Effect of hemoglobin on transfusion and neonatal adaptation in extremely low-birthweight infants

Association of low hemoglobin at birth and neurodevelopmental outcomes in preterm neonates ≤28 weeks' gestation: a retrospective cohort study

OBJECTIVE

To compare neurodevelopmental outcomes at 18-24 months corrected age (CA) for preterm infants who had hemoglobin levels <120 g/l versus those with hemoglobin level ≥120 g/l at birth.

METHODS

We included infants of ≤28 weeks gestational age (GA) born between January 2009 and June 2018. The primary outcome was neurodevelopmental impairment (NDI) at 18-24 months. Multivariable logistic regression was applied to determine the association.

RESULTS

Of the 2351 eligible neonates, 351 (14.9%) had hemoglobin levels <120 g/L at birth. Of the 2113 surviving infants, 1534 (72.5%) underwent developmental follow-up at 18-24 months CA. There was no statistically significant difference in ND outcomes between the two groups. The composite outcome of death or NDI was significantly higher in the low hemoglobin group.

CONCLUSION

In preterm infants ≤28 weeks GA, initial hemoglobin <120 g/L at birth was not associated with neurodevelopmental impairment at 18-24 months CA among survivors.

Early red blood cell transfusion and the occurrence of intraventricular hemorrhage in very preterm infants

BACKGROUND

Preterm infants are at risk of developing both intraventricular hemorrhage (IVH) and anemia of prematurity. Several studies reported an association between early postnatal red blood cell (RBC) transfusion and IVH, however the timing and causality between these two remains unclear.

AIMS

To describe the temporal sequence between administration of early RBC transfusion (within the first week of life) and diagnosis of IVH in very preterm infants.

STUDY DESIGN

Retrospective single center case-series.

SUBJECTS

132 very preterm infants (<32 weeks' gestation), admitted to a level III neonatal intensive care unit, studied with serial cranial ultrasound (CUS), and diagnosed with any grade of IVH.

OUTCOME MEASURES

Number and timing of early RBC transfusions in relation to the timing of IVH.

RESULTS

Median time of IVH diagnosis was 20.5 h after birth (interquartile range [IQR], 6.25-49.00 h). Of those who received an early RBC transfusion (36 %, 47/132), only 15 % (20/132) received it before the IVH diagnosis. Infants with RBC transfusion before IVH more frequently had lower birth weight, received less fequently antenatal steroids, required more often invasive mechanical ventilation and surfactant administration, had more often hypo- and hypercapnia, and received more fluid boluses, NaHCO3, and inotropes compared to the rest.

CONCLUSIONS

In the majority of infants, IVH was already present at the time of the first RBC transfusion. Studies including pre- and post RBC transfusion CUS are needed to assess the effect of early RBC transfusions on the development of IVH in preterm neonates.

Impact of Early Hemoglobin Levels on Neurodevelopment Outcomes of Two-Year-Olds in Very Preterm Children

OBJECTIVE

To evaluate, in very preterm infants, the hemoglobin (Hb) levels during the first 24 h and the neurodevelopment outcomes at 24 months of corrected age.

DESIGN, SETTING, AND PATIENTS

We conducted a secondary analysis of the French national prospective and population-based cohort EPIPAGE-2. The eligible study participants were live-born singletons who were born before 32 weeks of gestational age, with early Hb levels who were admitted to the neonatal intensive care unit.

MAIN OUTCOME MEASURES

The early Hb levels for an outcome survival at 24 months of corrected age without neurodevelopmental impairment were measured. The secondary outcomes were survival at discharge and without severe neonatal morbidity.

RESULTS

Of the 2158 singletons of <32 weeks with mean early Hb levels of 15.4 (±2.4) g/dL, 1490 of the infants (69%) had a follow-up at two years of age. An early Hb of 15.2 g/dL is the minimum receiving operating characteristic curve at the 24 months risk-free level, but the area under the curve at 0.54 (close to 50%) indicates that this rate was not informative. In logistic regression, no association was found between early Hb levels and outcomes at two years of age (aOR 0.966; 95% CI [0.775-1.204]; p = 0.758) but rather there was a correlation found with severe morbidity (aOR 1.322; 95% CI [1.003-1.743]; p = 0.048). A risk stratification tree showed that male newborns of >26 weeks with Hb of <15.5 g/dL (n = 703) were associated with a poor outcome at 24 months (OR 1.9; CI: [1.5-2.4] p < 0.01).

