The Iron Status of Very Low Birth Weight Infants Receiving Multiple Erythrocyte Transfusions during Hospitalization in the Neonatal Intensive Care Unit

Hyperferritinemia among very-low-birthweight infants in Thailand: a prospective cohort study

OBJECTIVES

To determine the incidence of hyperferritinemia in VLBW infants, and its association with neonatal morbidity.

STUDY DESIGN

Prospective cohort study in a tertiary-level hospital in Bangkok, from March 2022 to January 2023. Serum ferritin (SF) was measured in VLBW infants at one month and repeated monthly for those with hyperferritinemia (SF > 300 ng/mL).

RESULTS

Gestational age and birth weight were 29.7 ± 2.4 weeks (mean ± SD) and 1100 g (IQR, 830, 1340). Hyperferritinemia was identified in 30.1% (95% CI, 20.8-41.4). After adjustment, only packed red cell transfusion >15 mL/kg was associated with hyperferritinemia (RR 3.1; 95% CI, 1.5-6.4). All elevated SF levels returned to normal within four months. Hyperferritinemia was associated with severe bronchopulmonary dysplasia (RR 2.3, 95% CI, 1.0-5.4) and retinopathy of prematurity (RR 3.5, 95% CI, 1.4-8.6).

CONCLUSION

Hyperferritinemia is common among our VLBW infants, particularly after transfusion, and is associated with severe BPD and ROP.

Transfusion strategies for neonates: current perspectives

Background

Blood transfusion intervention has been proven to be a crucial therapeutic aid for preterm infants with serious morbidities such as sepsis, intraventricular hemorrhage, and cardiopulmonary insufficiencies. However, blood transfusion practices have also been shown to cause significant adverse outcomes, which may negate the therapeutic effect of the intervention. To address the varying policies regarding the administration of blood products, healthcare professionals have adopted a consensus-based approach. The absence of a standard protocol has resulted in conflicting outcomes in previous clinical studies.

Objective

This study aimed to evaluate the effectiveness of blood transfusion practices in preterm infants by analyzing past clinical research and identifying the current trends that have emerged as a result of recent trials.

Results

Recent trials have demonstrated comparable trends in mortality rates and other primary outcomes, including retinopathy of prematurity, intraventricular hemorrhage, bronchopulmonary dysplasia, and brain injury, following transfusion of blood products in both groups. Nevertheless, employing restrictive thresholds rather than adopting a liberal approach can reduce these outcomes.

Conclusion

The current literature does not provide clear support for either technique as opposing and contradictory results are evident. However, there is a slight inclination toward the restrictive transfusion threshold due to recent trials, which warrants further in-depth investigation into this issue.

Association between red blood cell transfusion and bronchopulmonary dysplasia: a systematic review and meta-analysis

Background

We aimed to determine the association between red blood cell transfusions (RBCT) and bronchopulmonary dysplasia (BPD) in neonates.

Methods

A systematic review and meta-analysis were conducted using data obtained from literature search of PubMed, Embase, and Web of Science from their inception till May 1, 2022. Two reviewers independently selected potentially relevant studies, and after data extraction, they assessed the methodological quality of the included studies using the Newcastle-Ottawa scale. Data were pooled using random-effects models in Review Manager 5.3. Subgroup-analysis was performed based on the number of transfusions and adjusted results.

Results

Of the 1,011 identified records, 21 total case-control, cross-sectional, and cohort studies were selected, which included a total of 6,567 healthy controls and 1,476 patients with BPD. The pooled unadjusted odds ratio ([OR], 4.01; 95% confidence interval [CI] 2.31-6.97) and adjusted OR (5.11; 95% CI 3.11-8.4) showed significant association between RBCT and BPD. A substantial heterogeneity was noted, which could be due to different variables controlled for in each study. The subgroup analysis showed that heterogeneity may be partially explained by the extent of transfusion.

