High-versus low-dose erythropoietin in extremely low birth weight infants. The European Multicenter rhEPO Study Group

Venous and arterial hematologic profiles of very low birth weight infants. European Multicenter rhEPO Study Group

OBJECTIVE

In very low birth weight (VLBW) infants, diagnostic and therapeutic decisions depend on hematologic values. As few data are available, we studied the course during the first 6 weeks of life.

DESIGN

Four prospective longitudinal cohort studies were retrospectively combined assessing hematologic profiles of 562 VLBW infants. For characterization of red blood cells and iron, infants receiving erythropoietin were excluded. For characterization of white blood cells and platelets, infants receiving antibiotics were excluded.

RESULTS

The third (3rd)/median/97th percentiles on day 3 were as follows: hemoglobin: 11.0/15.6/19.8 g/dL; hematocrit: 35/47/60%; red blood cells: 3.2/4.2/5.3 x 10(12)/L; reticulocytes:. 6/7.1/27.8%; platelets: 58/203/430 x 10(9)/L; white blood cells: 3. 6/9.5/38.3 x 10(9)/L; neutrophils:.7/4.7/25.3 x 10(9)/L; ferritin: 27/140/504 ng/mL; iron:.8/7.5/26.7 micromol/L; transferrin saturation: 2.6/22.7/79.8%. Transferrin saturation was <24% in 51%, ferritin concentration <100 ng/mL in 32%, and platelets <150 x 10(9)/L in 29% of this population. The steady decrease of red cell parameters was mitigated by transfusions. Neutrophils decreased steadily, and were <1.75 x 10(9)/L in 35% at 6 weeks.

CONCLUSIONS

Iron indices and platelet counts on day 3 and neutrophil counts at 2 to 6 weeks of age are lower than previously assumed in VLBW infants and lower than in larger prematures.

Prospective randomized trial of early versus late enteral iron supplementation in infants with a birth weight of less than 1301 grams

OBJECTIVES

To examine whether early enteral iron supplementation (EI) would improve serum ferritin as a measure of nutritional iron status at 2 months of age and would prevent definite iron deficiency (ID) in infants with a birth weight of <1301 g.

METHODS

Infants were randomly assigned to receive enteral iron supplementation of 2 to 6 mg/kg/day as soon as enteral feedings of >100 mL/kg/day were tolerated (EI) or at 61 days of life (late enteral iron supplementation [LI]). Nutritional iron status was assessed: 1) at birth, 2) at 61 days of life, 3) when the infants reached a weight of 1.6 times birth weight, and 4) before blood was transfused at a hematocrit of <.25. ID was defined by any one of the following criteria: ferritin, <12 microg/L; transferrin saturation, <17%; or increase of absolute reticulocyte counts by >50% one week after the onset of enteral iron supplementation. Restrictive red cell transfusion guidelines were followed and all transfusions were documented. Erythropoietin was not administered. The primary outcome variables were: 1) ferritin at 61 days and 2) the number of infants with ID.

RESULTS

Ferritin at 61 days was not different between the groups. Infants in the LI group were more often iron-deficient (26/65 vs 10/68) and received more blood transfusions after day 14 of life. No adverse effects of EI were noted.

CONCLUSIONS

EI is feasible and probably safe in infants with birth weight <1301 g. EI may reduce the incidence of ID and the number of late blood transfusions. ID may occur in very low birth weight infants despite early supplementation with iron and should be considered in the case of progressive anemia.preterm infant, iron supplementation, iron deficiency, blood transfusion.

The use of erythropoietin in neonates

Although much information has been accumulated about the clinical use of Epo in preterm infants, many questions remain unanswered. The evolution of clinical practice in the care of extremely ill, preterm infants continues to affect the number of transfusions required during hospitalization. Decreasing phlebotomy losses and instituting standardized transfusion guidelines have both been shown significantly to decrease the transfusion requirements of preterm infants. The administration of Epo likely decreases transfusion need even further; however, the direct impact of each of these actions has not been studied prospectively. It is likely that the combination of instituting rigorous and standardized transfusion guidelines, decreasing phlebotomy losses, and the appropriate use of Epo will have the greatest impact in decreasing transfusion requirements in all preterm and term neonates, regardless of the cause of their anemia.

