Prevention of necrotizing enterocolitis in preterm infants: a 20-year experience

Red Blood Cell Transfusion, Anemia, Feeding, and the Risk of Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of morbidity and mortality in preterm infants. Severe anemia and red blood cell (RBC) transfusion are associated with gut inflammation and injury in preclinical models and observational studies. However, there is uncertainty about the causal role of these factors in the pathogenesis of NEC. Observational studies have shown that withholding feeding during RBC transfusion may reduce the risk of NEC, although confirmatory data from randomized trials are lacking. In this review, we summarize data on feeding during RBC transfusion and its role in NEC and highlight ongoing randomized trials.

Age of onset of necrotising enterocolitis (NEC) and focal intestinal perforation (FIP) in very preterm and low birthweight infants: a systematic review

OBJECTIVE

Review of age of onset of necrotising enterocolitis (NEC) and focal intestinal perforation (FIP) in very preterm (≤32 weeks) and/or very low birthweight (VLBW, ≤1500 g) infants.

DESIGN

Preregistered review undertaken according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses in July 2021 and updated October 2021.

DATA SOURCES

MEDLINE/ PubMed, Embase, CINAHL and Cochrane Central Register of Controlled Trials.

ELIGIBILITY

Eligible studies reported age of onset of NEC and/or FIP in randomised controlled trials of >200 or observational studies of >500 infants.

DATA EXTRACTION AND SYNTHESIS

Titles/abstracts were screened; eligible articles underwent data extraction. Age of onset as day of life (DOL) and/or corrected gestational age (CGA) were extracted alongside study information, such as NEC definition, included population, intervention, location and dates studied. Weighted means were used to compare onset by birth gestation, study type, NEC definition, trial intervention, location and dates studied. Comparison was done by Mann-Whitney U test or one-way analysis of variance.

RESULTS

Of the 747 screened studies 188 were eligible. Removal of duplicates, studies without onset data and ineligible populations left 10 RCTs and 14 observational studies contributing 51 NEC cohorts; 49 reported onset DOL and 14 CGA. 2984 cases of NEC had average DOL onset of 16.7 (15.5 in RCTs, 16.9 in observational studies), and CGA onset of 30.1 weeks. Gestation did not impact DOL onset. No other demographic feature impacted NEC onset. Few studies included data on FIP.

CONCLUSIONS

Average onset of NEC in exclusively very preterm/very low birthweight infants is in the third week of life and unlike in cohorts including more mature or heavier infants is not impacted by birth gestation.

Early Enteral Feeding of the Preterm Infant-Delay until Own Mother's Breastmilk Becomes Available? (Israel, 2012-2017)

AIM

To consider the question of whether to initiate trophic feeds with formula in the absence of own mother's breastmilk or to wait for breastmilk to be available.

METHODS

A retrospective study of infants born prior to 32 weeks of gestation during the period 2012-2017 at a single tertiary center in Tel Aviv, Israel. Three TF groups were defined: exclusive breastmilk, mixed, and exclusive formula. Univariate and multivariate analyses were conducted. Logistic regression was used, and adjusted odds ratio and 95% interval were reported.

RESULTS

Univariate analysis demonstrated that infants in the exclusive breastmilk group were born earlier, had lower birth weights and lower Apgar scores, were given lower volumes of TF, and were more likely to have a longer hospital stay. Poor composite outcome was more common among the exclusive breastmilk group. Multivariate regression analysis revealed no differences in incidence of early neonatal morbidities between the groups, except for longer duration of parenteral nutrition in the exclusive breastmilk group.

CONCLUSION

In our cohort, exclusive formula TF was not associated with increased risk of any of the studied morbidities. Clinicians should consider this finding in deciding between early TF or fasting while waiting for own mother's breastmilk.

IL-17-related signature genes linked to human necrotizing enterocolitis

Objective

Necrotizing enterocolitis (NEC) is the most frequent life-threatening gastrointestinal disease experienced by premature infants in neonatal intensive care units all over the world. The objective of the present study was to take advantage of RNA-Seq data from the analysis of intestinal specimens of preterm infants diagnosed with NEC. Function enrichments with Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes were used to analyse previous data in order to identify biological and functional processes, which could provide more insight into the pathogenesis of NEC in infants.

Results

Gene set enrichment analysis indicated that the most significant biological pathways over-represented in NEC neonates were closely associated with innate immune functions. One of the striking observations was the highly modulated expression of inflammatory genes related to the IL-17 pathway including such as pro-inflammatory cytokines (CXCL8), chemokines (CXCL5 and CXCL10) and antimicrobials (DEF5A, DEF6A, LCN2, NOS2) in the intestine of neonates diagnosed with NEC. Interestingly, the increase in IL-17 expression appeared to be under the IL-17F form, as reported in Crohn's disease, another inflammatory bowel disease. Further investigation is thus still needed to determine the precise role of IL-17F and its downstream targets in NEC.

Conservative Non-intervention Approach for Hemodynamically Significant Patent Ductus Arteriosus in Extremely Preterm Infants

While persistent patent ductus arteriosus (PDA) in preterm infants has been known to be associated with increased mortality and morbidities including bronchopulmonary dysplasia, and necrotizing enterocolitis, there is minimal evidence supporting their causal relationships, and most traditional medical and/or surgical treatments have failed to show improvements in these outcomes. As such, the pendulum has swung toward the conservative non-intervention approach for the management of persistent PDA during the last decade; however, the benefits and risks of this approach are unclear. In this mini review, we focused on whom, when, and how to apply the conservative non-intervention approach for persistent PDA, especially in extremely preterm infants.

Routine versus Selective Fortification of Human Milk with Powdered Human Milk Fortifiers in Very Low Birth Weight (VLBW) Preterm Infants: A Retrospective Pre-Post Cohort Study

OBJECTIVES

The objective of this study was to show the effects of routine vs. selective fortification of human milk (HM) on short-term growth and metabolic parameters.

METHODS

Single-centre retrospective pre-post cohort study in India. Preterm infants ≤32 weeks' gestation and weighing ≤1500 g were included. Routine fortification: pre-fixed feed volume (100 ml/kg/day in our unit) at which fortification was done. Selective fortification: feed volume was gradually optimized till 180-200 ml/kg/day. If weight gain was below the expected threshold (<10 g/kg/day), then fortification was considered. Primary outcome measure was rate of growth till discharge.