Conclusion

The association between BPD and RBCT remains unclear based on the current data due to the substantial heterogeneity among the results. Well-designed studies are still needed in the future.

Optimizing iron supplementation by monitoring serum ferritin levels in premature infants

BACKGROUND

Iron (Fe) is essential for growth, but optimal intake is controversial. Our NICU practice was to supplement 2 mg/kg/d Fe for all preterm infants receiving human milk when they achieved full feeding volume. Adjusting Fe supplementation based on ferritin levels is thought to better address physiologic requirements. Our objective was to assess the impact of therapeutic monitoring of ferritin levels on the initiation and dosing of iron supplementation, hematocrit, transfusions, and oxygen radical diseases in preterm infants.

METHODS

Preterm infants (<  32 weeks gestation, n = 100) were included. Ferritin was measured when full feeds were achieved, and then every 2 weeks. Fe was started at 2 mg/kg/d or continued at current dose for ferritin 40-300μg/L, increased by 1-2 mg/kg/d for <  40μg/L, or discontinued for >  300μg/L. Outcomes were compared with a historical control group.

RESULTS

Ferritin levels were not predictable by dietary or transfusion histories. Using the ferritin protocol, 70% of infants received Fe at the time of full feeds, compared to 100% of controls. In contrast, all infants received Fe 4 weeks later, compared to 87% of controls. Mean age at Fe initiation increased (14.8±6.3 to 21.0±11.76 days). Peak doses were higher, with 32% receiving >  2 mg/kg day by 6 weeks, with fewer transfusions. The incidence of bronchopulmonary dysplasia and necrotizing enterocolitis did not change.

CONCLUSION

An iron protocol based on ferritin levels results in later initiation, higher doses, and fewer transfusions, without increasing oxygen radical diseases.

Serum erythroferrone levels during the first month of life in premature infants

OBJECTIVE

To examine erythroferrone (ERFE)-hepcidin iron regulation in premature infants under intensive care at risk of iron metabolic disorders.

STUDY DESIGN

A retrospective cohort recruited 31 infants with a birth weight of <1500 g hospitalized in a tertiary center. Their hematological status was measured at birth and 2 and 4 weeks of life.

RESULTS

ERFE was positively correlated with the reticulocyte hemoglobin content at 2 (r² = 0.2374) and 4 weeks (r² = 0.6005). An assumed negative correlation between ERFE and hepcidin was not determined during the neonatal period. Hepcidin was positively correlated with the leukocyte count (r² = 0.3089) and ferritin (r² = 0.7476) at birth and C-reactive protein (r² = 0.3591) at 2 weeks and negatively correlated with the reticulocyte count (r² = 0.2887) at 4 weeks.

CONCLUSION

The vulnerability of the ERFE-hepcidin pathway within 4 weeks may contribute to iron imbalance in premature infants.

Iron Metabolism and Brain Development in Premature Infants

Iron is important for a remarkable array of essential functions during brain development, and it needs to be provided in adequate amounts, especially to preterm infants. In this review article, we provide an overview of iron metabolism and homeostasis at the cellular level, as well as its regulation at the mRNA translation level, and we emphasize the importance of iron for brain development in fetal and early life in preterm infants. We also review the risk factors for disrupted iron metabolism that lead to high risk of developing iron deficiency and subsequent adverse effects on neurodevelopment in preterm infants. At the other extreme, iron overload, which is usually caused by excess iron supplementation in iron-replete preterm infants, might negatively impact brain development or even induce brain injury. Maintaining the balance of iron during the fetal and neonatal periods is important, and thus iron status should be monitored routinely and evaluated thoroughly during the neonatal period or before discharge of preterm infants so that iron supplementation can be individualized.

Enteral iron supplementation, red blood cell transfusion, and risk of bronchopulmonary dysplasia in very-low-birth-weight infants

BACKGROUND

Enteral iron supplementation and RBC transfusions are routinely administered to very-low-birth-weight (VLBW) infants, although the potential risks of these exposures have not been adequately quantified. This study evaluated the association between the cumulative dose of enteral iron supplementation, total volume of RBCs transfused, and risk of bronchopulmonary dysplasia (BPD) in VLBW infants.

