Do red cell transfusions increase the risk of necrotizing enterocolitis in premature infants?

Monitoring mesenteric tissue oxygenation with near-infrared spectroscopy during packed red blood cell transfusion in preterm infants

OBJECTIVE

To monitor altered mesenteric tissue oxygen saturation (StO2) before and after blood transfusion.

METHODS

We placed a 4-wavelength NIRS sensor (FORE-SIGHT, CASMED, Branford, CT USA) on the right lower abdominal quadrant prior to transfusion and measured StO2 for up to 48 hours post transfusion. Pulse oximetry (SpO2) data was collected simultaneously, with fractional tissue oxygen extraction (FTOE) and the [SpO2-StO2] difference calculated to normalize for hypoxic episodes. All data was combined and averaged in 30 minute windows for events before, during, and post transfusion to determine long term trends and analyzed using Repeated Measures ANOVA. 24 infants were enrolled in this study with 36 hours of data collected for 23 subjects and 48 hours for 16 subjects.

RESULTS

We found no significant differences in any of the parameters when compared pre and post transfusion values at 3, 6, 12, 24 and 36 hours post transfusion. For the 16 subjects monitored to 48 hours, there was a significant decrease in FTOE and near significant increase in StO2 and reciprocal decrease in [SpO2 - StO2] at 48 hours post transfusion.

CONCLUSIONS

There are several plausible mechanisms that may explain the relationship between necrotizing enterocolitis and PRBC transfusion; however, mesenteric tissue oxygen saturation changes did not clearly show that ischemia or re-perfusion injury to be one of the potential mechanisms.

Evaluation of caffeine and the development of necrotizing enterocolitis

OBJECTIVE

To test the association between medical or surgical necrotizing enterocolitis (NEC) and caffeine administration in premature infants.

STUDY DESIGN

This single-center, retrospective study evaluated patients admitted to a level 3 neonatal intensive care unit (NICU) over an 18-month period. All patients were evaluated for factors associated with the development of NEC including exposure to caffeine (dosing and duration), gestational age, birth weight, vasoactive medications and maternal illicit drug use.

RESULTS

There were 615 subjects included in the study; among these subjects, 7.3% (n = 45) developed NEC (35 subjects receiving caffeine and 10 subjects not receiving caffeine). The administration of caffeine (p = 0.008), birth weight (p = 0.014) and the use of vasopressors (p = 0.033) were associated with the development of NEC. When considering only infants with a birth weight less than 1500 g and less than 32 weeks gestation, the effects of caffeine and vasopressor use remained statistically significant (p = 0.047 and p = 0.045, respectively). The time to development of NEC did not differ statistically between patients receiving caffeine and those not receiving caffeine (p = 0.129).

CONCLUSION

A potential association between the administration of caffeine and the development of medical or surgical necrotizing enterocolitis in premature infants exists. Further investigation of dose-dependent effects and loading doses is warranted.

Packed red blood cell transfusion is not associated with increased risk of necrotizing enterocolitis in premature infants

OBJECTIVE

Recent reports have posited a temporal association between blood transfusion with packed red blood cells (BT) and necrotizing enterocolitis (NEC). We evaluated the relationship between BT and NEC among infants at three hospitals who were consented at birth into a prospective observational study of NEC.

STUDY DESIGN

We used a case-control design to match each case of NEC in our study population of infants born at<33 weeks postmenstrual age (PMA) to one control infant using hospital of birth, PMA, birth weight and date of birth.

RESULT

The number of transfusions per infant did not differ between 42 NEC cases and their controls (4.0 ± 4.6 vs 5.4 ± 4.1, mean ± s.d., P = 0.063). A matched-pair analysis did not identify an association of transfusion with NEC in either the 48-h or 7-day time periods before the onset of NEC. Stratifying on matched-sets, the Cox proportional hazard model did not identify any difference in the total number of BTs between the two groups (hazard ratio 0.78, 95% confidence interval 0.57 to 1.07, P = 0.11).

CONCLUSION

In contrast to previous studies, our case-control study did not identify a significant temporal association between BT and NEC. Additional large prospective randomized studies are needed to clarify the relationship between BT and NEC.

Can a national dataset generate a nomogram for necrotizing enterocolitis onset?

OBJECTIVE

Mother's own milk and donor human milk use is increasing as a means of necrotizing enterocolitis (NEC) prevention. Early onset of enteral feeding has been associated with improvement of many outcomes but has not been shown to reduce the incidence of NEC. Better definition of the window of risk for NEC by gestational strata should improve resource management with respect to donor human milk and enhance our understanding of NEC timing and pathogenesis. Our objective was to establish a NEC dataset of sufficient size and quality, then build a generalizable model of NEC onset from the dataset across gestational strata.

STUDY DESIGN

We used de-identified data from the Pediatrix national dataset and filtered out all diagnostic confounders that could be identified by either specific diagnoses or logical exclusions (example dual diagnoses), with a specific focus on NEC and spontaneous intestinal perforation (SIP) as the outcomes of interest. The median day of onset was plotted against the gestational age for each of these diagnoses and analyzed for similarities and differences in the day of diagnosis.

RESULT

Onset time of medical NEC was inversely proportional to gestation in a linear relationship across all gestational ages. We found the medical NEC dataset displayed characteristics most consistent with a homogeneous disease entity, whereas there was a skew towards early presentation in the youngest gestation groups of surgical NEC (suggesting probable SIP contamination).

