Recombinant erythropoietin and blood transfusion in selected preterm infants

Thresholds for blood transfusion in extremely preterm infants: A review of the latest evidence from two large clinical trials

There are two recently completed large randomized clinical trials of blood transfusions in the preterm infants most at risk of requiring them. Liberal and restrictive strategies were compared with composite primary outcome measures of death and neurodevelopmental impairment. Infants managed under restrictive guidelines fared no worse in regard to mortality and neurodevelopment in early life. The studies had remarkably similar demographics and used similar transfusion guidelines. In both, there were fewer transfusions in the restrictive arm. Nevertheless, there were large differences between the studies in regard to transfusion exposure with almost 3 times the number of transfusions per participant in the transfusion of prematures (TOP) study. Associated with this, there were differences between the studies in various outcomes. For example, the combined primary outcome of death or neurodevelopmental impairment was more likely to occur in the TOP study and the mortality rate itself was considerably higher. Whilst the reasons for these differences are likely multifactorial, it does raise the question as to whether they could be related to the transfusions themselves? Clearly, every effort should be made to reduce exposure to transfusions and this was more successful in the Effects of Transfusion Thresholds on Neurocognitive Outcomes (ETTNO) study. In this review, we look at factors which may explain these transfusion differences and the differences in outcomes, in particular neurodevelopment at age 2 years. In choosing which guidelines to follow, centers using liberal guidelines should be encouraged to adopt more restrictive ones. However, should centers with more restrictive guidelines change to ones similar to those in the studies? The evidence for this is less compelling, particularly given the wide range of transfusion exposure between studies. Individual centers already using restrictive guidelines should assess the validity of the findings in light of their own transfusion experience. In addition, it should be remembered that the study guidelines were pragmatic and acceptable to a large number of centers. The major focus in these guidelines was on hemoglobin levels which do not necessarily reflect tissue oxygenation. Other factors such as the level of erythropoiesis should also be taken into account before deciding whether to transfuse.

High Prevalence of Iron Deficiency Despite Standardized High-Dose Iron Supplementation During Recombinant Erythropoietin Therapy in Extremely Low Gestational Age Newborns

OBJECTIVE

To assess the effects of protocolized recombinant human erythropoietin (r-HuEPO) therapy and standardized high dose iron supplementation on hematologic and iron status measures in a cohort of extremely low gestational age newborns (ELGANs).

STUDY DESIGN

Charts of extremely low gestational age newborns admitted from 2006 to 2016 and who had received r-HuEPO per neonatal intensive care unit protocol were reviewed. The r-HuEPO was started at a dose of 900 IU/kg per week after 7 days of age and continued until 35 weeks postmenstrual age. Oral iron supplementation at 6-12 mg/kg per day was used to maintain a transferrin saturation of >20% during r-HuEPO treatment. Data on demographic features, hematologic and iron panel indices, red blood cell transfusions, and clinical outcomes were collected. Quartile groups were created based on serum ferritin levels at the conclusion of the r-HuEPO treatment and the quartiles were compared.

RESULTS

The cohort included 116 infants with mean gestational age 25.8 ± 1.5 weeks and birth weight 793 ± 174.1 g. The r-HuEPO promoted erythropoiesis as indicated by increasing hemoglobin, hematocrit, and reticulocyte count. Serum ferritin decreased over time and was ≤75 ng/mL in 60.2% of infants at the conclusion of r-HuEPO therapy; 87% received packed red blood cell transfusions. Transfusion volume, total iron intake, total iron binding capacity, and transferrin concentration differed among infants in the different serum ferritin quartiles (P < .05).

CONCLUSIONS

In extremely low gestational age newborns, r-HuEPO therapy promoted erythropoiesis. Despite a biomarker-based standardized high-dose iron supplementation, the majority of infants had evidence of iron deficiency to a degree that is associated with reduced brain function.

Early erythropoiesis-stimulating agents in preterm or low birth weight infants

BACKGROUND

Preterm infants have low plasma levels of erythropoietin (EPO), providing a rationale for the use of erythropoiesis-stimulating agents (ESAs) to prevent or treat anaemia and to provide neuro protection and protection against necrotising enterocolitis (NEC). Darbepoetin (Darbe) and EPO are currently available ESAs.

OBJECTIVES

To assess the effectiveness and safety of ESAs (erythropoietin (EPO) and/or Darbe) initiated early (before eight days after birth) compared with placebo or no intervention in reducing red blood cell (RBC) transfusions, adverse neurological outcomes, and feeding intolerance including necrotising enterocolitis (NEC) in preterm and/or low birth weight infants. Primary objective for studies that primarily investigate the effectiveness and safety of ESAs administered early in reducing red blood cell transfusions: To assess the effectiveness and safety of ESAs initiated early in reducing red blood cell transfusions in preterm infants. Secondary objectives: Review authors performed subgroup analyses of low (≤ 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO and the amount of iron supplementation provided: none, low (≤ 5 mg/kg/d), and high (> 5 mg/kg/d). Primary objective for studies that primarily investigate the neuro protective effectiveness of ESAs: To assess the effectiveness and safety of ESAs initiated early in reducing adverse neurological outcomes in preterm infants. Primary objective for studies that primarily investigate the effectiveness of EPO or Darbe administered early in reducing feeding intolerance: To assess the effectiveness and safety of ESAs administered early in reducing feeding intolerance (and NEC) in preterm infants. Other secondary objectives: To compare the effectiveness of ESAs in reducing the incidence of adverse events and improving long-term neurodevelopmental outcomes.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), MEDLINE via PubMed (1966 to 10 March 2017), Embase (1980 to 10 March 2017), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 10 March 2017). We searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised and quasi-randomised controlled trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of early initiation of EAS treatment versus placebo or no intervention in preterm or low birth weight infants.

