Transfusion-related acute gut injury: necrotizing enterocolitis in very low birth weight neonates after packed red blood cell transfusion

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.

Prevention and early recognition of necrotizing enterocolitis: a tale of 2 tools--eNEC and GutCheckNEC

BACKGROUND AND SIGNIFICANCE

Risk for neonatal necrotizing enterocolitis (NEC) is complex, reflecting its multifactorial pathogenesis.

PURPOSE

To improve risk awareness and facilitate communication among neonatal caregivers, especially nurses, 2 tools were developed.

DESIGN

GutCheck was derived and validated as part of a formal research study over 3 phases, evidence synthesis, expert consensus building, and statistical modeling. The Wetzel/Krisman tool, eNEC, was developed and tested as part of a quality improvement initiative in a single clinical setting using evidence synthesis, review by internal expert clinicians, and implementation and evaluation of its use by direct line neonatal staff. Refinement of both tools is under way to evaluate their effect on clinical decision making, early identification of NEC and surgical NEC.

METHODS AND MAIN OUTCOMES

Clinicians can take an active role to reduce NEC in their units by focusing on modifiable risk factors such as adoption of standardized feeding protocols, preferential feeding of human milk, and antibiotic and histamine blocker stewardship.

RESULTS

Feeding during transfusion remains controversial, but judicious use of transfusions, adoption of transfusion guidelines, and withholding feeding during transfusion are feasible measures with potential benefit to prevent NEC and confer little risk.

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

BACKGROUND

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

OBJECTIVES

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

SEARCH METHODS

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

SELECTION CRITERIA

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

DATA COLLECTION AND ANALYSIS

The methods of the Neonatal Cochrane Review Group were used.

MAIN RESULTS

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

AUTHORS' CONCLUSIONS

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

Methylglyoxal concentrations differ in standard and washed neonatal packed red blood cells

BACKGROUND

Preterm infants have a greater risk of necrotizing enterocolitis following transfusion. It is hypothesized that high glucose concentrations in red blood cell (RBC) preservatives lead to increased methylglyoxal (MG) metabolism, causing glycation-driven damage to transfused RBCs. Such changes to the RBCs could promote a proinflammatory state in transfusion recipients.

METHODS

Standard and washed RBCs in Adsol-3, two common neonatal preparations, were studied. Consecutive measurements were performed of glucose, MG, reduced glutathione, glyoxalase I activity (GLO-I), and D-lactate, the stable end product of MG detoxification by glyoxalase enzymes over the 42-d storage period.

RESULTS

RBC units consume glucose and produceD-lactate and MG during storage. In 28/30 units, the MG concentrations showed only small variations during storage. Two units had elevated MG levels (>10 pmol/mg Hb) during the first half of storage. Washing of the RBCs significantly reduced both MG and D-lactate.

CONCLUSION

This study shows two patterns of MG metabolism in packed RBCs for neonatal transfusion and raises the possibility that RBC units with higher MG levels may have increased glycation-driven damage in the transfused RBCs. Whether transfused MG could trigger an inflammatory response such as necrotizing enterocolitis in preterm neonates and whether washing could prevent this require further study.

The relationship between reticulated platelets, intestinal alkaline phosphatase, and necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) affects up to 10% of extremely-low-birthweight infants, with a 30% mortality rate. Currently, no biomarker reliably facilitates early diagnosis. Since thrombocytopenia and bowel ischemia are consistent findings in advanced NEC, we prospectively investigated two potential biomarkers: reticulated platelets (RP) and intestinal alkaline phosphatase (iAP).

METHODS

Infants born ≤ 32 weeks and/or ≤ 1500 g were prospectively enrolled from 2009 to 2012. Starting within 72 hours of birth, 5 weekly whole blood specimens were collected to measure RP and serum iAP. Additional specimens were obtained at NEC onset (Bell stage II or III) and 24 hours later. Dichotomous cut-points were calculated for both biomarkers. Non-parametric (Mann-Whitney) and Chi-square tests were used to test differences between groups. Differences in Kaplan-Meier curves were examined by log-rank test. The Cox proportional hazards model estimated hazard ratios.

