Clinical Practice Guideline for Red Blood Cell Transfusion Thresholds in Very Preterm Neonates.

Importance: Red blood cell (RBC) transfusion is a common medical intervention to treat anemia in very preterm neonates; however, best transfusion practices, such as thresholds, remain uncertain. Objective: To develop recommendations for clinicians on the use of RBC transfusions in very preterm neonates. Evidence Review: An international steering committee reviewed evidence from a systematic review of 6 randomized clinical trials (RCTs) that compared high vs low hemoglobin-based or hematocrit-based transfusion thresholds. The steering committee reached consensus on certainty-of-evidence ratings and worked with a panel from stakeholder organizations on reviewing the evidence. With input from parent representatives and the stakeholder panel, the steering committee used the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach to develop recommendations. Findings: A systematic review of 6 RCTs encompassing 3483 participants (1759 females [51.3%]; mean [SD] age range, 25.9-29.8 [1.5-3.0] weeks) was used as the basis of the recommendations. The ranges for higher hemoglobin concentration (liberal) vs lower hemoglobin concentration (restrictive) threshold study arms were similar across the trials. However, specific thresholds differed based on the severity of illness, which was defined using variable criteria in the trials. There was moderate certainty of evidence that low transfusion thresholds likely had little to no difference in important short-term and long-term outcomes. The recommended hemoglobin thresholds varied on the basis of postnatal week and respiratory support needs. At postnatal weeks 1, 2, and 3 or more, for neonates on respiratory support, the recommended thresholds were 11, 10, and 9 g/dL, respectively; for neonates on no or minimal respiratory support, the recommended thresholds were 10, 8.5, and 7 g/dL, respectively (to convert hemoglobin to grams per liter, multiply by 10.0). Conclusions and Relevance: This consensus statement recommends a restrictive RBC transfusion strategy, with moderate certainty of evidence, for preterm neonates with less than 30 weeks' gestation.

Infantile pyknocytosis, a neonatal hemolytic anemia with Heinz bodies: A cohort study.

Infantile pyknocytosis (IP) is a rare, probably misestimated, cause of non-immune neonatal hemolytic anemia evolving in two phases: an initial phase with severe jaundice, followed by a second phase with hemolytic anemia, which may require neonatal intensive care. The diagnosis of IP is based on the transient presence on blood smear of hyperdense, contracted, and/or spiculated red blood cells (pyknocytes), associated with the spontaneous resolution of clinico-biological features and the exclusion of other causes. If the etiology remains undetermined, some contributing factors, such as oxidative stress, have been proposed. We report the description of 16 patients with IP aiming at clarifying the circumstances associated with the development of this acquired disorder. In the acute phase, the mean hemoglobin nadir and pyknocyte count were 7.8 g/dL and 11%, respectively, and strikingly, Heinz bodies were evident in 50% of the newborns, but in 100% after prolonged incubation (4 hours). A high proportion of Mediterranean or African ancestry was noted in newborns, as well as a significant number of peripartum events, such as respiratory distress. If the etiology of IP is certainly multifactorial, our series reinforces the role of oxidative stress, which may, at least in part, find origin in desaturation episodes in newborns.

Efficacy of recombinant erythropoietin for the late treatment of anemia of prematurity in a level IV neonatal intensive care unit: a retrospective single-center cohort study.

OBJECTIVE: To describe the population to which we administered recombinant erythropoietin and to determine the effectiveness of this treatment as quantified by the change in hematocrit. STUDY DESIGN: This retrospective chart review study included infants who received erythropoietin for the treatment of anemia of prematurity. RESULTS: There were 132 infants representing 162 unique treatment courses included in the study. The average duration of therapy was 9 days (±7) and 6 doses (±2). The average change in hematocrit (Hct) was 6.2% (SD 3.9%, p < 0.001). Rise in Hct was associated with a higher number of rEPO doses (p < 0.001) and higher postmenstrual age (p < 0.001). In our small cohort we did not find an association between the number of rEPO doses and retinopathy of prematurity (ROP) requiring treatment. CONCLUSION: Erythropoietin is safe and effective at treating anemia of prematurity as evidenced by a clinically and statistically significant increase in Hct from baseline.