DATA COLLECTION AND ANALYSIS

We used the methods described in the Cochrane Handbook for Systematic Reviews of Interventions and the GRADE approach to assess the quality of evidence.

MAIN RESULTS

This updated review includes 34 studies enrolling 3643 infants. All analyses compared ESAs versus a control consisting of placebo or no treatment. Early ESAs reduced the risk of 'use of one or more [red blood cell] RBC transfusions' (typical risk ratio (RR) 0.79, 95% confidence interval (CI) 0.74 to 0.85; typical risk difference (RD) -0.14, 95% CI -0.18 to -0.10; I² = 69% for RR and 62% for RD (moderate heterogeneity); number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 6 to 10; 19 studies, 1750 infants). The quality of the evidence was low. Necrotising enterocolitis was significantly reduced in the ESA group compared with the placebo group (typical RR 0.69, 95% CI 0.52 to 0.91; typical RD -0.03, 95% CI -0.05 to -0.01; I² = 0% for RR and 22% for RD (low heterogeneity); NNTB 33, 95% CI 20 to 100; 15 studies, 2639 infants). The quality of the evidence was moderate. Data show a reduction in 'Any neurodevelopmental impairment at 18 to 22 months' corrected age in the ESA group (typical RR 0.62, 95% CI 0.48 to 0.80; typical RD -0.08, 95% CI -0.12 to -0.04; NNTB 13, 95% CI 8 to 25. I² = 76% for RR (high heterogeneity) and 66% for RD (moderate); 4 studies, 1130 infants). The quality of the evidence was low. Results reveal increased scores on the Bayley-II Mental Development Index (MDI) at 18 to 24 months in the ESA group (weighted mean difference (WMD) 8.22, 95% CI 6.52 to 9.92; I² = 97% (high heterogeneity); 3 studies, 981 children). The quality of the evidence was low. The total volume of RBCs transfused per infant was reduced by 7 mL/kg. The number of RBC transfusions per infant was minimally reduced, but the number of donors to whom infants who were transfused were exposed was not significantly reduced. Data show no significant difference in risk of stage ≥ 3 retinopathy of prematurity (ROP) with early EPO (typical RR 1.24, 95% CI 0.81 to 1.90; typical RD 0.01, 95% CI -0.02 to 0.04; I² = 0% (no heterogeneity) for RR; I² = 34% (low heterogeneity) for RD; 8 studies, 1283 infants). Mortality was not affected, but results show significant reductions in the incidence of intraventricular haemorrhage (IVH) and periventricular leukomalacia (PVL).

AUTHORS' CONCLUSIONS

Early administration of ESAs reduces the use of red blood cell (RBC) transfusions, the volume of RBCs transfused, and donor exposure after study entry. Small reductions are likely to be of limited clinical importance. Donor exposure probably is not avoided, given that all but one study included infants who had received RBC transfusions before trial entry. This update found no significant difference in the rate of ROP (stage ≥ 3) for studies that initiated EPO treatment at less than eight days of age, which has been a topic of concern in earlier versions of this review. Early EPO treatment significantly decreased rates of IVH, PVL, and NEC. Neurodevelopmental outcomes at 18 to 22 months and later varied in published studies. Ongoing research should evaluate current clinical practices that will limit donor exposure. Promising but conflicting results related to the neuro protective effect of early EPO require further study. Very different results from the two largest published trials and high heterogeneity in the analyses indicate that we should wait for the results of two ongoing large trials before drawing firm conclusions. Administration of EPO is not currently recommended because limited benefits have been identified to date. Use of darbepoetin requires further study.

Early erythropoiesis-stimulating agents in preterm or low birth weight infants

BACKGROUND

Preterm infants have low plasma levels of erythropoietin (EPO), providing a rationale for the use of erythropoiesis-stimulating agents (ESAs) to prevent or treat anaemia and to provide neuro protection and protection against necrotising enterocolitis (NEC). Darbepoetin (Darbe) and EPO are currently available ESAs.

