Circulating RBC volume, measured with biotinylated RBCs, is superior to the Hct to document the hematologic effects of delayed versus immediate umbilical cord clamping in preterm neonates

Developments in Transfusion Medicine: Pulmonary Transfusion Reactions and Novel Blood Cell Labeling Techniques

Staying updated on advancements in transfusion medicine is crucial, especially in critical care and perioperative setting, where timely and accurate transfusions can be lifesaving therapeutic interventions. This narrative review explores the landscape of transfusion-related adverse events, focusing on pulmonary transfusion reactions such as transfusion-associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI). TACO and TRALI are the leading causes of transfusion-related morbidity and mortality; however, specific treatments are lacking. Understanding the current incidence, diagnostic criteria, pathogenesis, treatment, and prevention strategies can equip clinicians to help reduce the incidence of these life-threatening complications. The review discusses emerging pathogenic mechanisms, including the possible role of inflammation in TACO and the mechanisms of reverse TRALI and therapeutic targets for TACO and TRALI, emphasizing the need for further research to uncover preventive and treatment modalities. Despite advancements, significant gaps remain in our understanding of what occurs during transfusions, highlighting the necessity for improved monitoring methods. To address this, the review also presents novel blood cell labeling techniques in transfusion medicine used for improving monitoring, quality assessment, and as a consequence, potentially reducing transfusion-related complications. This article aims to provide an update for anesthesiologists, critical care specialists, and transfusion medicine professionals regarding recent advancements and developments in the field of transfusion medicine.

Umbilical Cord Milking Versus Delayed Cord Clamping in Infants 28 to 32 Weeks: A Randomized Trial

OBJECTIVES

To determine whether rate of severe intraventricular hemorrhage (IVH) or death among preterm infants receiving placental transfusion with UCM is noninferior to delayed cord clamping (DCC).

METHODS

Noninferiority randomized controlled trial comparing UCM versus DCC in preterm infants born 28 to 32 weeks recruited between June 2017 through September 2022 from 19 university and private medical centers in 4 countries. The primary outcome was Grade III/IV IVH or death evaluated at a 1% noninferiority margin.

RESULTS

Among 1019 infants (UCM n = 511 and DCC n = 508), all completed the trial from birth through initial hospitalization (mean gestational age 31 weeks, 44% female). For the primary outcome, 7 of 511 (1.4%) infants randomized to UCM developed severe IVH or died compared to 7 of 508 (1.4%) infants randomized to DCC (rate difference 0.01%, 95% confidence interval: (-1.4% to 1.4%), P = .99).

CONCLUSIONS

In this randomized controlled trial of UCM versus DCC among preterm infants born between 28 and 32 weeks' gestation, there was no difference in the rates of severe IVH or death. UCM may be a safe alternative to DCC in premature infants born at 28 to 32 weeks who require resuscitation.

Preterm pigs for preterm birth research: reasonably feasible

Preterm birth will disrupt the pattern and course of organ development, which may result in morbidity and mortality of newborn infants. Large animal models are crucial resources for developing novel, credible, and effective treatments for preterm infants. This review summarizes the classification, definition, and prevalence of preterm birth, and analyzes the relationship between the predicted animal days and one human year in the most widely used animal models (mice, rats, rabbits, sheep, and pigs) for preterm birth studies. After that, the physiological characteristics of preterm pig models at different gestational ages are described in more detail, including birth weight, body temperature, brain development, cardiovascular system development, respiratory, digestive, and immune system development, kidney development, and blood constituents. Studies on postnatal development and adaptation of preterm pig models of different gestational ages will help to determine the physiological basis for survival and development of very preterm, middle preterm, and late preterm newborns, and will also aid in the study and accurate optimization of feeding conditions, diet- or drug-related interventions for preterm neonates. Finally, this review summarizes several accepted pediatric applications of preterm pig models in nutritional fortification, necrotizing enterocolitis, neonatal encephalopathy and hypothermia intervention, mechanical ventilation, and oxygen therapy for preterm infants.

Red Blood Cell Transfusion Thresholds for Anemia of Prematurity

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

Placental transfusion during neonatal resuscitation in an asphyxiated preterm model

BACKGROUND

Neonatal Resuscitation Program does not recommend placental transfusion in depressed preterm neonates.

METHODS

Our objectives were to study the effect of delayed cord clamping (DCC) with ventilation for 5 min (DCCV, n-5), umbilical cord milking (UCM) without ventilation (n-6), UCM with ventilation (UCMV, n-6), early cord clamping followed by ventilation (ECCV, n-6) on red cell volume (RCV), and hemodynamic changes in asphyxiated preterm lambs. Twenty-three preterm lambs at 127-128 days gestation were randomized to DCCV, UCM, UCMV, and ECCV. We defined asphyxia as heart rate <100/min.

RESULTS

The UCMV had the highest neonatal RCV as a percentage of fetoplacental volume compared to the other groups (UCMV 85.5 ± 10%, UCM 72 ± 10%, ECCV 65 ± 14%, DCCV 61 ± 10%, p < 0.01). The DCCV led to better ventilation (66 ± 1 mmHg) and higher pulmonary blood flow (75 ± 24 ml/kg/min). The carotid flow was significantly higher in UCM without ventilation. The fluctuations in carotid flow with milking were 25 ± 6% higher from baseline during UCM, compared to 6 ± 3% in UCMV (p < 0.01).

CONCLUSIONS

Cord milking with ventilation led to higher RCV than other interventions. Ventilation during cord milking reduced fluctuation in carotid flow compared to UCM alone. DCCV led to better ventilation and pulmonary blood flow but did not increase RCV.

IMPACT

The best practice of placental transfusion in a depressed preterm neonate remains unknown. Ventilation with an intact cord improves gas exchange and hemodynamics in an asphyxiated preterm model. Cord milking without ventilation led to lower red cell volume but higher carotid blood flow fluctuations compared to milking with ventilation. Our data can be translated to bedside and could impact preterm resuscitation.

Red cell transfusion thresholds for preterm infants: finally some answers

Extremely low birthweight infants become anaemic during their care in the neonatal intensive care unit because of the physiological anaemia experienced by all newborn infants compounded by early umbilical cord clamping, blood loss by phlebotomy for laboratory monitoring and delayed erythropoiesis. The majority of these infants receive transfusions of packed red blood cells, usually based on haemoglobin values below a certain threshold. The haemoglobin or haematocrit thresholds used to guide transfusion practices vary with infant status and among institutions and practitioners. Previous smaller studies have not given clear guidance with respect to the haemoglobin thresholds that should trigger transfusions or even if this is the best way to decide when to transfuse an infant. Two large clinical trials of similar design comparing higher and lower haemoglobin thresholds for transfusing extremely low birthweight infants were recently published, the ETTNO and TOP trials. These trials found reassuringly conclusive and concordant results. Within the range of haemoglobin transfusion thresholds studied, there was no difference in the primary outcome (which was the same in both studies), neurodevelopmental impairment at 2 years' corrected age or death before assessment, in either study. In addition, there was no difference in either study in either of the components of the primary outcome. In conclusion, haemoglobin transfusion thresholds within the ranges used in these trials, 11-13 g/dL for young critically ill or ventilated infants and 7-10 g/dL for stable infants not requiring significant respiratory support, can be safely used without expecting adverse consequences on survival or neurodevelopment.

Effects of spontaneous first breath on placental transfusion in term neonates born by cesarean section: A randomized controlled trial

BACKGROUND

The role of umbilical cord management in placental transfusion in cesarean section (CS) requires clarification. The spontaneous first breath may be more important than the timing of cord clamping for placental transfusion in neonates born by CS.

OBJECTIVE

This study aimed to evaluate the impact of cord clamping after the first spontaneous breath on placental transfusion in neonates born by CS.