CONCLUSION

Our national dataset demonstrates that NEC onset occurs in an inverse stereotypic, linear relationship with gestational age at birth. Medical NEC is the most reliable sub-cohort for the purpose of determining the temporal window of NEC risk.

Red blood cell transfusion is not associated with necrotizing enterocolitis: a review of consecutive transfusions in a tertiary neonatal intensive care unit

OBJECTIVE

To explore the association between red blood cell transfusion and necrotizing enterocolitis (NEC) in a neonatal intensive care unit with liberal transfusion practices.

STUDY DESIGN

A retrospective cohort study was conducted for all infants weighing <1500 g who received at least 1 packed red blood cell transfusion between January 2008 and June 2013 in a tertiary neonatal intensive care unit. The primary outcome was NEC, defined as Bell stage II or greater. The temporal association of NEC and transfusion was assessed using multivariate Poisson regression.

RESULTS

The study sample included 414 very low birth weight infants who received 2889 consecutive red blood cell transfusions. Twenty-four infants (5.8%) developed NEC. Four cases of NEC occurred within 48 hours of a previous transfusion event. Using multivariate Poisson regression, we did not find evidence of a temporal association between NEC and transfusion (P = .32).

CONCLUSION

There was no association between NEC and red blood cell transfusion. Our results differ from previous studies and suggest that the association between NEC and transfusion may be contextual.

Feeding preterm infants during red blood cell transfusion is associated with a decline in postprandial mesenteric oxygenation

OBJECTIVE

To evaluate the mesenteric tissue oxygenation response in preterm infants fed and not fed during red blood cell (RBC) transfusions.

STUDY DESIGN

Prospective, observational comparison of mesenteric oxygenation using near-infrared spectroscopy in preterm infants (<33 weeks' at birth) who were fed or not fed during RBC transfusion. Tissue oxygenation means were examined up to 48 hours after each transfusion event.

RESULTS

Mean mesenteric regional oxygen saturation (rSO2) slopes during RBC transfusion of fed (n = 9) vs not fed (n = 8) infants ranged from -0.23 to +0.23 (mean 0.04) with no differences between groups (P = .480). However, following transfusions, postprandial mesenteric oxygenation means significantly declined in infants fed during transfusion compared with infants not fed during transfusion (P < .001). Infants fed during RBC transfusion had a mean 2.16 point decrease in rSO2 mesenteric oxygenation with each sequential feeding post-transfusion, whereas infants not fed during RBC transfusion increased their rSO2 postprandial mesenteric oxygenation by a mean of 2.09 points.

CONCLUSIONS

Mesenteric tissue oxygenation during RBC transfusion is not influenced by feeding status. However, infants fed during RBC transfusion had, for the next 15 hours, decreasing postprandial mesenteric tissue oxygenation patterns compared with infants not fed during RBC transfusion. Feeding during RBC transfusions may increase the risk for mesenteric ischemia and the development of transfusion-related necrotizing enterocolitis in preterm infants.

Necrotizing enterocolitis in infants with congenital heart disease: the role of red blood cell transfusions

Necrotizing enterocolitis (NEC) is a rare but catastrophic complication that may occur in newborns with congenital heart disease (CHD). In the preterm population, transfusion of red blood cells (RBCs) and use of RBCs with longer storage time have been independently associated with the development of NEC. To date, it is not known whether similar associations exist for the term newborn with CHD. This retrospective study identified the incidence of NEC among 1,551 newborns admitted to the authors' cardiac intensive care unit between 7 January 2002 and 7 January 2010. The study was limited to term newborns (>36 weeks gestation). To understand the impact of RBC transfusions on the development of NEC, a nested 2:1 matched case-control analysis was undertaken to compare RBC transfusion patterns between an age-matched group and a cardiac lesion-matched control group. In the study population, NEC developed in 45 term infants during the postoperative period. Of these 45 infants, 30 (66.7%) had single-ventricle heart defects, whereas 22 (48.8%) required surgery for aortic arch obstruction. The median patient age at NEC diagnosis was 21 days. The RBC transfusion rate was higher among the patients who experienced NEC (0.21/day) than among the control subjects (0.10/day) (p = 0.048). A multivariate analysis indicated that onset of NEC was associated with a greater number of RBC transfusions (odds ratio [OR] 1.83; 95% confidence interval [CI] 1.07-7.47; p = 0.045). The duration of RBC storage was not significantly longer in the NEC group (9 days) than in the control cohort (7 days) (p = 0.16). Increased exposure to RBC transfusions is associated with the development of NEC in term infants with CHD. Longer storage of RBCs does not appear to increase this risk. Although causality cannot be confirmed, these data prompt a careful review of RBC transfusion practices with this population.

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.

Discrimination of GutCheck(NEC): a clinical risk index for necrotizing enterocolitis

OBJECTIVE

Better measures are needed to identify infants at risk for developing necrotizing enterocolitis (NEC) and facilitate communication about risk across transitions. Although NEC is multi-factorial, quantification of composite risk for NEC in an individual infant is not clearly defined. The objective of this study was to describe the derivation, validation and calibration testing of a novel clinical NEC risk index, GutCheck(NEC). Individual risk factors were weighted to assess composite odds of developing NEC. GutCheck(NEC) is designed to improve communication about NEC risk and coordination of care among clinicians across an infant's clinical course.