OBJECTIVES

To assess the effectiveness and safety of ESAs (erythropoietin (EPO) and/or Darbe) initiated early (before eight days after birth) compared with placebo or no intervention in reducing red blood cell (RBC) transfusions, adverse neurological outcomes, and feeding intolerance including necrotising enterocolitis (NEC) in preterm and/or low birth weight infants. Primary objective for studies that primarily investigate the effectiveness and safety of ESAs administered early in reducing red blood cell transfusions:To assess the effectiveness and safety of ESAs initiated early in reducing red blood cell transfusions in preterm infants. Secondary objectives:Review authors performed subgroup analyses of low (≤ 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO and the amount of iron supplementation provided: none, low (≤ 5 mg/kg/d), and high (> 5 mg/kg/d). Primary objective for studies that primarily investigate the neuro protective effectiveness of ESAs:To assess the effectiveness and safety of ESAs initiated early in reducing adverse neurological outcomes in preterm infants. Primary objective for studies that primarily investigate the effectiveness of EPO or Darbe administered early in reducing feeding intolerance:To assess the effectiveness and safety of ESAs administered early in reducing feeding intolerance (and NEC) in preterm infants. Other secondary objectives:To compare the effectiveness of ESAs in reducing the incidence of adverse events and improving long-term neurodevelopmental outcomes.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 2), MEDLINE via PubMed (1966 to 10 March 2017), Embase (1980 to 10 March 2017), and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 10 March 2017). We searched clinical trials databases, conference proceedings, and reference lists of retrieved articles for randomised and quasi-randomised controlled trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials of early initiation of EAS treatment versus placebo or no intervention in preterm or low birth weight infants.

DATA COLLECTION AND ANALYSIS

We used the methods described in the Cochrane Handbook for Systematic Reviews of Interventions and the GRADE approach to assess the quality of evidence.

MAIN RESULTS

This updated review includes 34 studies enrolling 3643 infants. All analyses compared ESAs versus a control consisting of placebo or no treatment.Early ESAs reduced the risk of 'use of one or more [red blood cell] RBC transfusions' (typical risk ratio (RR) 0.79, 95% confidence interval (CI) 0.74 to 0.85; typical risk difference (RD) -0.14, 95% CI -0.18 to -0.10; I2 = 69% for RR and 62% for RD (moderate heterogeneity); number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 6 to 10; 19 studies, 1750 infants). The quality of the evidence was low.Necrotising enterocolitis was significantly reduced in the ESA group compared with the placebo group (typical RR 0.69, 95% CI 0.52 to 0.91; typical RD -0.03, 95% CI -0.05 to -0.01; I2 = 0% for RR and 22% for RD (low heterogeneity); NNTB 33, 95% CI 20 to 100; 15 studies, 2639 infants). The quality of the evidence was moderate.Data show a reduction in 'Any neurodevelopmental impairment at 18 to 22 months' corrected age in the ESA group (typical RR 0.62, 95% CI 0.48 to 0.80; typical RD -0.08, 95% CI -0.12 to -0.04; NNTB 13, 95% CI 8 to 25. I2 = 76% for RR (high heterogeneity) and 66% for RD (moderate); 4 studies, 1130 infants). The quality of the evidence was low.Results reveal increased scores on the Bayley-II Mental Development Index (MDI) at 18 to 24 months in the ESA group (weighted mean difference (WMD) 8.22, 95% CI 6.52 to 9.92; I2 = 97% (high heterogeneity); 3 studies, 981 children). The quality of the evidence was low.The total volume of RBCs transfused per infant was reduced by 7 mL/kg. The number of RBC transfusions per infant was minimally reduced, but the number of donors to whom infants who were transfused were exposed was not significantly reduced. Data show no significant difference in risk of stage ≥ 3 retinopathy of prematurity (ROP) with early EPO (typical RR 1.24, 95% CI 0.81 to 1.90; typical RD 0.01, 95% CI -0.02 to 0.04; I2 = 0% (no heterogeneity) for RR; I2 = 34% (low heterogeneity) for RD; 8 studies, 1283 infants). Mortality was not affected, but results show significant reductions in the incidence of intraventricular haemorrhage (IVH) and periventricular leukomalacia (PVL).

AUTHORS' CONCLUSIONS

Early administration of ESAs reduces the use of red blood cell (RBC) transfusions, the volume of RBCs transfused, and donor exposure after study entry. Small reductions are likely to be of limited clinical importance. Donor exposure probably is not avoided, given that all but one study included infants who had received RBC transfusions before trial entry. This update found no significant difference in the rate of ROP (stage ≥ 3) for studies that initiated EPO treatment at less than eight days of age, which has been a topic of concern in earlier versions of this review. Early EPO treatment significantly decreased rates of IVH, PVL, and NEC. Neurodevelopmental outcomes at 18 to 22 months and later varied in published studies. Ongoing research should evaluate current clinical practices that will limit donor exposure. Promising but conflicting results related to the neuro protective effect of early EPO require further study. Very different results from the two largest published trials and high heterogeneity in the analyses indicate that we should wait for the results of two ongoing large trials before drawing firm conclusions. Administration of EPO is not currently recommended because limited benefits have been identified to date. Use of darepoetin requires further study.

Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

OBJECTIVES

To assess the effectiveness and safety of early initiation of EPO or darepoetin (initiated before eight days after birth) in reducing red blood cell (RBC) transfusions in preterm and/orlow birth weight infants.

SEARCH METHODS

The Cochrane Library, MEDLINE, EMBASE, CINAHL, reference lists of identified trials and reviews, Pediatric Academic Societies Annual meetings 2000 to 2013 (Abstracts2View(TM)) and clinical trials registries (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp) were searched in July 2013.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of early (< eight days of age) initiation of EPO treatment versus placebo or no intervention in preterm and/or low birth weightinfants.

DATA COLLECTION AND ANALYSIS

The methods of the Neonatal Cochrane Review Group were used.