RESULTS

A total of 177 infants were enrolled in the study, 15 (8.5%) of which developed NEC (40% required surgery and 20% died). 14 (93%) NEC infants had "low" (≤ 2.3%) reticulated platelets, and 9 (60%) had "high" iAP (>0 U/L) in at least one sample before onset. Infants with "low" RP were significantly more likely to develop NEC [HR=11.0 (1.4-83); P=0.02]. Infants with "high" iAP were at increased risk for NEC, although not significant [HR=5.2 (0.7-42); P=0.12]. Median iAP levels were significantly higher at week 4 preceding the average time to NEC onset by one week (35.7 ± 17.3 days; P=0.02).

CONCLUSION

Decreased RP serves as a sensitive marker for NEC onset, thereby enabling early preventative strategies. iAP overexpression may signal NEC development.

Restrictive versus liberal red blood cell transfusion thresholds in very low birth weight infants: a systematic review and meta-analysis

AIM

A systematic review was conducted to examine the effects of restrictive versus liberal red blood cell (RBC) transfusion thresholds on clinically important outcomes in very low birth weight (VLBW) infants.

METHODS

Randomised controlled trials (RCTs) of varying RBC transfusion thresholds in VLBW infants were identified by searching MEDLINE, EMBASE, CINAHL, all of the Cochrane Library and other supplementary sources. Selected studies included one of the following outcomes: total number of red blood cell transfusions, donor exposure rate, cranial ultrasonographically diagnosed brain injury, retinopathy of prematurity, bronchopulmonary dysplasia, necrotising enterocolitis or death. Studies to be included were selected by two reviewers who also assessed the risk of bias of each trial. Data extraction and analyses were independently performed by two reviewers. All data were analysed using RevMan 5.

RESULTS

Six RCTs were identified. One trial did not meet the inclusion criteria, while two had inadequate methodological quality. Pooled analysis of two trials showed that the restrictive transfusion group received a significantly lower mean number of transfusions per infant (mean difference (MD) -1.35, 95% confidence interval (CI) [-2.61, -0.09]) and donor exposure rate (MD -0.54, 95% CI [-0.93, -0.15]). No other statistically significant differences were observed.

CONCLUSION

Restrictive RBC transfusion thresholds in VLBW infants may be utilised without incurring clinically important increases in the risk of death or major short-term neonatal morbidities.

Transfusion and hemovigilance in pediatrics

Hemovigilance is an essential part of the transfusion process and is defined as surveillance procedures covering the whole transfusion chain, from collection of blood and its components, intended to collect and assess information on unexpected or undesirable effects resulting from the therapeutic use of labile blood products and to prevent their occurrence or recurrence. The UK surveillance scheme has collected data for 16 years and is a model demonstrating how information on adverse incidents can be used to improve patient safety, influencing the management of donors and improved education and training for the many people involved in the transfusion process.

Packed red cell transfusions alter mesenteric arterial reactivity and nitric oxide pathway in preterm lambs

BACKGROUND

Cases of necrotizing enterocolitis occurring within 48 h of packed red blood cell (PRBC) transfusions are increasingly being described in observational studies. Transfusion-associated gut injury is speculated to result from an abnormal mesenteric vascular response to transfusion. However, the mechanism of disruption of the balance between mesenteric vasoconstriction and relaxation following transfusion is not known.

METHODS

Preterm lambs (n = 16, 134 d gestation; term: 145-147 d) were delivered and ventilated for 24 h. All the lambs received orogastric feeds with colostrum. In addition, 10 of these lambs received PRBC transfusions. Vasoreactivity was evaluated in isolated mesenteric arterial rings using norepinephrine and endothelin-1 as vasoconstrictors. Endothelium-dependent (A23187, a calcium ionophore) and endothelium-independent (SNAP) nitric oxide (NO) donors were used as vasorelaxants. Mesenteric arterial endothelial NO synthase (eNOS), soluble guanylyl cyclase (sGC), and phosphodiesterase 5 (PDE5) mRNA analyses and protein assays were performed.

RESULTS

Transfusion with PRBC significantly increased mesenteric vasoconstriction to norepinephrine and endothelin-1 and impaired relaxation to A23187 and SNAP. Mesenteric arterial eNOS protein decreased following PRBC transfusion. No significant changes were noted in sGC and PDE5 mRNA or protein assays.