METHODS

We recruited women with a live singleton pregnancy at ≥37.0 weeks of gestation admitted for CS. The interventions performed, such as physiologic-based cord clamping (PBCC), intact-umbilical cord milking (I-UCM), 30-s delay in cord clamping (30-s DCC), and 60-s delay in cord clamping (60-s DCC), were noted and placed in a sealed envelope. The sealed envelope was opened immediately before delivery to perform randomization.

RESULTS

A total of 123 infants were eligible for evaluation. Of these, 31, 30, 32, and 30 were assigned to the PBCC, I-UCM, 30-s DCC, and 60-s DCC groups, respectively. The mean hemoglobin (Hb) and mean hematocrit (Hct) were significantly higher in the 60-s DCC group than in the PBCC group (p = 0.028 and 0.019, respectively), but no difference was noted among the I-UCM, 30-s DCC, and PBCC groups at 36 h of age. Further, no significant differences were observed in the mean Hb and mean Hct among the I-UCM, 60-s DCC, and 30-s DCC groups. Peak total serum bilirubin (TSB) levels were higher in the 60-s DCC group than in the I-UCM and PBCC groups (p = 0.017), but there was no difference between the 60-s DCC and 30-s DCC groups during the first week of life. The phototherapy requirement was higher in 60-s DCC than in IUCM and 30-sDCC (p = 0.001).

CONCLUSIONS

Our findings demonstrated that PBCC, 30-s DCC, and I-UCM in neonates born by CS had no significant differences from each other on placental transfusion. The Hb and Hct in the neonates were higher after 60-s DCC than after PBCC.

Placental Transfusion for Asphyxiated Infants

The current recommendation for umbilical cord management of non-vigorous infants (limp, pale, and not breathing) who need resuscitation at birth is to immediately clamp the umbilical cord. This recommendation is due in part to insufficient evidence for delayed cord clamping (DCC) or umbilical cord milking (UCM). These methods may provide a neuroprotective mechanism that also facilitates cardiovascular transition for non-vigorous infants at birth.

Effect of timing of umbilical cord clamping and other strategies to influence placental transfusion at preterm birth on maternal and infant outcomes

BACKGROUND

Infants born preterm (before 37 weeks' gestation) have poorer outcomes than infants at term, particularly if born before 32 weeks. Early cord clamping has been standard practice over many years, and enables quick transfer of the infant to neonatal care. Delayed clamping allows blood flow between the placenta, umbilical cord and baby to continue, and may aid transition. Keeping baby at the mother's side enables neonatal care with the cord intact and this, along with delayed clamping, may improve outcomes. Umbilical cord milking (UCM) is proposed for increasing placental transfusion when immediate care for the preterm baby is needed. This Cochrane Review is a further update of a review first published in 2004 and updated in 2012.

OBJECTIVES

To assess the effects on infants born at less than 37 weeks' gestation, and their mothers of: 1) delayed cord clamping (DCC) compared with early cord clamping (ECC) both with immediate neonatal care after cord clamping; 2) DCC with immediate neonatal care with cord intact compared with ECC with immediate neonatal care after cord clamping; 3) DCC with immediate neonatal care after cord clamping compared with UCM; 4) UCM compared with ECC with immediate neonatal care after cord clamping.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (10 November 2017), and reference lists of retrieved studies. We updated the search in November 2018 and added nine new trial reports to the awaiting classification section to be assessed at the next update.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing delayed with early clamping of the umbilical cord (with immediate neonatal care after cord clamping or with cord intact) and UCM for births before 37 weeks' gestation. Quasi-RCTs were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. Random-effects are used in all meta-analyses. Review authors assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

This update includes forty-eight studies, involving 5721 babies and their mothers, with data available from 40 studies involving 4884 babies and their mothers. Babies were between 24 and 36+6 weeks' gestation at birth and multiple births were included. The data are mostly from high-income countries. Delayed clamping ranged between 30 to 180 seconds, with most studies delaying for 30 to 60 seconds. Early clamping was less than 30 seconds and often immediate. UCM was mostly before cord clamping but some were milked after cord clamping. We undertook subgroup analysis by gestation and type of intervention, and sensitivity analyses by low risk of selection and attrition bias.All studies were high risk for performance bias and many were unclear for other aspects of risk of bias. Certainty of the evidence using GRADE was mostly low, mainly due to imprecision and unclear risk of bias.Delayed cord clamping (DCC) versus early cord clamping (ECC) both with immediate neonatal care after cord clamping (25 studies, 3100 babies and their mothers)DCC probably reduces the number of babies who die before discharge compared with ECC (average risk ratio (aRR) 0.73, 95% confidence interval (CI) 0.54 to 0.98, 20 studies, 2680 babies (moderate certainty)).No studies reported on 'Death or neurodevelopmental impairment' in the early years'.DCC may make little or no difference to the number of babies with severe intraventricular haemorrhage (IVH grades 3 and 4) (aRR 0.94, 95% CI 0.63 to 1.39, 10 studies, 2058 babies, low certainty) but slightly reduces the number of babies with any grade IVH (aRR 0.83, 95% CI 0.70 to 0.99, 15 studies, 2333 babies, high certainty).DCC has little or no effect on chronic lung disease (CLD) (aRR 1.04, 95% CI 0.94 to 1.14, 6 studies, 1644 babies, high certainty).Due to insufficient data, we were unable to form conclusions regarding periventricular leukomalacia (PVL) (aRR 0.58, 95% CI 0.26 to 1.30, 4 studies, 1544 babies, low certainty) or maternal blood loss of 500 mL or greater (aRR 1.14, 95% CI 0.07 to 17.63, 2 studies, 180 women, very low certainty).We identified no important heterogeneity in subgroup or sensitivity analyses.Delayed cord clamping (DCC) with immediate neonatal care with cord intact versus early cord clamping (ECC) (one study, 276 babies and their mothers)There are insufficient data to be confident in our findings, but DCC with immediate neonatal care with cord intact may reduce the number of babies who die before discharge, although the data are also compatible with a slight increase in mortality, compared with ECC (aRR 0.47, 95% CI 0.20 to 1.11, 1 study, 270 babies, low certainty). DCC may also reduce the number of babies who die or have neurodevelopmental impairment in early years (aRR 0.61, 95% CI 0.39 to 0.96, 1 study, 218 babies, low certainty). There may be little or no difference in: severe IVH; all grades IVH; PVL; CLD; maternal blood loss ≥ 500 mL, assessed as low certainty mainly due to serious imprecision.Delayed cord clamping (DCC) with immediate neonatal care after cord clamping versus umbilical cord milking (UCM) (three studies, 322 babies and their mothers) and UCM versus early cord clamping (ECC) (11 studies, 1183 babies and their mothers)There are insufficient data for reliable conclusions about the comparative effects of UCM compared with delayed or early clamping (mostly low or very low certainty).

AUTHORS' CONCLUSIONS

Delayed, rather than early, cord clamping may reduce the risk of death before discharge for babies born preterm. There is insufficient evidence to show what duration of delay is best, one or several minutes, and therefore the optimum time to clamp the umbilical cord remains unclear. Whilst the current evidence supports not clamping the cord before 30 seconds at preterm births, future trials could compare different lengths of delay. Immediate neonatal care with the cord intact requires further study, and there are insufficient data on UCM.The nine new reports awaiting further classification may alter the conclusions of the review once assessed.

Cut umbilical cord milking: an ineffective method of placental transfusion in preterm infants?

Objective: To determine if umbilical cord milking performed on a cut umbilical cord segment increased the hemoglobin/hematocrit, with a reduction in the incidence of intraventricular hemorrhage, need for blood transfusions, and pressor requirement in infants with <35-weeks gestation.Study design: This was a single center, observational study in the NICU. One-hundred-six neonates received cut umbilical cord milking and two hundred ninety seven served as historical controls.Result: There were no statistically significant differences between the two groups in hemoglobin/hematocrit, peak bilirubin values, the incidence of intraventricular hemorrhage, need for blood transfusions, and the use of pressors.Conclusion: This is the first study using the cut umbilical cord milking technique that includes neonates with <35-weeks gestation. The procedure is safe but did not result in an increase in hemoglobin/hematocrit, nor did it reduce the incidence of intraventricular hemorrhage, need for blood transfusions, and pressor use.