RESULTS

The median rate of weight gain (g/kg/day) in the routine fortification group [10.8 (3.3, 17.1)] was comparable with that in the selective fortification group [8.4 (0, 14.2), p = 0.6]. Serum phosphorus showed a significantly higher value (5.9 vs. 4.8, p = 0.03), while rest of the metabolic parameters showed a trend towards a favourable outcome in the selective fortification group. Adverse outcomes showed a trend towards decreased feed intolerance, necrotizing enterocolitis, and sepsis in the selective fortification group.

CONCLUSIONS

Selective fortification had a comparable growth rate and showed a trend towards better metabolic parameters and lesser adverse outcomes compared with routine fortification of HM.

Standardized slow enteral feeding protocol reduces necrotizing enterocolitis in micropremies

BACKGROUND

Compared to early enteral feeds, delayed introduction and slow enteral feeding advancement to reduce necrotizing enterocolitis (NEC) is not well studied in micropremies (<750g birth weight).

METHODS

Pre-post case control study. Micropremies who followed a standardized slow enteral feeding (SSEF) protocol (September 2009 to March 2015) were compared with a similar group of historical controls (PreSSEF, January 2003 to July 2009). Enteral feeding withheld for first 10-14 days and advanced at <10 ml/kg/day in the SSEF group.

RESULTS

Ninety-two infants in the SSEF group were compared with 129 PreSSEF group. Birth weight and gestational age in SSEF and PreSSEF were similar. Breast milk initiation rate was higher in SSEF (87.0 vs. 72.0%, p = 0.01) compared to PreSSEF, but were similar at full enteral feeds. Compared with PreSSEF, feeding initiation day, full enteral feeding day, parenteral nutrition days, and total central line days were longer in SSEF. There was significant reduction in NEC (1.1 vs. 16.2%, p < 0.01), surgical NEC (0.0 vs. 7.8%, p < 0.01) and NEC/death (7.6 vs. 29.5%, p < 0.01), in SSEF compared to PreSSEF. SSEF, compared to PreSSEF, had more cholestasis (41.8 vs 28.8%, p = 0.04), higher peak serum alkaline phosphatase (638 vs. 534 IU/dL, p < 0.01), but similar rates of late-onset sepsis (39.1 vs 43.4%, p = 0.53). In infants who survived to discharge, SSEF had higher discharge weight, lower extra-uterine growth restriction, and similar length of stay, compared to PreSSEF.

CONCLUSIONS

A SSEF protocol significantly reduces the incidence of NEC and combined NEC/death in micropremies.

Slow enteral feeding decreases risk of transfusion associated necrotizing enterocolitis

BACKGROUND

Necrotizing Enterocolitis (NEC) is a multifactorial condition where PRBC transfusion is associated with necrotizing enterocolitis (TANEC) in about a third of all cases of NEC. We have investigated the role of feeding practices in incidence of TANEC. We sought to compare infants diagnosed with TANEC versus infants diagnosed with classic NEC and investigated the effects of a standardized slow enteral feeding (SSEF) protocol on TANEC incidence as well as the effects of SSEF on growth of infants with NEC.

METHODS

We conducted a retrospective cohort study, where medical records of infants born in a tertiary care neonatal intensive care unit (level IIIb) from January 1997 to May 2014 with birth weight < 1500 grams and gestational age≤34 weeks with NEC stage IIa or greater according to the modified Bell's staging were reviewed.

RESULTS

During the study period, 111 infants developed NEC, and 41/111 (37%) were diagnosed with TANEC. Infants with TANEC were smaller, more premature, had higher SNAPPE scores and were more anemic prior to transfusion compared with infants with 'classic NEC'. The severity of NEC did not differ between the two groups, however, infants with TANEC had worse outcomes and longer NICU stays. Introduction of SSEF protocol, led to a significant decrease in TANEC. There was no difference in weight and head circumference of infants in the two groups at 2 years corrected age.

CONCLUSION

SSEF led to a significant reduction in the incidence of TANEC without impairing growth at 2 years corrected age.

Multicenter neonatal databases: Trends in research uses

BACKGROUND

In the US, approximately 12.7% of all live births are preterm, 8.2% of live births were low birth weight (LBW), and 1.5% are very low birth weight (VLBW). Although technological advances have improved mortality rates among preterm and LBW infants, improving overall rates of prematurity and LBW remains a national priority. Monitoring short- and long-term outcomes is critical for advancing medical treatment and minimizing morbidities associated with prematurity or LBW; however, studying these infants can be challenging. Several large, multi-center neonatal databases have been developed to improve research and quality improvement of treatments for and outcomes of premature and LBW infants. The purpose of this systematic review was to describe three multi-center neonatal databases.

METHODS

We conducted a literature search using PubMed and Google Scholar over the period 1990 to August 2014. Studies were included in our review if one of the databases was used as a primary source of data or comparison. Included studies were categorized by year of publication; study design employed, and research focus.

RESULTS

A total of 343 studies published between 1991 and 2014 were included. Studies of premature and LBW infants using these databases have increased over time, and provide evidence for both neonatology and community-based pediatric practice.

CONCLUSIONS

Research into treatment and outcomes of premature and LBW infants is expanding, partially due to the availability of large, multicenter databases. The consistency of clinical conditions and neonatal outcomes studied since 1990 demonstrates that there are dedicated research agendas and resources that allow for long-term, and potentially replicable, studies within this population.

Mandatory Closure Versus Nonintervention for Patent Ductus Arteriosus in Very Preterm Infants

OBJECTIVE

To determine whether a nonintervention approach for treating hemodynamically significant patent ductus arteriosus (PDA) is associated with decreased mortality and/or morbidity compared with a mandatory closure approach in extremely low birth weight infants.

STUDY DESIGN

We reviewed the medical records of 178 infants of 23-26 weeks' gestational age with PDA, requiring ventilator treatment, and with hemodynamically significant PDA ≥2 mm in size. Mandatory closure was used during period I (July 2009 to December 2011, n = 81), and nonintervention was used during period II (January 2012 to June 2014, n = 97).