CONCLUSION

PRBC transfusion in enterally fed preterm lambs promotes mesenteric vasoconstriction and impairs vasorelaxation by reducing mesenteric arterial eNOS.

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.

Does non-transferrin bound iron contribute to transfusion related immune-modulation in preterms?

OBJECTIVE

There is increasing awareness that allogeneic transfusion is potentially harmful in preterm neonates secondary to transfusion related immunomodulation (TRIM). Non-transferrin bound iron (NTBI) may contribute to TRIM by promoting oxidative damage and pro-inflammatory cytokine release. The current study aimed to determine if transfusion early in the neonatal period resulted in an increase in circulating NTBI, oxidative stress and immune activation.

DESIGN

Prospective observational study.

SETTING

One transfusion event was studied in infants ≤28 weeks gestation between 2 and 6 weeks postnatal age (n=33) admitted to a tertiary neonatal intensive care unit.

METHODS

Serum NTBI, inflammatory cytokines and malondialdehyde (MDA) were measured from the donor pack, prior to and at 2-4 and 24 h post-transfusion.

RESULTS

Median (range) age at transfusion was 17 (14-39) days with the pretransfusion haemoglobin level 9.6 (7.4-10.4) g/dl. NTBI was detectable in 18 (51%) of the transfusion packs. NTBI levels were higher after transfusion (p<0.01) returning to pretransfusion levels by 24 h. Post-transfusion NTBI level correlated with the age of transfused blood (p<0.001) and was positively correlated with plasma MDA (p=0.01) but not IL-1β, IL-6, IL8 or TNFα.

CONCLUSIONS

Circulating NTBI is transiently elevated following blood transfusion in preterm newborns. This increase was related to the age of blood transfused and correlated with increases in oxidative stress but not pro-inflammatory cytokines. While further studies are necessary to determine whether these transient effects influence clinical outcome, the current data do not support a significant role in the very preterm neonate for NTBI in TRIM.

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-related necrotizing enterocolitis: a conceptual framework

Necrotizing enterocolitis (NEC) is a disease primarily of prematurity characterized by partial or entire gut necrosis and is associated with significant mortality and morbidity. Recent studies report that approximately 25% to 35% of very low-birth-weight infants less than 1500 g receiving packed red blood cell transfusions develop temporally associated NEC, known as transfusion-related NEC (TR-NEC). Although there are many known risk factors for NEC, this article focuses on 3 contributing factors: packed red blood cell transfusions, enteral feedings, and gastrointestinal immaturity. Previous data suggest that these factors may interact to affect neonatal intestinal tissue oxygenation, which may lead to tissue ischemia, resulting in intestinal injury. This article presents a conceptual framework that combines current theoretical perspectives for TR-NEC, and reviews previous research examining related variables and how their interaction may increase the risk for TR-NEC development. In addition, incorporation of the proposed framework to guide future research and nursing care in this area is discussed.

Factors affecting the severity of necrotizing enterocolitis

OBJECTIVE

The severity of necrotizing enterocolitis (NEC) ranges from mild to rapidly fatal. However, the factors determining the severity are not known. Our objective was to identify statistical associations with NEC severity using a large database.

METHOD

We conducted a retrospective, multi-institutional, multiyear, study of neonates with confirmed NEC.

RESULTS

Two-hundred-twenty neonates with Bell's stage ≥ II NEC had 225 NEC episodes (157 stage II and 68 stage III). In the 3 d before NEC was diagnosed, those who went on to stage III disease were more likely to have elevations in C - reactive protein (p < 0.0001), immature to total neutrophil ratio (p = 0.0005), and mean platelet volume (p = 0.0001), and low pH (p < 0.0001) and platelet count (p < 0.0001). Regression analysis indicated higher odds that NEC would be severe if there was an antecedent RBC transfusion (p < 0.0001) or if the first feedings were not colostrum (p = 0.017). The two factors best predicting death from NEC were; (1) a low pH (p = 0.0005) and (2) lack of early colostrum (p = 0.003).

