Impact of necrotizing enterocolitis on length of stay and hospital charges in very low birth weight infants

Economic benefits and costs of human milk feedings: a strategy to reduce the risk of prematurity-related morbidities in very-low-birth-weight infants

Infants born at very low birth weight (VLBW; birth weight <1500 g) are at high risk of mortality and are some of the most expensive patients in the hospital. Additionally, VLBW infants are susceptible to prematurity-related morbidities, including late-onset sepsis, bronchopulmonary dysplasia (BPD), necrotizing enterocolitis, and retinopathy of prematurity, which have short- and long-term economic consequences. The incremental cost of these morbidities during the neonatal intensive care unit (NICU) hospitalization is high, ranging from $10,055 (in 2009 US$) for late-onset sepsis to $31,565 for BPD. Human milk has been shown to reduce both the incidence and severity of some of these morbidities and, therefore, has an indirect impact on the cost of the NICU hospitalization. Furthermore, human milk may also directly reduce NICU hospitalization costs, independent of the indirect impact on the incidence and/or severity of these morbidities. Although there is an economic cost to both the mother and institution for providing human milk during the NICU hospitalization, these costs are relatively low. This review describes the total cost of the initial NICU hospitalization, the incremental cost associated with these prematurity-related morbidities, and the incremental benefits and costs of human milk feedings during critical periods of the NICU hospitalization as a strategy to reduce the incidence and severity of these morbidities.

Slow advancement of enteral feed volumes to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

Early enteral feeding practices are potentially modifiable risk factors for necrotising enterocolitis in very preterm or very low birth weight (VLBW) infants. Observational studies suggest that conservative feeding regimens, including slowly advancing enteral feed volumes, reduce the risk of necrotising enterocolitis. However, slow feed advancement may delay establishment of full enteral feeding and be associated with metabolic and infectious morbidities secondary to prolonged exposure to parenteral nutrition.

OBJECTIVES

To determine the effect of slow rates of enteral feed advancement on the incidence of necrotising enterocolitis, mortality, and other morbidities in very preterm or VLBW infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group Specialised Register. We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2014, Issue 8), MEDLINE, EMBASE, and CINAHL (to September 2014), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of slow (up to 24 ml/kg per day) versus faster rates of advancement of enteral feed volumes upon the incidence of necrotising enterocolitis in very preterm or VLBW infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial eligibility and risk of bias and undertook data extraction. We analysed the treatment effects in the individual trials and reported the risk ratio and risk difference for dichotomous data and mean difference for continuous data, with respective 95% confidence intervals. We used a fixed-effect model in meta-analyses and explored the potential causes of heterogeneity in sensitivity analyses.

MAIN RESULTS

We identified six randomised controlled trials in which a total of 618 infants participated. Most participants were stable preterm infants of birth weight between 1000 g and 1500 g. Few participants were extremely preterm, extremely low birth weight, or growth-restricted. The trials typically defined slow advancement as daily increments of 15 ml/kg to 20 ml/kg and faster advancement as 30 ml/kg to 35 ml/kg. Meta-analyses did not detect statistically significant effects on the risk of necrotising enterocolitis (typical risk ratio (RR) 0.96, 95% confidence interval (CI) 0.55 to 1.70) or all-cause mortality (typical RR 1.57, 95% CI 0.92 to 2.70). Infants who had slow advancement took significantly longer to regain birth weight (reported median differences 2 to 6 days) and to establish full enteral feeding (1 to 5 days).

AUTHORS' CONCLUSIONS

The available trial data suggest that advancing enteral feed volumes at daily increments of 30 ml/kg to 35 ml/kg does not increase the risk of necrotising enterocolitis in very preterm or VLBW infants. Advancing the volume of enteral feeds at slow rates resulted in several days delay in regaining birth weight and establishing full enteral feeds. The applicability of these findings to extremely preterm, extremely low birth weight, or growth-restricted infants is limited. Further randomised controlled trials in these populations may be warranted to resolve this uncertainty.

Necrotizing enterocolitis: the mystery goes on

Necrotizing enterocolitis (NEC) has largely been present in neonatal intensive care units for the past 60 years. NEC prevalence has corresponded with the continued development and sophistication of neonatal intensive care. Despite major efforts towards its eradication, NEC has persisted and appears to be increasing in some centers. The pathophysiology of this disease remains poorly understood. Several issues have hampered our quest to develop a better understanding of this disease. These include the fact that what we have historically termed 'NEC' appears to be several different diseases. Animal models that are commonly used to study NEC pathophysiology and treatment do not directly reflect the most common form of the disease seen in human infants. The pathophysiology appears to be multifactorial, reflecting several different pathways to intestinal necrosis with different inciting factors. Spontaneous intestinal perforations, ischemic bowel disease secondary to cardiac anomalies as well as other entities that are clearly different from the most common form of NEC seen in preterm infants have been put into the same database. Here I describe some of the different forms of what has been called NEC and make some comments on its pathophysiology, where available studies suggest involvement of genetic factors, intestinal immaturity, hemodynamic instability, inflammation and a dysbiotic microbial ecology. Currently utilized approaches for the diagnosis of NEC are presented and innovative technologies for the development of diagnostic and predictive biomarkers are described. Predictions for future strategies are also discussed.