RESULTS

During period I, 64% of infants were first treated with indomethacin, and 82% were ultimately ligated surgically. During period II, no infant was treated with indomethacin and/or ligation. The average postnatal day of PDA closure was day 13 and day 44 during periods I and II, respectively. There was significantly more use of diuretics and fluid restriction during period II compared with period I. There was no difference in mortality or morbidities such as necrotizing enterocolitis or intraventricular hemorrhage. The incidence of bronchopulmonary dysplasia (BPD) and the propensity score adjusted OR of BPD were significantly lower during period II compared with period I.

CONCLUSIONS

Despite longer PDA exposure, nonintervention was associated with significantly less BPD compared with mandatory closure. Additional study is warranted to determine the benefits and risks of non-intervention for the hemodynamically significant PDA in extremely low birth weight infants.

[Reduction in necrotising enterocolitis after implementing an evidence-based enteral nutrition protocol in very low birth weight newborns]

INTRODUCTION

An unexpected increase in the incidence of necrotising enterocolitis (NEC) cases was observed in our hospital. Just in case, our feeding policy could be responsible, it was decided to conduct a systematic review and develop a clinical guideline regarding enteral nutrition of very low birth weight infants (VLBW).

OBJECTIVE

To assess the impact of the new feeding protocol in the incidence of NEC.

METHOD

A "before" (2011) and "after" (May 2012 - April 2013) study was performed on the new feeding protocol. This included initiation of enteral feeding in the absence of haemodynamic problems, a trophic feeding period of 5-7 days, and subsequent increments of 20-30ml/kg/day, of breast milk/donor human milk from the beginning. Probiotics were not administered.

PRIMARY OUTCOME

incidence of NEC II 2 Bell's stage.

SECONDARY OUTCOMES

focal intestinal perforation, overall mortality and mortality due to NEC, nosocomial sepsis; weight at 28 days and 36 weeks; % of infants with weight <p10 at discharge; and length of stay.

RESULTS

Of the 270 VLBW infants, 155 were included in the "before" group, and 115 in the "after" group. NEC significantly decreased (12/155 vs 1/115, P=.008). A decrease in mortality rate was also observed (17.4% vs 7.8%, P=.02). In four cases NEC was part of the sequence of events that led to death in the first cohort, with none in the second. There was no difference in the incidence of focal intestinal perforation or of the other secondary variables analysed.

CONCLUSIONS

Implementation of an evidence-based enteral feeding protocol leads to a decrease in incidence of NEC, without increasing hospital stay or the incidence of sepsis.

Gene expression profiling in necrotizing enterocolitis reveals pathways common to those reported in Crohn's disease

BACKGROUND

Necrotizing enterocolitis (NEC) is the most frequent life-threatening gastrointestinal disease experienced by premature infants in neonatal intensive care units. The challenge for neonatologists is to detect early clinical manifestations of NEC. One strategy would be to identify specific markers that could be used as early diagnostic tools to identify preterm infants most at risk of developing NEC or in the event of a diagnostic dilemma of suspected disease. As a first step in this direction, we sought to determine the specific gene expression profile of NEC.

METHODS

Deep sequencing (RNA-Seq) was used to establish the gene expression profiles in ileal samples obtained from preterm infants diagnosed with NEC and non-NEC conditions. Data were analyzed with Ingenuity Pathway Analysis and ToppCluster softwares.

RESULTS

Data analysis indicated that the most significant functional pathways over-represented in NEC neonates were associated with immune functions, such as altered T and B cell signaling, B cell development, and the role of pattern recognition receptors for bacteria and viruses. Among the genes that were strongly modulated in neonates with NEC, we observed a significant degree of similarity when compared with those reported in Crohn's disease, a chronic inflammatory bowel disease.

CONCLUSIONS

Gene expression profile analysis revealed a predominantly altered immune response in the intestine of NEC neonates. Moreover, comparative analysis between NEC and Crohn's disease gene expression repertoires revealed a surprisingly high degree of similarity between these two conditions suggesting a new avenue for identifying NEC biomarkers.

Patent Ductus Arteriosus in Preterm Infants

Despite a large body of basic science and clinical research and clinical experience with thousands of infants over nearly 6 decades,(1) there is still uncertainty and controversy about the significance, evaluation, and management of patent ductus arteriosus in preterm infants, resulting in substantial heterogeneity in clinical practice. The purpose of this clinical report is to summarize the evidence available to guide evaluation and treatment of preterm infants with prolonged ductal patency in the first few weeks after birth.

Randomized Clinical Trial of Preoperative Feeding to Evaluate Intestinal Barrier Function in Neonates Requiring Cardiac Surgery

OBJECTIVES

To evaluate intestinal barrier function in neonates undergoing cardiac surgery using lactulose/mannitol (L/M) ratio measurements, and to determine correlations with early breast milk feeding.

STUDY DESIGN

This was a single-center, prospective, randomized pilot study of 27 term-born neonates (≥ 37 weeks gestation) requiring cardiac surgery who were randomized to 1 of 2 preoperative feeding groups: nil per os (NPO) or trophic (10 mL/kg/day) breast milk feeds. At 3 time points (preoperative [preop], postoperative [postop] day 7, and postop day 14), subjects were administered an oral L/M solution, after which urine L/M ratios were measured using gas chromatography, with higher ratios indicative of increased intestinal permeability. Trends over time in the mean urine L/M ratios for each group were estimated using a general linear mixed model.

RESULTS

There were no adverse events related to preoperative trophic feeding. In the NPO group (n = 13), the mean urine L/M ratio was 0.06 at preop, 0.12 at postop day 7, and 0.17 at postop day 14. In the trophic breast milk feeds group (n = 14), the mean urine L/M ratio was 0.09 at preop, 0.19 at postop day 7, and 0.15 at postop day 14. In both groups, L/M ratios were significantly higher at postop day 7 and postop day 14 compared with preop (P < .05).

CONCLUSION

Neonates have increased intestinal permeability after cardiac surgery extending to at least postop day 14. This pilot study was not powered to detect differences in benefit or adverse events comparing the NPO and trophic breast milk feeds groups. Further studies to identify mechanisms of intestinal injury and therapeutic interventions are warranted.

TRIAL REGISTRATION

Registered with ClinicalTrials.gov: NCT01475357.

