-versus-host disease is performed by irradiation of blood products. With a sufficient reduction of leukocytes, the risk for TA-GvHD can be decreased. With consistent advances in current state-of-the-art blood filters, we herein propose that double filtration can sufficiently reduce leukocytes to reduce the risk for TA-GvHD.

Materials

Thirty RBC concentrates were filtered with leukocyte filters, followed by storage at 1–6 ^oC for 72 hours, and then a second filtration was performed. Residual leukocytes in the double-filtered RBC units (n = 30) were assessed with flow cytometric methods, and an additional assay with isolated peripheral blood mononuclear cells (PBMCs) (n = 6) was done by both flow cytometric methods and an automated hematology analyzer. Quality of the RBCs after filtration was evaluated by hematological and biochemical tests. In vitro T cell expansion was performed using anti-CD3/CD28-coated Dynabeads or anti-CD3 (OKT3). In vivo experiment for GvHD was performed by using NOD.Cg-Prkdc^scid Il2rg^tm1Wjl/SzJ (NSG) mice.

Results

Double-filtered blood products showed residual leukocyte levels below detection limits, which calculated to be below 1200–2500 cells per blood unit. In vitro expansion rate of T cells showed that 6x10³ and 1x10³ cell-seeded specimens showed 60.8±10.6 fold and 10.2±9.7-fold expansion, respectively. Cell expansion was not sufficiently observed in wells planted with 1x10² or 10 cells. In vivo experiments showed that mice injected with 1x10⁵ or more cells cause fatal GvHD. GvHD induced inflammation was observed in mice injected with 1x10⁴ or more cells. No evidence of GvHD was found in mice injected with 10³ cells.

Conclusions

Our study suggests that additional removal of contaminating lymphocytes by a second leukodepletion step may further reduce the risk for TA-GvHD.

Hemolysis risk after packed red blood cells transfusion with infusion pumps

OBJECTIVE

To evaluate the hemolysis biomarkers of packed red blood cells transfused by two different linear peristaltic infusion pumps at two infusion rates.

METHOD

An experimental and randomized study was designed simulating the clinical practice of transfusion. Two linear peristaltic infusion pumps from different manufactures were studied in triplicate at 100 mL/h and 300mL/h infusion rates. The chosen hemolysis biomarkers were total hemoglobin, free hemoglobin, hematocrit, potassium and degree of hemolysis. They were analyzed before and after each infusion.

RESULTS

Potassium showed statistically significant variations in all scenarios of the experiment (P<0.010). In a separated analysis, potassium increased mainly at 300mL/h rate (P=0.021) and free hemoglobin had significant variation when comparing infusion pumps from different manufacturers (P=0.026). Although hematocrit, total hemoglobin and degree of hemolysis had increased after infusion, no statistically significance variations were identified.

CONCLUSIONS

Hemolysis risk induced by a linear peristaltic infusion pump was identified by an increase in free hemoglobin and potassium markers. As the potassium biomarker is often increased in aged packed red blood cells, we do not recommend using them in this scenario. Additional studies should be performed about other markers and using larger samples in order to reinforce the transfusion practice in nursing.

Laboratory assessment of the quality of adult and neonatal red cell concentrates manufactured from whole blood, exchange transfusion or intrauterine transfusion red cell units

BACKGROUND

We evaluated the quality of red cell components in additive solution over 42 days of storage when re-manufactured from neonatal exchange transfusion (ExTx) or intrauterine transfusion (IUT) units on day 7 for issue to adults, neonates or infants.

MATERIALS AND METHODS

Red cell concentrates (RCC) manufactured from WB were compared to RCC re-manufactured from ExTx or IUT on day 7, and red cell splits (RCS) manufactured from WB were compared to RCS re-manufactured from ExTx or IUT on day 7. All components were stored at 2-6°C and tested throughout storage until day 42 for in vitro parameters of red cell quality. One RCS manufactured from each of WB, ExTx or IUT, was irradiated on day 14 and tested on day 28 along with a non-irradiated RCS from the same unit.

RESULTS

All the re-manufactured arms had no worse haemolysis, red cell microvesicle (RCMV) release or ATP over storage compared to controls. All arms complied with the 0·8% haemolysis UK specification, except for re-manufactured RCS from the IUT arm irradiated on day 14 and tested on day 28. Re-manufactured units had significantly decreased potassium levels compared to control over storage (P < 0·001 all).