A Randomized Controlled Trial of Immediate versus Delayed Umbilical Cord Clamping in Multiple-Birth Infants Born Preterm

BACKGROUND

Delayed cord clamping (DCC) improves placental transfusion and increases blood volume in preterm infants when compared with immediate cord clamping (ICC). However, evidence to support DCC in multiple-birth preterm infants is still lacking.

OBJECTIVE

To compare the outcomes of ICC versus DCC in preterm infants of multiple births.

STUDY DESIGN

Women with a multiple pregnancy, including twins and triplets with a gestational age of 28-36 weeks, were randomized to receive ICC (23 women and 50 infants) or DCC for 30-60 s (24 and 51 infants). The infants' hematocrit on admission, superior vena cava (SVC) flow measured within 24 h, and hematocrit at 8 weeks of age were compared. The use of uterotonic agents during delivery was not controlled in this study.

RESULT

All infants were delivered by cesarean section (CS) except for 2 sets of twins, 1 in each group. Maternal and infant baseline characteristics in both groups were comparable. There were no significant differences between the groups in admission hematocrit, SVC flow measured within 24 h, hematocrit at 8 weeks of age, or any other neonatal outcomes. The incidence of maternal postpartum hemorrhage (PPH) was higher in the DCC group (4.3% in ICC vs. 25% in DCC, p = 0.04).

CONCLUSION

DCC for 30-60 s did not improve placental transfusion or increase systemic blood flow in multiple-birth infants born preterm, mostly by CS, when compared with ICC. The finding of a higher PPH rate in the DCC group raises concerns about the maternal safety of this procedure in this patient population.

Reduced blood volume decreases cerebral blood flow in preterm piglets

KEY POINTS

Preterm infants often have poor cardiovascular function that is associated with adverse neurodevelopmental outcomes. Preterm infants may be vulnerable to hypovolaemia due to excessive vasodilatation and leaky capillaries. Following reduction in blood volume, cardiac output and mean arterial pressure were reduced to the same extent in term and preterm piglets. Cerebral blood flow was maintained following blood volume reduction in term but not in preterm piglets. Effective detection and treatment of functional hypovolaemia may reduce the risk of brain injury in preterm infants.

ABSTRACT

Preterm infants often have impaired cardiovascular function that may contribute to poor neurodevelopmental outcomes. The study aimed to determine the effects of reduced blood volume on cardiovascular function, including cerebral blood flow, in preterm and term piglets. In preterm (97/115 days) and term piglets, up to 10% of the estimated blood volume was removed. Removal of blood was stopped if MAP dropped below 20 mmHg. Heart rate, cardiac contractility and relaxation, cardiac output, mean arterial pressure (MAP), and cerebral blood flow were measured at baseline and again after blood volume reduction. The volume of blood removed was less in preterm piglets than in term piglets (5.1 ± 1.8 vs. 7.7 ± 0.9 mL kg^-1 , mean ± SD, P < 0.001). Cardiac output and MAP decreased to the same extent in term and preterm piglets. Cerebral blood flow decreased in preterm but not term piglets and cerebral vascular conductance increased in term piglets only. Compensatory responses to maintain cerebral blood flow after blood volume reduction are active in term piglets but not in preterm piglets. As a result, even a small reduction in blood volume, or an increase in the capacity of the circulatory system leading to functional hypovolaemia, may lead to a significant reduction in cerebral blood flow and contribute to brain injury in preterm neonates.

A method for red blood cell biotinylation in a closed system

BACKGROUND

Several circumstances require the accurate measurement of red blood cell (RBC) survival and clearance, such as determination of posttransfusion recovery of stored RBCs to investigate the effect of new additive solutions. To this end, biotin as a marker of RBCs to track donor RBCs in the blood of the recipient has been used in many studies. However, so far only experimental, nonvalidated, biotin-labeled red cell concentrates (RCCs) are transfused. The goal of this study was to produce a standardized biotin-labeled RCC product in a fast, simple, and sterile manner that can be used for clinical research and for the evaluation of new blood products according to Good Practice Guidelines (GPG) for blood establishments.

STUDY DESIGN AND METHODS

RCC fractions were labeled with two different concentrations of biotinylation reagent in a closed system, to prevent bacterial contamination of the end product. Using flow cytometry, the reproducibility and robustness of the biotin labeling was assessed, as well as the stability of the biotin label on the (un-)irradiated RCC fraction. Additionally, parameters such as phosphatidylserine (PS) exposure, sodium (Na), potassium (K), free hemoglobin, adenosine triphosphate (ATP), pH, and morphology were determined prior to and after biotin labeling to rule out detrimental effects of the labeling procedure on the RCC.

RESULTS

Our data show that RCCs can be labeled under sterile conditions in a closed system with two different biotinylation reagent concentrations, without affecting the biological activity.

CONCLUSION

An easy, rapid (<2 hr), and robust method was developed to manufacture biotin-labeled RCCs for clinical research compliant to GPG.

Italian Recommendations for Placental Transfusion Strategies

At delivery, if the cord is not clamped, blood continues to pass from the placenta to the newborn during the first minutes of life, allowing the transfer of 25-35 ml/kg of placental blood to the newborn, depending on gestational age, the timing of cord clamping, the position of the infant at birth, the onset of respiration, and administration of uterotonics to the mother. However, deriving benefits from delayed cord clamping (DCC) are not merely related to placental-to-fetal blood transfusion; establishing spontaneous ventilation before cutting the cord improves venous return to the right heart and pulmonary blood flow, protecting the newborn from the transient low cardiac output, and systemic arterial pressure fluctuations. Recent meta-analyses showed that delayed cord clamping reduces mortality and red blood cell transfusions in preterm newborns and increases iron stores in term newborns. Various authors suggested umbilical cord milking (UCM) as a safe alternative when delayed cord clamping is not feasible. Many scientific societies recommend waiting 30-60 s before clamping the cord for both term and preterm newborns not requiring resuscitation. To improve the uptake of placental transfusion strategies, in 2016 an Italian Task Force for the Management of Umbilical Cord Clamping drafted national recommendations for the management of cord clamping in term and preterm deliveries. The task force performed a detailed review of the literature using the GRADE methodological approach. The document analyzed all clinical scenarios that operators could deal with in the delivery room, including cord blood gas analysis during delayed cord clamping and time to cord clamping in the case of umbilical cord blood banking. The panel intended to promote a more physiological and individualized approach to cord clamping, specifically for the most preterm newborn. A feasible option to implement delayed cord clamping in very preterm deliveries is to move the neonatologist to the mother's bedside to assess the newborn's clinical condition at birth. This option could safely guarantee the first steps of stabilization before clamping the cord and allow DCC in the first 30 s of life, without delaying resuscitation. Contra-indications to placental transfusion strategies are clinical situations that may endanger mother 's health and those that may delay immediate newborn's resuscitation when required.

Image-based red blood cell counter for multiple species of wild and domestic animals

ABSTRACT RBC count plays an important role in animal diagnosis. Despite the many technologies available in different automated hematology analyzers, when it comes to the blood of wild animals it is still difficult to find an easy and affordable solution for multiple species. This study aims to evaluate the proposed automatic red blood cell counter. Blood samples (1 ocelot - Leopardus pardalis, 1 monkey - Cebus apella, 1 coati - Nasua nasua, 62 dogs - Canis familiaris, and 5 horses - Equus caballus) were analyzed using three methods: 1-manual count, 2-automatic count by image, and 3-semi-automatic count by image; blood from dogs and horses were also analyzed by a fourth method: 4-automatic count by impedance. The counts in methods 2 and 3 were produced by the proposed red blood cell counter. Results were compared using Pearson's correlation and plots with different methods as the criterion standard. RBC counts in methods 1, 2, and 3 correlated very well with those in the method 4 (r ≥ 0.94). RBC counts produced by method 2 were highly correlated with method 3 (r = 0.998). The results indicate that the proposed method can be used as an automatic or semi-automatic counting method in clinics that are currently using the manual method for RBC assessment.