MAIN RESULTS

The updated review includes 27 studies enrolling 2209 infants. One study enrolling infants at a mean age of > eight days and one duplicate publication were excluded. One new study using darepoetin was identified.Early EPO reduced the risk of the 'use of one or more RBC transfusions' (typical risk ratio (RR) 0.79, 95% confidence interval (CI) 0.73 to 0.85; typical risk difference (RD) -0.14, 95% CI -0.18 to -0.10; I(2) = 54% for both; number needed to treat to benefit (NNTB) 7, 95% CI 6 to 10; 16 studies, 1661 infants).The total volume of RBCs transfused per infant was reduced (typical mean difference (MD) 7 mL/kg, 95% CI -12 to - 2; I(2) = 63%; 7 studies, 581 infants). The number of RBC transfusions per infant was minimally reduced (typical MD -0.27, 95% CI -0.42 to -0.12; I(2) = 64%; 13 studies, 951 infants). The number of donors to whom the infants were exposed was significantly reduced (MD-0.54, 95% CI -0.89 to -0.20; I(2) = 0%; 3 studies, 254 infants).There was a non-significant increase in the risk of stage ≥ 3 retinopathy of prematurity (ROP) with early EPO (typical RR 1.37, 95% CI 0.87 to 2.17; I(2) = 0%; typical RD 0.03, 95% CI -0.01 to 0.06; I(2) = 29%; 7 studies, 801 infants). A post hoc analysis including all studies that reported on ROP stage ≥ 3, regardless of the age of the infant when EPO treatment was started, showed a significantly increased typical RR of 1.48 (95% CI 1.02 to 2.13; P = 0.04; I(2) = 0%) and typical RD of 0.03 (95% CI 0.00 to 0.06; P = 0.03; I(2) = 50%; 10 studies, 1303 infants) with a number needed to treat to harm (NNTH) of 33 (95% CI 17 to infinity). In an Italian study in which the authors compared the use of early intravenous EPO with subcutaneous EPO the overall incidence of stage ≥ 3 was 15%, similar to the incidence of 17% in the study by Romagnoli and co-workers.The rates for mortality and morbidities including intraventricular haemorrhage and necrotizing enterocolitis were not significantly changed by early EPO treatment. Neurodevelopmental outcomes at 18 to 22 months varied.

AUTHORS' CONCLUSIONS

Early administration of EPO reduces the use of RBC transfusions, the volume of RBCs transfused, and donor exposure after study entry. The small reductions are likely to be of limited clinical importance. Donor exposure is probably not avoided since all but one study included infants who had received RBC transfusions prior to trial entry. In this update there was no significant increase in the rate of ROP (stage ≥ 3) for studies that initiated EPO treatment at less than eight days of age. In a post hoc analysis including all studies that reported on ROP stage ≥ 3 regardless of age at initiation of treatment there was an increased risk of ROP. The rates for mortality and morbidities including intraventricular haemorrhage and necrotizing enterocolitis were not significantly changed by early EPO treatment. Neurodevelopmental outcomes at 18 to 22 months vary in the studies published to date. Ongoing research should deal with the issue of ROP and evaluate current clinical practice that will limit donor exposure. Due to the limited benefits and the possibly increased risk of ROP, administration of EPO is not recommended. Darbepoetin requires further study. The possible neuroprotective role of EPO in neonates will be reviewed in separate Cochrane reviews.

Risk factors of transfusion in anemia of very low birth weight infants

PURPOSE

Anemia of prematurity is frequent in preterm infants, for which red blood cell (RBC) transfusion remains the treatment of choice. In this study, we attempted to evaluate the characteristics and risk factors of anemia of prematurity, and suggest ways to reduce anemia and the need for multiple transfusions.

MATERIALS AND METHODS

Preterm infants weighing less than 1500 g (May 2008-May 2009) were divided into two groups depending on whether they received RBC transfusions (transfusion group and non transfusion group). Hemoglobin (Hb) concentration, phlebotomy blood loss, and the amount of RBC transfusion were analyzed. Risk factors of anemia and RBC transfusions were analyzed.

RESULTS

Fifty infants that survived were enrolled in the present study: 39 in the transfusion group and 11 in the non transfusion group. Hb concentrations gradually decreased by eight weeks. In the transfusion group, gestational age and birth weight were smaller, bronchopulmonary dysplasia and sepsis were more frequent, full feeding was delayed, parenteral nutrition and days spent in the hospital were prolonged, and phlebotomy blood loss was greater than that in the non transfusion group.

CONCLUSION

Anemia of prematurity was correlated with increased laboratory blood loss, decreased birth weight, prolonged parenteral nutrition, and delayed body weight gain. Accordingly, reducing laboratory phlebotomy loss and parenteral nutrition, as well as improving body weight gain, may be beneficial to infants with anemia of prematurity.

Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anaemia.

OBJECTIVES

To assess the effectiveness and safety of early initiation of EPO in reducing red blood cell (RBC) transfusions in preterm and/or low birth weight infants.

SEARCH METHODS

The Cochrane Central Register of Controlled Trials (The Cochrane Library), MEDLINE, EMBASE, CINAHL, abstracts from scientific meetings published in Pediatric Research and reference lists of identified trials and reviews were searched through July 2009. Searches were repeated in March 2012 including searches of Pediatric Academic Societies Annual meetings 2000 to 2012 (Abstracts2View(TM)) and clinical trials registries (clinicaltrials.gov; controlled-trials.com; and who.int/ictrp).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials of early (< eight days of age) initiation of EPO treatment versus placebo or no intervention in preterm and/or low birth weight neonates.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were accomplished using the methods of the Neonatal Cochrane Review Group.