Standardized Slow Enteral Feeding Protocol and the Incidence of Necrotizing Enterocolitis in Extremely Low Birth Weight Infants

BACKGROUND

Compared with early enteral feeds, the delayed introduction and slow advancement of enteral feedings to reduce the incidence of necrotizing enterocolitis (NEC) are not well studied in extremely low birth weight (ELBW) infants.

OBJECTIVE

To study the effects of a standardized slow enteral feeding (SSEF) protocol in ELBW infants.

METHODS

ELBW infants who followed an SSEF protocol (September 2009 to December 2012) were compared with a similar group of historical controls (January 2003 to July 2009). Short-term outcomes between the 2 groups were compared by propensity score (PS) analysis.

RESULTS

One hundred twenty-five infants in the SSEF group were compared with 294 historical controls. Compared with the controls, feeding initiation day, full enteral feeding day, parenteral nutrition (PN) days, and total central line days were longer in the SSEF group. There was no significant difference in overall NEC (5.6% vs 11.2%, respectively; P = .10) or surgical NEC (1.6% vs 4.8%, respectively; P = .17) between the SSEF group and controls. However, in infants with birth weight <750 g, NEC (2.1% vs 16.2%, respectively; P < .01) or combined NEC/death (12.8% vs 29.5%, respectively; P = .03) was significantly less in the SSEF group compared with controls. In infants who survived to discharge, there was no significant difference in the discharge weight or length of stay in PS-adjusted analysis.

CONCLUSIONS

An SSEF protocol significantly reduces the incidence of NEC and combined NEC/death in infants with birth weight <750 g. Despite taking longer to achieve full enteral feeding on this protocol, surviving ELBW infants demonstrated comparable weight gain at discharge without prolonging their hospital stay.

Necrotizing enterocolitis: the road to zero

Necrotizing enterocolitis (NEC) continues to be the most severe gastrointestinal emergency facing the preterm neonate. The pathogenesis of NEC is still a complex and poorly understood process, but with increasing understanding of the role of enteral feeding, gut immunity and the altered gut microbiota, new opportunities to reduce overall NEC rates are now possible. Prevention strategies continue to lead as the most suitable approaches to reducing NEC, as early diagnosis and rapid effective treatment of NEC are still not optimal. Programmatic changes are equally important as subscribing to individual prevention strategies. The primary focus of this review is to summarize the best strategies we currently have to eliminate NEC within an institution.

Challenges in the practice of human milk nutrition in the neonatal intensive care unit

The use of human milk for preterm infants has increased over the past decade reflecting an improved awareness of the benefits of human milk. Inherent in this paradigm shift is the recognition that human milk is a living tissue; full of immune cells, probiotics and hundreds of compounds that confer bioactivity and immune protective properties. Together these factors deliver a powerful effect in reducing clinical morbidities such as necrotizing enterocolitis and sepsis in the preterm infant. However, as breastfeeding is not possible for the very premature infant, human milk needs to be introduced in the neonatal intensive care unit through alternative means, resulting in significant handling and manipulation of maternal milk. This presents risks in quality control and provision of optimal nutrition delivery. Therefore, a comprehensive approach to standardizing preterm infant nutrition is essential to optimize the collection, storage, fortification and delivery of human milk to preterm neonates. In this paper we discuss the challenges presented by supporting human milk nutrition, and the rationale for the development of the Supporting Premature Infant Nutrition (SPIN) program at our institution.

Outcomes of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009

OBJECTIVE

To assess adverse fetal outcomes and short-term prognoses of infants exposed to oseltamivir or zanamivir in utero during pandemic (H1N1) 2009 in Japan.

STUDY DESIGN

Case series study. We asked the 2611 obstetric facilities in Japan that are members of the Japan Society of Obstetrics and Gynecology to participate, and data were provided from 157 facilities. We evaluated the numbers of pregnancy complications and neonatal abnormalities.

RESULTS

We evaluated 624 infants born to 619 women given oseltamivir and 50 infants born to 50 women given zanamivir. Of patients given oseltamivir before gestational week 22, 3 experienced miscarriage and 1 experienced induced abortion. The overall rate of congenital malformations was 2.1% (14/670). In infants exposed during the first trimester, the rate of malformations was 1.3% (2/156) with oseltamivir and 0.0% (0/15) with zanamivir, although in infants exposed during the second and third trimesters, this rate was 2.6% (12/464) with oseltamivir and 0.0% (0/35) with zanamivir. Increased rates of miscarriage in women given antiviral drugs before gestational week 22 (0.9% [3/322]), preterm delivery in women given antiviral drugs before gestational week 37 (5.5% [33/600]), stillbirth (0% [0/670]), neonatal death (0.15% [1/670]), birthweight <2500 g (8.7% [58/670]), small-for-gestational-age infants (8.4% [56/670]), necrotizing enterocolitis (0.0%), intraventricular hemorrhage (0.0%), seizures (0.15% [1/670]), and other transient abnormalities in the neonatal period (4.3% [29/670]) were not observed in those exposed to antiviral drugs before the corresponding episodes or complications.

CONCLUSION

Short-term prognoses of infants exposed to oseltamivir or zanamivir in utero were not adversely affected.

Intestinal perforation in very-low-birth-weight infants with necrotizing enterocolitis

PURPOSE

To identify risk factors for intestinal perforation in very-low-birth-weight (VLBW) infants with necrotizing enterocolitis (NEC).

METHODS

Retrospective case-control study over a 10-year period, using univariate and multivariate logistic regression analyses to compare all VLBW infants treated for perforated NEC, with two age and weight-matched groups: infants with non-perforated NEC and infants without NEC.

RESULTS

Twenty infants with perforated NEC were matched to 20 infants with non-perforated NEC and 38 infants without NEC. Infants with perforated NEC were younger (p<0.01) and had higher rates of abdominal distention, metabolic acidosis, hyperglycemia and elevated liver enzymes (p<0.05). On logistic regression analysis, abdominal distention was associated with an increased risk of intestinal perforation (OR 39.8, 95% CI 2.71-585) and late onset of NEC (one-day increments) was associated with a decreased risk (OR 0.93, 95% CI 0.87-1.0).