Placental transfusion: a review

Recently there have been a number of studies and presentations on the importance of providing a placental transfusion to the newborn. Early cord clamping is an avoidable, unphysiologic intervention that prevents the natural process of placental transfusion. However, placental transfusion, although simple in concept, is affected by multiple factors, is not always straightforward to implement, and can be performed using different methods, making this basic procedure important to discuss. Here, we review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking and cut-umbilical cord milking, and the evidence in term and preterm newborns supporting this practice. We will also review several factors that influence placental transfusion, and discuss perceived risks versus benefits of this procedure. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution.

Providing a Placental Transfusion in Newborns Who Need Resuscitation

Over the past decade, there have been several studies and reviews on the importance of providing a placental transfusion to the newborn. Allowing a placental transfusion to occur by delaying the clamping of the umbilical cord is an extremely effective method of enhancing arterial oxygen content, increasing cardiac output, and improving oxygen delivery. However, premature and term newborns who require resuscitation have impaired transitional hemodynamics and may warrant different methods to actively provide a placental transfusion while still allowing for resuscitation. In this review, we will provide evidence for providing a placental transfusion in these circumstances and methods for implementation. Several factors including cord clamping time, uterine contractions, umbilical blood flow, respirations, and gravity play an important role in determining placental transfusion volumes. Finally, while many practitioners agree that a placental transfusion is beneficial, it is not always straightforward to implement and can be performed using different methods, making this basic procedure important to discuss. We will review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking, and cut-umbilical cord milking. We will also review resuscitation with an intact cord and the evidence in term and preterm newborns supporting this practice. We will discuss perceived risks versus benefits of these procedures. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution.

Circulatory Management Focusing on Preventing Intraventricular Hemorrhage and Pulmonary Hemorrhage in Preterm Infants

The goal of modern neonatal care of extremely preterm infants is to reduce mortality and long-term neurological impairments. Preterm infants frequently experience cerebral intraventricular or pulmonary hemorrhage, which usually occurs within 72 hours after birth and can lead to long-term neurological sequelae and mortality. These serious hemorrhagic complications are closely related to perinatal hemodynamic changes, including an increase in the afterload on the left ventricle of the heart after the infant is separated from the placenta, and an increased preload from a left-to-right shunt caused by a hemodynamically significant patent ductus arteriosus (PDA). The left ventricle of a preterm myocardium has limited ability to respond to such an increase in afterload and preload, and this can result in cardiac dysfunction and hemodynamic deterioration. We suggest that delayed umbilical cord clamping or umbilical cord milking to maintain optimal blood pressure and systemic blood flow (SBF), careful assessment to keep the afterload at an acceptable level, and a strategy of early targeted treatment of significant PDA to improve perfusion during this critical time period may reduce or prevent these serious complications in preterm infants.

Neonatal Resuscitation with an Intact Cord: A Randomized Clinical Trial

OBJECTIVE

To assess whether providing ventilation during delayed cord clamping (V-DCC) increases placental transfusion compared with delayed cord clamping alone (DCC only).

STUDY DESIGN

Inborn premature infants (23^0/7-31^6/7 weeks' gestational age) were randomized to receive at least 60 seconds of V-DCC (initial continuous positive airway pressure) with addition of positive pressure ventilation if needed) or without assisted ventilation (DCC only). For the DCC-only group, infants were dried and stimulated by gently rubbing the back if apneic. The primary outcome was the peak hematocrit in the first 24 hours of life. Delivery room outcomes were analyzed from video recordings and a data acquisition system. Hemodynamic measurements were performed with the use of functional echocardiography, near-infrared spectroscopy, and electrical cardiometry.

RESULTS

There was no difference in the primary outcome of peak hematocrit in the first 24 hours of life. The onset of breathing was similar between both groups (25 ± 20 and 27 ± 28 seconds, P = .627); however, infants receiving DCC received a greater duration of stimulation than V-DCC (41 ± 19 and 20 ± 21 seconds P = .002). There were no differences in delivery room interventions, early hemodynamics (cerebral oxygenation by near-infrared spectroscopy, cardiac output and stroke volume by electrical cardiometry, or superior vena cava flow by of functional echocardiography), or neonatal outcomes.

CONCLUSIONS

V-DCC was feasible but did not lead to any measurable clinical improvements immediately after delivery or reduce subsequent neonatal morbidity. Caretakers should consider providing adequate stimulation before cord clamping.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02231411.

Effectiveness of Delayed Cord Clamping in Reducing Postdelivery Complications in Preterm Infants: A Systematic Review

This systematic review evaluates the effectiveness of delayed cord clamping in preterm infants on reducing postdelivery complications of anemia, hemodynamic instability, and the development of intraventricular hemorrhages. Interventions included varying durations of delayed cord clamping with and without cord milking as compared with immediate cord clamping, shorter delays in cord clamping, and delayed cord clamping without cord milking. A comprehensive search of randomized controlled trials, observational, cohort, and before-after studies was conducted between 1946 and 2015 in the electronic databases of Ovid MEDLINE, Embase, and Google Scholar. Studies were critically appraised using the Critical Appraisal Skills Program guidelines. Twenty-seven studies were included in the review from 1997 to 2015 from varying countries. Outcome measures included hematocrit/hemoglobin levels, measured or calculated blood volumes levels, number and volume of blood transfusions, presence of hypotension and need for treatment, and development of intraventricular hemorrhage. Delayed cord clamping can lead to improved outcomes measures in preterm infants. This review supports the current recommendation to perform delayed cord clamping during preterm deliveries.

Duration of Cord Clamping and Neonatal Outcomes in Very Preterm Infants

BACKGROUND

Delayed cord clamping (DCC, ≥30 s) increases blood volume in newborns and is associated with fewer blood transfusions and short-term neonatal complications. The optimal timing of cord clamping for very preterm infants should maximize placental transfusion without interfering with stabilization and resuscitation.

AIM

We compared the effect of different durations of DCC, 30-45 s vs. 60-75 s, on delivery room (DR) and neonatal outcomes in preterm infants <32 weeks gestational age (GA).

METHODS

This is a single-center prospective observational study. Data were collected prospectively from eligible infants from two groups: 30-45 s DCC group (January 2008 to February 2011, n = 187) and 60-75 s DCC group (March 2011 to April 2014, n = 166).

RESULTS

The 60-75 s DCC group compared to the 30-45 s DCC group had higher hematocrits at <2 hours (49.2% vs. 47.4%, p = 0.02). In infants <28 weeks GA, the 12-36 hours hematocrit was higher in the 60-75 s DCC group compared to the 30-45 s DCC group (47.9% vs. 42.1%, p = 0.002). The 60-75 s DCC group had reductions in DR intubation (11% vs. 22%, p = 0.004), hypothermia on admission (1% vs. 5%, p = 0.01), surfactant therapy (13% vs. 28%, p = 0.001), intubation in the first 24 hours (20% vs. 34%, p = 0.004), any intubation (27% vs. 40%, p = 0.007), and any red blood cell transfusion (20% vs. 33%, p = 0.008) during the hospitalization compared to the 30-45 s DCC group. These reductions remained significant after adjusting for GA, gender and >48 hours of antenatal steroid exposure. There was no difference between the two groups in neonatal death, intraventricular hemorrhage, chronic lung disease, late onset sepsis, necrotizing enterocolitis and severe retinopathy of prematurity.