STUDY DESIGN

On the basis of a synthesis of research evidence about NEC risk and an e-Delphi study including 35 neonatal experts, we identified NEC risk factors believed by the experts to be most relevant for a NEC risk index, then applied a logistic model building process to derive and validate GutCheck(NEC). De-identified data from the Pediatrix BabySteps Clinical Data Warehouse (discharge date 2007 to 2011) were split into three samples for derivation, validation and calibration. By comparing infants with medical NEC, surgical NEC and those who died to infants without NEC, we derived the logistic model using the un-matched derivation set. Discrimination was then tested in a case-control matched validation set and an un-matched calibration set using receiver operating characteristic curves.

RESULT

Sampled from a cohort of 58 820 infants, the randomly selected derivation set (n=35 013) revealed nine independent risk factors (gestational age, history of packed red blood cell transfusion, unit NEC rate, late-onset sepsis, multiple infections, hypotension treated with inotropic medications, Black or Hispanic race, outborn status and metabolic acidosis) and two risk reducers (human milk feeding on both days 7 and 14 of life, and probiotics). Unit NEC rate carried the most weight in the summed score. Validation using a 2:1 matched case-control sample (n=360) demonstrated fair to good discrimination. In the calibration set (n=23 447), GutCheck(NEC) scores (range 0 to 58) discriminated those infants who developed surgical NEC (area under the curve (AUC)=0.84, 95% confidence interval (CI) 0.82 to 0.84) and NEC leading to death (AUC=0.83, 95% CI 0.81 to 0.85), more accurately than medical NEC (AUC= 0.72, 95% CI 0.70 to 0.74).

CONCLUSION

GutCheck(NEC) represents weighted composite risk for NEC and discriminated infants who developed NEC from those who did not with very good accuracy. We speculate that targeting modifiable NEC risk factors could reduce national NEC prevalence.

Transfusion practices in a neonatal intensive care unit in a city in Brazil

Objective

Newborn infants are the most heavily transfused population inside intensive care units. The hemoglobin level used to indicate the need of transfusions is not well established. The aim of this study was to evaluate transfusional practices in newborns in the neonatal intensive care units of one specific city.

Methods

Red blood cell transfusion practices of all transfused newborns in all five of the neonatal intensive care units of the city were analyzed. Data are reported as descriptive statistics, including numbers and percentages and means and standard deviation. Univariate analysis, followed by stepwise logistic regression was performed in respect to transfusional data and outcomes.

Results

A total of 949 patients were admitted to the intensive care units during the 12-month study period with 20.9% receiving at least one transfusion, most (62.4%) of whom received more than one transfusion. The mean number of transfusions per infant was 2.7 ± 2.16; in the liberal transfusion group the mean number was 1.59 ± 1.63 and in the restrictive group it was 1.08 ± 1.51. The mean hemoglobin and hematocrit levels were 9.0 g/dL (±1.4 g/dL) and 27.4% (±4.3%), respectively. The most common indications for blood transfusions were sepsis and prematurity.

Conclusion

This study shows that the characteristics and the transfusion practices for newborns admitted in the neonatal intensive care units of Juiz de Fora are similar to recent pubications. There was no significant reduction in the number of transfusions per child in the restrictive group compared to the liberal group. Restrictive transfusions are an independent risk factor for peri-intraventricular hemorrhages and death.

Effect of birth weight on the association between necrotising enterocolitis and red blood cell transfusions in <=1500 g infants

CONTEXT

Reports evaluating a possible association between necrotising enterocolitis (NEC) and blood transfusion have been predominantly case-control studies. As the possible associations of disease with any variable on which cases and controls have been matched cannot be explored, a cohort study would offer a solution to this problem.

OBJECTIVE

Our objective was to evaluate the association between exposure to a packed red blood cell (PRBC) transfusion and development of NEC in a cohort where biases of matching are omitted.

DESIGN

In a retrospective cohort, exposed infants were defined as those who received a transfusion and did not develop NEC or developed NEC within 48 h of the transfusion. All others were considered unexposed.

SETTING

A single regional perinatal centre in Memphis, Tennessee, USA.

PATIENTS

3060 ≤1500 g birth weights (BW) were included.

OUTCOME MEASURES

The relative risk of developing NEC after exposure to a PRBC transfusion was measured.

RESULTS

3060 infants were identified. 174 infants (5.7%) developed NEC; 116 of the 174 infants (67%) were exposed. NEC infants had a significantly lower BW (924 vs 1042 g) and required a longer stay on a ventilator (7 vs 2 days). Divided into groups, infants with BW ≤750 , 751-1000 , 1001-1250 g and 1251-1500 g (n=52, 51, 46 and 25, respectively) had a relative risk of 0.14, 0.46, 1.83 and 1.78 (p<0.01, 0.02, 0.07 and 0.17), respectively, to develop NEC after an exposure. Infants with longest ventilator days were also significantly less likely to develop NEC after an exposure; relative risk=0.11 (p<0.01).

CONCLUSIONS

Exposure to transfusions was less likely associated with NEC in ≤1000 g infants and remained a risk factor in 1001-1500 infants. BW has to be factored in any study evaluating the association between PRBC transfusions and NEC.