Current concepts in the surgical approach to necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common surgical emergency occurring in neonatal intensive care unit (NICU) patients. Among patients with NEC, those that require surgery experience the poorest outcomes and highest mortality. Surgical intervention, while attempting to address the intestinal injury and ongoing mulitfactorial physiologic insults in NEC is associated with its own stresses that may compound the ongoing physiologic derangement. Surgery is thus reserved for those patients with clear indication for intervention such as pneumoperitoneum, confirmed stool or pus in the peritoneal cavity, or worsening clinical status. The purpose of this review is to briefly describe the physiologic stress induced by surgical intervention in the preterm, low birth weight patient with NEC and to provide a contemporary overview of available surgical management options for NEC. The optimal surgical plan employed is strongly influenced by clinical judgment and theoretical benefits in terms of minimizing physiologic stressors while providing temporary and/or definitive treatment in a timely fashion. While the choice of operation has not been shown to have a significant effect on any clinically important outcomes, ongoing investigations continue to study both short and long-term outcomes in patients with NEC.

Necrotizing enterocolitis (NEC) and the risk of intestinal stricture: the value of C-reactive protein

Necrotizing enterocolitis (NEC) is a severe complication frequently seen during the neonatal period associated with high mortality rate and severe and prolonged morbidity including Post-NEC intestinal stricture. The aim of this study is to define the incidence and risk factors of these post-NEC strictures, in order to better orient their medicosurgical care. Sixty cases of NEC were retrospectively reviewed from a single tertiary center with identical treatment protocols throughout the period under study, including systematic X-ray contrast study. This study reports a high rate of post-NEC intestinal stricture (n = 27/48; 57% of survivors), either in cases treated surgically (91%) and after the medical treatment of NEC (47%). A colonic localization of the strictures was more frequent in medically-treated patients than in those with NEC treated surgically (87% vs. 50%). The length of the strictures was significantly shorter in case of NEC treated medically. No deaths were attributable to the presence of post-NEC stricture. The mean hospitalization time in NICU and the median age at discontinuation of parenteral nutrition were longer in the group with stricture, but this difference was not significant. The median age at discharge was significantly higher in the group with stricture (p = 0.02). The occurrence of post-NEC stricture was significantly associated with the presence of parietal signs of inflammation and thrombopenia (<100 000 platelets/mm³). The mean maximum CRP concentration during acute phase was significantly higher in infants who developed stricture (p<0.001), as was the mean duration of the elevation of CRP levels (p<0.001). The negative predictive value of CRP levels continually <10 mg/dL for the appearance of stricture was 100% in our study. In conclusion, this retrospective and monocentric study demonstrates the correlation between the intensity of the inflammatory syndrome and the risk of secondary intestinal stricture, when systematic contrast study is performed following NEC.

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.

Long term healthcare costs of infants who survived neonatal necrotizing enterocolitis: a retrospective longitudinal study among infants enrolled in Texas Medicaid

BACKGROUND

Infants who survive advanced necrotizing enterocolitis (NEC) at the time of birth are at increased risk of having poor long term physiological and neurodevelopmental growth. The economic implications of the long term morbidity in these children have not been studied to date. This paper compares the long term healthcare costs beyond the initial hospitalization period incurred by medical and surgical NEC survivors with that of matched controls without a diagnosis of NEC during birth hospitalization.

METHODS

The longitudinal healthcare utilization claim files of infants born between January 2002 and December 2003 and enrolled in the Texas Medicaid fee-for-service program were used for this research. Propensity scoring was used to match infants diagnosed with NEC during birth hospitalization to infants without a diagnosis of NEC on the basis of gender, race, prematurity, extremely low birth weight status and presence of any major birth defects. The Medicaid paid all-inclusive healthcare costs for the period from 6 months to 3 years of age among children in the medical NEC, surgical NEC and matched control groups were evaluated descriptively, and in a generalized linear regression framework in order to model the impact of NEC over time and by birth weight.

RESULTS

Two hundred fifty NEC survivors (73 with surgical NEC) and 2,909 matched controls were available for follow-up. Medical NEC infants incurred significantly higher healthcare costs than matched controls between 6-12 months of age (mean incremental cost = US$ 5,112 per infant). No significant difference in healthcare costs between medical NEC infants and matched controls was seen after 12 months. Surgical NEC survivors incurred healthcare costs that were consistently higher than that of matched controls through 36 months of age. The mean incremental healthcare costs of surgical NEC infants compared to matched controls between 6-12, 12-24 and 24-36 months of age were US$ 18,274, 14,067 (p < 0.01) and 8,501 (p = 0.06) per infant per six month period, respectively. These incremental costs were found to vary between sub-groups of infants born with birth weight < 1,000g versus ≥ 1,000g (p < 0.05).

CONCLUSIONS

The all-inclusive healthcare costs of surgical NEC survivors continued to be substantially higher than that of matched controls through the early childhood development period. These results can have important treatment and policy implications. Further research in this topic is needed.