CONCLUSION

In this study cohort increasing DCC duration from 30-45 s to 60-75 s is associated with decreased hypothermia on admission, neonatal respiratory interventions and red blood cell transfusions without increase in neonatal mortality and morbidities.

Umbilical Cord Milking Versus Delayed Cord Clamping in Preterm Infants

BACKGROUND AND OBJECTIVE

Delayed cord clamping (DCC) is recommended for premature infants to improve blood volume. Most preterm infants are born by cesarean delivery (CD), and placental transfusion may be less effective than in vaginal delivery (VD). We sought to determine whether infants <32 weeks born by CD who undergo umbilical cord milking (UCM) have higher measures of systemic blood flow than infants who undergo DCC.

METHODS

This was a 2-center trial. Infants delivered by CD were randomly assigned to undergo UCM or DCC. Infants delivered by VD were also randomly assigned separately. UCM (4 strippings) or DCC (45-60 seconds) were performed. Continuous hemodynamic measurements and echocardiography were done at site 1.

RESULTS

A total of 197 infants were enrolled (mean gestational age 28 ± 2 weeks). Of the 154 infants delivered by CD, 75 were assigned to UCM and 79 to DCC. Of the infants delivered by CD, neonates randomly assigned to UCM had higher superior vena cava flow and right ventricular output in the first 12 hours of life. Neonates undergoing UCM also had higher hemoglobin, delivery room temperature, blood pressure over the first 15 hours, and urine output in the first 24 hours of life. There were no differences for the 43 infants delivered by VD.

CONCLUSIONS

This is the first randomized controlled trial demonstrating higher systemic blood flow with UCM in preterm neonates compared with DCC. UCM may be a more efficient technique to improve blood volume in premature infants delivered by CD.

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%).

Measurement of posttransfusion red cell survival with the biotin label

The goal of this review is to summarize and critically assess information concerning the biotin method to label red blood cells (RBC) for use in studies of RBC and transfusion biology-information that will prove useful to a broad audience of clinicians and scientists. A review of RBC biology, with emphasis on RBC senescence and in vivo survival, is included, followed by an analysis of the advantages and disadvantages of biotin-labeled RBC (BioRBC) for measuring circulating RBC volume, posttransfusion RBC recovery, RBC life span, and RBC age-dependent properties. The advantages of BioRBC over (51)Cr RBC labeling, the current reference method, are discussed. Because the biotin method is straightforward and robust, including the ability to follow the entire life spans of multiple RBC populations concurrently in the same subject, BioRBC offers distinct advantages for studying RBC biology and physiology, particularly RBC survival. The method for biotin labeling, validation of the method, and application of BioRBCs to studies of sickle cell disease, diabetes, and anemia of prematurity are reviewed. Studies documenting the safe use of BioRBC are reviewed; unanswered questions requiring future studies, remaining concerns, and regulatory barriers to broader application of BioRBC including adoption as a new reference method are also presented.

Changes in circulating red cell volume during the first 6 weeks of life in very-low-birth-weight infants

BACKGROUND

Little is known about the change in circulating red cell volume (RCV) of very-low-birth-weight (VLBW) infants during the first weeks of life.

METHODS

RCV was measured during the first 5 d in 35 VLBW infants using chromium-51 labeling of the infants' red blood cells (RBCs). RCV was measured again at 6 wk of age in 12 infants, and the volumes of RBCs lost by phlebotomy and those gained by transfusion were recorded between the RCV measurements. In six infants, the volume of waste blood on materials contaminated with blood during phlebotomy, which would usually be discarded, was measured by radioactive counting.

RESULTS

The mean RCV in the first several days of life was 39.6 ml (35.7 ml/kg; range: 20.1-58.7 ml/kg). Of the 12 infants whose RCV was measured twice, all but one had a decrease in absolute RCV. The mean RCV initially and at 6 wk were 37.3 and 26.6 ml, respectively. The mean volume of RBCs lost through phlebotomy was 29.2 ml, and the mean volume of RBCs given by transfusion was 34.5 ml.

CONCLUSION

During the first 6 wk of life, when the anemia of prematurity is evolving, the RCV falls despite complete replacement of RBCs lost by diagnostic phlebotomy with transfused RBCs.

Optimal timing for clamping the umbilical cord after birth

This article provides a brief overview of pros and cons of clamping the cord too early (within seconds) after birth. It also highlights evolving data that suggest that delaying cord clamping for 30 to 60 seconds after birth is beneficial to the baby, with no measurable negative effects either the baby or the mother.

Effect of timing of umbilical cord clamping and other strategies to influence placental transfusion at preterm birth on maternal and infant outcomes

BACKGROUND

Optimal timing for clamping the umbilical cord at preterm birth is unclear. Early clamping allows for immediate transfer of the infant to the neonatologist. Delaying clamping allows blood flow between the placenta, the umbilical cord and the baby to continue. The blood which transfers to the baby between birth and cord clamping is called placental transfusion. Placental transfusion may improve circulating volume at birth, which may in turn improve outcome for preterm infants.

OBJECTIVES

To assess the short- and long-term effects of early rather than delaying clamping or milking of the umbilical cord for infants born at less than 37 completed weeks' gestation, and their mothers.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (31 May 2011). We updated this search on 26 June 2012 and added the results to the awaiting classification section.

SELECTION CRITERIA

Randomised controlled trials comparing early with delayed clamping of the umbilical cord and other strategies to influence placental transfusion for births before 37 completed weeks' gestation.

DATA COLLECTION AND ANALYSIS

Three review authors assessed eligibility and trial quality.

MAIN RESULTS

Fifteen studies (738 infants) were eligible for inclusion. Participants were between 24 and 36 weeks' gestation at birth. The maximum delay in cord clamping was 180 seconds. Delaying cord clamping was associated with fewer infants requiring transfusions for anaemia (seven trials, 392 infants; risk ratio (RR) 0.61, 95% confidence interval (CI) 0.46 to 0.81), less intraventricular haemorrhage (ultrasound diagnosis all grades) 10 trials, 539 infants (RR 0.59, 95% CI 0.41 to 0.85) and lower risk for necrotising enterocolitis (five trials, 241 infants, RR 0.62, 95% CI 0.43 to 0.90) compared with immediate clamping. However, the peak bilirubin concentration was higher for infants allocated to delayed cord clamping compared with immediate clamping (seven trials, 320 infants, mean difference 15.01 mmol/L, 95% CI 5.62 to 24.40). For most other outcomes (including the primary outcomes infant death, severe (grade three to four) intraventricular haemorrhage and periventricular leukomalacia) there were no clear differences identified between groups; but for many there was incomplete reporting and wide CIs. Outcome after discharge from hospital was reported for one small study; there were no significant differences between the groups in mean Bayley II scores at age seven months (corrected for gestation at birth (58 children)).No studies reported outcomes for the women.

AUTHORS' CONCLUSIONS

Providing additional placental blood to the preterm baby by either delaying cord clamping for 30 to 120 seconds, rather than early clamping, seems to be associated with less need for transfusion, better circulatory stability, less intraventricular haemorrhage (all grades) and lower risk for necrotising enterocolitis. However, there were insufficient data for reliable conclusions about the comparative effects on any of the primary outcomes for this review.