Factors associated with successful epoetin alfa therapy in premature infants

OBJECTIVE

To determine the impact of two different recombinant human erythropoietin (epoetin alfa) dosing strategies on the number of red blood cell (RBC) transfusions, and explore relationships between specific patient and drug regimen variables with epoetin alfa therapy outcomes.

DESIGN

Retrospective cohort study.

SETTING

Level III university neonatal intensive care unit.

METHODS

Infants who received epoetin alfa therapy three times weekly for more than one week were categorized into two epoetin alfa dosing strategy groups: group A (300-749 units/kg/wk) and group B (750-1200 units/kg/wk). The following patient variables were collected and their relationship to therapy outcomes (corrected reticulocyte count [%], hematocrit [%], and number of RBC transfusions after therapy was started) were evaluated using independent Student's t-test, correlation analysis, and stepwise linear regression: birth weight (kg), gestational age (weeks), postnatal age at therapy onset (days), duration of mechanical ventilation (days), number of RBC transfusions before epoetin alfa therapy, phlebotomy loss (mL/kg), epoetin alfa dosage (units/kg/dose), iron dosage (mg/kg/d), duration of therapy (days), and postconceptional age at therapy discontinuation (weeks).

RESULTS

The charts of 44 patients were reviewed. No significant impact on outcome was attributed to overall dosing strategy (group A vs. group B). Linear regression identified postnatal age at therapy onset as a significant contributor to mean hematocrit (R2 = 2 0.116; p = 0.023) and postconceptional age at therapy discontinuation as a significant contributor to number of transfusions during and after epoetin alfa use (R2 = 0.118; p = 0.022). A significant positive correlation was found between weekly mean epoetin alfa dosage and mean reticulocyte count (r = 0.326; p = 0.046), mean iron dosage and mean reticulocyte count (r = 0.439; p = 0.006), and ventilator days and total number of transfusions (r = 0.606; p < 0.001). A significant negative correlation was found between number of transfusions and reticulocyte count (r = -0.367; p = 0.023).

CONCLUSIONS

Epoetin alfa dosing strategy, as defined in our study, did not significantly affect the number of transfusions. However, postnatal age at therapy initiation, postconceptional age at therapy discontinuation, mean epoetin alfa dosage, and iron dosage correlate with specific outcomes of epoetin alfa therapy in premature infants.

Changing practices of red blood cell transfusions in infants with birth weights less than 1000 g

OBJECTIVE

Extremely low birth weight (ELBW) infants frequently undergo transfusion because they are critically ill, often need artificial ventilation, and have the highest blood sampling loss in relation to their weight. During the last decade our transfusion guidelines were changed 3 times to become more restrictive. We hypothesized that these modifications substantially decreased the number of transfusions in our ELBW infants.

METHODS

We performed a single-center analysis of 256 infants with birth weights from 500 to 999 g who were admitted from 1989 to 1997 and included 3 study periods, each starting with newly modified transfusion guidelines in April 1989, September 1991, and January 1995. We evaluated prospectively recorded clinical data and retrospective chart analysis for transfusion-related information.

RESULTS

The median number of transfusions per infant decreased from 7 in the first period to 2 in the third period, whereas donor exposure decreased from 5 to 1 and blood volume transfused decreased from 131 to 37 mL/kg birth weight (P <.01). The median venous hematocrit measured before transfusion decreased from 43% to 35% in infants who underwent ventilation and from 41% to 31% in spontaneously breathing infants. The median birth weight decreased from 870 to 740 g and the median gestational age from 27 to 25 completed weeks (P <.01). The overall survival rate was 75% and did not change. The incidences of retinopathy, intraventricular hemorrhage, and patent ductus arteriosus remained unchanged.