CONCLUSION

Identification of abdominal distention at an early age in VLBW infants should lead to increased vigilance for signs of perforated NEC and may enable early intervention.

Impact of patient selection on outcomes of PDA in very low birth weight infants

AIM

The aim of this study was to observe whether our patient selection maximized the benefits of PDA ligation by comparing the outcomes in a surgically ligated group of PDA to a medically closed group.

STUDY DESIGN

If a hemodynamically significant ductus arteriosus (HSDA) was found to meet both clinical and echocardiographic criteria (stage≥3), as proposed by NcNamara and Hellman, medical treatment was initiated with oral ibuprofen (maximum 2 courses). If the PDA of these patients failed to close medically, timed surgical closure was performed.

RESULT

Medical treatment was effective in 75 (72%) cases, and 29 (28%) patients required surgical ligation. The mean gestational age and birth weight were each significantly lower and the initial PDA shunt size was significantly larger in the surgically treated group. Additionally, the mean durations of mechanical ventilation, oxygen dependence and hospital admission were significantly longer in the surgically ligated group. However, our logistic regression analysis demonstrated no statistically significant difference in the outcomes of hospitalization (CLD, NEC, ARF, sepsis, IVH, ROP, PVL and death) between the two groups.

CONCLUSION

Comprehensive HSDA patient selection may maximize the benefits of timed PDA ligation without adverse outcomes in very low birth weight infants.

The hepatic bile acid transporters Ntcp and Mrp2 are downregulated in experimental necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of premature infants and is characterized by an extensive hemorrhagic inflammatory necrosis of the distal ileum and proximal colon. We have previously shown that, during the development of experimental NEC, the liver plays an important role in regulating inflammation in the ileum, and accumulation of ileal bile acids (BA) along with dysregulation of ileal BA transporters contributes to ileal damage. Given these findings, we speculated that hepatic BA transporters would also be altered in experimental NEC. Using both rat and mouse models of NEC, levels of Cyp7a1, Cyp27a1, and the hepatic BA transporters Bsep, Ntcp, Oatp2, Oatp4, Mrp2, and Mrp3 were investigated. In addition, levels of hepatic BA transporters were also determined when the proinflammatory cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-18, which are both elevated in NEC, are neutralized during disease development. Ntcp and Mrp2 were decreased in NEC, but elevated ileal BA levels were not responsible for these reductions. However, neutralization of TNF-α normalized Ntcp, whereas removal of IL-18 normalized Mrp2 levels. These data show that the hepatic transporters Ntcp and Mrp2 are downregulated, whereas Cyp27a1 is increased in rodent models of NEC. Furthermore, increased levels of TNF-α and IL-18 in experimental NEC may play a role in the regulation of Ntcp and Mrp2, respectively. These data suggest the gut-liver axis should be considered when therapeutic modalities for NEC are developed.

Repeated bowel perforations with Ibuprofen lysine: a case report

Non-steroidal anti-inflammatory drugs (NSAID) have been used to close the patent ductus arteriosus in neonates for over two decades. Ibuprofen lysine, a parenteral NSAID, is labeled for the treatment of patent ductus arteriosus in neonates who do not respond to conventional medical management. While sharing many of the same adverse effects as indomethacin, spontaneous bowel perforation has not been reported. We describe a premature infant that experienced isolated bowel perforations after treatment with ibuprofen lysine for symptomatic patent ductus arteriosus.

Astrovirus and digestive disorders in neonatal units

AIM

To describe clinical signs associated with Human Astrovirus (HAstV) in stools in neonatal units.

METHODS

During 2005-2006, all stool virology performed for isolated digestive symptoms or suspicion of neonatal infection was tested for HAstV by an amplified enzyme-linked immunoassay (IDEIA™ Astrovirus test, Dako Cytomation). Each newborn with a positive result (HAstV+ group) was retrospectively matched with the first following symptomatic newborn in the same care unit having a negative stool virology (HAstV- group). Clinical data were collected during two 3-day periods (just after faecal samples collection and 1 week before) and compared within and between each group.

RESULTS

Human astrovirus was detected in faeces of 68 newborns [gestational age: 31.4(28.8-34) weeks] at a post-natal age of 23 (15-42) days without seasonal dominance. Human astrovirus+ and HAstV- groups were comparable. Bloody stool (54.4% versus 14.7%, p < 0.01) and stage II-III necrotizing enterocolitis (20.6% versus 4.4%, p < 0.05) were more frequently observed in HAstV+ than in HAstV- group; these associations were confirmed by logistic regression analysis.

CONCLUSION

This descriptive study argues for a possible association between HAstV and digestive symptoms in newborns specifically in preterm infants.

What happens when the patent ductus arteriosus is treated less aggressively in very low birth weight infants?

OBJECTIVE

It remains unclear whether indomethacin (INDO) and/or surgical ligation (LIGATE) are necessary to improve outcomes in premature infants with a patent ductus arteriosus (PDA). We have adopted a conservative approach to PDA management that emphasizes waiting for spontaneous closure unless certain cardiorespiratory distress criteria are met.

STUDY DESIGN

This was a before-after observational study in infants born 501 to 1,500 g in two distinct epochs. Era 1 (January 2005 to December 2007) featured traditional management with INDO and LIGATE used early to close all moderate and large PDAs in infants receiving any respiratory support. Era 2 (January 2008 to June 2009) emphasized modest fluid restriction, watchful waiting and limited INDO and LIGATE to only those infants with large PDAs who met certain cardiorespiratory distress criteria.

RESULT

Era 1 included 139 infants with a PDA, mean (s.d.) gestational age 27.5 (2) weeks; Era 2 72 infants, mean (s.d.) gestational age 27.5 (2) weeks. In Era 2, INDO use significantly decreased (79% of infants to 26%, P<0.001), and 28 day total fluids decreased (140 vs. 130  ml kg(-1) day(-1), P<0.001). LIGATE rate was 45% in Era 1, 33% in Era 2 (P=0.11). There were no significant differences in supplemental oxygen, nasal continuous positive airway pressure, or mechanical ventilation days. There were no significant differences in mortality or individual morbidities. The combined outcome of chronic lung disease (CLD) or mortality after Day 7 significantly increased (Era 1, 40%, Era 2, 54%, P=0.04). More infants were discharged home with a PDA in Era 2, but most resolved spontaneously and the need for closure therapy after discharge from the neonatal intensive care unit (NICU) did not increase. Multiple regression analysis demonstrated Era 2 management did not predict an increased risk of one or more interlinked morbidities.