MAIN RESULTS

The May 2012 update did not identify any new studies for inclusion. A number of randomised controlled trials were excluded as they compared one EPO dosing regimen with another, did not provide the numbers of infants randomised to the EPO and the placebo group, or the dose of EPO was not stated. The update includes 27 studies that enrolled 2293 preterm infants. Early EPO reduced the risk of the "use of one or more RBC transfusions" [typical risk ratio (RR); 0.80 (95% confidence interval (CI) 0.75 to 0.86); typical risk difference (RD) -0.13, (95% CI -0.17 to -0.09); number needed to benefit (NNTB) = eight, (95% CI 6 to 11); 16 studies, 1,825 infants].There was moderate heterogeneity for this outcome [RR (P = 0.004; I(2) = 56.7%); RD (P = 0.003; I(2) = 56.0%)].A total of six studies enrolling 515 infants reported on the total volume of red blood cells transfused per infant. The significant typical mean difference (MD) was a reduction of 6 mL/kg of blood transfused (mL/kg) per infant (95% CI -11 to - 1). There was moderate heterogeneity for this outcome (P = 0.02; I(2) = 63.0%). The results from 14 studies enrolling 1131 infants reported on the number of red blood cell transfusions per infant. The significant typical MD for number of red blood cell transfusions per infant was -0.33, (95% CI -0.48 to -0.18). There was high heterogeneity for this outcome (P = 0.00001, I(2) = 78%). Two studies enrolling 188 infants reported on the number of donors to whom the infant was exposed; the MD was significantly reduced -0.63, (-1.07 to -0.19). There was no heterogeneity for this outcome (P = 0.59; I(2) = 0%).There was a significant increase in the risk of stage ≥ 3 retinopathy of prematurity (ROP) in the early EPO group [typical RR; 1.65, (95% CI 1.12 to 2.43); typical RD; 0.05 (95% CI 0.01 to 0.08); number needed to harm (NNTH); 20, (95% CI 13 to 100); eight studies, 984 infants]. There was no heterogeneity for this outcome for RR (P = 0.87; I(2) = 0%), but there was moderate heterogeneity for RD (P = 0.006; I(2) = 65%). The rates for mortality and other neonatal morbidities were not significantly changed by early EPO treatment nor were neurodevelopmental outcomes at 18 to 22 months in the small number of infants tested to-date.

AUTHORS' CONCLUSIONS

Early administration of EPO reduces the use of RBC transfusions and the volume of RBCs transfused. These small reductions are of limited clinical importance. Donor exposure is probably not avoided since most studies included infants who had received RBC transfusions prior to trial entry. There was a significant increase in the rate of ROP (stage ≥ 3). Early EPO does not significantly decrease or increase any of the other important adverse outcomes. Ongoing research should deal with the issue of ROP and evaluate the current clinical practice that will limit donor exposure. Due to the limited benefits and the increased risk of ROP, early administration of EPO is not recommended. Evidence is lacking for the possible neuro protective role of EPO in preterm infants. This topic will be reviewed in separate Cochrane reviews for preterm and term and late preterm infants.

Erythropoietin in neonatal brain protection: the past, the present and the future

Over the last decade, neuroprotective effects of erythropoietin (Epo) and its underlying mechanisms in terms of signal transduction pathways have been defined and there is a growing interest in the potential therapeutic use of Epo for neuroprotection. Several mechanisms by which Epo provides neuroprotection are recognized. In this review, we focused on the neuroprotective mechanisms of Epo and provide a short overview on both experimental and clinical studies, testing Epo as a neuroprotective agent in the neonatal brain injury, and the safety concerns with the clinical use of Epo treatment in neonates.

Anaemia of prematurity: pathophysiology and treatment

Most infants with birth weight <1.0 kg are given multiple red blood cell (RBC) transfusions within the first few weeks of life. The anaemia of prematurity is caused by untimely birth occurring before placental iron transport and fetal erythropoiesis are complete, by phlebotomy blood losses taken for laboratory testing, by low plasma levels of erythropoietin due to both diminished production and accelerated catabolism, by rapid body growth and need for commensurate increase in red cell volume/mass, and by disorders causing RBC losses due to bleeding and/or hemolysis. RBC transfusions are the mainstay of therapy with recombinant human erythropoietin largely unused because it fails to substantially diminish RBC transfusion needs--despite exerting substantial erythropoietic effects on neonatal marrow.

Erythropoietin for infants with hypoxic-ischemic encephalopathy

PURPOSE OF REVIEW

Perinatal asphyxia, intraventricular hemorrhage and stroke are common causes of neonatal brain injury, with hypoxia-ischemia as the final common pathway of injury. Erythropoietin (Epo) has potential to lessen neurologic sequelae due to hypoxia-ischemia. The purpose of this review is to highlight new clinical trials and experimental evidence that expand our understanding of Epo as a potential treatment for perinatal brain injury.

