Timing of Red Blood Cell Transfusions and Occurrence of Necrotizing Enterocolitis: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Observational studies often report that anemia and red blood cell (RBC) transfusions are associated with a higher risk of necrotizing enterocolitis (NEC) among extremely low-birthweight (ELBW) infants. Objective: To evaluate whether there is a temporal association between 72-hour hazard periods of exposure to RBC transfusions and NEC among ELBW infants randomized to either higher or lower hemoglobin transfusion thresholds. Design, Setting, and Participants: This post hoc secondary analysis of 1690 ELBW infants who survived to postnatal day 10 enrolled in the Transfusion of Prematures (TOP) randomized multicenter trial between December 1, 2012, and April 12, 2017, was performed between June 2021 and July 2023. Exposures: First, the distribution of RBC transfusions and the occurrence of NEC up to postnatal day 60 were examined. Second, 72-hour posttransfusion periods were categorized as hazard periods and the pretransfusion periods of variable duration as control periods. Then, the risk of NEC in posttransfusion hazard periods was compared with that in pretransfusion control periods, stratifying the risk based on randomization group (higher or lower hemoglobin transfusion threshold group). Main Outcomes and Measures: The primary outcome was incidence of NEC stage 2 or 3. Secondary outcomes included the incidence rates of NEC within five 10-day intervals, taking into account the number of days at risk. Results: Of 1824 ELBW infants randomized during the TOP trial, 1690 were included in the present analysis (mean [SD] gestational age, 26.0 [1.5] weeks; 899 infants [53.2%] were female). After categorizing 4947 hazard periods and 5813 control periods, we identified 133 NEC cases. Fifty-nine of these cases (44.4%) occurred during hazard periods. Baseline and clinical characteristics of infants with NEC during hazard periods did not differ from those of infants with NEC during control periods. The risk of NEC was 11.9 per 1000 posttransfusion hazard periods and 12.7 per 1000 control periods (adjusted risk ratio, 0.95; 95% CI, 0.68-1.32; P = .74). This risk did not differ significantly between randomization groups, but the incidence rate of NEC per 1000 days peaked between postnatal days 20 and 29 in the lower hemoglobin transfusion threshold group. Conclusions and Relevance: The findings of this post hoc analysis suggest that, among ELBW infants with the hemoglobin ranges occurring in the TOP trial, exposure to RBC transfusions was not temporally associated with a higher risk of NEC during 72-hour posttransfusion hazard periods. Given that the incidence rate of NEC peaked between postnatal days 20 and 29 among infants with lower hemoglobin values, a more in-depth examination of this at-risk period using larger data sets is warranted. Trial Registration: ClinicalTrials.gov Identifier: NCT01702805.

Development of a Risk Assessment Model for Predicting Red Blood Cell Transfusion in Neonatal Patients.

BACKGROUND: The goal was to develop a risk assessment model for predicting red blood cell (RBC) transfusion in neonatal patients to assist hospital blood supply departments in providing small portions of RBCs to those requiring RBC transfusion on time. METHODS: Clinical information was collected from 1,201 children admitted to the neonatal unit. Clinical factors associated with predicting RBC transfusion were screened, and prediction models were developed using stepwise and multifactorial logistic regression analyses, followed by the evaluation of prediction models using receiver operating characteristic curves, calibration curves, and decision curve analysis (DCA). RESULTS: Overall, 81 neonatal patients were transfused with RBCs, and the variables of gestational age at birth, age < 1 month, receipt of mechanical ventilation, and infant anemia were included in the final prediction model. The area under the curve of the prediction model was 0.936 (0.921 - 0.949), which was significantly higher than that of the individual indicators of gestational age at birth, age at admission < 1 month, receipt of mechanical ventilation, and infant anemia (p < 0.001). DCA showed a standardized net benefit for the possible risk of infant RBC transfusion at 0.1 - 1.0. CONCLUSIONS: We developed a risk assessment model to predict the risk of RBC transfusion in neonatal patients that can effectively assess the risk of RBC transfusion in children.