CONCLUSION

Tolerance of the PDA with watchful waiting for spontaneous closure, modest fluid reduction, and less INDO use is a reasonable treatment strategy that is not associated with significant changes in NICU mortality or individual morbidities. We did note an increase in the combined outcome of CLD or mortality after Day 7, thus our investigation supports the urgency of a randomized controlled trial comparing traditional PDA management with a true control group similar to our Era 2 management to answer important questions of short and long-term outcomes.

Necrotizing enterocolitis in the premature infant: neonatal nursing assessment, disease pathogenesis, and clinical presentation

Necrotizing enterocolitis (NEC) remains one of the most catastrophic comorbidities associated with prematurity. In spite of extensive research, the disease remains unsolved. The aims of this article are to present the current state of the science on the pathogenesis of NEC, summarize the clinical presentation and severity staging of the disease, and highlight the nursing assessments required for early identification of NEC and ongoing care for infants diagnosed with this gastrointestinal disease. The distributions of systemic and intestinal clinical signs that are most sensitive to nursing assessment and associated with Bell Staging Criteria are presented. These descriptive data are representative of 117 cases of NEC diagnosed in low-gestational-age infants (<29 weeks' gestation). The data highlight the clinical signs most commonly observed in infants with NEC and thus provide NICU nurses an evidence-based guide for assessment and care of infants with NEC.

Learning to live with patency of the ductus arteriosus in preterm infants

Treatment of persistent patency of the ductus arteriosus in preterm infants remains heterogeneous and controversial. Routine early treatment to induce ductal closure is not beneficial, but the potential criteria for, timing of, methods for and benefits of later ductal closure have not been determined. Management strategies for infants awaiting spontaneous closure or meeting criteria for treatment may be based on pathophysiological considerations but require evaluation in clinical trials. Better diagnostic tools allowing the identification of infants who might benefit from ductal closure, supplemented by data from clinical trials confirming realization of that potential, are urgently needed.

Early enteral feeding in conservatively managed stage II necrotizing enterocolitis is associated with a reduced risk of catheter-related sepsis

AIMS

To compare the effect of fasting period duration on complication rates in neonates managed conservatively for necrotizing enterocolitis (NEC) Bell stage II.

METHODS

We conducted a multicenter study to analyze retrospectively multiple data collected by standardized questionnaire on all admissions for NEC between January 2000 and December 2006. NEC was staged using modified Bell criteria. We divided the conservatively managed neonates with NEC Bell stage II into two groups (those fasted for <5 days and those fasted for >5 days) and compared the complication rates.

RESULTS

Of the 47 conservatively managed neonates Bell stage II, 30 (64%) fasted for <5 days (range 1-4 days) and 17 (36%) for >5 days (range 6-16 days). There were no significant differences for any of the patient characteristics analyzed. One (3%) and four (24%) neonates, respectively, developed post-NEC bowel stricture. One (3%) and two neonates (12%) suffered NEC relapse. None and five (29%) neonates developed catheter-related sepsis.

CONCLUSION

Shorter fasting after NEC appears to lower morbidity after the acute phase of the disease. In particular, shorter-fasted neonates have significantly less catheter-related sepsis. We found no benefit in longer fasting.

Hormonal influences of early postnatal indomethacin and ibuprofen in neonatal rats

OBJECTIVE

Indomethacin and ibuprofen are administered to preterm neonates for symptomatic patent ductus arteriosus. The drugs suppress prostaglandins (PGs) which modulate growth and secretion of various hormones. We examined the hypothesis that early postnatal indomethacin and ibuprofen influence growth and GH-IGF-I-insulin and HPA axes in neonatal rats.

DESIGN

Rat pups received IP injections of saline (Sal) on P1, P2, and P3; 10mg/kg ibuprofen on P1 followed by 5mg/kg on P2 and P3; or 0.2mg/kg indomethacin on P1 followed by 0.1mg/kg on P2 and P3. Serum and hepatic GH, GHBP and IGF-I; and serum corticosterone and insulin levels were determined.

RESULTS

Ibuprofen suppressed somatic growth in the sucking rats, but the effect was transient, resolving by P14. Indomethacin had an opposite, latent effect on body weight and liver to body weight ratios in weanling rats. Both indomethacin and ibuprofen had profound hormonal effects that differed in magnitude and timing. Indomethacin resulted in a sustained elevation in corticosterone levels at P21, while ibuprofen increased serum and hepatic GH levels. Both drugs suppressed GHBP in serum at P7 and P14; and liver at P4 and P7, but a rebound increase in serum GHBP was noted at P21 with Ibuprofen only. Both drugs increased serum IGF-I at P7. The effect remained sustained with indomethacin.

CONCLUSIONS

These results provide evidence for an involvement of PGs in the regulation of growth as well as the GH-IGF and HPA axes. Therefore, early postnatal exposure to PG inhibitors may further exacerbate postnatal growth restriction and ability to cope with stress.

Can we cut the incidence of necrotizing enterocolitis in half--today?

Necrotizing enterocolitis (NEC) is a common gastrointestinal emergency of neonates. Population studies estimate the incidence of NEC at between 0.3 and 2.4 per 1000 live births in the United States, with a predominance of cases among preterm neonates born at the earliest gestational ages. The disease burden of NEC includes an overall disease-specific mortality rate of 15-20%, with yet higher rates in those of earliest gestations. The NEC burden also includes an increase in hospital costs approximating $100,000/case, as well as severe late sequellae including parenteral nutrition-associated liver disease and short bowel syndrome. Differentiating NEC from other forms of acquired neonatal intestinal disease is critical to assessing the success of NEC prevention strategies. Promising new prevention strategies are now being tested; one such is prophylactic heparin-binding epidermal growth factor-like growth factor (HB-EGF) administration. However, two prevention strategies have already been shown in meta-analyses to reduce the incidence of NEC, but we speculate that these are not being fully utilized. They are; 1) implementing a written set of feeding guidelines (also called standardized feeding regimens) for newborn intensive care unit (NICU) patients, and 2) implementing programs to increase the availability of human milk for patients at risk of developing NEC.