Packed red blood cell transfusion is an independent risk factor for necrotizing enterocolitis in premature infants

OBJECTIVE

To determine whether a temporal association exists between antecedent packed red blood cell (PRBC) transfusions and necrotizing enterocolitis (NEC) in premature infants.

STUDY DESIGN

This case-control study included inborn infants from a single center who developed NEC during a 2-year period. For every NEC infant, two matched controls from the same period were chosen based on gestational age and birth weight. Transfusion-related NEC was defined as antecedent PRBC transfusion within 48 h prior to the onset of any symptoms attributable to NEC. Bivariate analyses were used to compare baseline characteristics of all infants. To determine the raw odds ratio for the presence of exposure (transfusion) versus outcome (NEC), the hospital course (ages 6 to 63 days) of all study infants was divided into 48-h epochs; occurrence of transfusion and NEC was noted within each epoch. Generalized estimating equations were used to estimate the adjusted odds for developing NEC within an epoch with and without antecedent transfusion, controlling chronological age within infant as well as for gestational age, gender, feeding status in prior 48-h epoch and indicators of disease severity.

RESULT

There were 3652 48-h epochs and 557 transfusions among 49 NEC infants and 97 controls; 17 infants had transfusion-related NEC, yielding a raw odds ratio of 3.01 (P<0.001). The adjusted odds ratios were 2.97 (P=0.003) for transfusion and 2.76 (P=0.05) for feeding status in the prior 48-h epoch. Infants who were being fed in the 48-h period prior to transfusion were more than eight times more likely to develop NEC than infants who were neither fed nor transfused.

CONCLUSION

Antecedent PRBC transfusion appears to be an independent risk factor for developing NEC during the subsequent 48-h period.

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.

Transfusion-associated necrotizing enterocolitis: translating knowledge into nursing practice

Necrotizing enterocolitis (NEC) is a leading cause of prolonged hospitalizations for premature infants in the United States. In a recent large retrospective study, a significant proportion of NEC cases were shown to occur within 48 hours of packed red blood cell (PRBC) transfusion, especially in growing preterm neonates of older postnatal age. A small body of evidence consistently demonstrates that 25-35 percent of NEC cases are temporally associated with PRBC transfusion and that cases of NEC associated with transfusion are generally more severe with a higher rate of surgical intervention and mortality. Awareness of this association is vital for potential prevention and early recognition of NEC. The neonatal nurse has a primary role in care strategies that may affect NEC. This review of literature was compiled to educate neonatal nurses about the existence of transfusion-associated necrotizing enterocolitis and guide the translation of knowledge into nursing practice at the bedside.

Analysis of the association between necrotizing enterocolitis and transfusion of red blood cell in very low birth weight preterm infants

Purpose

To investigate the association between necrotizing enterocolitis (NEC) and red blood cell transfusions in very low birth weight (VLBW) preterm infants.

Methods

We studied were 180 VLBW preterm infants who were admitted to the neonatal intensive care unit of CHA Gangnam Hospital from January of 2006 to December of 2009. The subjects were divided into 2 groups: an NEC group (greater than stage II on the modified Bell's criteria) and a control group (less than stage II on the modified Bell's critieria). We defined red blood cell transfusion before NEC diagnosis as the frequency of transfusion until NEC diagnosis (mean day at NEC diagnosis, day 18) in the NEC group and the frequency of transfusion until 18 days after birth in the control group.

Results

Of the 180 subjects, 18 (10%) belonged to the NEC group, and 14 (78%) of these 18 patients had a history of transfusion before NEC diagnosis. The NEC group received 3.1±2.9 transfusions, and the control group received 1.0±1.1 transfusions before the NEC diagnosis (P=0.005). In a multivariate logistic regression corrected for gestational age, Apgar score at 1 minute, the presence of respiratory distress syndrome, patent ductus arteriosus, premature rupture of membrane, disseminated intravascular coagulopathy and death were confounding factors. The risk of NEC increased 1.63 times (95% confidence interval, 1.145 to 2.305; P=0.007) with transfusion before the NEC diagnosis.

Conclusion

The risk for NEC increased significantly with increased transfusion frequency before the NEC diagnosis.

Association between red cell transfusions and necrotizing enterocolitis

OBJECTIVE

Several case reports and retrospective studies have reported a temporal association between red blood cell (RBC) transfusions and necrotizing enterocolitis (NEC). In this article, we review the clinical evidence and biological plausibility of the association between RBC transfusions and NEC.

METHODS

A literature search was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RESULTS

Among all cases of NEC, 25 -40% patients were noted to have received an RBC transfusion within a 48 hour period prior to onset of NEC. Compared to infants who developed NEC unrelated to transfusion, neonates with transfusion-associated NEC were born at an earlier gestation, had lower birth weights, and had a delayed onset at 3-5 weeks of postnatal age.

CONCLUSIONS

Based on current clinical evidence, transfusion-associated NEC appears to be a plausible clinical entity. However, there is a need for cautious interpretation of data because all the studies that have been conducted until date are retrospective, and therefore, susceptible to bias. A large, prospective, multi-center trial is needed to evaluate the association between RBC transfusion and NEC.

Red blood cell transfusion-related necrotizing enterocolitis in very-low-birthweight infants: a near-infrared spectroscopy investigation

BACKGROUND

Recent evidence suggests that antecedent red blood cell (RBC) transfusions increase the risk for necrotizing enterocolitis (NEC), the most common gastrointestinal emergency encountered by very-low-birthweight (VLBW) infants. The underlying mechanism for this association is unknown. Altered oxygenation of the mesenteric vasculature during RBC transfusion has been hypothesized to contribute to NEC development and was investigated in this study.