Association between perioperative red blood cell transfusions and postoperative venous thromboembolism: A systematic review and meta-analysis.

BACKGROUND: Whether perioperative red blood cell transfusions increases the risk of postoperative venous thromboembolism is controversial and uncertain.We aims to explore the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism by conducting a meta-analysis. OBJECTIVE: To conduct a meta-analysis to systematically evaluate the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism. METHODS: PubMed, Embase, Cochrane, and Web of Science databases were searched to identify studies examining the relationship between perioperative red blood cell transfusions and the risk of postoperative venous thromboembolism. The databases were searched from establishment to August 2023.Two researchers independently screened literature and extracted data according to inclusion and exclusion criteria. Newcastle-ottawa Scale was used for quality assessment. Meta-analysis of data was performed using RevMan 5.4 software. RESULTS: A total of 15 studies involving 1,880,990 patients were included in this study.Meta-analysis showed that perioperative red blood cell transfusions increased the risk of postoperative venous thromboembolism [OR = 1.61, 95%CI (1.37, 1.89), P < 0.001]. Subgroup analyses showed that the transfusion dose,transfusion timing,study population and follow-up time were closely related to the risk of postoperative venous thromboembolism. CONCLUSIONS: In summary, this meta-analysis demonstrated a significant positive association between perioperative red blood cell transfusions and postoperative venous thromboembolism.Healthcare professionals should pay attention to the influence of blood transfusions on postoperative venous thromboembolism, strengthen management and prevention.

A Comprehensive Patient Blood Management Program During Cardiopulmonary Bypass in Patients Over 60 Years of Age.

Purpose: There is currently no consensus on the most appropriate blood transfusion strategy for older adults undergoing cardiovascular surgery. We aimed to investigate the potential benefits of the patient blood management (PBM) program specifically for advanced age patients, and to evaluate the relationship of age and PBM in cardiovascular surgery. Patients and Methods: We collected data from patients over 60 years old who underwent on-pump cardiovascular surgery. We compared transfusion and clinical outcomes between the pre-PBM and post-PBM groups using a propensity score matching method. Then, we conducted a subgroup analysis within the original cohort, specifically focusing on patients aged of 75 and above with multivariable adjusted models. Results: Data of 9703 older adults were analyzed. Red blood cell (RBC) transfusion rates during cardiopulmonary bypass (CPB) (31.6% vs 13.1%, P<0.001), during the operation (50.8% vs 39.0%, P<0.001) and after the operation (5.6% vs 3.1%, P<0.001) were significantly reduced, and mortality and the risk of some adverse events were also reduced after the PBM. Subgroup analysis showed that there was no interaction between age and PBM, and advanced age (over age 75) did not modify the effect of PBM program in reducing RBC transfusion (Pinteraction=0.245), on mortality (Pinteration=0.829) and on certain complications. Conclusion: The comprehensive PBM program could reduce RBC transfusion without adverse outcomes in older patients undergoing CPB. Even patients over age 75 may benefit from a more stringent transfusion indication. Comprehensive blood conservation measures should be applied to optimize the blood management for older patients.

Impact of Red Blood Cell Transfusion on Subsequent Cardiovascular Events in Patients with Acute Heart Failure and Anemia.

Red blood cell (RBC) transfusion therapy is often performed in patients with acute heart failure (AHF) and anemia; however, its impact on subsequent cardiovascular events is unclear. We examined whether RBC transfusion influences major adverse cardiovascular events (MACE) after discharge in patients with AHF and anemia.We classified patients with AHF and anemia (nadir hemoglobin level < 10 g/dL) according to whether they received RBC transfusion during hospitalization. The endpoint was MACE (composite of all-cause death, non-fatal acute coronary syndrome/stroke, or heart failure readmission) 180 days after discharge. For survival analysis, we used propensity score matching analysis with the log-rank test. As sensitivity analysis, we performed inverse probability weighting analysis and multivariable Cox regression analysis.Among 448 patients with AHF and anemia (median age, 81 years; male, 55%), 155 received RBC transfusion and 293 did not. The transfused patients had worse clinical features than the non-transfused patients, with lower levels of nadir hemoglobin and serum albumin and a lower estimated glomerular filtration rate. In the propensity-matched cohort of 87 pairs, there was no significant difference in the MACE-free survival rate between the 2 groups (transfused, 73.8% vs. non-transfused, 65.3%; P = 0.317). This result was consistent in the inverse probability weighting analysis (transfused, 76.0% vs. non-transfused, 68.7%; P = 0.512), and RBC transfusion was not significantly associated with post-discharge MACE in the multivariable Cox regression analysis (adjusted hazard ratio: 1.468, 95% confidence interval: 0.976-2.207; P = 0.065).In conclusion, this study suggests that RBC transfusions for anemia may not improve clinical outcomes in patients with AHF.