Strategies for feeding the preterm infant

According to many experts in neonatal nutrition, the goal for nutrition of the preterm infant should be to achieve a postnatal growth rate approximating that of the normal fetus of the same gestational age. Unfortunately, most preterm infants, especially those born very preterm with extremely low birth weight, are not fed sufficient amounts of nutrients to produce normal fetal rates of growth and, as a result, end up growth-restricted during their hospital period after birth. Growth restriction is a significant problem, as numerous studies have shown definitively that undernutrition, especially of protein, at critical stages of development produces long-term short stature, organ growth failure, and both neuronal deficits of number and dendritic connections as well as later behavioral and cognitive outcomes. Furthermore, clinical follow-up studies have shown that among infants fed formulas, the nutrient content of the formula is directly and positively related to mental and motor outcomes later in life. Nutritional requirements do not stop at birth. Thus, delaying nutrition after birth 'until the infant is stable' ignores the fundamental point that without nutrition starting immediately after birth, the infant enters a catabolic condition, and catabolism does not contribute to normal development and growth. Oxygen is necessary for all metabolic processes. Recent trends to limit oxygen supply to prevent oxygen toxicity have the potential, particularly when the blood hemoglobin concentration falls to less than 8 g/dl, to develop growth failure. Glucose should be provided at 6-8 mg/min/kg as soon after birth as possible and adjusted according to frequent measurements of plasma glucose to achieve and maintain concentrations >45 mg/dl but <120 mg/dl to avoid the frequent problems of hyperglycemia and hypoglycemia. Similarly, lipid is required to provide at least 0.5 g/kg/day to prevent essential fatty acid deficiency. However, the high rate of carbohydrate and lipid supply that preterm infants often get, based on the incomplete assumption that this is necessary to promote protein growth, tends to produce increased fat in organs like the liver and heart as well as adipose tissue. More and better essential fatty acid nutrition is valuable, but more organ and adipose fat has no known benefit and many problems. Amino acids and protein are essential not only for body growth but for metabolic signaling, protein synthesis, and protein accretion. 3.5-4.0 g/kg/day are necessary to produce normal protein balance and growth in very preterm infants. Attempts to promote protein growth with insulin has many problems - it is ineffective while contributing to even further organ and adipose tissue fat deposition. Enteral feeding always is indicated and to date nearly all studies have shown that minimal enteral feeding approaches (e.g., 'trophic feeds') promote the capacity to feed enterally. Milk has distinct advantages over formulas in avoiding necrotizing enterocolitis (NEC), and while feeding is associated with NEC, minimal enteral feeding regimens produce less NEC than those geared towards more aggressive introduction of enteral feeding. Finally, overfeeding has the definite potential to produce adipose tissue, or obesity, which then leads to insulin resistance, glucose intolerance, and diabetes. This scenario occurs more commonly as infants are fed more and gain weight more rapidly after birth, regardless of their birth weight. Infants with IUGR and postnatal growth failure may be uniquely 'set up' for this outcome, while infants with in utero obesity, such as infants of diabetic mothers, already are well along this adverse outcome pathway.

Clinical predictors of necrotizing enterocolitis in premature infants

BACKGROUND

Necrotizing enterocolitis (NEC) has emerged as the most common neonatal gastrointestinal emergency, is the most common cause of death in neonates undergoing surgery, and accounts for yearly additional hospital charges in excess of $6.5 million. Prematurity is the only common variable identified in case-controlled studies exploring this disease.

OBJECTIVES

To improve the understanding of the relationship between factors related to intestinal inflammation and ischemia and the enteral feeding regimen in the context of the premature gut, thereby identifying antecedents of NEC.

METHODS

Data were collected from the medical records of 247 premature infants for this retrospective case-controlled study. Diagnosis of NEC, as defined by Bell Stages IIA-IIIB, was required for study group assignment (n = 84). Multivariate analysis techniques were used to predict the relationships between selected variables on the outcome of NEC.

RESULTS

Premature infants were 13 times more likely to develop NEC if the infant required increased respiratory support to maintain oxygenation during the early neonatal period and 6.4 times more likely to develop NEC if the infant did not receive nutritionally fortified enteral feedings of breast milk. When both factors were present, the odds of NEC increased 28.6 times when compared with infants without these factors.

DISCUSSION

The study findings extend knowledge of antecedents to NEC beyond prematurity, highlighting the role that respiratory support and nutritional fortification of enteral feedings play in the pathogenesis of this disease. Early identification of antecedents to NEC will improve critical care management of the neonate and, in turn, decrease the incidence of this devastating gastrointestinal disease. The study findings will guide further inquiry in neonatal nutrition, physiologic and metabolic functioning, and acute clinical management of the neonate.

Predictors of necrotizing enterocolitis in preterm growth-restricted neonates

OBJECTIVE

The purpose of this study was to test the hypothesis that multivessel fetal Doppler imaging provides enhanced prediction of necrotizing enterocolitis (NEC) in preterm placental insufficiency.

STUDY DESIGN

Placental-based growth-restricted fetuses (abdominal circumference <5%, abnormal umbilical artery [UA] Doppler imaging) were examined. UA, middle cerebral artery, ductus venosus, and umbilical vein (UV) were evaluated prenatally and were assessed for their ability to predict NEC in neonates who were delivered at <37 weeks of gestation.

RESULTS

Thirty-nine of 404 neonates (9.7%) experienced NEC. Among these, the mortality rate was 15.4% (6/39 neonates; odds ratio, 2.7; 95% CI, 1.03-7.11). NEC cases had higher UA Doppler indices prenatally (P = .023), lower gestational ages and birthweight at delivery (P < .0001, respectively), 5-minute Apgar scores of <7, and higher umbilical cord artery base deficit (P < .01, respectively). NEC was more likely after prenatal UV pulsations (odds ratio, 2.4; 95% CI, 1.13-5.14; P = .028) and severe cardiovascular abnormality (composite variable incorporating UA- absent or reversed end diastolic velocity, absent or reversed ductus venosus a-wave, or UV pulsations; odds ratio, 2.1; 95% CI, 1.06-4.05; P = .029) Logistic regression revealed birthweight and base deficit as the main contributors of NEC (r(2) = 0.20; P < .0001). Receiver operating characteristic analyses revealed birthweight of <790 g (sensitivity, 74.4%; specificity, 72.9%; P < .0001) and gestational age of < or =32.2 weeks (sensitivity, 94.9%; specificity, 45.8%; P < .0001) as optimal cut-offs that provide an odds ratio for NEC of 8.2 (95% CI, 3.9-17.6; P < .0001).