CONCLUSIONS

Early low Hb levels are associated with major neonatal morbidities in VP singletons, but not with neurodevelopment outcomes at two years of age, except in male infants of >26 Weeks GA.

Early anemia and neonatal morbidity in extremely low birth-weight preterm infants

Background: Extremely low birth-weight (ELBW) preterm infants remain at high risk for mortality and major morbidities, and nearly all need packed red blood cell transfusions within their first weeks of life. The overall objective of this study was to assess the association between anemia at admission to neonatal intensive care unit (NICU) with the neonatal morbidity and mortality in ELBW infants.Methods: This retrospective study was conducted on 106 patients with ELBW admitted at our level III NICU from January 2006 to December 2015. The subjects were divided into two groups: (1) patients with anemia at admission and (2) patients without anemia. Their characteristics and outcomes were compared. Statistical analysis was performed using the Statistical Package for the Social Sciences software, version 24.0 (IBM New York, USA), and a value of p < 0.05 was considered statistically significant.Results: Of the 106 ELBW, 34 (32%) presented with anemia at admission and 72 (68%) without anemia. Anemia-naive presented mean hemoglobin at the admission of 12.8 ± 1.5 g/dl and nonanemic 16.8 ± 2.1 g/dl, p < .001). The anemic group presented a lower gestational age (26 ± 2 vs. 27 ± 2 SD weeks, p = .025), greater need for inotropic support (52.9 vs. 31.9%, p = .041), longer period of invasive mechanical ventilation (9 vs. 2 days, p = .012), higher FiO₂ need (0.8 vs. 0.4, p < .001), more frequent hemodynamically significant patent ductus arteriosus (HS-PDA) (64.7 vs. 41.7%, p = .006) and severe intra-periventricular hemorrhage (IPVH) (41.2 vs. 16.7%, p = 0.005). The multivariate analysis confirmed an association between anemia at admission and HS-PDA (OR = 3.2; 95% CI: 1.1-9.5, p = 0.044) and severe IPVH (OR = 3.3; 95% CI: 1.0-9.9, p = .038). In anemic infants, ionotropic support and IPVH >2 were considered independent factors for mortality.Conclusion: In this ELBW series, the presence of anemia at admission to the NICU was associated with HS-PDA and severe IPVH. Preventive strategies for early anemia must be encouraged.

Initial hematocrit values after birth and peri/intraventricular hemorrhage in extremely low birth weight infants

OBJECTIVE

Ischemia followed by reperfusion plays a significant role in the pathogenesis of peri/intraventricular hemorrhage (P/IVH). Delayed cord clamping promotes placental transfusion to newborn and is associated with decreased P/IVH. We hypothesized that extremely low birth weight (ELBW) infants with higher initial hematocrit (Hct) after birth are less likely to develop P/IVH.

STUDY DESIGN

Pre- and postnatal data on inborn ELBW infants over 7 years were reviewed. We examined the relationship between P/IVH in the first week and initial Hct using logistic regression modeling.

RESULTS

We studied 225 infants with a median gestational age (GA) 25.7 (22.4-31.7). Forty-one percent had grade I-IV P/IVH. In univariate analysis, cesarean section (CS) and higher GA, birth weight, 5-minute Apgar, and initial Hct were associated with decreased likelihood of P/IVH while higher maximum PCO₂ in first 3 days and use of inotropes/vasopressors, postnatal steroid for hypotension, hypernatremia, transfusion, and use of insulin for hyperglycemia during the first week of life were associated with increased likelihood of P/IVH. In multiple regression analysis, only GA, CS, and initial Hct remained significantly associated with P/IVH. Adjusting for GA and CS, the odds of P/IVH was higher with Hct < 40% (OR 2.04, 95% CI [1.11, 3.76]) and Hct < 45% (2.38 [1.19, 4.76]).