CONCLUSIONS

Strategies that reduce the severity of NEC would lower costs and improve outcomes. This study suggests that testable theories to accomplish this include means of; (1) reducing transfusions and (2) assuring early colostrum feedings.

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.

The role of the intestinal microbiota in the pathogenesis of necrotizing enterocolitis

Development of necrotizing enterocolitis (NEC) requires a susceptible host, typically a premature infant or an infant with congenital heart disease, enteral feedings and bacterial colonization. Although there is little doubt that microbes are critically involved in the pathogenesis of NEC, the identity of specific causative pathogens remains elusive. Unlike established normal adult gut microbiota, which is quite complex, uniform, and stable, early postnatal bacterial populations are simple, diverse, and fluid. These properties complicate studies aimed at elucidating characteristics of the gut microbiome that may play a role in the pathogenesis of NEC. A broad variety of bacterial, viral, and fungal species have been implicated in both clinical and experimental NEC. Frequently, however, the same species have also been found in physiologically matched healthy individuals. Clustered outbreaks of NEC, in which the same strain of a suspected pathogen is detected in several patients suggest, but do not prove, a causative relationship between the specific pathogen and the disease. Studies in Cronobacter sakazakii, the best characterized NEC pathogen, have demonstrated that virulence is not a property of a bacterial species as a whole, but rather a characteristic of certain strains, which may explain why the same species can be pathogenic or non-pathogenic. The fact that a given microbe may be innocuous in a full-term, yet pathogenic in a pre-term infant has led to the idea of opportunistic pathogens in NEC. Progress in understanding the infectious nature of NEC may require identifying specific pathogenic strains and unambiguously establishing their virulence in animal models.

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.

Biomarkers for prediction and diagnosis of necrotizing enterocolitis

This article summarizes the commonly used biomarkers currently available for diagnosis of necrotizing enterocolitis. The most exciting advances in diagnostic tests were the use of new nucleic acid sequencing techniques (eg, next-generation sequencing) and molecular screening methods (eg, proteomics and microarray analysis) for the discovery of novel biomarkers. The new technology platform coupled with stringent protocols of biomarker discovery and validation would enable neonatologists to study biologic systems at a level never before possible and discover unique biomarkers for specific organ injury and/or disease entity.

Pharmacological treatment of neonatal seizures: a systematic review

Pharmacologic treatment options for neonatal seizures have expanded over the past 2 decades, and there is no consensus on optimal treatment strategy. We systematically reviewed the published literature to determine which medication(s) are most effective for treating neonatal seizures, by retrieving trials and observational investigations via PubMed (through August 2011) that focused on pharmacological seizure treatment of neonates (≤ 28 days old) and utilized continuous or amplitude-integrated EEG to confirm seizure diagnosis and cessation. Our search identified 557 initial articles and 14 additional studies after reference reviews, with 16 meeting inclusion criteria. Of these, 2 were randomized trials and only 3 additional investigations included comparison groups. We found limited evidence regarding the best pharmacologic treatment for neonatal seizures, but were able to devise a treatment algorithm from available data. These findings have the potential to serve as a clinical reference and to inform the design of comparative effectiveness investigations for neonatal antiepileptics.

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.

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.

Necrotizing enterocolitis after red blood cell transfusion in preterm infants with patent ductus arteriosus: a case series

AIM

Both patent ductus arteriosus (PDA) and packed red blood cell (PRBC) transfusion are risk factors for necrotizing enterocolitis (NEC). The combination of PDA and PRBC transfusion may have a synergistic effect on the intestinal circulation.

METHODS

We present four cases of NEC in very low birth weight (VLBW) infants within 14 h after PRBC transfusion.

RESULTS

All infants were growing on full enteral feeding, and they all had a PDA.

CONCLUSION

We are concerned that the simultaneous presence of a PDA and PRBC transfusion in VLBW infants may place the infant at even greater risk of NEC than each of these factors alone.

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.