CONCLUSION

Placental disease predisposes the severely growth-restricted neonate to necrotizing enterocolitis. Even when arterial and venous Doppler variables are taken into consideration, birthweight remains the predominant risk factor for NEC. Further research should focus on the critical transition to neonatal life to identify relevant triggers in predisposed neonates.

Feeding strategies in the ELBW infant

Necrotizing enterocolitis (NEC) remains a common emergency that carries high morbidity and mortality for extremely low birth weight infants. To date there have been no multicenter randomized controlled trials to evaluate different feeding strategies and NEC. Clinicians must weigh their experience against small amounts of data in deciding the best way to feed their patients. Currently published feeding protocols and evidence for the same will be reviewed. Also reviewed is the evidence for use of human milk, initiation and advancement of feedings, and the use of probiotics.

Factors affecting successful closure of hemodynamically significant patent ductus arteriosus with indomethacin in extremely low birth weight infants

BACKGROUND

The incidence of patent ductus arteriosus (PDA) is high in extremely low birth weight (ELBW) infants. Indomethacin has been widely used in the prophylaxis and treatment of hemodynamically significant PDA. This retrospective study was undertaken to identify factors such as birth weight, gestational age, gender, fetal growth retardation, ductal size, timing of the first dose of indomethacin and side effects of indomethacin, which may affect the successful closure of the PDA with indomethacin in ELBW infants.

METHODS

A cohort of 139 ELBW infants who had received indomethacin treatment for PDA during a consecutive period of more than three years (September 2000 to December 2003) was retrospectively analyzed. Administration

RESULTS

of indomethacin was associated with closure of PDA in 108 (77.7%) of 139 ELBW infants, and only 19.4% of infants required surgical ligation of the ductus eventually. There was no significant relationship between closure of PDA with gestational age, gender, fetal growth retardation, and ductal size. A higher birth weight and early use of indomethacin after birth could significantly increase the closure rate of PDA (P<0.05). Side effects of indomethacin such as transient oliguria and hyponatremia during indomethacin therapy did not affect PDA closure.

CONCLUSIONS

Indomethacin is effective for the treatment of PDA in ELBW infants. A higher rate of ductal closure is related to the increase of birth weight. PDA closure with indomethacin is age-related, and early administration of indomethacin could increase PDA closure and reduce the incidence of hyponatremia. There is no significant difference in major morbidities such as bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH), necrotizing enterocolitis (NEC), and retinopathy of prematurity (ROP) after early treatment. Early screening for hemodynamically significant PDA in ELBW infants and early treatment with indomethacin are recommended.

Probiotics: role in pathophysiology and prevention in necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an inflammatory bowel disease largely affecting low birth weight, premature infants. Once acquired, NEC is accompanied by significant mortality and morbid sequelae. Our understanding of the pathophysiology of NEC continues to evolve, and the development of NEC is likely multifactorial with resultant bowel injury mediated through a final, common inflammatory pathway. The predisposition for NEC appears to involve the interplay between intestinal integrity and function, enteral feeding and bacterial colonization, and regulation of the gastrointestinal and systemic inflammatory response. Commensal organisms or probiotics have been shown to be crucial in the development and modulation of each of these factors within the intestinal epithelium. As a result, probiotic supplementation has been proposed as a promising new intervention for the prevention of NEC. To understand the potential utility of probiotics in NEC, we will discuss: the components of gut defense; the role of the intestinal ecosystem in modulating immunity and inflammation; bacterial colonization patterns in the preterm infant compared with patterns seen in the healthy, full-term infant; the evidence for probiotic use in other populations and diseases; and finally, the evidence of probiotic use specific to the preterm infant and NEC.

Probiotics and other preventative strategies for necrotising enterocolitis

Necrotising enterocolitis (NEC) remains one of the commonest causes of death and significant morbidity in preterm infants after the first few postnatal days. NEC affects approximately 5-10% of infants born at <or=28 weeks; about a third will die. Although there do not appear to be any 'simple fixes', it is clear that there are many clinical strategies that affect NEC. There is controlled trial evidence for breast milk, fluid regimes, enteral antibiotics, immunonutrients and probiotic supplements. This paper will review the evidence relevant to current populations of preterm infants and determine which, if any, can be safely and effectively introduced into current clinical practice.

Does early enteral feeding of very low birth weight infants increase the risk of necrotizing enterocolitis?

BACKGROUND/OBJECTIVE

In this retrospective study, we intended to test whether early enteral feeding (EEF) of very low birth weight (VLBW) preterm babies increases the risk of necrotizing enterocolitis (NEC) or not.

SUBJECTS AND METHODS

Overall, 297 VLBW preterm babies admitted to the neonatal intensive care unit (NICU) between April 2003 and April 2006 were included. The study consisted of two periods: the first period was between April 2003 and October 2004, when babies were not fed enterally until they were extubated (167 preterm VLBWs). The second period was between November 2004 and April 2006, when babies were fed even when they were intubated, starting preferably on the first day of life (130 preterm VLBWs). Criteria for withholding enteral feeding in both periods were hypotension necessitating vasopressor agent use, abdominal distention, abdominal tenderness and suspected or proven NEC. Possible risk factors for NEC were also recorded.

RESULTS

The overall incidence of NEC in VLBW preterm babies was 6.7% and did not differ between the two study periods: 7.2% in the late and 6.2% in the EEF regimens. On logistic regression analysis, the most important risk factors associated with NEC were sepsis (P<0.001) and blood culture positivity (P<0.001). The average daily weight gain was significantly higher in the early fed babies (P=0.011).

CONCLUSIONS

The EEF of VLBW preterm babies does not increase the risk of NEC. Increased daily weight gain is an important reason to feed these babies earlier.