Red blood cell transfusion in neurocritical patients: a systematic review and meta-analysis.

BACKGROUND: Anemia can lead to secondary brain damage by reducing arterial oxygen content and brain oxygen supply. Patients with acute brain injury have impaired self-regulation. Brain hypoxia may also occur even in mild anemia. Red blood cell (RBC) transfusion is associated with increased postoperative complications, poor neurological recovery, and mortality in critically ill neurologic patients. Balancing the risks of anemia and red blood cell transfusion-associated adverse effects is challenging in neurocritical settings. METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and MEDLINE (PubMed) from inception to January 31, 2024. We included all randomized controlled trials (RCTs) assessing liberal versus restrictive RBC transfusion strategies in neurocritical patients. We included all relevant studies published in English. The primary outcome was mortality at intensive care unit (ICU), discharge, and six months. RESULTS: Of 5195 records retrieved, 84 full-text articles were reviewed, and five eligible studies were included. There was no significant difference between the restrictive and liberal transfusion groups in ICU mortality (RR: 2.53, 95% CI: 0.53 to 12.13), in-hospital mortality (RR: 2.34, 95% CI: 0.50 to 11.00), mortality at six months (RR: 1.42, 95% CI: 0.42 to 4.78) and long-term mortality (RR: 1.22, 95% CI: 0.64 to 2.33). The occurrence of neurological adverse events and most major non-neurological complications was similar in the two groups. The incidence of deep venous thrombosis was lower in the restrictive strategy group (RR: 0.41, 95% CI: 0.18 to 0.91). CONCLUSIONS: Due to the small sample size of current studies, the evidence is insufficiently robust to confirm definitive conclusions for neurocritical patients. Therefore, further investigation is encouraged to define appropriate RBC transfusion thresholds in the neurocritical setting.

Challenging the dogma: Red blood cell-directed autoimmunity as risk factor for red blood cell alloimmunisation after blood transfusion.

Red blood cell autoimmunity and alloimmunity are potentially linked. Quantification of this association can tailor extensively matched red blood cell transfusions in patients with autoimmunity. Using an incident new-user cohort comprising 47 285 previously non-transfused, non-alloimmunised patients, we compared transfusion-induced red blood cell alloimmunisation incidences in direct antiglobulin test (DAT)-positive and control patients. Additionally, we performed case-control analyses to handle potential confounding by clinical immunomodulators. Among (IgG and/or C3d) DAT-positive patients (N = 380), cumulative red blood cell alloimmunisation incidences after 10 units transfused reached 4.5% (95% confidence interval [CI] 2.5-8.2) versus 4.2% (CI 3.9-4.5, p = 0.88) in controls. In case-control analyses, alloimmunisation relative risks among DAT-positive patients increased to 1.7 (CI 1.1-2.8). Additional adjustments for pre-DAT transfusion exposure or the extent of Rh/K mismatching did not impact results. In conclusion, while patients with DAT positivity show an intrinsically increased alloimmune red blood cell response, their absolute risk is comparable to control patients due to counteracting co-existing immunosuppressive conditions. Consequently, isolated DAT positivity in patients lacking overt haemolysis or complicated alloantibody testing does not seem to warrant extended matching strategies.

Increased platelet to red blood cell transfusion ratio associated with acute kidney injury in children with life-threatening bleeding.