STUDY DESIGN AND METHODS

Oxygenation patterns among four VLBW infants who developed transfusion-related NEC (TR-NEC) were compared to four VLBW infants with similar gestational age who were transfused but did not develop NEC (non-NEC). Cerebral and mesenteric patterns were recorded before, during, and 48 hours after RBC transfusion using near-infrared spectroscopy (NIRS) technology. Percentage change from mean baseline regional oxygen saturation values and cerebrosplanchnic oxygenation ratios were analyzed.

RESULTS

All TR-NEC infants (24-29 weeks' gestation; 705-1080 g) demonstrated greater variation in mesenteric oxygenation patterns surrounding transfusions than non-NEC infants (27.6-30 weeks' gestation; 980-1210 g). TR-NEC infants received larger mean volumes of total blood (27.75 ± 8.77 mL/kg) than non-NEC infants (15.25 ± 0.5 mL/kg).

CONCLUSION

Wide fluctuation and decreases in mesenteric oxygenation patterns are more pronounced in TR-NEC infants, especially before TR-NEC onset, compared to non-NEC infants. Greater total volume of infused blood was associated with TR-NEC in preterm infants. Using NIRS, larger prospective studies are needed to further evaluate potential risk factors for NEC in this high-risk population.

A clinical perspective of necrotizing enterocolitis: past, present, and future

Necrotizing enterocolitis (NEC) primarily affects premature infants. It is less common in term and late preterm infants. The age of onset is inversely related to the postmenstrual age at birth. In term infants, NEC is commonly associated with congenital heart diseases. NEC has also been associated with other anomalies. More than 85% of all NEC cases occur in very low birth weight infants or in very premature infants. Despite incremental advances in our understanding of the clinical presentation and pathophysiology of NEC, universal prevention of this disease continues to elude us even in the twenty-first century.

Thrombocytosis and thrombocytopenia in the NICU: incidence, mechanisms and treatments

OBJECTIVE

Quantitative and qualitative platelet abnormalities of neonates must be defined using evidence-based reference ranges, constructed according to gestational and postnatal age.

METHODS

Platelet counts, and demographic and outcome data, were obtained from neonates in the Intermountain Healthcare system in the western USA and template bleeding times were determined from neonates in Italy.

RESULTS

Reference ranges were constructed by excluding values from neonates with diagnoses associated with abnormal platelet counts (small for gestational age (SGA), pregnancy-induced hypertension (PIH), infection and necrotizing enterocolitis (NEC)). Values remaining in the database after excluding these diagnoses were organized into 5th to 95th percentile ranges. At 23-25 weeks gestation, thrombocytopenia (<5th percentile) was defined by a platelet count <100,000/µl. Severe thrombocytopenia (platelet count <50,000/µl) occurred in 2.4% of neonatal intensive care unit (NICU) admissions and was largely due to acquired consumptive causes (bacterial and fungal sepsis, NEC and extracorporeal membrane oxygenation). No correlation was found between platelet count and subsequent central nervous system (CNS), pulmonary or gastrointestinal (GI) bleeding. The mortality rate did not correlate with the lowest platelet count but was proportionate to the number of platelet transfusions received. Platelet transfusions, administered according to guidelines, were given to 7% of NICU admissions, but a change in the guidelines from "count-based" to "mass-based" was associated with a reduction to 4%, with no increase in CNS, pulmonary, GI or cutaneous haemorrhage. Bleeding times were twice as long in neonates <33 weeks gestation as in term neonates, and shortened to term values by day of life ten.

CONCLUSIONS

When reference ranges for platelets, appropriate to gestational and postnatal ages, are used, more uniformity occurs in definitions. This uniformity will foster consistency in diagnosis, treatment and outcomes-reporting.

Plasma cytokines and markers of endothelial activation increase after packed red blood cell transfusion in the preterm infant

BACKGROUND

Transfusion of packed red blood cells (PRBCs) saves lives in the neonatal critical care setting and is one of the most common interventions in the preterm infant. The number and volume of PRBC transfusions are associated with several major neonatal morbidities, although a direct causal link between transfusion and major neonatal morbidity is still to be proven. Transfusion-related immunomodulation (TRIM) may underlie these adverse outcomes, yet it has received little attention in the high-risk preterm infant.

METHODS

One transfusion event was studied in infants ≤28 wk gestation between 2 and 6 wk postnatal age (n = 28). Plasma inflammatory cytokines and markers of endothelial activation were measured in the infants before and 2-4 h after transfusion, as well as in the donor pack.

RESULTS

Median (range) age at transfusion was 18 (14-39) days with the pretransfusion hemoglobin level at 9.8 (7.4-10.2) g/dl. Interleukin (IL)-1β (P = 0.01), IL-8 (P = <0.001), tumor necrosis factor-α (P = 0.008), and monocyte chemoattractant protein (P = 0.01) were increased after transfusion. A similar elevation in markers of endothelial activation was seen after transfusion with increased plasma macrophage inhibitory factor (P = 0.005) and soluble intracellular adhesion molecule-1 (P = <0.001).