RECENT FINDINGS

Several trials of Epo treatment are reviewed: two phase I/II trials of high-dose Epo given to preterm infants established pharmacokinetic and safety profiles, and a trial of Epo treatment for term infants with moderate hypoxic-ischemic encephalopathy found reduced disability. Potential risks and benefits of high-dose Epo are discussed. New evidence related to Epo receptor expression, signal transduction pathways, and mechanisms of neuroprotection are reviewed.

SUMMARY

Cautious optimism is warranted regarding the use of high-dose Epo as a treatment option for neonatal brain injury. To date, Epo has been well tolerated to use in neonatal populations and now studies of neuroprotective efficacy are underway.

Anemia in the preterm infant: erythropoietin versus erythrocyte transfusion--it's not that simple

Since the late 1980s recombinant human erythropoietin (r-EPO) has been studied as an alternative to packed red blood cell (RBC) transfusion for the treatment of anemia of prematurity in very low birth weight infants. Initial trials and reports focused on r-EPO's ability to prevent or treat anemia of prematurity with the goal of eliminating RBC transfusion but achieved limited success. New concerns about the safety of r-EPO administration have emerged. Past cost-benefit analyses of r-EPO administration versus transfusion for the treatment of anemia of prematurity have been nearly balanced. Autologous transfusion, blood-sparing technologies, changes in RBC transfusion technique and safety, and further elucidation of the risk-benefit ratio of r-EPO therapy may change the cost-benefit analysis.

Anemia in the preterm infant: erythropoietin versus erythrocyte transfusion--it's not that simple

Since the late 1980s recombinant human erythropoietin (r-EPO) has been studied as an alternative to packed red blood cell (RBC) transfusion for the treatment of anemia of prematurity in very low birth weight infants. Initial trials and reports focused on r-EPO's ability to prevent or treat anemia of prematurity with the goal of eliminating RBC transfusion but achieved limited success. New concerns about the safety of r-EPO administration have emerged. Past cost-benefit analyses of r-EPO administration versus transfusion for the treatment of anemia of prematurity have been nearly balanced. Autologous transfusion, blood-sparing technologies, changes in RBC transfusion technique and safety, and further elucidation of the risk-benefit ratio of r-EPO therapy may change the cost-benefit analysis.

When to transfuse preterm babies

The physiological anaemia experienced by preterm babies is exacerbated by common care practices such as early clamping of the umbilical cord at birth and gradual exsanguination by phlebotomy for laboratory monitoring. The need for subsequent transfusion with red blood cells can be reduced by delaying cord clamping for 30-60 s in infants who do not require immediate resuscitation. The need for transfusions can be further reduced by limiting phlebotomy losses, providing good nutrition, and using standard guidelines for transfusion based on haemoglobin or haematocrit. What those guidelines should be is not clear. Analysis of two recent large clinical trials comparing restrictive and liberal transfusion guidelines leads to several conclusions. Restrictive transfusion guidelines may reduce the number of transfusions given, but there is no reduction in donor exposures if a single-donor transfusion programme is used. There is some evidence that more liberal transfusion guidelines may help to prevent brain injury, but information on the impact of transfusion practice on long-term outcome is lacking. Until further guidance emerges, transfusion thresholds lower than those used in the two trials should not be used, as there is no evidence that lower thresholds are safe.

Effects of erythropoietin on erythrocyte deformability in non-transfused preterm infants

AIM

Suppression of erythropoiesis due to low plasma erythropoietin levels is an important factor in the development of anaemia of prematurity. Premature infants may therefore be treated with recombinant human erythropoietin (rhEPO). This prospective, randomised and controlled study was designed to find out whether rhEPO treatment improves erythrocyte deformability in preterm infants.

METHODS

Sixteen infants were treated with rhEPO (250 IU/kg three times weekly) a total of 15 times beginning on day of life 5 whereas fifteen infants served as controls. Haemoglobin concentration, haematocrit, reticulocyte count, ferritin level and erythrocyte deformability were measured on days 5, 14, 28, 42 and 63. Erythrocyte elongation was determined as an indicator of erythrocyte deformability using a shear stress diffractometer (Rheodyn SSD) at shear forces of 0.3 to 60 Pa.

RESULTS

Haemoglobin concentration was significantly higher on days 28 and 42 and reticulocyte percentage on day 28 in the rhEPO group compared to the controls. Serum ferritin was lower in the rhEPO group on day 28. Erythrocyte deformability was significantly increased on days 28 and 42 in the infants receiving rhEPO. We found a strong relationship between erythrocyte elongation and reticulocyte count.

CONCLUSION

RhEPO markedly increases the erythropoiesis in preterm infants in the critical first weeks of life and the anaemia of prematurity is obviously reduced. The erythrocyte deformability improved under rhEPO treatment. Erythrocyte deformability was significantly related to the reticulocyte count indicating that the improvement of erythrocyte deformability was due to the formation of well-deformable young erythrocytes.

Early erythropoietin for preventing red blood cell transfusion in preterm and/or low birth weight infants

BACKGROUND

Hematocrit falls after birth in preterm infants due to physiological factors and blood letting. Low plasma levels of erythropoietin (EPO) in preterm infants provide a rationale for the use of EPO to prevent or treat anemia.

PRIMARY OBJECTIVE

To assess the effectiveness and safety of early initiation of EPO (initiated before eight days after birth) in reducing red blood cell transfusions in preterm and/or low birth weight infants.