Rethinking placental transfusion and cord clamping issues

A brief delay in clamping the umbilical cord results in a placental transfusion that supplies the infant with a major source of iron during the first few months of life. Cord circulation continues for several minutes after birth and placental transfusion results in approximately 30% more blood volume. Gravity influences the amount of placental transfusion that an infant receives. Placing the infant skin-to-skin requires a longer delay of cord clamping (DCC) than current recommendations. Uterotonics are not contraindicated with DCC. Cord milking is a safe alternative to DCC when one must cut the cord prematurely. Recent randomized controlled trials demonstrate benefits for term and preterm infants from DCC. The belief that DCC causes hyperbilirubinemia or symptomatic polycythemia is unsupported by the available research. Delay of cord clamping substantively increases iron stores in early infancy. Inadequate iron stores in infancy may have an irreversible impact on the developing brain despite oral iron supplementation. Iron deficiency in infancy can lead to neurologic issues in older children including poor school performance, decreased cognitive abilities, and behavioral problems. The management of the umbilical cord in complex situations is inconsistent between birth settings. A change in practice requires collaboration between all types of providers who attend births.

Functional echocardiographic assessment of myocardial performance in anemic premature infants: a pilot study

This prospective observational study conducted in a neonatal intensive care unit aimed to evaluate echocardiographic changes provoked by anemia and transfusion of packed red blood cells (pRBCs) in premature infants. In this study, 32 anemic premature infants had serial echocardiographic assessment of left ventricular (LV) systolic performance, LV preload, and afterload immediately before, within 48 h, and up to 120 h after the transfusion of pRBCs. Pretransfusional evaluations also were compared with similar assessments of 71 nonanemic inpatient premature infants analogous for sex, gestational age at birth, and postnatal age. Left ventricular systolic performance was estimated from fractional shortening, LV output, and LV myocardial performance index (LVMPI). The LV preload was estimated from the LV end-diastolic dimension and the ratio of left atrium-to-aortic root dimension (LA/Ao ratio). The LV afterload was estimated from end-systolic wall stress. The LVMPI was found to decrease with increasing corrected gestational age in both the nonanemic (R = 0.173; p = 0.03) and anemic (R = 0.460; p = 0.007) infants. The LVMPI was the only index that changed after transfusion of pRBCs, decreasing in the younger anemic infants (p = 0.011) and increasing in the older anemic infants (p = 0.012). Finally, a significant inverse relationship between pre- and posttransfusional LVMPI values (R = 0.730; p < 0.001) was noted. The LVMPI may allow for identification of preterm infants more likely to be helped by transfusion of pRBCs.

One pathway to academic success: autobiography of Dr Ronald G. Strauss

Often, I have been asked by "junior faculty"-who are usually burdened by substantial responsibilities in service and teaching-how they can launch their career in research as a means to succeed in academic medicine. Obviously, the answers/solutions are as diverse as are the circumstances of each questioner. In the following article, I offer the approach that I applied to my career-acknowledging that "one shoe doesn't fit all" and that others will advise differently. However, one truism exists whenever one seeks excellence in anything-the opportunity must be present to commit uninterrupted time for thought/concentration, organization, training/mentoring/study, and effort/hard work. Without such an opportunity, success in research will be elusive.

Red blood cell (RBC) volume can be independently determined in vivo in humans using RBCs labeled at different densities of biotin

BACKGROUND

Anemia is a serious problem in critically ill neonates. To investigate the pathophysiology of anemia and responses to red blood cell (RBC) transfusions and erythropoietin therapy, repeated measurement of red blood cell volume (RCV) and blood volume is useful. To extend our previous sheep study in which RBCs were labeled at four different biotin densities, we assessed the validity of this multidensity method for in vivo measurement of circulating RCV in humans.

STUDY DESIGN AND METHODS

In eight healthy adults, autologous RBCs were biotinylated at each of four biotin densities (6, 18, 54, and 162 µg biotinylation reagent/mL RBC), mixed, and infused intravenously; blood was sampled at 10, 20, and 60 minutes. At each time, RCV was calculated from dilution of individual RBC populations enumerated by flow cytometry. RCV measurements from the population of RBCs biotinylated at 6 µg/mL were chosen as the reference values because this density had been previously validated against the 51Cr method in vitro and in vivo in humans.

RESULTS

Values for RCVs were not significantly different among the four densities of biotinylated RBCs at any of the three time points and did not change over 60 minutes.

CONCLUSIONS

These studies provide evidence that four densities of biotinylated RBCs can be used in vivo for simultaneous, independent, accurate measurements of RCV in humans. We speculate that this method will also be useful for repeated measurement of RCV and blood volume in infants and other patient populations in whom radioactive labels should be avoided.

Red blood cell (RBC) volume can be independently determined in vivo in the sheep using ovine RBCs labeled at different densities of biotin

BACKGROUND

To investigate the pathophysiology of anemia and responses to red blood cell (RBC) transfusions and erythropoietin, repeated measurement of the circulating red blood cell volume (RCV) would be useful. Ovine erythropoiesis is similar to human erythropoiesis. Accordingly, a method for measuring RCV using either human or sheep RBCs labeled at different biotin densities has been previously validated in vitro. Here preclinical studies validating this method for in vivo measurement of circulating RCV in sheep are reported.

STUDY DESIGN AND METHODS

For each sheep, autologous RBCs were biotinylated were at four discrete densities (12, 24, 48, and 96µg biotinylation reagent/mL RBCs). The densities were mixed and infused intravenously. Blood was sampled five times over 1 hour beginning at 4 minutes. RCV values were determined based on dilution of each population of biotinylated RBCs and by the [(14) C]cyanate method.

RESULTS

There was no difference among RCVs measured at all densities through 16 minutes; however, by 60 minutes, RBCs biotinylated at the highest density overestimated RCV by 7.6%. RCV values increased 41% over the hour, consistent with equilibration with a pool of RBCs sequestered in the spleen. RCV by the [(14) C]cyanate method paralleled results by the biotin method but averaged 8% greater.

CONCLUSIONS

These studies provide evidence that all four densities of biotinylated RBCs can be used in sheep to simultaneously and independently determine RCV. We speculate that the multidensity biotinylation method will be useful both for multiple simultaneous measurements and for repeated measurement of circulating RCV and blood volume in humans.

Alternative positions for the baby at birth before clamping the umbilical cord

BACKGROUND

The third stage of labour is from birth of the baby until delivery of the placenta. Clamping the umbilical cord is one component of active management of the third stage. Deferring cord clamping allows blood flow between the baby and the placenta to continue; net transfer to the baby is called placental transfusion. If the cord is clamped immediately placental transfusion is restricted. Gravity is one of several factors that may influence the volume and duration of placental transfusion at both vaginal and caesarean births. Hence raising or lowering the baby whilst the cord is intact may influence placental transfusion, which in turn may affect outcome for the baby and the woman.

OBJECTIVES

To compare the effects of alternative positions for the baby between birth and cord clamping on outcome for the baby, outcome for the mother and on use of health service resources.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (July 2010).

SELECTION CRITERIA

Randomised trials comparing alternative positions for the baby at vaginal and caesarean birth, before clamping of the umbilical cord.

DATA COLLECTION AND ANALYSIS

We independently assessed trial eligibility and quality. When necessary, we contacted study authors for additional information.

MAIN RESULTS

Thirty-seven studies (7559 mother-infant pairs) were excluded: 33 (7296) because they did not compare alternative positions for the baby before clamping the umbilical cord and four (263) due to quasi-random allocation. No studies met the inclusion criteria. One additional trial is ongoing.

AUTHORS' CONCLUSIONS

No randomised trials have assessed the influence of gravity on placental transfusion. Large, well-designed randomised trials are needed to assess whether gravity influences placental transfusion at vaginal and caesarean births and, if so, whether this affects short-term and long-term outcome for the baby and for the mother.

Immunologic and infectious consequences of immediate versus delayed umbilical cord clamping in premature infants: a prospective, randomized, controlled study

AIM

To evaluate the immunologic and infectious consequences of delayed versus immediate cord clamping in premature infants (<35 weeks) during the neonatal period.

METHODS

This was a prospective, masked, randomized, controlled, single-center study. Prior to delivery 35 infants were randomly assigned to immediate cord clamping (ICC) at 5-10 s and 30 infants to delayed cord clamping (DCC), at 30-45 s (14 and 15 infants in each group were <1500 g, respectively).