A Comprehensive Approach to Neonatal Peripheral Blood Findings of Preterm and Full-term Infants: an Updated Review.

BACKGROUND: Peripheral blood film morphology in neonates is significantly different from the adults as neonatal erythrocytes show a marked heterogeneity. Moreover, there seem to be a more significant numbers of irregular shaped red blood cells such as stomatocytes, keratocytes, schistocytes, and acantocytes in newborns, particularly in preterm infants. This review study focused on the red blood cell morphology in term and preterm neonates to detect clues to distinguish between the peripheral blood film of newborns under physiological and pathological conditions. METHODS: The peripheral blood findings and blood cell counts in preterm and term neonates were studied and compared to each other using available scientific databases and indexing systems such as PubMed and Google Scholar. RESULTS: This approach is a simple, cost-effective, quick, and informative method to distinguish between physiological and pathological conditions in neonates and detect hematological disorders. CONCLUSIONS: Peripheral blood film plays a crucial role in diagnosing anemia and blood-related diseases, determining the type of anemia, and identifying specific morphological abnormalities of red cell membrane disorders.

Evaluation of the impact of diagnostic blood loss and red blood cell transfusion in very-low-birth-weight anaemic neonates during hospitalization: A multi-centre retrospective clinical study.

BACKGROUND AND OBJECTIVES: Diagnostic blood loss is a significant factor in the development of anaemia in neonates with very low birth weight. This study aimed to assess the clinical efficacy of intervention approaches involving varying diagnostic blood loss and red blood cell transfusion volumes in neonates with very low birth weights experiencing anaemia during hospitalization. MATERIALS AND METHODS: A total of 785 newborns with anaemia weighing less than 1500 g were enrolled from 32 hospitals in China. The study involved monitoring diagnostic blood loss and red blood cell transfusion and evaluating relevant interventions such as red blood cell transfusion and clinical outcomes. Three intervention approaches were established based on the difference between blood loss and transfusion (Intervention Approaches 0, 1 and 2). The primary outcomes measured were unsatisfactory weight gain during hospitalization and neonatal mortality. The secondary outcomes included related complications. RESULTS: In the non-hospital-acquired anaemia group, Intervention Approach 2 had the highest incidence of below-normal weight gain (odds ratio [OR]: 3.019, 95% confidence interval [CI]: 1.081-8.431, p = 0.035). Multivariate analysis revealed that Intervention Approach 1 had a protective effect on weight gain. In the hospital-acquired anaemia group, Intervention Approach 2 had the highest incidence of below-normal weight gain (OR: 3.335, 95% CI: 1.785-6.234, p = 0.000) and mortality (OR: 5.341, 95% CI: 2.449-11.645, p = 0.000), while Intervention Approach 1 had the lowest incidence of intraventricular haemorrhage. Intervention Approach 1 demonstrated favourable outcomes in both anaemia groups. CONCLUSION: Intervention Approach 1 improved weight gain and reduced mortality and complications in both the non-hospital-acquired and hospital-acquired anaemia groups.

Erythrokinetic mechanism(s) causing the "late anemia" of hemolytic disease of the fetus and newborn.

A transfusion-requiring "late anemia" can complicate the management of neonates convalescing from hemolytic disease of the fetus and newborn (HDFN). This anemia can occur in any neonate after HDFN but is particularly prominent in those who received intrauterine transfusions and/or double-volume exchange transfusions. Various reports describe this condition as occurring based on ongoing hemolysis, either due to passive transfer of alloantibody through breast milk or persistence of antibody not removed by exchange transfusion. However, other reports describe this condition as the result of inadequate erythrocyte production. Both hypotheses might have merit, because perhaps; (1) some cases are primarily due to continued hemolysis, (2) others are primarily hypoproductive, and (3) yet others result from a mixture of these two mechanisms. We propose prospective collaborative studies that will resolve this issue by serially quantifying end-tidal carbon monoxide. Doing this will better inform the assessment and treatment of neonates recovering from HDFN.