SECONDARY OBJECTIVES

Subgroup analyses of low (< 500 IU/kg/week) and high (> 500 IU/kg/week) doses of EPO and, within these subgroups, analyses of the use of low (< 5 mg/kg/day) and high (> 5 mg/kg/day) doses of supplemental iron, in reducing red blood cell transfusions in these infants.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE, CINAHL, abstracts from scientific meetings published in Pediatric Research and reference lists of identified trials and reviews were searched in November 2005. No language restrictions were applied.

SELECTION CRITERIA

Randomised or quasi-randomized controlled trials of early initiation of EPO treatment (started before 8 days of age) vs. placebo or no intervention in preterm (< 37 weeks) and/or low birth weight (< 2500 g) neonates. For inclusion, the studies needed to provide information on at least one outcome of interest.

DATA COLLECTION AND ANALYSIS

Data were abstracted by the two authors on pre-tested data collection forms. Data were entered by one review author (AO) and checked for accuracy by the other (SA). Data were analysed using RevMan 4.2.8. The statistical methods included 'typical' relative risk (RR), risk difference (RD), number needed to treat to benefit (NNTB) and needed to treat to harm (NNTH) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes reported with their 95% confidence intervals (CI). A fixed effects model was used for meta-analyses. Heterogeneity tests, including the I(-)squared (I(2)) statistic, were performed to assess the appropriateness of pooling the data.

MAIN RESULTS

Twenty-three studies enrolling 2074 preterm infants in 18 countries were included in the review. All studies except one applied transfusion guidelines. The quality of the trials varied. Most trials were of small sample size. Only one study clearly stated that infants were excluded if they had received red blood cell transfusion prior to study entry (Arif 2005). A total of 16 studies, including 1825 infants reported on the primary outcome of "use of one or more red cell transfusions". The summary estimates were significant [typical RR; 0.80 (95% CI 0.75, 0.86); typical RD; -0.13 (95% CI -0.17, -0.09); typical NNTB; 8 (95% CI 6, 11)]. There was statistically significant heterogeneity [for RR (p< 0.004), I(2) = 56.7%; for RD (p = 0.003), I(2 ) = 56.0%]. Similar results were obtained in secondary analyses based on different combinations of high doses of EPO and high and low iron supplementation. There were insufficient data to draw conclusions for low doses EPO in combination with high or low dose of iron. Two studies (n = 188) reported a significant reduction in the number of donors to whom the infant was exposed [typical WMD; -0.63 (95% CI -1.07, -0.19)]. A significant reduction in the total volume (ml/kg) of blood transfused per infant [typical WMD; -6 ml (95% CI -1, -11)] and in the number of transfusions per infant [typical WMD -0.27 (95% CI -0.12, -0.42 )] was noted. There was a significant increase in the risk of stage > 3 retinopathy of prematurity (ROP) in the EPO group [typical RR; 1.71 (95% CI 1.15, 2.54); typical RD; 0.05 (95% CI 0.01, 0.09); NNTH; 20 (95% CI 11, 100)]. The non-significant results for ROP (any stage reported) showed a similar trend. The increased risk for ROP may be associated with use of higher doses of supplemental of iron in the EPO group than in the control group. The rates for mortality, sepsis, intraventricular haemorrhage, periventricular leukomalacia, necrotizing enterocolitis, bronchopulmonary dysplasia, neutropenia, hypertension, length of hospital stay or long-term neurodevelopmental outcomes were not significantly change by the administration of EPO.

AUTHORS' CONCLUSIONS

Early administration of EPO reduces the use one or more red blood cell transfusions, the volume of red blood cells transfused, and the number of donors and transfusions the infant is exposed to following study entry. The small reductions are of limited clinical importance. Any donor exposure is likely not avoided as most studies included infants, who had received red cell transfusions prior to trial entry. There was a significant increase in the rate of ROP (stage >3). Animal data and observational studies in humans support a possible association between treatment with EPO and the development of ROP. EPO does not significantly decrease or increase any of the other important neonatal adverse outcomes including mortality. The incidence of ROP should be ascertained in the studies that have already been conducted but did not report on this outcome. Any ongoing research should deal with the issue of ROP and evaluate the current clinical practice that will limit donor exposure through satellite units. Research efforts should focus on limiting donor exposure (to as few donors as possible) during the first few days of life in sick neonates, when red blood cell transfusions are most likely to be required and cannot be prevented by early (or late) EPO treatment. Due to the limited benefits and the increased risk of ROP, early administration of EPO is not recommended.

Does Insulin-Like Growth Factor 1 Contribute in Red Blood Cell Transfusions to the Pathogenesis of Retinopathy of Prematurity during Retinal Neovascularization?

BACKGROUND

Red blood cell (RBC) transfusions are associated with the development of retinopathy of prematurity (ROP). During the period of retinal neovascularization a rise of insulin-like growth factor 1 (IGF-1) may trigger rapid growth of new blood vessels.

OBJECTIVES

To study endocrine factors in RBC transfusions that might be of importance for ROP.

METHODS

IGF-1, IGF-2 and their binding proteins 1-3 (IGFBP-1-3) were determined by radioimmunoassays in 7 very-low-birthweight (VLBW) infants with ROP >or= stage 2 receiving a RBC transfusion, in 10 controls (VLBW infants with ROP <or= stage 1, no transfusion), in supernatants of 7 RBCs and of 5 washed RBCs (WRBC).