CONCLUSION

RCC or RCS re-manufactured from ExTx or IUT units on day 7 are suitable for transfusion up to the standard day 35 of storage. Re-manufactured RCS from ExTx units (but not IUT), may be irradiated up to day 14 and stored for 14 days post-irradiation.

Supernatant reduction of stored gamma-irradiated red blood cells minimizes potentially harmful substances present in transfusion aliquots for neonates

BACKGROUND

In neonate transfusion, the use of a dedicated red blood cell (RBC) unit decreases donor exposure. A separate safety measure involves gamma irradiation of the RBCs to abrogate the possibility of transfusion-associated graft-versus-host disease. However, in combination, storage of gamma-irradiated RBCs leads to accumulation of potentially harmful substances in the supernatant.

STUDY DESIGN AND METHODS

For this study, RBCs were pooled and split into three study arms. Centrifugation or gravity was used to pack RBCs of matched units thereby reducing the amount of supernatant that would be present in neonate transfusion aliquots; these were compared to matched control units. Supernatant measurements of potassium, hemoglobin (Hb), RBC microvesicle (RMV) content, and mannitol were made in aliquots prepared weekly up to 21 days after gamma irradiation. RBC morphology and osmotic fragility were also assessed to determine if supernatant reduction methods affected the storage lesion.

RESULTS

Potassium and mannitol were significantly decreased in transfusion aliquots prepared with either of the supernatant reduction methods. On Day 21, potassium levels from supernatant-reduced aliquots were below those of Day 7 control aliquots. A decrease in free Hb was only detected on Day 21 in centrifuged aliquots. RMVs were significantly reduced in centrifuged aliquots and significantly increased in gravity-settled aliquots. The only measurable effect on storage lesion was a small increase in osmotic fragility of the RBCs subjected to supernatant reduction.

CONCLUSION

Supernatant reduction by centrifugation effectively reduces potassium, mannitol, and RMVs in aliquots from gamma-irradiated RBCs stored up to 21 days.

Transfusion reactions: prevention, diagnosis, and treatment

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.

Transfusion of irradiated red blood cell units with a potassium adsorption filter: A randomized controlled trial

BACKGROUND

The irradiation of red blood cells (RBCs) causes damage of the RBC membrane with increased potassium (K) leak during storage compared with nonirradiated RBC units of similar age. A previous in vitro study showed a mean reduction of K of 94 ± 5% with a potassium adsorption filter (PAF).

STUDY DESIGN AND METHODS

A prospective, single-center, nonblinded, randomized controlled trial (RCT) was designed to evaluate the safety and efficacy of transfusing irradiated RBC units with the PAF. Patients 18 years of age or older who received irradiated RBC units due to chemotherapy-induced anemia were randomly assigned to receive irradiated RBC units with the PAF (PAF group) or with the standard blood infusion set (control group). Primary outcome measures were safety and efficacy of the PAF (absolute change in hemoglobin [Hb] and K, respectively, in patient's blood values after transfusing the irradiated RBC units with or without the PAF).

RESULTS

A total of 63 irradiated RBC units were transfused to 17 patients in the control group, and a total of 56 irradiated RBC units were transfused to 13 patients in the PAF group. The absolute change of Hb (9.3 ± 6.3 g/L vs. 8.1 ± 5.8 g/L; p = 0.3) and the absolute change of K (-0.01 ± 0.4 mmol/L vs. -0.01 ± 0.3 mmol/L; p = 0.2) were comparable between the two groups of the trial.

CONCLUSION

The transfusion of 1 irradiated RBC unit with the PAF was as safe and efficacious as the transfusion of 1 irradiated RBC unit with the standard blood infusion set in patients with chemotherapy-induced anemia.

Red Blood Cell Transfusion

Blood is classified as a drug and transfusion is one of the most commonly performed procedures in the USA. General knowledge of blood manufacturing, shelf life and storage media, common component modifications, blood types, and product compatibility allows the clinician to better communicate their needs and to understand what options may be available when ordering blood products. All transfusions offer benefits, and the clinician must comprehend the possible adverse events, especially those related to TRALI, which continues to be the most common cause of transfusion-related death reported to FDA, with TACO as the second most-commonly reported event. Transfusing in the setting of hemorrhagic blood loss adds additional challenges regarding volume overload, coagulopathy, and optimum transfusion ratios of red cells, plasma, platelets, and cryoprecipitate. The information imparted in this chapter will help equip the clinician with the knowledge needed to make the best decisions for patients requiring blood products, especially injured patients.