Frequency of red blood cell transfusions in preterm neonates in Brazil: A systematic review and meta-analysis.

BACKGROUND AND OBJECTIVES: Red blood cell transfusions are frequent in preterm neonates. The proportion of preterm neonates transfused in Brazil remains unknown. We systematically reviewed the literature to estimate the frequency of red blood cell transfusions in preterm neonates in Brazil. MATERIALS AND METHODS: The LILACS, EMBASE, Cochrane, SciELO, MEDLINE (PubMed), Web of Science, Scopus, BDTD and 27 national university institutional databases were searched for studies that analysed red blood cell transfusion in preterm neonates in Brazil without period restriction. The Preferred Reporting Items in Systematic Reviews and Meta-Analyses guidelines were followed, and the GRADE methodology was applied. A random-effects model along with the restricted maximum likelihood method was used, and the Freeman-Tukey transformed proportion was used to estimate effect size. RESULTS: Nine studies, representing 6548 preterm neonates, were included in the qualitative and quantitative analyses. The mean gestational age ranged from 26.0 to 31.6 weeks. Most of the studies were from the Southeast region. The pooled estimated frequency of red blood cell transfusions was 58.0% (95% confidence interval = 52.0%-64.0%, p < 0.001) with low certainty. There was statistically significant heterogeneity among studies (I2 = 92.5%, p < 0.001). CONCLUSION: In this current meta-analysis of the evidence available, which included moderate and extremely preterm neonates, the observed frequency of red blood cell transfusions in preterm neonates in Brazil was 58.0% and this estimate can help health programming. Some Brazilian regions were not included in this study, and further research is needed to provide a more representative overview of Brazil.

Associations of High-Sensitive Cardiac Troponin T in Healthy Newborns and Prolonged Second Stage of Labor, Neonatal and Maternal Factors: A Prospective Study.

INTRODUCTION: High-sensitivity cardiac troponin T (hs-cTnT) is not used routinely as a diagnostic biomarker in newborns. The high precision of hs-cTnT assays increases the ability to determine small differences in cTnT over time and to detect troponin T elevation; thus, we believe that hs-cTnT assays might improve clinical care. We explored the plausible association between hs-cTnT levels (ng/L) in healthy newborns and prolonged second stage of labor, neonatal, and maternal factors. METHODS: A prospective study was performed among healthy newborns in the Obstetrics and Gynecology Department at Hillel Yaffe Medical Center in Israel in January-June 2021. The sociodemographic characteristics of the participants, maternal age, gravidity, parity, Pitocin use, epidural analgesia, and neonatal anemia were obtained from the electronic medical records. Gestational age was determined by ultrasound biometric measurements. We classified second-stage labor as normal or prolonged using the WHO guidelines. Samples from umbilical cord blood were drawn using syringes rinsed with anticoagulant by a specialist in pediatrics. The remaining blood was used to determine hs-cTnT levels (ng/L), which was defined as a continuous quantitative variable with the median value and the 25th-75th percentiles. RESULTS: Overall, 184 cord blood samples were performed from healthy newborns (60.6% males) with a median hs-cTnT of 39.03 (25th-75th percentiles = 30.53-54.09) ng/L. A multivariable linear regression model showed no significant association between neonatal anemia and hs-cTnT levels (ng/L) (p = 0.8). Gestational age (B coefficient -4.24, p < 0.001) and gravidity (B coefficient -2.41, p = 0.03) were negatively associated with hs-cTnT levels (ng/L), while Pitocin use (B coefficient 6.91, p = 0.04) and prolonged second stage of labor (B coefficient 18.07, p = 0.02) were positively associated with hs-cTnT levels (ng/L). CONCLUSIONS: High hs-cTnT levels (ng/L) were documented in the cord blood of healthy newborns. Hs-cTnT levels were positively correlated with a prolonged second stage of labor and Pitocin use and negatively correlated with longer gestational age and higher gravidity. Hs-cTnT may signify labor-related fetal distress. A larger surveillance study is mandatory to establish this correlation and assess for possible prognostic significance of elevated hs-cTnT in this context.