RESULTS

Neonatal characteristics of the ICC and DCC groups were comparable. There was no significant difference between the ICC and DCC groups in the complement or in the immunoglobulin levels. All were within the normal range for age. All infectious parameters (events of sepsis or "rule-out sepsis", days of antibiotic therapy, and number of antibiotic courses during hospitalization and infections within the first month of life in cases of earlier discharge) were comparable in both groups. Similar results were found in the subgroup of infants <1500 g. Gender analysis showed only modest differences.

CONCLUSIONS

Delayed compared to immediate cord clamping did not affect the immunologic or the infectious status of infants born at <35 weeks during the neonatal period.

Seven-month developmental outcomes of very low birth weight infants enrolled in a randomized controlled trial of delayed versus immediate cord clamping

OBJECTIVE

The results from our previous trial revealed that infants with delayed cord clamping (DCC) had significantly lesser intraventricular hemorrhage (IVH) and late-onset sepsis (LOS) than infants with immediate cord clamping (ICC). A priori, we hypothesized that infants with DCC would have better motor function by 7 months corrected age.

STUDY DESIGN

Infants between 24 and 31 weeks were randomized to ICC or DCC and follow-up evaluation was completed at 7 months corrected age.

RESULT

We found no differences in the Bayley Scales of Infant Development (BSID) scores between the DCC and ICC groups. However, a regression model of effects of DCC on motor scores controlling for gestational age, IVH, bronchopulmonary dysplasia, sepsis and male gender suggested higher motor scores of male infants with DCC.

CONCLUSION

DCC at birth seems to be protective of very low birth weight male infants against motor disability at 7 months corrected age.

Red blood cell volume can be independently determined in vitro using sheep and human red blood cells labeled at different densities of biotin

BACKGROUND

The development of valid methods for repeatedly measuring red blood cell (RBC) volume (RCV) in the same individual would be useful in furthering understanding of the physiology and pathophysiology of the pregnant woman, fetus, and infant under a variety of conditions.

STUDY DESIGN AND METHODS

Small volumes (5 to 100 mL) of either sheep or human blood were used to test the hypothesis that there is no significant difference in RCV and blood volume determined in vitro using as many as five populations of RBCs labeled at distinct biotin densities. By varying the mass of biotinylating reagent, the density of biotin on the surface of RBCs was incrementally increased to produce discrete populations as assessed by flow cytometric enumeration. Calculation of RCV for each biotin-labeled RBC population was based on the dilution principle.

RESULTS

All biotin densities, except the most densely labeled, where variance was the greatest, accurately quantitated the in vitro blood volume to within 10 percent of the correct value. There was no bias of either overestimation or underestimation in the determination of the blood volume using either sheep or human RBCs.

CONCLUSION

These in vitro results provide evidence that the multidensity biotin labeling method is sufficiently accurate to utilize in vivo for repeated determination of circulating RCV and blood volume.

Red cell volume can be accurately determined in sheep using a nonradioactive biotin label

The sheep has served as an informative animal model for investigation of human fetal and newborn erythropoiesis and red blood cell (RBC) kinetics. We previously validated the permanent label (14C)cyanate for measuring red cell volume (RCV) in sheep. Here, we validate biotin labeling of RBCs as a nonradioactive method for measuring RCV in sheep with the anticipation that it can be applied in studies of human infants. The RCV was determined simultaneously using two techniques for quantitation of the biotin label. The first one quantified total blood concentration of biotin label on biotin-labeled RBCs using (125I)streptavidin. The second one enumerated biotin-labeled RBCs by flow cytometry after incubation with fluorescein-conjugated avidin. RCV measurements made using the two biotin quantitation techniques were validated against both (14C)cyanate and 51Cr as reference methods. Both biotin techniques produced RCV values that agreed well with the reference methods and with each other, producing correlation coefficients averaging >or =0.93. Sequential repetitive measurements in the same animal also agreed with the (14C)cyanate method and each other (average difference <10%). These results establish biotin-labeled RBCs as an accurate method for performing RCV measurements in sheep. This biotin method can be applied in studies that model neonatal erythropoiesis.

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.

Management of anemia in the newborn

Red blood cell (RBC) transfusions are administered to neonates and premature infants using poorly defined indications that may result in unintentional adverse consequences. Blood products are often manipulated to limit potential adverse events, and meet the unique needs of neonates with specific diagnoses. Selection of RBCs for small volume (5-20 mL/kg) transfusions and for massive transfusion, defined as extracorporeal bypass and exchange transfusions, are of particular concern to neonatologists. Mechanisms and therapeutic treatments to avoid transfusion are another area of significant investigation. RBCs collected in anticoagulant-additive solutions and administered in small aliquots to neonates over the shelf life of the product can decrease donor exposure and has supplanted the use of fresh RBCs where each transfusion resulted in a donor exposure. The safety of this practice has been documented and procedures established to aid transfusion services in ensuring that these products are available. Less well established are the indications for transfusion in this population; hemoglobin or hematocrit alone are insufficient indications unless clinical criteria (e.g. oxygen desaturation, apnea and bradycardia, poor weight gain) also augment the justification to transfuse. Comorbidities increase oxygen consumption demands in these infants and include bronchopulmonary dysplasia, rapid growth and cardiac dysfunction. Noninvasive methods or assays have been developed to measure tissue oxygenation; however, a true measure of peripheral oxygen offloading is needed to improve transfusion practice and determine the value of recombinant products that stimulate erythropoiesis. The development of such noninvasive methods is especially important since randomized, controlled clinical trials to support specific practices are often lacking, due at least in part, to the difficulty of performing such studies in tiny infants.

A randomized clinical trial comparing immediate versus delayed clamping of the umbilical cord in preterm infants: short-term clinical and laboratory endpoints

BACKGROUND

Most neonates less than 1.0 kg birth weight need red blood cell (RBC) transfusions. Delayed clamping of the umbilical cord 1 minute after delivery transfuses the neonate with autologous placental blood to expand blood volume and provide 60 percent more RBCs than after immediate clamping. This study compared hematologic and clinical effects of delayed versus immediate cord clamping.

STUDY DESIGN AND METHODS

After parental consent, neonates not more than 36 weeks' gestation were randomly assigned to cord clamping immediately or at 1 minute after delivery. The primary endpoint was an increase in RBC volume/mass, per biotin labeling, after delayed clamping. Secondary endpoints were multiple clinical and laboratory comparisons over the first 28 days including Score for Neonatal Acute Physiology (SNAP).

RESULTS

Problems with delayed clamping techniques prevented study of neonates of less than 30 weeks' gestation, and 105 neonates 30 to 36 weeks are reported. Circulating RBC volume/mass increased (p = 0.04) and weekly hematocrit (Hct) values were higher (p < 0.005) after delayed clamping. Higher Hct values did not lead to fewer RBC transfusions (p > or = 0.70). Apgar scores after birth and daily SNAP scores were not significantly different (p > or = 0.22). Requirements for mechanical ventilation with oxygen were similar. More (p = 0.03) neonates needed phototherapy after delayed clamping, but initial bilirubin levels and extent of phototherapy did not differ.

CONCLUSIONS

Although a 1-minute delay in cord clamping significantly increased RBC volume/mass and Hct, clinical benefits were modest. Clinically significant adverse effects were not detected. Consider a 1-minute delay in cord clamping to increase RBC volume/mass and RBC iron, for neonates 30 to 36 weeks' gestation, who do not need immediate resuscitation.

A systematic review and meta-analysis of a brief delay in clamping the umbilical cord of preterm infants

BACKGROUND

The optimal timing of clamping the umbilical cord in preterm infants at birth is the subject of continuing debate.

OBJECTIVE

To investigate the effects of a brief delay in cord clamping on the outcome of babies born prematurely.