CONCLUSION

Higher initial Hct is associated with decreased P/IVH. Initial Hct < 45% was associated with a 2-fold increase in P/IVH. We speculate that lower initial Hct represents a lower intravascular volume status and promotes cerebral hypoperfusion preceding P/IVH.

Resuscitation of extremely preterm infants - controversies and current evidence

Despite significant advances in perinatal medicine, the management of extremely preterm infants in the delivery room remains a challenge. There is an increasing evidence for improved outcomes regarding the resuscitation and stabilisation of extremely preterm infants but there is a lack of evidence in the periviable (gestational age 23-25 wk) preterm subgroup. Presence of an experienced team during the delivery of extremely preterm infant to improve outcome is reviewed. Adaptation from foetal to neonatal cardiorespiratory haemodynamics is dependent on establishing an optimal functional residual capacity in the extremely preterm infants, thus enabling adequate gas exchange. There is sufficient evidence for a gentle approach to stabilisation of these fragile infants in the delivery room. Evidence for antenatal steroids especially in the periviable infants, delayed cord clamping, strategies to establish optimal functional residual capacity, importance of temperature control and oxygenation in delivery room in extremely premature infants is reviewed in this article.

Predictive factors and practice trends in red blood cell transfusions for very-low-birth-weight infants

BACKGROUND

Red blood cell (RBC) transfusions in very-low-birth-weight (VLBW) infants, while common, carry risk. Our objective was to determine clinical predictors of and trends in RBC transfusions among VLBW infants.

METHODS

RBC transfusion practice and its clinical predictors in 1,750 VLBW (≤1,500 g) infants were analyzed in a single-center cohort across sequential epochs: 2000-2004 (Epoch 1), 2005-2009 (Epoch 2), and 2010-2013 (Epoch 3).

RESULTS

Overall, 1,168 (67%) infants received ≥1 transfusions. The adjusted likelihood of ≥1 transfusions decreased for each 1-g/dl increment in initial hemoglobin concentration following birth, for females, and for each 100-g increment in birth weight. The adjusted likelihood of ≥1 transfusions increased with infants receiving mechanical ventilation, with increasing length of hospital stay, necrotizing enterocolitis, and nonlethal congenital anomalies requiring surgery. The adjusted mean (SEM) number of transfusions per patient was decreased in Epoch 3, compared with Epoch 1 and Epoch 2. For an initial hemoglobin of ≥16.5 g/dl, the predicted probability of being transfused was ≤50%.

CONCLUSION

Adjusted RBC transfusions declined and female sex conferred an unexplained protection over the study period. Modest increases in initial hemoglobin by placentofetal transfusion at delivery may reduce the need for RBC transfusion.

Umbilical cord milking reduces need for red cell transfusions and improves neonatal adaptation in preterm infants: Meta-analysis

AIM

To assess effects of umbilical cord milking (UCM) on early blood pressure stabilization, hemoglobin (Hb), as well as incidence of transfusion and complications in preterm infants.

METHODS

This meta-analysis was conducted by searching the Pubmed, EMBASE and Cochrane Library (until July 2014) databases. Any clinical trials, including randomized control trials, comparing UCM to immediate cord clamping (ICC) were analyzed.

RESULTS

Six studies were included in this meta-analysis. In total, 292 preterm infants were treated with UCM, while 295 received ICC. Compared to ICC, UCM increased initial Hb significantly by 1.84 g/dL (weighted mean difference; 95%CI: 0.91-2.76; P < 0.0001) and decreased the incidence of transfusion with a pooled risk ratio of 0.74 (95%CI: 0.61-0.90; P = 0.002). Incidence of necrotizing enterocolitis (NEC), intraventricular hemorrhage (IVH) and mortality were significantly lower with UCM compared with ICC. Apgar score and temperature were not significantly different between the two groups.

CONCLUSIONS

By facilitating the early stabilization of blood pressure, UCM at preterm birth was found to be comparatively safe and associated with lower blood transfusion exposure and lower incidence of IVH, NEC and death.

Haemoglobin level at birth is associated with short term outcomes and mortality in preterm infants

BACKGROUND

Blood volume and haemoglobin (Hb) levels are increased by delayed umbilical cord clamping, which has been reported to improve clinical outcomes of preterm infants. The objective was to determine whether Hb level at birth was associated with short term outcomes in preterm infants born at ≤32 weeks gestation.