Blood Donor Sex and Outcomes in Transfused Infants.

Red blood cell transfusion is common in neonatal intensive care. Multiple trials have evaluated different thresholds for when to administer red blood cell transfusion. In contrast, there has been less focus on studies of the characteristics of red blood cells transfused into neonates. In this review, the authors summarize the emerging literature on the potential impact of the sex of blood donors on outcomes in transfused neonates using a systematic search strategy. The authors review the uncertainty generated from studies with conflicting findings and discuss considerations regarding the impact of blood donor sex and other characteristics on neonatal outcomes.

Anemia, Iron Supplementation, and the Brain.

The developing brain is particularly vulnerable to extrinsic environmental events such as anemia and iron deficiency during periods of rapid development. Studies of infants with postnatal iron deficiency and iron deficiency anemia clearly demonstrated negative effects on short-term and long-term brain development and function. Randomized interventional trials studied erythropoiesis-stimulating agents and hemoglobin-based red blood cell transfusion thresholds to determine how they affect preterm infant neurodevelopment. Studies of red blood cell transfusion components are limited in preterm neonates. A biomarker strategy measuring brain iron status and health in the preanemic period is desirable to evaluate treatment options and brain response.

Erythrocyte transfusions are associated with retinopathy of prematurity in extremely low gestational age newborns.

AIM: Retinopathy of prematurity (ROP) is a major morbidity in preterm infants causing visual impairment including blindness. Prevention and timely treatment are critical. We investigated the potential role of red blood cell (RBC) transfusions as risk factor for ROP development. METHODS: Retrospective cohort study of data from 68 tertiary level neonatal intensive care units in Germany. Preterm infants born at 22 + 0 to 28 + 6 weeks of gestation between January 2009 and December 2021 were enrolled. RESULTS: We included n = 12 565 infants. Prevalence of any ROP was 49.2% with most infants being diagnosed with stage 1 (21.5%) and 2 disease (17.2%). ROP stage 3 was present in 10.2%, stage 4 in 0.3%, and ROP requiring treatment in 6.6%. Infants with ROP had significantly more frequently a history of RBC transfusions. Adjusting for confounders, RBC transfusions were associated with increased odds of ROP (OR 1.4, p < 0.001), ROP progression (OR 2.1, p < 0.01) and ROP requiring treatment (OR 3.6, p < 0.001). Restrictive transfusion approaches correlated with decreased (OR 0.7, p < 0.001), liberal regimes with increased odds (OR 1.2, p = 0.001). CONCLUSION: The present study confirmed an association of RBC transfusions and ROP. Our findings emphasise the need for anaemia prevention and critical re-evaluation of transfusion practices in preterm infants.

Trial-related blood sampling and red blood cell transfusions in preterm infants.

AIM: To determine if trial-related blood sampling increases the risk of later red blood cell (RBC) transfusion in very preterm infants, we compared the volume of clinical- and trial-related blood samples, in a specific trial and correlated to subsequent RBC transfusion. METHODS: For 193 very preterm infants, participating in the FortiColos trial (NCT03537365), trial-related blood volume drawn was in accordance with ethical considerations established by the European Commission. Medical records were reviewed to assess the number and accumulated volume (mL/kg) of blood samples (both clinical- and trial-related). Data were compared with the need of RBC transfusions during the first 28 days of life. RESULTS: Mean (SD) gestational age and birth weight was 28 ± 1 weeks and 1168 ± 301 g. In total, 11% of total blood volume was drawn for sampling (8.1 ± 5.1 mL/kg) and trial-related sampling accounted for 1.6 ± 0.6 mL/kg. Trial-related blood sampling had no impact on RBC transfusion (p = 0.9). CONCLUSION: Clinical blood sampling in very preterm infants is associated with blood loss and subsequent need for RBC transfusions. In a specific trial requiring blood samples, we found no additional burden of trial-related blood sampling. The study suggests that trial-related sampling is safe if European criteria are followed.