INTRODUCTION: Transfusion may increase the risk of organ failure through immunomodulatory effects. The primary objective of this study was to assess for patient or transfusion-related factors that are independently associated with the risk of acute kidney injury (AKI) and acute respiratory distress syndrome (ARDS) in a cohort of children with life-threatening bleeding from all etiologies. METHODS: In a secondary analysis of the prospective observational massive transfusion in children (MATIC) study, multivariable logistic regression was performed in an adjusted analysis to determine if blood product ratios or deficits were independently associated with AKI or ARDS in children with life-threatening bleeding. RESULTS: There were 449 children included with a median (interquartile range, IQR) age of 7.3 years (1.7-14.7). Within 5 days of the life-threatening bleeding event, AKI occurred in 18.5% and ARDS occurred in 20.3% of the subjects. Every 10% increase in the platelet to red blood cell transfusion ratio is independently associated with a 12.7% increase in the odds of AKI (adjusted odds ratio 1.127; 95% confidence interval 1.025-1.239; p-value .013). Subjects with operative or medical etiologies were independently associated with an increased risk of AKI compared to those with traumatic injury. No transfusion-related variables were independently associated with the risk of developing ARDS. CONCLUSION: The use of increased platelet to red blood cell transfusion ratios in children with life-threatening bleeding of any etiology may increase the risk of AKI but not ARDS. Prospective trials are needed to determine if increased platelet use in this cohort increases the risk of AKI to examine possible mechanisms.

Using the daily rate of rise in hemoglobin S to manage RBC depletion/exchange treatment in sickle cell disease.

BACKGROUND: Red blood cell exchange is often used prophylactically in patients with sickle cell disease, with the goal to maintain hemoglobin S (HbS) below a target threshold level. We reviewed whether the daily "rate of rise" (RoR) in HbS that occurs between procedures can be used for patient management. For some patients not achieving their HbS goals despite efficient exchanges, the post-procedure hematocrit (Hct) target is increased to potentially suppress HbS production. This case series explores the utility of this approach, other clinical uses of the daily RoR in HbS, and the factors that influence it. STUDY DESIGN AND METHODS: A total of 660 procedures from 24 patients undergoing prophylactic RBC depletion/exchange procedures were included. Laboratory values and clinical parameters were collected and used to calculate the daily RoR in HbS. Factors such as Hct or medications that might influence the RoR in HbS were evaluated. RESULTS: The RoR in HbS varied widely between patients but remained relatively stable within individuals. Surprisingly, this value was not significantly influenced by changes in post-procedure Hct or concurrent hydroxyurea use. A patient's average RoR in HbS effectively predicted the pre-procedure HbS at the following visit (R2 = 0.65). DISCUSSION: The RoR in HbS is a relatively consistent parameter for individual patients that is unaffected by medication use or procedural Hct targets and may be useful in determining intervals between procedures.

Post-transfusion biotin-labeled red blood cell survival studies in pediatric sickle cell disease with antibodies of uncertain significance.

BACKGROUND: Red blood cell (RBC) antibodies are common in multiply transfused patients with sickle cell disease (SCD). Unlike RBC alloantibodies, the potential of autoantibodies to cause post-transfusion hemolysis may be uncertain. Biotin-labeling provides a direct measurement of red cell survival (RCS) over time, thus can be used to assess the clinical significance of RBC antibodies. Antibodies to biotinylated RBC (B-RBC) occasionally are detected after exposure, which may impact B-RBC survival in subsequent RCS studies. STUDY DESIGN AND METHODS: Pediatric patients with SCD receiving monthly chronic transfusions underwent RCS studies, receiving aliquots of allogeneic RBC labeled at distinct densities of biotin (2-18 µg/mL). B-RBC survival was followed for 4 months post-transfusion, and B-RBC antibody screening for 6 months. Patients with warm autoantibodies (WAA) or B-RBC antibodies are reported here. RESULTS: RBC antibodies were detected during RCS in four patients: one with WAA, one with WAA followed by B-RBC-specific antibodies, and two with transient B-RBC antibodies within the first 5 weeks of exposure. B-RBC half-lives (T50) ranged 37.6-61.7 days (mean 47.8 days). There was no evidence of increased hemolysis or accelerated B-RBC clearance in the presence of WAA or B-RBC antibodies. DISCUSSION: Biotinylation of allogenic RBC can be used to assess the possible effects of RBC antibodies on transfusion survival in individual cases, particularly when it is uncertain if the detected antibodies may result in hemolysis. In the cases presented here, neither WAA nor B-RBC antibodies were associated with significant shortening of B-RBC survival in individuals with SCD.