METHODS

Data were collected retrospectively from electronic records: Standardised Electronic Neonatal Database, Electronic Patient Record, Pathology (WinPath), and Blood Bank Electronic Database. The study was conducted in a tertiary perinatal centre with around 5,500 deliveries and a neonatal unit admission of 750 infants per year. All inborn preterm infants of 23 to 32 weeks gestational age (GA) admitted to the neonatal unit from January 2006 to September 2012 were included. The primary outcomes were intra-ventricular haemorrhage, necrotising entero-colitis, broncho-pulmonary dysplasia, retinopathy of prematurity, and death before discharge. The secondary outcomes were receiving blood transfusion and length of intensive care and neonatal unit days. The association between Hb level (g/dL) at birth and outcomes was analysed by multiple logistic regression adjusting for GA and birth weight (BWt).

RESULTS

Overall, 920 infants were eligible; 28 were excluded because of missing data and 2 for lethal congenital malformation. The mean (SD) GA was 28.3 (2.7) weeks, BWt was 1,140 (414) g, and Hb level at birth was 15.8 (2.6) g/dL.Hb level at birth was significantly associated with all primary outcomes studied (P <0.001) in univariate analyses. Once GA and BWt were adjusted for, only death before discharge remained statistically significant; the OR of death for infants with Hb level at birth <12 g/dL compared with those with Hb level at birth of ≥18 g/dL was 4.1 (95% CI, 1.4-11.6). Hb level at birth was also significantly associated with blood transfusion received (P <0.01) but not with duration of intensive care or neonatal unit days.

CONCLUSIONS

Low Hb level at birth was significantly associated with mortality and receiving blood transfusion in preterm infants born at ≤32 weeks gestation. Further studies are needed to determine the association between Hb level at birth and long-term neurodevelopmental outcomes.

Residual blood volume in the umbilical cord of extremely premature infants

BACKGROUND

The aim of this study was to investigate residual blood volume in the umbilical cord of extremely premature infants.

METHODS

Twenty extremely premature infants were held at or below the placenta while the umbilical cord was clamped and cut at approximately 2-3 cm from the umbilicus within 30 s after birth. The umbilical cord was then clamped near the placenta to obtain a length of approximately 30 cm and cut. The residual blood volume in the segment of cord was drained and measured in milliliters.

RESULTS

Mean birthweight was 846 ± 172 g (range, 587-1180 g). The average length of the clamped segment of umbilical cord was 29.8 ± 1.5 cm (range, 27-32 cm). Total residual blood volume and residual blood volume per cm were 15.5 ± 6.7 mL (range, 6-25 mL) and 0.5 ± 0.2 mL/cm (range, 0.2-0.8 mL/cm), respectively. The residual cord blood volume per kilogram of infant weight per 30 cm was 17.7 ± 5.5 mL/kg/30 cm (range, 8.9-29.0 mL/kg/30 cm).

CONCLUSION

Infants could receive approximately 18 mL/kg of whole blood by one-time milking of 30 cm umbilical cord. With an average hematocrit of 40%, this volume is equivalent to approximately 13 mL of packed red blood cells (hematocrit 55%).

Effects of umbilical cord milking on the need for packed red blood cell transfusions and early neonatal hemodynamic adaptation in preterm infants born ≤1500 g: a prospective, randomized, controlled trial

OBJECTIVE

The aim of this study was to evaluate the effects of umbilical cord milking (UCM) on the need for packed red blood cell (PRBC) transfusion and hematologic and hemodynamic parameters in very-low-birth-weight infants.

METHODS

The infants were randomized into 2 groups: group 1 (UCM) and group 2 (control). The primary outcome was the number of PRBC transfusions during the first 35 days of life. The secondary outcome measures were the hemodynamic variables during the first 24 hours of life.

RESULTS

A total of 44 infants were included with 22 infants in each group. Two of 21 infants in group 1 and 4 of 21 infants in group 2 received transfusion in the first 3 days of life (P=0.384). The number and volume of PRBC transfusions were similar in both groups. However, the levels of hemoglobin (Hb) at the first and 24th hour of life were significantly higher in group 1. Phlebotomy volume was found as a statistically significant risk factor for the need for PRBC transfusion (P=0.005).