RESULTS

IGF-1 (mean +/- SD) in infants with ROP was 20.0 +/- 4.2 microg/l, in controls 35.9 +/- 15.2 microg/l (Mann-Whitney U test, p = 0.030). IGF-1 in RBC was 12.88 +/- 5.03 microg/l and in WRBC 0.45 +/- 0.74 microg/l (average of the three-course washing procedure). IGF-2 in infants with ROP was 485.67 +/- 158.73 microg/l, in controls 389.9 +/- 102.8 microg/l (not significant), in RBC 109.50 +/- 117.89 microg/l, in WRBC 61.07 +/- 30.0 microg/l. Except for IGFBP-3 other IGFBPs were barely or not detectable in RBC or WRBC.

CONCLUSIONS

Considering lower IGF-1 concentrations in preterm infants than in adults (factor 20), the IGF-1 in RBC transfusions is equivalent to a single dose of 1 microg/kg IGF-1 (5-10% of the adult dose with proved metabolic responses). Endocrinological relationships between the donor's load and the acceptor's individual features are a new aspect of potential side effects of RBC transfusions. Further research is necessary to clarify the share of the described IGF administration on the development of ROP.

Controversies in the Management of the Anemia of Prematurity Using Single-Donor Red Blood Cell Transfusions and/or Recombinant Human Erythropoietin

Many controversial questions regarding the practice of neonatal red blood cell (RBC) transfusions exist, so that practices and policies vary widely. This article will critically assess information pertaining to two of these controversies, namely, the transfusion of RBCs stored for up to 42 days after collection vs the transfusion of fresh RBCs stored 7 days or less after donation and the use of recombinant human erythropoietin (rHuEPO) in attempts to either diminish the severity of or to treat the anemia of prematurity. Based on both theoretical considerations and several published clinical trials, RBCs from one donor stored up to 42 days in extended storage preservative solutions can safely provide all RBCs needed by most infants for small-volume transfusions. Based on a large number of clinical trials and a meta-analysis of these trials, it is impossible to provide firm guidelines for the use of rHuEPO in the treatment of the anemia of prematurity. Clearly, rHuEPO has efficacy in stimulating erythropoiesis in preterm infants, but success in the elimination or marked reduction in the need for RBC transfusions has not been definitively demonstrated.

Erythropoietin and prematurity--where do we stand?

Erythropoietin (EPO) treatment for anemia of prematurity is still controversial. Large multicentric trials demonstrate that administration of EPO+Fe cannot prevent early transfusions, particularly in very low birth weight newborns and in infants with severe neonatal diseases, but may have some beneficial effect to prevent late transfusions. Current treatment of anemia of prematurity should be multifactorial trying to minimize all causes that reduce erthrocytic mass (phlebotomies, use of noninvasive procedures) and promoting all factors that increase it (placental transfusion, adequate nutrition support). To evaluate the real impact of EPO treatment it is mandatory to follow similar transfusion protocols for preterm infants in all the studies. The aim of EPO+Fe administration should be to avoid new late transfusions in very low birth weight preterm infants or to prevent the first transfusion after the second week of life in less immature premature with the objective of reducing the number of donors rather than the number of transfusions. We have limited the use of EPO+Fe to infants <30 weeks gestational age and birth weight <or=1250 g as well as to infants weighing 1250-1500 g with initial severe disease. The comparison of outcomes before (28 months period with EPO+Fe treatment to all premature <or=32 weeks gestational age) and after 20 months of implementation of the new protocol showed a significant decrease in EPO+Fe treatment candidates (40.3% vs. 85.9%, P<0.001) without changes in the percentage of transfusions in both periods. Therefore if EPO treatment is to be given it should be limited to preterm infants with a birth weight <1000 g or those of 1000-1250 g associated with risk factors for blood transfusion. It should be started at 3-7 days of life at doses of 250 U/kg subcutaneously, three times a week, for 4-6 weeks depending on gestational age with oral iron 2-12 mg/kg/day to keep ferritin levels greater than 100 ng/mL.

[Blood product transfusion in the neonatal period]

Newborn infants in intensive care units, especially those born premature, are at particular risk for blood transfusion adverse effects. Aside improvements in the preparation of specific blood products for the neonatal period, such as multiple packed cells preparations from a single donor for multiple transfusions in premature infants, progress has involved prophylaxis of anemia of prematurity as well. Recombinant human erythropoietin has proven to be beneficial with high range evidence. Also, alternative methods have been proposed to compensate for the delay in the effect of rHuEPO, such as delayed clamping of umbilical cord at birth, or autologous placental blood transfusion. However, a better understanding of the indications of blood transfusion and the provision of practice guidelines may justify a re-evaluation of prophylactic strategies for anemia of prematurity.

Issues in transfusing preterm infants in the NICU

Decisions regarding whether or not to transfuse preterm infants in the neonatal intensive care unit are often difficult. Although numbers of red blood cell transfusions have decreased in recent years, transfusions are still a common occurrence. For each infant, the advantages of transfusion must be balanced against the consequences and potential risks. This article examines physiologic and iatrogenic causes of anemia in preterm infants, clinical consequences of anemia, the use of transfusions and their risks, and the role of erythropoietin therapy.