Effect of Early Erythropoietin on Retinopathy of Prematurity: A Stratified Meta-Analysis.

BACKGROUND: Recombinant human erythropoietin (rhEPO) lost its role in minimizing red blood cell transfusion in very preterm infants after it had been associated with severe retinopathy of prematurity (ROP). Previous systematic reviews did not stratify ROP by gestation and birth weight (BW). OBJECTIVES: The aim of this study was to investigate the effect of early prophylactic rhEPO on ROP in a stratified meta-analysis of randomized controlled trials (RCTs). METHODS: The databases EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials were searched in January 2022 and complemented by citation searching. RCTs comparing early rhEPO treatment with no treatment or placebo were selected if they were published in a peer-reviewed journal and reported ROP outcomes. Previously unpublished data were requested from the study authors to allow stratified analyses by gestational age (GA) and BW. Data were extracted and analyzed using the standard methods of the Cochrane Neonatal Review Group. Pre-specified outcomes were "ROP stage ≥3" (primary outcome) and "any ROP." RESULTS: Fourteen RCTs, comprising 2,040 infants of <29 weeks of GA, were included for meta-analysis. Data syntheses showed no effects of rhEPO on ROP stage ≥3 or on any ROP, neither in infants of <29 weeks GA, nor in infants of <1,000 g BW, nor in any GA strata. The risk ratio (95% confidence interval) for ROP stage ≥3 in infants of <29 weeks of GA was 1.13 (0.84, 1.53), p = 0.41 (quality of evidence: moderate). CONCLUSIONS: The present meta-analysis detected no effects of early rhEPO on ROP in any comparison, but most stratified analyses were limited by low statistical power.

Case Comparison of Preterm Infant Stability During Packed Red Blood Cell Transfusions.

BACKGROUND: Very preterm infants (less than 32 weeks gestational age) experience acute morbidity during their stay in a neonatal intensive care unit. Because of their prematurity and frequent laboratory testing, they experience anemia, requiring correction with packed red blood cell (PRBC) transfusion(s). PRBC transfusions have been linked to neonatal morbidity, such as necrotizing enterocolitis, but never signs and symptoms of physiological stability. OBJECTIVE: The secondary data analysis aimed to examine very preterm infants' physiological stability before, during, and after PRBC transfusions. METHODS: A within-case, mixed-methods design was used in a secondary data analysis for 16 transfusion cases from 13 very preterm infants. RESULTS: The findings showed very preterm infants with physiological variables falling within defined limits based on gestational age during the transfusion. Two contrasting case exemplars will be presented. DISCUSSION: PRBC transfusions are necessary and prevent morbidity in very preterm infants. Observing instability during transfusions and prospectively studying hypothermia, cardiac instability, and thermal gradients is essential to design interventions to decrease morbidity associated with PRBC transfusions.

Red Blood Cell Transfusion Thresholds for Anemia of Prematurity.

Anemia of prematurity affects the majority of preterm infants, particularly extremely low birthweight infants. Anemia of prematurity arises from both innate and iatrogenic causes and results in more than 80% of extremely preterm infants receiving red blood cell transfusions during the first month after birth. Multiple randomized controlled trials were conducted to evaluate the effect of using lower versus higher transfusion thresholds based on hemoglobin levels. These trials showed no difference in the primary outcome of neurodevelopmental impairment at 2 years of age between lower and higher thresholds. However, some uncertainties about transfusion thresholds remain. This review elaborates the following: 1) the etiology, prevention, and treatment of anemia of prematurity with a focus on red blood cell transfusions, 2) the history of randomized controlled trials on the treatment of anemia of prematurity, and 3) limitations of the evidence and remaining questions about thresholds for red blood cell transfusions in preterm infants.

Diagnosing Anemia in Neonates: An Evidence-Based Approach.