CONCLUSIONS

UCM in delivery room results in a higher Hb level in the first day of life. In these groups of infants, phlebotomy losses may impact the transfusion need.

Unique risks of red blood cell transfusions in very-low-birth-weight neonates: associations between early transfusion and intraventricular hemorrhage and between late transfusion and necrotizing enterocolitis

Red blood cell transfusions can be life-saving for neonates with severe anemia or active hemorrhage. However, risks of transfusions exist and should always be weighed against potential benefits. At least two transfusion risks are unique to very low birth weight neonates. The first is an association between transfusions given in the first days after birth and the subsequent occurrence of a grade 3 or 4 intraventricular hemorrhage. The second is an association between "late" RBC transfusions and the subsequent occurrence of necrotizing enterocolitis. Much remains to be discovered about the pathogenesis of these two outcomes. Moreover, work is needed to clearly establish whether transfusions are causatively-associated with these outcomes or are co-variables. This review will provide basic data establishing these associations and propose mechanistic explanations.

Whole-blood viscosity in the neonate: effects of gestational age, hematocrit, mean corpuscular volume and umbilical cord milking

OBJECTIVE

The American College of Obstetrics and Gynecology Committee on Obstetric Practice recently endorsed delayed cord clamping at preterm delivery. However, the committee report expressed the concern by some practitioners that delayed clamping or cord milking might induce hyperviscosity in preterm neonates. To address this issue we: (1) established reference ranges for whole-blood viscosity among preterm neonates (viscosity reference ranges had previously been reported only in term neonates) and (2) determined the effect of umbilical cord milking at deliveries <32 weeks gestation on subsequent blood viscosity measurements.

STUDY DESIGN

This was a prospective study in two Neonatal Intensive Care Units. Blood viscosity was measured using a cone and plate viscometer. Associations were sought with gestation, hematocrit/hemoglobin and mean corpuscular volume. Reference ranges were determined for preterm infants <32 weeks gestation. Then, after umbilical cord milking at deliveries <32 weeks, viscosity was measured at birth and again during the 12 h after birth. In neonates with viscosities >95th % range, we sought signs of hyperviscosity (plethora, hypotonia, hypoglycemia, hyperbilirubinemia, thrombocytopenia).

RESULT

Viscosity at higher and lower sheer rates were linearly related (n=32, r=0.971). Within the range of hematocrits measured (29-63%) viscosity correlated with hematocrit (r=0.877) and hemoglobin (r=0.853) but not with erythrocyte size (r=0.179). Viscosity was related to gestational age (n=58), primarily due to the lower hematocrits at lower gestational ages. In the 12 h after cord milking viscosity ranged from 3.1 to 9.5 centipoise. Three of twenty preterm, neonates had viscosities >95th % reference range. However, all values were well below those where hyperviscosity is defined in term neonates and all lacked features of hyperviscosity.

CONCLUSION

Cord blood viscosity is directly proportional to hematocrit/hemoglobin, lower at early gestation and not associated with erythrocyte size. Cord milking at preterm delivery is associated with a low risk of clinical hyperviscosity. Practioners should not refrain from cord milking at preterm delivery because of a concern that it will commonly cause neonatal hyperviscosity.

Recent advances toward defining the benefits and risks of erythrocyte transfusions in neonates

Like many treatments available to small or ill neonates, erythrocyte transfusions carry both benefits and risks. This review examines recent publications aimed at better defining those benefits and those risks, as means of advancing evidence-based neonatal intensive care unit transfusion practices. Since decisions regarding whether to not to order an erythrocyte transfusion are based, in part, on the neonate's blood haemoglobin concentration, the authors also review recent studies aimed at preventing the haemoglobin from falling to a point where a transfusion is considered.

Using umbilical cord blood for the initial blood tests of VLBW neonates results in higher hemoglobin and fewer RBC transfusions

OBJECTIVE

We previously described a method for reducing early phlebotomy losses from very low birth weight (VLBW) neonates by obtaining the initial blood tests from otherwise discarded fetal blood from the placenta. In the present study we sought to; (1) measure the feasibility of performing this method in actual practice, (2) test the hypothesis that this method would result in higher hemoglobin concentrations and lower erythrocyte transfusion rates in the first week after birth.