CONCLUSION

Production of inflammatory cytokines and immunoactivation of the endothelium observed after the transfusion of PRBCs in the preterm infant may be a manifestation of TRIM. The implications of this emerging phenomenon within the preterm neonatal population warrant further investigation.

What really causes necrotising enterocolitis?

Background. One of the most serious gastrointestinal disorders occurring in neonates is necrotising enterocolitis (NEC). It is recognised as the most common intra-abdominal emergency and is the leading cause of short bowel syndrome. With extremely high mortality and morbidity, this enigmatic disease remains a challenge for neonatologists around the world as its definite aetiology has yet to be determined. As current medical knowledge stands, there is no single well-defined cause of NEC. Instead, there are nearly 20 risk factors that are proposed to increase the likelihood of developing NEC. Aims and Objectives. The aim of this project was to conduct a comprehensive literature review around the 20 or so well-documented and less well-documented risk factors for necrotising enterocolitis. Materials and Methods. Searches of the Medline, Embase, and Science direct databases were conducted using the words "necrotising enterocolitis + the risk factor in question" for example, "necrotising enterocolitis + dehydration." Search results were ordered by relevance with bias given to more recent publications. Conclusion. This literature review has demonstrated the complexity of necrotising enterocolitis and emphasised the likely multifactorial aetiology. Further research is needed to investigate the extent to which each risk factor is implicated in necrotising enterocolitis.

Neonates presenting with bloody stools and eosinophilia can progress to two different types of necrotizing enterocolitis

OBJECTIVE

We hypothesized that neonates with bloody stools and concomitant eosinophilia are likely to have atopic enteropathy rather than necrotizing enterocolitis (NEC).

STUDY DESIGN

This was a retrospective cross-sectional study using electronic medical records and paper charts. Records of neonates admitted to any Intermountain Healthcare NICU between 1 January 2005 and 30 June 2010 were eligible if 'bloody stools' were listed in any archive. Qualifying records were divided into two groups depending on whether or not within 72 h of passing bloody stool eosinophil counts were above the 95th percentile reference range limit for age.

RESULT

Bloody stools were identified in 275 predominantly Caucasian neonates. Fifty-four of these had eosinophilia and 221 had normal eosinophil counts. Those with eosinophilia were born at a slightly younger gestational age (31.3 ± 4.6 vs 32.6 ± 4.0 weeks, mean ± s.d., P=0.032). Contrary to our hypothesis, those with eosinophilia did not have a lower rate of pneumatosis or bowel resection, or death ascribed to NEC. Eosinophilia was more common among those who had a red blood cell (RBC) transfusion within 48 h before passing bloody stools (P<0.001). Those with a recent RBC transfusion were the only neonates to have NEC surgery or to die from NEC. Preceding the bloody stools, those with no antecedent transfusion had been fed a larger volume (P=0.014), and had trends toward receiving calorically enriched feedings (P=0.055) and recent addition of human milk fortifier (P=0.060). Eosinophil counts following RBC transfusion tended to increase for 3-6 days, but when bloody stools were not preceded by transfusion the eosinophil counts were more static over that period.

CONCLUSION

In this predominantly Caucasian group of neonates with bloody stools, the presence of eosinophilia did not identify a benign condition distinct from NEC. A total of 44% of these neonates had transfusion-associated NEC. Eosinophils could have a previously unrecognized role in the pathogenesis of this NEC subtype.

Transfusion-associated necrotizing enterocolitis: evidence and uncertainty

Transfusion-associated necrotizing enterocolitis (TANEC) has been described as necrotizing enterocolitis (NEC) that arises within 48 hours of a blood transfusion. It has been shown to be associated with 25% to 35% of NEC cases in recent studies. Evidence related to TANEC is limited to observational, retrospective studies. Infants who develop TANEC tend to be smaller, born preterm, more severely ill, and develop NEC after 30 days of age. Evidence in 2 studies support holding feedings during transfusion to protect the preterm gut from the cascade of events that lead to NEC, but higher quality research, including prospective randomized controlled trials, is needed to evaluate the effect of feeding on TANEC.

Do transfusions cause necrotizing enterocolitis? The complementary role of randomized trials and observational studies

A systematic review and a meta-analysis of the published literature on the association between transfusions in newborns and the occurrence of transfusion-associated necrotizing enterocolitis were performed. We discuss the differences between findings in randomized trials, and the results of observational studies that first explored this putative link. We suggest the following framework: where observational studies play a hypothesis generating- role for therapies and harm, and randomized studies allow an acid test of that hypothesis. It is acknowledged that not all questions can be subject to a randomized evaluation, but argued that this particular association is amenable to such a test.

Transfusion-related acute gut injury: feeding, flora, flow, and barrier defense

TRAGI (transfusion-related acute gut injury) is an acronym we proposed to characterize a severe neonatal gastrointestinal reaction temporally related to a transfusion of packed blood red cells (PRBCs) for anemia in very low birth weights. The following are in support of a causative relationship: (1) the timing of necrotizing enterocolitis after a PRBC transfusion not being random, (2) traditional risk factors for necrotizing enterocolitis are often absent, (3) significant anemia appears to be a universal finding, (4) the age of donor blood is often slightly older than controls, (5) TRAGI is not postnatal age dependent, and (6) TRAGI does not show a centering at 31 weeks' postconceptual age as does nontransfusion-related NEC. Although TRAGI is linked to the timing of PRBC transfusions, we propose a novel hypothesis that the convergence at 31 weeks' postconceptual age for classic NEC approximates the age of presentation of other oxygen delivery and neovascularization syndromes (eg, retinopathy of prematurity), suggesting its etiologic link to a generalized systemic maturational mechanism or another common developmental theme. This report will begin by reviewing the history of the clinical presentation and discovery of TRAGI and will then analyze various pathophysiologic mechanisms that may account for the phenomenon when clinicians render therapies. We will end by a call to action for randomized clinical trials to test various etiologic theories.