It is important for clinicians who render neonatal care to precisely and reproducibly diagnose anemia; however, confusion arises from various definitions. For the simplicity and consistency of detection, we advocate defining neonatal anemia as a hemoglobin level or hematocrit below the 5th percentile of the reference population, which is highly dependent on gestational and postnatal ages. Thus, a newborn infant delivered at 24 weeks' gestation will have anemia with a blood hemoglobin concentration much lower than a hemoglobin concentration defining anemia at term. Moreover, a hemoglobin concentration defining anemia at term birth is higher than that defining anemia in the same infant 60 days after birth. Diagnosing neonatal anemia can be evidence-based and consistent by using reference intervals derived from large neonatal databases. To do this, we advocate defining anemia as a hemoglobin level that plots below the 5th percentile lower reference interval, defining moderately severe anemia as a hemoglobin value between the 1st and 5th percentile, and defining severe anemia as a hemoglobin level that plots below the 1st percentile. The information provided in this review can easily be adopted by clinical laboratories and individual neonatal care units, thereby fostering application of these definitions for all infants whose hemoglobin levels are measured. Additional normative values included in this review describing various other erythrocyte metrics can likewise be easily adopted. Doing so will codify and standardize the diagnosis of neonatal anemia and will facilitate identifying the cause of the anemia, thus pointing the way to proper additional diagnostic testing and treatment.

Risk factors for anemia of prematurity among 30-35-week preterm infants.

BACKGROUND: The risk factors for anemia of prematurity (AOP) among late preterm infants are unelucidated. We identified risk factors for declining hemoglobin (Hb) concentration and triggering factors for AOP treatment in infants born at 30-35 gestational weeks. METHODS: From 2012 to 2020, we conducted a single-center retrospective study of infants born at 30-35 weeks of gestation without congenital anomalies or severe hemorrhage. The primary outcome was AOP development, defined by initiation of treatments including red blood cell transfusion, subcutaneous injections of erythropoietin, and iron supplementation. A multivariable logistic regression model was used to investigate potential risk factors for AOP. RESULTS: A total of 358 infants were included. Lower gestational age (odds ratio, 0.19; 95% confidence interval 0.11-0.32), small for gestational age (SGA; 7.17, 2.15-23.9), low maternal Hb level before birth (0.66, 0.49-0.87), low Hb at birth (0.71, 0.57-0.89), and multiple large blood samplings (1.79; 1.40-2.29) showed significantly higher odds for AOP development. CONCLUSIONS: Gestational age, SGA, low maternal Hb before birth, Hb at birth, and high number of large blood samplings were positively associated with AOP development in infants born at 30-35 gestational weeks.

Placental abruption and neonatal anemia.

OBJECTIVE: Placental abruption can cause maternal blood loss and maternal anemia. It is less certain whether abruption can cause fetal blood loss and neonatal anemia. STUDY DESIGN: Retrospective multi-hospital 24-month analysis of women with placental abruption and their neonates. RESULTS: Of 55,111 births, 678 (1.2%) had confirmed abruption; 83% of these neonates (564) had one or more hemoglobins recorded in the first day. Four-hundred-seventy (83.3%) had a normal hemoglobin (≥5th% reference interval) while 94 (16.7%) had anemia, relative risk 3.26 (95% CI, 2.66-4.01) vs. >360,000 neonates from previous reference interval reports. The relative risk of severe anemia (<1st% interval) was 4.96 (3.44-7.16). When the obstetrician identified the abruption as "small" or "marginal" the risk of anemia was insignificant. CONCLUSIONS: Most abruptions do not cause neonatal anemia but approximately 16% do. If an abruption is not documented as small, it is important to surveille the neonate for anemia.

Neonatal Anemia.

All neonates experience a downtrend in their hematocrit values immediately following the birth through normal falls in erythropoietin (Epo) production, transition to adult hemoglobin, and hemodilution with somatic growth. However, this drop is more pronounced in critically ill and preterm neonates and can lead to potentially pathologic anemia that impairs tissue oxygen delivery. In this review, we highlight the mechanisms underlying physiologic anemia and anemia of prematurity and briefly review the evidence for the treatment of anemia in the neonatal population, including the use of red blood cell transfusions, erythropoietic stimulating agents, and iron supplementation.