Cerebral amyloid angiopathy decades after red blood cell transfusions: a report of two cases from a prospective cohort.

BACKGROUND AND PURPOSE: Patients who underwent red blood cell (RBC) transfusion from donors who later developed multiple spontaneous intracerebral hemorrhages (ICHs) have recently been identified to have increased risk of ICH themselves. This increased risk of ICH was hypothesized to be related to iatrogenic cerebral amyloid angiopathy (iCAA) transmission. Two cases are presented who had RBC transfusion as an infant and presented with CAA at a relatively young age decades later. METHOD: Cases were identified by prospectively asking all patients at our CAA outpatient clinic (November 2023 to January 2024) about a medical history with RBC transfusion or history with a high likelihood for RBC transfusion (e.g., hemolytic disease, trauma with massive hemorrhage). Eligible patients were all diagnosed with CAA, CAA with concomitant hypertensive arteriopathy or iCAA, and without hereditary CAA. RESULTS: Between November 2023 and January 2024, 2/35 (6%, 95% confidence interval 2%-19%) outpatient clinic patients had a history of RBC transfusion and none had a high likelihood medical history. The cases presented at age 47 and 57 and had already developed severe CAA. CONCLUSIONS: Red blood cell transfusion might be a possible mechanism for iCAA; however, further prospective data collection and experimental evidence concerning blood transmission of amyloid-ß are needed.

Ultra-restrictive red blood cell transfusion strategies in extensively burned patients.

In recent years, due to the shortage of blood products, some extensive burn patients were forced to adopt an "ultra-restrictive" transfusion strategy, in which the hemoglobin levels of RBC transfusion thresholds were < 7 g/dl or even < 6 g/dl. This study investigated the prognostic impacts of ultra-restrictive RBC transfusion in extensive burn patients. This retrospective multicenter cohort study recruited extensive burns (total body surface area ≥ 50%) from three hospitals in Eastern China between 1 January 2016 and 30 June 2022. Patients were divided into an ultra-restrictive transfusion group and a restrictive transfusion group depending on whether they received timely RBC transfusion at a hemoglobin level < 7 g/dl. 1:1 ratio propensity score matching (PSM) was performed to balance selection bias. Modified Poisson regression and linear regression were conducted for sensitive analysis. Subsequently, according to whether they received timely RBC transfusion at a hemoglobin level < 6 g/dl, patients in the ultra-restrictive transfusion group were divided into < 6 g/dl group and 6-7 g/dl group to further compare the prognostic outcomes. 271 eligible patients with extensive burns were included, of whom 107 patients were in the ultra-restrictive transfusion group and 164 patients were in the restrictive transfusion group. The ultra-restrictive transfusion group had a significantly lower RBC transfusion volume than the restrictive transfusion group (11.5 [5.5, 21.5] vs 17.3 [9.0, 32.5] units, p = 0.004). There were no significant differences between the two groups in terms of in-hospital mortality, risk of infection, hospital length of stay, and wound healing time after PSM or multivariate adjustment (p > 0.05). Among the ultra-restrictive transfusion group, patients with RBC transfusion threshold < 6 g/dl had a significantly higher hospital mortality than 6-7 g/dl (53.1% vs 21.3%, p = 0.001). For extensive burn patients, no significant adverse effects of ultra-restrictive RBC transfusion were found in this study. When the blood supply is tight, it is acceptable to adopt an RBC transfusion threshold of < 7 g/dL but not < 6 g/dL.

Alternative blood transfusion triggers: a narrative review.