Assessing the Rates, Predictors, and Complications of Blood Transfusion Volume in Posterior Arthrodesis for Adolescent Idiopathic Scoliosis

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To determine predictors of and 30-day complications associated with blood transfusion volume after posterior spinal fusion for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Posterior arthrodesis is a common procedure performed for AIS, and patients frequently require perioperative blood transfusions. Few studies, however, have examined the rates and potential complications associated with blood transfusion volume.

METHODS

Patients undergoing posterior arthrodesis for AIS were selected from the National Surgical Quality Improvement Program pediatric database from 2012 to 2013. Patients were stratified on the basis of blood transfusion volume and patient demographics and comorbidities, operative characteristics, and 30-day complications were recorded. Multivariate analyses were performed to determine predictors of transfusion as well as the effect of transfusion volume on 30-day complication rates.

RESULTS

A total of 1691 patients were included. Male sex (P = 0.010), esophageal or gastrointestinal disease (P = 0.016), cardiac risk factors (P = 0.037), preoperative inotrope requirement (P = 0.031), total operative time of 300 minutes or more (P < 0.001), and posterior arthrodesis of 13 or more vertebral segments (P < 0.001) were independent risk factors for requiring blood transfusion. Total transfusion volume of 20 mL/kg or more was the minimum volume independently associated with increased rates of total complications (P = 0.018), with a complication rate of 5.9%.

CONCLUSION

We present the first large, comprehensive analysis of complications related to blood transfusion events and transfusion volume on short-term postoperative complications after posterior arthrodesis for AIS. Although transfusion in general is not associated with 30-day adverse events, a volume of 20 mL/kg was associated with higher complication rates.

LEVEL OF EVIDENCE

4.

Familial pseudohyperkalemia in blood donors: a novel mutation with implications for transfusion practice

BACKGROUND

Familial pseudohyperkalemia (FP) is a dominantly inherited condition in which red blood cells (RBCs) have an increased cold-induced permeability to monovalent cations. Potassium leaks into the supernatant of all stored blood with time, but FP RBCs leak potassium more rapidly. We investigated two unrelated blood donors whose RBC donations demonstrated unexpectedly high potassium after 5 and 6 days' storage. We matched the observed pattern of RBC cation leak to a previously recognized family with FP (FP-Cardiff) and investigated the likely cause with targeted DNA analysis.

STUDY DESIGN AND METHODS

Cation leakage from the donor RBCs and from standard donor units was measured. DNA analysis of donors and family members with FP-Cardiff was performed. Allele frequencies were obtained from human variation databases.

RESULTS

Both implicated donors were found to have increased cold-induced potassium leak identical in pattern to affected members of the family with FP-Cardiff. We found a heterozygous substitution Arg723Gln in the ATP-binding cassette, Subfamily B, Member 6 protein that segregated with FP in the Cardiff family and was also present in both blood donors. Arg723Gln is listed in human variation databases with an allele frequency of approximately 1:1000.

CONCLUSIONS

We describe a novel FP mutation that may affect 1:500 European blood donors and causes rapid loss of potassium from stored RBCs. This finding has implications for neonates and infants receiving large-volume RBC transfusions. Genomic screening of donors could be used to identify donors with this mutation and potentially improve the quality and safety of donor units.

Red blood cell in vitro quality and function is maintained after S-303 pathogen inactivation treatment

BACKGROUND

Over the past decade there has been a growth in the development of pathogen reduction technologies to protect the blood supply from emerging pathogens. This development has proven to be difficult for red blood cells (RBCs). However the S-303 system has been shown to effectively inactivate a broad spectrum of pathogens, while maintaining RBC quality.

STUDY DESIGN AND METHODS

A paired three-arm study was performed to compare the in vitro quality of S-303-treated RBCs with RBCs stored at room temperature (RT) for the duration of the treatment (18-20 hr) and control RBCs stored at 2 to 6°C. Products were sampled weekly over 42 days of storage (n = 10) and tested using an array of in vitro assays to measure quality, metabolism, and functional variables.

RESULTS

During S-303 treatment there was a slight loss of RBCs and hemoglobin (Hb < 5 g). Hemolysis, glucose consumption, and potassium release were similar in all groups during the 42 days of storage. S-303-treated RBCs had a significantly lower lactate concentration and pH compared to the paired controls. The S-303-treated RBCs had significantly higher adenosine triphosphate than the RT and control RBCs. There was a significant loss of 2,3-diphosphoglycerate in the S-303-treated products, which was also observed in the RT RBCs. Flow cytometry analysis demonstrated similar RBC size, morphology, expression of CD47, and glycophorin A in all groups.