Necrotizing enterocolitis and the role of anemia of prematurity

Necrotizing enterocolitis (NEC) is one of the most common surgical diseases of preterm infants, with significant short- and long-term morbidity and mortality. Although the etiology of NEC remains elusive, multiple factors adversely affecting the intestinal mucosal integrity of preterm infants are known to be associated with NEC. Anemia and red blood cell (RBC) transfusion-related gut injury have been shown to have strong correlation with NEC. Anemia potentially compromises mucosal integrity with subsequent poor healing, and this injury may be augmented by yet unknown factors associated with RBC transfusions. Although convincing evidence is lacking, there is a need for guidelines to keep the hematocrit within clinically and physiologically relevant limits by appropriate interventions. Further investigations need to focus on assessing the interplay between anemia, chronically hypoxemic/hypoperfused intestines, and early iron therapy or other pharmacologic approaches for prevention/treatment of anemia and RBC transfusions.

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 'Effects of Transfusion Thresholds on Neurocognitive Outcome of Extremely Low Birth-Weight Infants (ETTNO)' Study: Background, Aims, and Study Protocol

Background: Infants with extremely low birth weight uniformly develop anemia of prematurity and frequently require red blood cell transfusions (RBCTs). Although RBCT is widely practiced, the indications remain controversial in the absence of conclusive data on the long-term effects of RBCT. Objectives: To summarize the current equipoise and to outline the study protocol of the 'Effects of Transfusion Thresholds on Neurocognitive Outcome of extremely low birth-weight infants (ETTNO)' study. Methods: Review of the literature and design of a large pragmatic randomized controlled trial of restrictive versus liberal RBCT guidelines enrolling 920 infants with birth weights of 400-999 g with long-term neurodevelopmental follow-up. Results and Conclusions: The results of ETTNO will provide definite data about the efficacy and safety of restrictive versus liberal RBCT guidelines in very preterm infants.

A randomized, masked study of weekly erythropoietin dosing in preterm infants

OBJECTIVE

To compare reticulocyte responses of once-per-week erythropoietin (EPO) dosing with 3-times-a-week dosing in preterm infants.

STUDY DESIGN

Infants weighing ≤ 1500 g and ≥ 7 days of age were randomized to once-per-week EPO, 1200 U/kg/dose, or 3-times-a-week EPO, 400 U/kg/dose, subcutaneously for 4 weeks, along with iron and vitamin supplementation. Complete blood counts, absolute reticulocyte counts (ARCs), transfusions, phlebotomy losses, and adverse events were recorded.

RESULTS

Twenty preterm infants (962 ± 55 g, 27.9 ± 0.4 weeks, 17 ± 3 days of age) were enrolled. Groups were similar at baseline. Infants in both groups had increased ARCs, which were similar between treatment groups at the start and end of 4 weeks. Hematocrit remained stable, and similar numbers of transfusions were administered. No adverse effects of either dosing schedule were noted.

CONCLUSIONS

Preterm infants respond to weekly EPO by increasing ARCs and maintaining hematocrit. We speculate that once-per-week EPO dosing might be beneficial to preterm infants requiring increased erythropoiesis.

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.

Clinical and research issues in neonatal anemia and thrombocytopenia

PURPOSE OF REVIEW

Anemia and thrombocytopenia are the most common hematological problems in neonates. Red blood cell (RBC) and platelet transfusions are the mainstays of therapy, but data to guide neonatal transfusion practices have been sparse. Recombinant hematopoietic growth factors represent another therapeutic alternative, but their use in this population requires a solid understanding of the developmental differences between fetal and adult hematopoiesis.

RECENT FINDINGS

Recently, follow-up studies from children randomized as neonates to either liberal or restrictive RBC transfusion approaches were published. Results of these studies have so far been contradictory and have generated more questions than answers. New developmental stage-specific problems associated with RBC transfusions were also uncovered, such as the transfusion-associated necrotizing enterocolitis. Finally, two thrombopoietin (Tpo) mimetics were approved by the FDA for the treatment of adults with chronic immune thrombocytopenia, thus offering a novel potential therapeutic alternative for thrombocytopenic neonates.

SUMMARY

In this review, we will discuss the currently available data regarding neonatal RBC and platelet transfusion thresholds, as well as the potential limitations, and concerns associated with the use of erythropoietin and Tpo mimetics in this patient population. Finally, we will point out specific areas wherein additional research is critically needed.