BACKGROUND: Anemia, characterized by low hemoglobin levels, is a global public health concern. Anemia is an independent factor worsening outcomes in various patient groups. Blood transfusion has been the traditional treatment for anemia; its triggers, primarily based on hemoglobin levels; however, hemoglobin level is not always an ideal trigger for blood transfusion. Additionally, blood transfusion worsens clinical outcomes in certain patient groups. This narrative review explores alternative triggers for red blood cell transfusion and their physiological basis. MAIN TEXT: The review delves into the physiology of oxygen transport and highlights the limitations of using hemoglobin levels alone as transfusion trigger. The main aim of blood transfusion is to optimize oxygen delivery, necessitating an individualized approach based on clinical signs of anemia and the balance between oxygen delivery and consumption, reflected by the oxygen extraction rate. The narrative review covers different alternative triggers. It presents insights into their diagnostic value and clinical applications, emphasizing the need for personalized transfusion strategies. CONCLUSION: Anemia and blood transfusion are significant factors affecting patient outcomes. While restrictive transfusion strategies are widely recommended, they may not account for the nuances of specific patient populations. The search for alternative transfusion triggers is essential to tailor transfusion therapy effectively, especially in patients with comorbidities or unique clinical profiles. Investigating alternative triggers not only enhances patient care by identifying more precise indicators but also minimizes transfusion-related risks, optimizes blood product utilization, and ensures availability when needed. Personalized transfusion strategies based on alternative triggers hold the potential to improve outcomes in various clinical scenarios, addressing anemia's complex challenges in healthcare. Further research and evidence are needed to refine these alternative triggers and guide their implementation in clinical practice.

Transfusion targets and adverse events in pediatric perioperative acute Anemia.

STUDY OBJECTIVE: To evaluate the association between pretransfusion and posttransfusion hemoglobin concentrations and the outcomes of children undergoing noncardiac surgery. DESIGN: Retrospective review of patient records. We focused on initial postoperative hemoglobin concentrations, which may provide a more useful representation of transfusion adequacy than pretransfusion hemoglobin triggers (the latter often cannot be obtained during acute surgical hemorrhage). SETTING: Single-center, observational cohort study. PATIENTS: We evaluated all pediatric patients undergoing noncardiac surgery who received intraoperative red blood cell transfusions from January 1, 2008, through December 31, 2018. INTERVENTIONS: None. MEASUREMENTS: Associations between pre- and posttransfusion hemoglobin concentrations (g/dL), hospital-free days, intensive care unit admission, postoperative mechanical ventilation, and infectious complications were evaluated with multivariable regression modeling. MAIN RESULTS: In total, 113,713 unique noncardiac surgical procedures in pediatric patients were evaluated, and 741 procedures met inclusion criteria (median [range] age, 7 [1-14] years). Four hundred ninety-eight patients (68%) with a known preoperative hemoglobin level had anemia; of these, 14% had a preexisting diagnosis of anemia in their health record. Median (IQR) pretransfusion hemoglobin concentration was 8.1 (7.4-9.2) g/dL and median (IQR) initial postoperative hemoglobin concentration was 10.4 (9.3-11.6) g/dL. Each decrease of 1 g/dL in the initial postoperative hemoglobin concentration was associated with increased odds of transfusion within the first 24 postoperative hours (odds ratio [95% CI], 1.62 [1.37-1.93]; P < .001). No significant relationships were observed between postoperative hemoglobin concentrations and hospital-free days (P = .56), intensive care unit admission (P = .71), postoperative mechanical ventilation (P = .63), or infectious complications (P = .74). CONCLUSIONS: In transfused patients, there was no association between postoperative hemoglobin values and clinical outcomes, except the need for subsequent transfusion. Most transfused patients presented to the operating room with anemia, which suggests a potential opportunity for perioperative optimization of health before surgery.

Anaemia and red blood cell transfusion in women with placenta accreta spectrum: an analysis of 38,060 cases.