CONCLUSION

RBCs treated with S-303 for pathogen reduction had similar in vitro properties to the paired controls and were within transfusion guidelines.

Blood banking/immunohematology: special relevance to pediatric patients

Blood banking/immunohematology is an area of laboratory medicine that involves the preparation of blood and blood components for transfusion as well as the selection and monitoring of those components following transfusion. The preparation, modification, and indications of both traditional and newer products are described in this review, along with special considerations for neonates, patients undergoing hematopoietic stem cell transplantation, those with sickle cell disease, and others. Immunohematological techniques are critical in the provision of blood and blood products and are briefly discussed.

Risk of extracorporeal life support circuit-related hyperkalemia is reduced by prebypass ultrafiltration

OBJECTIVES

Pediatric patients who receive large volume blood transfusions are at risk for experiencing transfusion-related hyperkalemic cardiac arrest. Prebypass ultrafiltration of blood used to prime cardiopulmonary bypass circuits is commonly used in pediatric cardiac surgery to create a more physiologic and electrolyte balanced priming solution prior to initiation of cardiopulmonary bypass. This study was undertaken to determine the efficacy of prebypass ultrafiltration in normalizing extracorporeal life support circuit priming solution before initiating extracorporeal life support.

DESIGN

Prospective study.

SETTING

PICU and neonatal ICU in a tertiary academic center.

PATIENTS

Patients requiring venovenous extracorporeal life support.

INTERVENTIONS

Prebypass ultrafiltration of extracorporeal life support circuits.

MEASUREMENTS AND MAIN RESULTS

Hematocrit, electrolyte, and lactate concentrations were measured in blood-primed extracorporeal life support circuits before and after ultrafiltration and in blood collected from patients before and after initiation of extracorporeal life support. Clinically significant elevation of K concentration was observed in all extracorporeal life support circuits prior to prebypass ultrafiltration, despite the fact that 93% of red blood cell units were collected ≤ 7 days prior to use. Prebypass ultrafiltration significantly reduced concentrations of K (10.9 vs 6.0 mEq/L, p = 0.001) and lactate (7.0 vs 3.6 mmol/L, p < 0.001) and increased hematocrit (37% vs 48%, p < 0.001) and concentrations of ionized calcium (0.64 vs 1.16 mg/dL, p < 0.001) and Na (129 vs 144 mEq/L, p < 0.001). Serum electrolyte concentrations remained within the normal physiologic range in all patients following initiation of venovenous extracorporeal life support with circuits that underwent prebypass ultrafiltration.

CONCLUSIONS

Prebypass ultrafiltration normalizes the electrolyte balance of blood-primed extracorporeal life support circuits. Prebypass ultrafiltration processing may reduce the risk of transfusion-related hyperkalemic cardiac arrest in small children who require venovenous extracorporeal life support.

Severe hyperkalemia during cardiopulmonary bypass: etiology and effective therapy

Hyperkalemia is considered a medical emergency as it can result in severe disturbances in cardiac rhythm and death. Although many causes of hyperkalemia exist, exogenous red blood cell transfusions are being recognized as the primary perioperative etiology. The authors report a case of severe intraoperative hyperkalemia associated with the use of allogeneic blood products (packed red blood cells), during a surgical mission to a developing country. The patient was undergoing repeat mitral valve replacement with cardiopulmonary bypass (CPB) and developed significant hyperkalemia with a serum potassium value of 9.9 mEq/L. Successful intraoperative therapies were instituted with a gradual reduction in the serum potassium value to 4.8 mEq, which allowed the patient to be weaned from CPB. The authors review the etiology of hyperkalemia in children including its relationship with allogeneic red blood cell transfusions and treatment modalities including specific therapies which can be instituted during CPB.

Potassium changes associated with blood transfusion in pediatric patients

Storing packed red blood cells (pRBCs) increases the potassium concentration. This effect is characterized in citrate phosphate dextrose/citrate phosphate dextrose adenine units but not published for Adsol (AS-5) units. The change in whole-blood potassium concentration in pediatric patients during routine transfusion is also poorly characterized. In this study, pediatric patients undergoing transfusion had pre- and posttransfusion whole-blood potassium measurements. The pRBC unit transfused and the unit's segment were sampled, with potassium concentration measured. In addition, potassium concentration in AS-5 units was measured over 42 days of storage. Unit extracellular potassium increased in AS-5 units after day 7 at 0.83 mmol/L/d. The mean change in patient potassium concentration was 0.08 mmol/L (range, -0.5 to 0.5 mmol/L). No correlation with unit age or unit potassium concentration was identified with change in patient whole-blood potassium concentration. The lack of clinical effect on patient potassium does not support the use of "fresh" pRBC units with routine pediatric transfusion.