METHODS

We conducted two studies in three Intermountain Healthcare NICUs. The first was a feasibility analysis involving 96 VLBW neonates, measuring the success of obtaining the NICU admission laboratory blood tests this way. The second study used case-control methodology to test the hypothesis that this method would result in a higher blood hemoglobin 12 to 24 h after birth, and a lower proportion receiving an erythrocyte transfusion in the first week.

RESULT

In 91 of 96 VLBW neonates (95%) the initial blood tests were successfully obtained with this method. The success rate was not diminished by delayed cord clamping or cord milking, as it was successful in 35 of 36 (97%) such instances. Cases and controls were well matched on demographic and level of illness comparisons. Among cases the hemoglobin generally increased between birth and 12 to 24 h later, but among controls the hemoglobin generally decreased (P<0.05). In the week following birth fewer cases received vasopressors (P<0.01) and erythrocyte transfusions (P<0.001).

CONCLUSION

We judge that it is feasible to collect the initial blood tests of VLBW neonates using otherwise discarded umbilical cord/placental blood, in that this can be accomplished in about 95% of VLBW deliveries. This method, which can be used in addition to either delayed clamping of the umbilical cord or cord milking, results in higher hemoglobin concentrations, less vasopressor use and fewer transfusions in the first week.

Effect of umbilical cord milking in term and near term infants: randomized control trial

OBJECTIVE

The objective of the study was to investigate the effect of umbilical cord milking as compared with early cord clamping on hematological parameters at 6 weeks of age among term and near term neonates.

STUDY DESIGN

This was a randomized control trial. Eligible neonates (>35 weeks' gestation) were randomized in intervention and control groups (100 each). Neonates of both groups got early cord clamping (within 30 seconds). The cord of the experimental group was milked after cutting and clamping at 25 cm from the umbilicus, whereas in control group cord was clamped near (2-3 cm) the umbilicus and not milked. Both groups got similar routine care. Unpaired Student t and Fisher exact tests were used for statistical analysis.

RESULTS

Baseline characteristics were comparable in the 2 groups. Mean hemoglobin (Hgb) (11.9 [1.5] g/dL and mean serum ferritin 355.9 [182.6] μg/L) were significantly higher in the intervention group as compared with the control group (10.8 [0.9] g/dL and 177.5 [135.8] μg/L), respectively, at 6 weeks of age. The mean Hgb and hematocrit at 12 hours and 48 hours was significantly higher in intervention group (P = .0001). The mean blood pressure at 30 minutes, 12 hours, and 48 hours after birth was significantly higher but within normal range. No significant difference was observed in the heart rate, respiratory rate, polycythemia, serum bilirubin, and need of phototherapy in the 2 groups.

CONCLUSION

Umbilical cord milking is a safe procedure and it improved Hgb and iron status at 6 weeks of life among term and near term neonates.

Associations between "early" red blood cell transfusion and severe intraventricular hemorrhage, and between "late" red blood cell transfusion and necrotizing enterocolitis

Transfusion of banked donor erythrocytes can be life saving for small and ill neonates with severe anemia or active hemorrhage. However, risks of transfusions exist and must be weighed against potential benefits each time a transfusion is considered. The present review seeks to bring together the published data supporting 2 newly postulated risks of transfusions among very low-birth-weight neonates. The first is an association between "early" red blood cell transfusions, those administered in the first few days after birth, and the subsequent occurrence of a grade 3 or 4 intraventricular hemorrhage. The second is an association between "late" RBC transfusions and the subsequent occurrence of necrotizing enterocolitis. Much remains to be discovered about the pathogenetic links between transfusion and these adverse outcomes. Moreover, work is needed to clearly establish whether transfusions are causatively associated with these adverse outcomes or are covariables. The purpose of this chapter is to review the associations between transfusion and intraventricular hemorrhage and between transfusions and necrotizing enterocolitis and to use these associations to hypothesize that evidence-based improvements in transfusion practice have the potential to improve neonatal intensive care unit outcomes.