Placenta accreta spectrum (PAS) has become a significant life-threatening issue due to its increased incidence and associated morbidity and mortality. Pregnancy is often associated with states of anaemia, and severe maternal haemorrhage represents a major risk factor for red blood cell (RBC) transfusion. The present study retrospectively analyzed the prevalence of anaemia, transfusion requirements and outcome in women with PAS. Using data from the German Statistical Office pregnant patients with deliveries hospitalized between January 2012 and December 2021 were included. Primary outcome was the prevalence of anemia and administration of RBCs. Secondary outcome were complications in women with PAS who received RBC transfusion. In total 6,493,606 pregnant women were analyzed, of which 38,060 (0.59%) were diagnosed with PAS. The rate of anaemia during pregnancy (60.36 vs. 23.25%; p < 0.0001), postpartum haemorrhage (47.08 vs. 4.41%; p < 0.0001) and RBC transfusion rate (14.68% vs. 0.72%; p < 0.0001) were higher in women with PAS compared to women without PAS. Women with PAS who had bleeding and transfusion experienced significantly more peripartum complications than those who did not. A multiple logistic regression revealed that the probability for RBC transfusion in all pregnant women was positively associated with anaemia (OR 21.96 (95% CI 21.36-22.58)). In women with PAS, RBC transfusion was positively associated with the presence of renal failure (OR 11.27 (95% CI 9.35-13.57)) and congestive heart failure (OR 6.02 (95% CI (5.2-7.07)). Early anaemia management prior to delivery as well as blood conservation strategies are crucial in women diagnosed with PAS.

Haemolytic transfusion reactions caused by non-ABO red cell antibodies reported to the Norwegian Haemovigilance System 2004-2020.

BACKGROUND AND OBJECTIVES: The aim of this study was to analyse the reports received in the Norwegian Haemovigilance System from 2004 to 2020 on acute and delayed haemolytic transfusion reactions caused by non-ABO red cell antibodies. MATERIALS AND METHODS: Antibody specificity, clinical symptoms and outcomes were included when available. RESULTS: After transfusion of 3.7 million red cell concentrates, reports on 78 cases of haemolytic transfusion reactions caused by non-ABO red cell antibodies were received, corresponding to an incidence of 1 in 47,000 transfused red cell concentrates. There were 30 acute and 48 delayed haemolytic transfusion reactions. A total of 113 red cell antibodies were found: 82 alloantibodies, 6 autoantibodies and 25 cases where the antibody specificity could not be determined. Two fatalities occurred: one caused by anti-Wra and one caused by an unidentified red cell antibody. The most frequently reported antibody specificities were those in the Rh and Kidd blood group systems, representing 24% and 14%, respectively, of all the antibodies identified. In six cases, errors occurred, leading to the issuing of blood units without the required phenotype match. CONCLUSIONS: Despite the possible underreporting, the low number of serious haemolytic transfusion reactions reflects an adequate pre-transfusion practice by the Norwegian blood banks.

Current concepts in the use of cell salvage in obstetrics.

PURPOSE OF REVIEW: The worldwide leading cause of maternal death is severe maternal hemorrhage. Maternal hemorrhage can be profound leading to an entire loss of blood volume. In the past two decades, Patient Blood Management has evolved to improve patient's care and safety. In surgeries with increased blood loss exceeding 500 ml, the use of cell salvage is strongly recommended in order to preserve the patient's own blood volume and to minimize the need for allogeneic red blood cell (RBC) transfusion. In this review, recent evidence and controversies of the use of cell salvage in obstetrics are discussed. RECENT FINDINGS: Numerous medical societies as well as national and international guidelines recommend the use of cell salvage during maternal hemorrhage. SUMMARY: Intraoperative cell salvage is a strategy to maintain the patient's own blood volume and decrease the need for allogeneic RBC transfusion. Historically, cell salvage has been avoided in the obstetric population due to concerns of iatrogenic amniotic fluid embolism (AFE) or induction of maternal alloimmunization. However, no definite case of AFE has been reported so far. Cell salvage is strongly recommended and cost-effective in patients with predictably high rates of blood loss and RBC transfusion, such as women with placenta accreta spectrum disorder. However, in order to ensure sufficient practical experience in a multiprofessional obstetric setting, liberal use of cell salvage appears advisable.