Decreased survival in necrotizing enterocolitis is significantly associated with neonatal and maternal blood group: the AB isoagglutinin hypothesis

OBJECTIVE

To determine the effect of neonatal and maternal blood group on the mortality risk from necrotizing enterocolitis (NEC).

STUDY DESIGN

Retrospective chart review of all neonates admitted to the neonatal intensive care unit over 24 years. Data on birth date, gestational age, maternal/neonatal blood group, number of transfusions, and survival time (defined as date of birth to date of death/discharge) were collected on those with NEC.

RESULT

276 neonates with Bell stage II-III NEC were analyzed. AB neonates had a significantly higher risk of mortality from NEC compared with other blood groups (HR 2.87; 95% CI 1.40 to 5.89; P=0.003). Multivariate analysis showed AB blood group to be an independent risk factor for mortality from NEC.

CONCLUSION

Neonatal and maternal blood groups are significantly associated with a neonate's survival from NEC. The increased mortality of AB neonates may be related to factors such as neonatal blood group antigens and/or transplacental transfer of isoagglutinins.

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.

Transfusion-associated necrotising enterocolitis in very low birth weight premature infants

OBJECTIVE

Our aim was to determine the relationship between red blood cell transfusion and necrotising enterocolitis (NEC) in all admitted very low birth weight (VLBW) infants with or without transfusion.

STUDY DESIGN

All VLBW neonates were categorised into five groups: (i) subjects that developed NEC <48 h after transfusion (n = 15); (ii) subjects that developed NEC >48 h after transfusion (n = 31); (iii) subjects that were never transfused but developed NEC, (n = 50); (iv) subjects that were transfused but did not develop NEC, (n = 250) and (v) subjects that were neither transfused nor developed NEC (n = 301).

RESULTS

A group of 647 infants were enrolled in the study. Mean gestational age and birth weight of the patients were 29 ± 3.1 weeks and 1157 ± 237 g, respectively. The mean age at the onset of NEC in the NEC groups were 20 ± 2.3 days, 12 ± 3 days and 11 ± 2.6 days, respectively (P < 0.05). The mean interval from the last transfusion to the onset of NEC was 16.8 ± 8.8 h in group 1 and 240 ± 50 h in group 2 (P < 0.05).

CONCLUSION

In this study, we sought to evaluate all VLBW infants, whether they received a transfusion or not. We suggest that transfusion associated NEC exists, but many other factors influence this multifactorial disease. The age of NEC onset was later in transfused vs non-transfused patients, whereas the interval between transfusion and NEC was shorter in transfused vs non-transfused patients.

The safety and efficacy of red cell transfusions in neonates: a systematic review of randomized controlled trials

Premature neonates commonly receive red blood cell (RBC) transfusions. This study systematically identified and appraised randomized controlled trials (RCTs) where the intervention was 'transfusion of red blood cells' from searches of multiple databases. Primary review outcomes were mortality, neurodevelopmental and respiratory endpoints. Two reviewers extracted data and assigned overall quality. Twenty-seven RCTs were identified and grouped into four predefined categories: trials comparing RBC transfusion versus no transfusion/placebo (n = 3); different thresholds for transfusion (n = 6); differing doses or administration schedule (n = 4), or different types or products of RBC (n = 14). In the threshold group of trials, enrolling 679 neonates, no significant differences in mortality (relative risk 1·22, 95% confidence interval 0·84-1·75) or chronic lung disease were found. Only two trials assessed neurodevelopment outcomes, both within the threshold group, but with differing results. The largest subgroup of RCTs by number evaluated different media for storage of red cells (n = 7), enrolling 221 neonates. The methodological quality of many RCTs was poor. The design of future RCTs can be informed by the lessons from this review. Many trials failed to report on outcomes that would be considered of primary importance to clinicians. Consistent reporting of adverse events is required, and endpoints need to include neurodevelopmental outcomes.

Necrotizing enterocolitis risk: state of the science

Necrotizing enterocolitis (NEC) is the most common cause of gastrointestinal-related morbidity and mortality in the neonatal intensive care unit (NICU). Its onset is sudden and the smallest, most premature infants are the most vulnerable. Necrotizing enterocolitis is a costly disease, accounting for nearly 20% of NICU costs annually. Necrotizing enterocolitis survivors requiring surgery often stay in the NICU more than 90 days and are among those most likely to stay more than 6 months. Significant variations exist in the incidence across regions and units. Although the only consistent independent predictors for NEC remain prematurity and formula feeding, others exist that could increase risk when combined. Awareness of NEC risk factors and adopting practices to reduce NEC risk, including human milk feeding, the use of feeding guidelines, and probiotics, have been shown to reduce the incidence of NEC. The purpose of this review is to examine the state of the science on NEC risk factors and make recommendations for practice and research.