METHODS

A retrospective meta-analysis of randomised trials in preterm infants was conducted. Data were collected from published studies identified by a structured literature search in EMBASE, PubMed, CINAHL and the Cochrane Library. All infants born below 37 weeks gestation and enrolled into a randomised study of delayed cord clamping (30 s or more) versus immediate cord clamping (less than 20 s) after birth were included. Systematic search and analysis of the data were done according to the methodology of the Cochrane collaboration.

RESULTS

Ten studies describing a total of 454 preterm infants were identified which met the inclusion and assessment criteria. Major benefits of the intervention were higher circulating blood volume during the first 24 h of life, less need for blood transfusions (p = 0.004) and less incidence of intraventricular hemorrhage (p = 0.002).

CONCLUSIONS

The procedure of a delayed cord clamping time of at least 30 s is safe to use and does not compromise the preterm infant in the initial post-partum adaptation phase.

Delayed umbilical cord clamping for reducing anaemia in low birthweight infants: implications for developing countries

BACKGROUND

Cheap and effective interventions are needed to reduce the risk of infant anaemia in developing countries. Delayed cord clamping (DCC) has been shown to be a simple, safe and cost-free delivery procedure that augments red cell mass in appropriate-for-gestational-age term and preterm infants. It is not known, however, whether DCC is similarly safe and effective in small-for-gestational-age (SGA) infants. We analysed the available evidence to generate a balanced inference on the use of DCC in developing countries.

OBJECTIVES

To examine the short- and long-term effects in SGA infants of DCC compared with immediate clamping, and to assess the relationship between time of clamping and the potential postnatal haematological complications of DCC in SGA infants.

SEARCH STRATEGY

PubMed (1966 to January 2006), EMBASE (1988 to January 2006) and The Cochrane Library (Issue 1, 2006) were searched. Reference lists of published trials were examined and major journals of perinatal and tropical medicine were hand-searched.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing delayed with immediate cord clamping in infants born between 30 and 42 completed weeks of gestation and which included a proportion of SGA infants.

DATA COLLECTION AND ANALYSIS

Three reviewers assessed eligibility and trial quality.

MAIN RESULTS

To date, no trials have specifically reported the effects of DCC in SGA infants. Three trials were included, of 190 term and 40 preterm infants, a proportion of whom were SGA. DCC was associated with higher haemoglobin levels in term infants at follow-up [two trials, 127 infants, weighted mean difference (WMD) 9.17 g/L, 95% confidence interval (CI) 5.94-12.40]. In preterm infants, the proportion who required a blood transfusion in the 1st 6 weeks after birth was lower after DCC (one trial, 38 infants, RR 0.56, 95% CI 0.34-0.94). It was not possible to infer from the available data whether SGA infants were at greater risk of adverse effects in the early neonatal period.

CONCLUSIONS

DCC in a group that contains both AGA and SGA infants was associated with higher haemoglobin levels at 2-3 months of age in term infants and a reduction in the number of blood transfusions needed in the 1st 4- 6 weeks of life in preterm infants. No reliable conclusions could be drawn about the potential adverse effects of DCC. The paucity of information on DCC in SGA infants justifies further research, especially in developing countries where the baseline risk for polycythaemia-hyperviscosity syndrome is likely to be lower than in industrialised countries.

Neonatal resuscitation where resources are limited

This article reviews neonatal resuscitation techniques that can be used where resources are limited. The topic of delayed cord clamping is discussed in detail as an example of an evidence evaluation in which an important segment of the research has been conducted in developing countries. Thermal protection, clearing the airway, and assisted ventilation are discussed as areas in which some evidence exists from research in the developing world, but more work is needed to bring the full benefit of appropriate intervention to newborns in settings where resources are limited.

Infants' blood volume in a controlled trial of placental transfusion at preterm delivery

OBJECTIVE

To investigate whether it was possible to promote placental blood transfer to infants at preterm delivery by (1) delaying cord clamping, (2) holding the infant below the placenta, and (3) administering an oxytocic agent to the mother, we measured the infants' blood volumes.

DESIGN

Randomized study.

METHODS

Forty-six preterm infants (gestational age: 24[0/7] to 32[6/7] weeks) were assigned randomly to either placental blood transfer promotion (delayed cord clamping [DCC] group, ie, > or =30 seconds from moment of delivery) or early cord clamping (ECC) with conventional management (ECC group). Eleven of 23 and 9 of 23 infants assigned randomly to DCC and ECC, respectively, were delivered through the vaginal route. The study was conducted at a tertiary perinatal center, the Queen Mother's Hospital (Glasgow, United Kingdom).

RESULTS

The infants' mean blood volume in the DCC group (74.4 mL/kg) was significantly greater than that in the ECC group (62.7 mL/kg; 95% confidence interval for advantage: 5.8-17.5). The blood volume was significantly increased by DCC for infants delivered vaginally. The infants in the DCC group delivered through cesarean section had greater blood volumes (mean: 70.4 mL/kg; range: 45-83 mL/kg), compared with the ECC group (mean: 64.0 mL/kg; range: 48-77 mL/kg), but this was not significant. Additional analyses confirmed the effect of DCC (at least 30 seconds) to increase average blood volumes across the full range of gestational ages studied.

CONCLUSIONS

The blood volume was, on average, increased in the DCC group after at least a 30-second delay for both vaginal and cesarean deliveries. However, on average, euvolemia was not attained with the third stage management methods outlined above.

Severe malarial anemia of low parasite burden in rodent models results from accelerated clearance of uninfected erythrocytes

Severe malarial anemia (SMA) is the most frequent life-threatening complication of malaria and may contribute to the majority of malarial deaths worldwide. To explore the mechanisms of pathogenesis, we developed a novel murine model of SMA in which parasitemias peaked around 1.0% of circulating red blood cells (RBCs) and yet hemoglobin levels fell to 47% to 56% of baseline. The severity of anemia was independent of the level of peak or cumulative parasitemia, but was linked kinetically to the duration of patent infection. In vivo biotinylation analysis of the circulating blood compartment revealed that anemia arose from accelerated RBC turnover. Labeled RBCs were reduced to 1% of circulating cells by 8 days after labeling, indicating that the entire blood compartment had been turned over in approximately one week. The survival rate of freshly transfused RBCs was also markedly reduced in SMA animals, but was not altered when RBCs from SMA donors were transferred into naive recipients, suggesting few functional modifications to target RBCs. Anemia was significantly alleviated by depletion of either phagocytic cells or CD4+ T lymphocytes. This study demonstrates that immunologic mechanisms may contribute to SMA by promoting the accelerated turnover of uninfected RBCs.

[Variations in serum ferritin and erythrocyte index in the first eight weeks of life in term newborn infants]

OBJECTIVE

To describe changes in erythrocyte index during the first 8 weeks of life in neonates in relation to their iron store.

MATERIAL AND METHODS

We performed a longitudinal study of a group of healthy term newborn infants, in whom we evaluated erythrocyte index and serum ferritin (SF) values at birth and at weeks 4 and 8 of age. Depending on the comparison made in SF values between birth and 2 months, the infants were divided into two groups: group I (without variation in SF) and group II (with a decrease in SF).

RESULTS

A total of 110 neonates were included, with 46 neonates in group I and 64 in group II. No differences in demographic or hematologic data were found, including neonates with anemia or a decrease in hemoglobin values (5.2 vs. 5.5 g/dL). SF decreased to lower values in group II than in group I (215 vs. 194 microg/L, p < 0.001), with a greater number of neonates with low iron stores at 2 months of age (0.15 vs. 0.37, p < 0.01; RR 2.464, 95 % CI: 1.162-5.227).

CONCLUSIONS

In healthy term newborn infants, erythrocyte index at birth showed no relation with iron store. SF values at 2 months of age depended on SF concentrations at birth. Decreased hemoglobin and SF values are part of physiological adaptation in the first few months of life.