CONCLUSION

Over this 9-year period with increasingly restrictive transfusion guidelines, the transfusion number decreased by 71% and the donor exposure by 80% in ELBW infants without adverse clinical effects.

HFE gene mutation and transferrin saturation in very low birthweight infants

AIM

To determine if there is an association between high transferrin saturation and the C282Y HFE gene mutation in very low birthweight (VLBW) infants.

METHODS

One hundred and forty three VLBW infants receiving recombinant erythropoietin and 3 to 9 mg/kg/day of enteral iron were studied. Genomic DNA was extracted from filter paper cards. The C282Y mutation was determined by restriction fragment length polymorphism analysis.

RESULTS

Six infants were heterozygous for the mutation; none was homozygous. Ten infants had a transferrin saturation above 80% at least once. No infant was positive for both transferrin saturation above 80% and the mutation.

CONCLUSIONS

The data strongly suggest that there is no association between high transferrin saturation and the HFE gene mutation in VLBW infants during the first weeks of life.

[Recombinant human erythropoietin in premature infants. Evaluation of a one year experience]

Recently, recombinant human erythropoietin (rhEPO) has been claimed to diminish red blood cell transfusions in premature infants. After a year of experience, we investigated whether early rhEPO treatment would reduce the need for transfusion.

PATIENTS AND METHODS

Fifty premature infants of gestational age < or = 32 weeks admitted to our NICU in 1997, received rhEPO 750 UI/kg/week from day 3 to 5 for six weeks. They were compared with 50 untreated controls admitted in 1996.

RESULTS

The treatment and control groups did not differ for gestational age, weight at birth, CRIB score, and blood losses. We were not able to detect any difference in the number of transfused infants, and in the number of transfusions per infant until discharge. However, treated infants received significantly fewer transfusions per infant between day 16 and day 45 (0.42 +/- 0.67 vs. 0.8 +/- 0.99). Infants with a birth weight between 1,000-1,250 g received fewer transfusions in the EPO group.

CONCLUSION

rhEPO treatment can be useful, but in association with other procedures: conservative transfusion criteria, minimization of phlebotomy losses and early iron supplementation.

Hematopoietic growth factor levels in term and preterm infants

The problems of immunologic adaptation during the transitional period from intra- to extrauterine life are responsible for the physiologic immaturity of the immune function in newborn infants. In preterm neonates the immunodeficiency is more severe and prolonged and is associated with a higher incidence of infections and sepsis. Furthermore, due to immaturity of the hematologic system, anemia, thrombocytopenia, and neutropenia are frequently observed in very low birth weight infants. The dysregulation of cytokine and hematopoietic growth factor synthesis is an important contributory factor to the complex deficiency of immunologic and hematologic function in the neonate and may explain the reduced incidence of acute graft-versus-host disease observed after cord blood transplantation in children. Human milk is a rich source of most of the cytokines that are reduced in the neonate. Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and erythropoietin are currently under evaluation in newborn infants with septic neutropenia or anemia of prematurity.

Erythropoietin to prevent and treat the anemia of prematurity

Human recombinant erythropoietin was first cloned in 1985, and is currently available for clinical use for a variety of anemias. Following successful clinical trials using erythropoietin to treat adults with the anemia of end-stage renal disease, the first clinical trial evaluating the use of erythropoietin in preterm infants to treat anemia was published in 1990. Since that initial report, numerous clinical trials have reported various levels of success in the treatment of this anemia. Most recently, erythropoietin has been used in the first weeks of life in an attempt to prevent the anemia of prematurity. This review describes mechanisms of erythropoiesis in the fetus and neonate, and focuses on recent clinical trials evaluating the use of erythropoietin to prevent and treat anemia in preterm infants.