Red blood cell transfusion-related dynamics of extracellular vesicles in intensive care patients: a prospective subanalysis.

Extracellular vesicles (EVs) accumulate during packed red blood cell (PRBC) storage. To date, the involvement of EVs in transfusion-related immunomodulation (TRIM) has not been prospectively evaluated in intensive care unit (ICU) patients. This was a prospective subanalysis of a recent observational feasibility study in postoperative ICU patients after: (1) open aortic surgery (Aorta), (2) bilateral lung transplantation (LuTx), and (3) other types of surgery (Comparison). Patient plasma was collected three times each before and after leukoreduced PRBC transfusion at 30-min intervals. The total number of EVs and EVs derived from erythrocytes (EryEVs), total platelets (total PEVs), activated platelets, granulocytes (GEVs), monocytes, and myeloid cells in PRBC samples and patient plasma were analyzed by flow cytometry. Statistical analysis was performed by Spearman's correlation test, linear mixed models and pairwise comparisons by Wilcoxon matched-pairs test. Twenty-three patients (Aorta n = 5, LuTx n = 9, Comparison n = 9) were included in the final analysis. All EV subgroups analyzed were detectable in all PRBCs samples (n = 23), but concentrations did not correlate with storage time. Moreover, all EVs analyzed were detectable in all plasma samples (n = 138), and EV counts were consistent before transfusion. Concentrations of total EVs, EryEVs, total PEVs, and GEVs increased after transfusion compared with baseline in the entire cohort but not in specific study groups. Furthermore, the change in plasma EV counts (total EVs and EryEVs) after transfusion correlated with PRBC storage time in the entire cohort. Extracellular vesicles were detectable in all PRBC and plasma samples. Individual EV subtypes increased after transfusion in the entire cohort, and in part correlated with storage duration. Future clinical studies to investigate the role of EVs in TRIM are warranted and should anticipate a larger sample size.Trial registration: Clinicaltrials.gov: NCT03782623.

Association of initial lactate levels and red blood cell transfusion strategy with outcomes after severe trauma: a post hoc analysis of the RESTRIC trial.

BACKGROUND: The appropriateness of a restrictive transfusion strategy for those with active bleeding after traumatic injury remains uncertain. Given the association between tissue hypoxia and lactate levels, we hypothesized that the optimal transfusion strategy may differ based on lactate levels. This post hoc analysis of the RESTRIC trial sought to investigate the association between transfusion strategies and patient outcomes based on initial lactate levels. METHODS: We performed a post hoc analysis of the RESTRIC trial, a cluster-randomized, crossover, non-inferiority multicenter trials, comparing a restrictive and liberal red blood cell transfusion strategy for adult trauma patients at risk of major bleeding. This was conducted during the initial phase of trauma resuscitation; from emergency department arrival up to 7 days after hospital admission or intensive care unit (ICU) discharge. Patients were grouped by lactate levels at emergency department arrival: low (< 2.5 mmol/L), middle (≥ 2.5 and < 4.0 mmol/L), and high (≥ 4.0 mmol/L). We compared 28 days mortality and ICU-free and ventilator-free days using multiple linear regression among groups. RESULTS: Of the 422 RESTRIC trial participants, 396 were analyzed, with low (n = 131), middle (n = 113), and high (n = 152) lactate. Across all lactate groups, 28 days mortality was similar between strategies. However, in the low lactate group, the restrictive approach correlated with more ICU-free (ß coefficient 3.16; 95% CI 0.45 to 5.86) and ventilator-free days (ß coefficient 2.72; 95% CI 0.18 to 5.26) compared to the liberal strategy. These findings persisted even after excluding patients with severe traumatic brain injury. CONCLUSIONS: Our results suggest that restrictive transfusion strategy might not have a significant impact on 28-day survival rates, regardless of lactate levels. However, the liberal transfusion strategy may lead to shorter ICU- and ventilator-free days for patients with low initial blood lactate levels.