STUDY DESIGN AND METHODS

Retrospective, multicenter observational cohort study in Atlanta, Georgia. Cumulative supplemental enteral iron exposure and total volume of RBCs transfused were measured until the age at assessment of BPD. Multivariable generalized linear models were used to control for confounding, and the reliability of the factors was assessed in 1000 bootstrap models.

RESULTS

A total of 598 VLBW infants were studied. In multivariable analyses, a greater cumulative dose of supplemental enteral iron exposure was associated with an increased risk of BPD (adjusted relative risk per 50-mg increase, 1.07; 95% confidence interval [CI], 1.02-1.11; p = 0.002). Similarly, a greater volume of RBCs transfused was associated with a higher risk of BPD (adjusted relative risk per 20-mL increase, 1.05; 95% CI, 1.02-1.07; p < 0.001). Both factors were reliably associated with BPD (>50%). Volume of RBCs transfused was similar to gestational age in reliability as a risk factor for BPD (present in 100% of models) and was more reliable than mechanical ventilation at 1 week of age.

CONCLUSION

The cumulative dose of supplemental enteral iron exposure and total volume of RBC transfusion are both independently associated with an increased risk of BPD in VLBW infants.

Multiple red blood cell transfusions and iron overload in very low birthweight infants

BACKGROUND AND OBJECTIVES

To estimate the risk of iron overload in very low birthweight (VLBW) infants who receive more than two red blood cell (RBC) transfusions, in comparison with those who receive two or less during their hospital stay.

MATERIALS AND METHODS

Prospective open cohort study in VLBW infants with >2 (exposed) and ≤2 (non-exposed) RBC transfusions. Ferritin, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured at birth and after each RBC transfusion. The incidence of iron overload was determined. Risk factors were analysed using a logistic regression model. RBC transfusion volume correlations with ferritin, ALT and AST were calculated with Spearman's rank correlation coefficient, as well as correlations between ferritin and aminotransferases.

RESULTS

A total of 63 patients were enrolled, 18 of which were exposed and 45 non-exposed. Twelve patients developed severe iron overload, eight exposed (44·5%) vs. four (8·8%) non-exposed (RR: 5, 95% CI: 1·7-14·6). Multivariate analysis showed that the number of transfusions increased the risk of iron overload (OR: 2·07, 95% CI: 1·36-2·14) while a higher one-minute Apgar score was associated with a lower risk (OR: 0·56, 95% CI: 0·32-0·99). Severe iron overload mainly occurred with a transfusion volume higher than 120 ml/kg. There was a positive correlation between ferritin and transfusion (r = 0·53; P < 0·001).

CONCLUSION

There was a higher risk of iron overload in exposed infants in comparison with non-exposed infants. Severe iron overload in VLBW infants may occur with a total transfusion volume >120 ml/kg.

Iron Supplements for Infants at Risk for Iron Deficiency

Professional societies have published recommendations for iron dosing of preterm neonates, but differences exist between guidelines. To help develop standardized guidelines, we performed a 10-year analysis of iron dosing in groups at risk for iron deficiency: IDM (infants of diabetic mothers), SGA (small for gestational age), and VLBW premature neonates (very low birth weight, <1500 g). We analyzed iron dosing after red cell transfusions and erythropoiesis-stimulating agents (ESA). Of IDM, 11.8% received iron in the hospital; 9.8% of SGA and 27.1% of VLBW neonates received iron. Twenty percent of those who received iron had it started by day 14; 63% by 1 month. Supplemental iron was stopped after red cell transfusions in 73% of neonates receiving iron. An ESA was administered to 1677, of which 33% received iron within 3 days. This marked variation indicates that a consistent approach is needed, and using this report and a literature review, we standardized our iron-dosing guidelines.