Fulminant necrotizing enterocolitis in a multihospital healthcare system

OBJECTIVE

A subset of necrotizing enterocolitis (NEC) cases is fulminant, characterized by rapid progression to death with massive bowel necrosis found at laparotomy or autopsy. We sought to identify and report all such cases in a multihospital healthcare system during the past 9 years and to characterize this entity using case-control methodologies.

STUDY DESIGN

This was a multicentered, cross-sectional, historic cohort study conducted using Intermountain Healthcare hospital patient data. All neonates who died of NEC within 48 h of onset, during 2001 to 2009, were compared with two matched control groups: (1) demographically matched controls who developed non-fulminant NEC, (2) demographically matched controls that did not develop NEC.

RESULT

During this period, 2 71 327 live births occurred in the Intermountain Healthcare hospitals. Of these, 318 had a diagnosis of NEC (Bell stage ≥II). Also during this period, 205 other neonates were transferred into an Intermountain hospital for treatment of NEC. Of these 523 NEC cases, 35 (6.7%) had a fulminant course. Compared with the non-fulminant cases, the fulminant group were born at lower weight (1088±545 vs 1652±817 g, P=0.000) and earlier gestational age (27.5±3.3 vs 31.1±4.4 weeks, P=0.000), and were more likely to have: (1) radiographic evidence of portal venous air (P=0.000), (2) hematocrit <22% (P=0.000), (3) increase in feeding volume >20 ml/kg/day (P=0.003), (4) immature to total (I/T) neutrophil ratio >0.5 (P=0.005), (5) blood lymphocyte count <4000/μl (P=0.018), (6) an increase in concentration of human milk fortifier within 48 h before developing NEC (P=0.020).

CONCLUSION

Portal venous air, anemia, rapid feeding escalation, a high I/T neutrophil ratio, a low lymphocyte count and recent increases in fortifier may all be associated with fulminant NEC.

Hematological interventions in NICU care: the use of rEpo, IVIG, and rG-CSF

This article focuses on the use of rEpo, IVIG, and rG-CSF in the NICU. It discusses the most recent studies and the most definitive and clinically relevant evidence, rather than summarizing all published studies. The last section was written for NICU practice groups that choose to use any of these medications and are seeking a consistent approach for doing so. The section provides the author's approach to the use of rEpo, IVIG, and rG-CSF, revealing personal preferences, interpretations, and experiences, and is based on the dictum, "if you are going to use it, use it the same way each time."

Transfusion associated necrotizing enterocolitis: a meta-analysis of observational data

BACKGROUND AND OBJECTIVES

Several studies have reported the possibility of an association between recent exposure to transfusion and development of necrotizing enterocolitis (NEC). Our objective was to systematically review and meta-analyze the association between transfusion and NEC (TANEC), identify predictors of TANEC, and the assess impact of TANEC on outcomes.

METHODS

Medline, Embase, CINAHL, and bibliographies of identified articles were searched for studies assessing association with recent (within 48 hours) exposure to transfusion and NEC. Two reviewers independently collected data and assessed the quality of the studies for bias in sample selection, exposure assessment, confounders, analyses, outcome assessments, and attrition. Meta-analyses were performed by using random effect model, and odds ratio and 95% confidence interval were calculated.

RESULTS

Eleven retrospective case-control studies and 1 cohort study of moderate risk of bias were included. Ten case-control studies had NEC not associated with transfusion as control patients (unmatched). Recent exposure to transfusion was associated with NEC. Neonates who developed TANEC were younger by 1.5 weeks, were of 528 g lower birth weight, were more likely to have patent ductus arteriosus, and were more likely receiving ventilatory support. TANEC infants had higher risk of mortality. Two pre-post comparative studies of 20 patients reported reduction of TANEC after withholding feeds during transfusion.

CONCLUSIONS

Recent exposure to transfusion was associated with NEC in neonates. Neonates who developed TANEC were at overall higher risk of NEC. TANEC patients were at higher risk of mortality, but additional studies adjusting for confounders are needed.

Increased odds of necrotizing enterocolitis after transfusion of red blood cells in premature infants

OBJECTIVES

To determine if infants with very low birth weight who receive packed red blood cell (PRBC) transfusions have increased odds of developing necrotizing enterocolitis (NEC), to determine the rate of NEC after PRBC transfusion, and to characterize the blood transfused preceding the onset of NEC.

STUDY DESIGN

A retrospective cohort design was used. The study population included infants with a birth weight of <1500 g who were from a single center. NEC after transfusion was defined as NEC that occurred in the 48 hours after initiation of PRBC transfusion. Statistical analysis included unadjusted and multivariable analyses.

RESULTS

The study sample included 2311 infants. A total of 122 infants (5.3%) developed NEC, and 33 (27%) of 122 NEC cases occurred after transfusion. NEC occurred after 33 (0.5%) of 6484 [corrected] transfusions. Infants who received a transfusion had increased adjusted odds (odds ratio: 2.3 [95% confidence interval: 1.2-4.2]) of developing NEC compared with infants who did not receive a transfusion. PRBCs transfused before NEC were predominantly (83%) from male donors and were a median of 5 days old.

CONCLUSIONS

In our study sample, PRBC transfusion was associated with increased odds of NEC. The rate of NEC after transfusion was 1.4%. From our data we could not determine if PRBC transfusions were part of the causal pathway for NEC or were indicative of other factors that may be causal for NEC.