Transfusion-related necrotizing enterocolitis: a conceptual framework

Necrotizing enterocolitis (NEC) is a disease primarily of prematurity characterized by partial or entire gut necrosis and is associated with significant mortality and morbidity. Recent studies report that approximately 25% to 35% of very low-birth-weight infants less than 1500 g receiving packed red blood cell transfusions develop temporally associated NEC, known as transfusion-related NEC (TR-NEC). Although there are many known risk factors for NEC, this article focuses on 3 contributing factors: packed red blood cell transfusions, enteral feedings, and gastrointestinal immaturity. Previous data suggest that these factors may interact to affect neonatal intestinal tissue oxygenation, which may lead to tissue ischemia, resulting in intestinal injury. This article presents a conceptual framework that combines current theoretical perspectives for TR-NEC, and reviews previous research examining related variables and how their interaction may increase the risk for TR-NEC development. In addition, incorporation of the proposed framework to guide future research and nursing care in this area is discussed.

Implementation of a pediatric trauma massive transfusion protocol: one institution's experience

BACKGROUND

Massive transfusion protocols (MTPs) with fixed ratios of blood products may improve outcomes in coagulopathic adult trauma patients. However, there is a paucity of data on transfusion support protocols for pediatric trauma patients, whose mechanisms of injury may differ from those seen in adults. We hypothesized that an MTP would improve outcomes in children, through a balanced blood product resuscitation.

STUDY DESIGN AND METHODS

A pediatric trauma MTP, with a fixed ratio of red blood cells (RBCs):fresh-frozen plasma (FFP):platelets:cryoprecipitate in quantities based on the patient's weight, was initiated at a pediatric hospital. Data on clinical status, resuscitation volumes, and hospital course were collected and compared to data from pre-MTP trauma patients requiring transfusion.

RESULTS

Fifty-three patients were enrolled over a 15-month period and compared to 49 pre-MTP patients. Seventy-two percent of MTP patients had at least one coagulation value outside of the normal range upon emergency department (ED) arrival, and the median time to FFP transfusion decreased fourfold after MTP implementation (p<0.0001). A total of 49% of MTP patients received greater than 70 mL/kg blood products, and the 24-hour median FFP:RBC transfusion ratio was twofold higher in these patients than the pre-MTP cohort (median, 1:1.8 vs. 1:3.6; p=0.002). No improvement in mortality was observed after MTP implementation, taking into consideration injury severity, prothrombin time, and partial thromboplastin time.

CONCLUSIONS

A pediatric trauma MTP is feasible and allows for rapid provision of balanced blood products for transfusion to coagulopathic children. Larger studies are warranted to determine whether such protocols will improve outcomes for pediatric trauma patients.

Transfusion-associated hyperkalemia

The supernatant potassium concentration [K+] of red blood cell (RBC) units is frequently much higher than normal human plasma potassium levels, especially in units nearing the end of their storage life. Clinical hyperkalemia resulting from RBC transfusions has been recognized as a transfusion complication for decades, and there have been reported cardiac arrests attributed to transfusion-associated hyperkalemia. This review summarizes the evidence surrounding RBC [K+] levels, effects of irradiation and washing on [K+], the evidence for clinical hyperkalemia and cardiac arrests resulting from transfusion, predictors of post-transfusion hyperkalemia, and their preventative strategies. Key points include: (a) the [K+] (in mmol/L) increases linearly and is approximately equal to the number of days of RBC unit storage; (b) irradiation causes a rapid increase in [K+]; (c) there is potentially sufficient potassium in the supernatant of current RBC preparations to lead to hyperkalemia with large transfusion volumes; (d) any rise in patient potassium after transfusion is usually transient due to the redistribution of the potassium load; (e) transfusion-associated hyperkalemic cardiac arrests probably do occur, although it is difficult to prove this fact conclusively; and (f) promising strategies to combat transfusion-associated hyperkalemia include RBC washing, the use of in-line potassium filters, and the use of traditional treatments for hyperkalemia such as the use of insulin.