Fetal cholinergic anti-inflammatory pathway and necrotizing enterocolitis: the brain-gut connection begins in utero

Necrotizing enterocolitis (NEC) is an acute neonatal inflammatory disease that affects the intestine and may result in necrosis, systemic sepsis and multisystem organ failure. NEC affects 5-10% of all infants with birth weight ≤ 1500 g or gestational age less than 30 weeks. Chorioamnionitis (CA) is the main manifestation of pathological inflammation in the fetus and is strong associated with NEC. CA affects 20% of full-term pregnancies and upto 60% of preterm pregnancies and, notably, is often an occult finding. Intrauterine exposure to inflammatory stimuli may switch innate immunity cells such as macrophages to a reactive phenotype ("priming"). Confronted with renewed inflammatory stimuli during labour or postnatally, such sensitized cells can sustain a chronic or exaggerated production of proinflammatory cytokines associated with NEC (two-hit hypothesis). Via the cholinergic anti-inflammatory pathway, a neurally mediated innate anti-inflammatory mechanism, higher levels of vagal activity are associated with lower systemic levels of proinflammatory cytokines. This effect is mediated by the α7 subunit nicotinic acetylcholine receptor (α7nAChR) on macrophages. The gut is the most extensive organ innervated by the vagus nerve; it is also the primary site of innate immunity in the newborn. Here we review the mechanisms of possible neuroimmunological brain-gut interactions involved in the induction and control of antenatal intestinal inflammatory response and priming. We propose a neuroimmunological framework to (1) study the long-term effects of perinatal intestinal response to infection and (2) to uncover new targets for preventive and therapeutic intervention.

The cost of using donor human milk in the NICU to achieve exclusively human milk feeding through 32 weeks postmenstrual age

OBJECTIVES

Donor human milk (DHM) is increasingly being used in neonatal intensive care units (NICUs) to achieve exclusive human milk (EHM) feedings in preterm infants. The aim of the study was to determine the cost of DHM to achieve EHM feeding for very preterm infants. The hypothesis was that the cost of DHM per infant is modulated by the availability of mother's own milk (MOM).

SUBJECTS AND METHODS

Preterm infants (<1,500 g at birth weight or <33 weeks in gestational age) were retrospectively evaluated for a 1-year interval. MOM, DHM, and formula feeding categories were determined. A DHM feeding log was retrospectively analyzed for feeding volumes (in milliliters) and duration (in days). Four categories were created, based on maternal ability to provide sufficient breastmilk volumes and her intention to breastfeed. The volume, duration, and cost of DHM were calculated for each category.

RESULTS

Forty-six of the 64 (72%) infants admitted to the NICU who were <33 weeks in gestational age received DHM. Four categories of DHM use were observed. The mean costs of DHM were $27 for infants of mothers who provided sufficient breastmilk through to discharge, $154 for infants of mothers who had insufficient milk supply during admission, $281 for infants of mothers who went home on formula but received any volume of MOM during admission, and $590 for infants who received no MOM during admission.

CONCLUSIONS

Most NICU mothers (72%) of very preterm infants were unable to provide all of the milk necessary for an EHM diet. Few infants (15%) received exclusively DHM. The cost of DHM per NICU infant ranged from $27 to $590 and was influenced by the mother's willingness or ability to provide human milk.

Delayed introduction of progressive enteral feeds to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

The introduction of enteral feeds for very preterm (< 32 weeks) or very low birth weight (< 1500 g) infants is often delayed for several days or longer after birth due to concern that early introduction may not be tolerated and may increase the risk of necrotising enterocolitis (NEC). However, delaying enteral feeding could diminish the functional adaptation of the gastrointestinal tract and prolong the need for parenteral nutrition with its attendant infectious and metabolic risks.

OBJECTIVES

To determine the effect of delayed introduction of progressive enteral feeds on the incidence of necrotising enterocolitis, mortality and other morbidities in very preterm or very low birth weight infants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2013, Issue 3), MEDLINE (1966 to April 2013), EMBASE (1980 to April 2013), CINAHL (1982 to April 2013), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of delayed (more than four days after birth) versus earlier introduction of progressive enteral feeds on the incidence of NEC, mortality and other morbidities in very preterm or very low birth weight infants.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We identified seven randomised controlled trials in which a total of 964 infants participated. Few participants were extremely preterm (< 28 weeks) or extremely low birth weight (< 1000 g). The trials defined delayed introduction as later than five to seven days after birth and early introduction as less than four days after birth. Meta-analyses did not detect statistically significant effects on the risk of NEC (typical risk ratio (RR) 0.92 (95% confidence interval (CI) 0.64 to 1.34) or all-cause mortality (typical RR 1.26 (95% CI 0.78 to 2.01)). Three of the trials restricted participation to growth-restricted infants with Doppler ultrasound evidence of abnormal fetal circulatory distribution or flow. Planned subgroup analyses of these trials did not find any statistically significant effects on the risk of NEC or all-cause mortality. Infants who had delayed introduction of enteral feeds took longer to establish full enteral feeding (reported median difference two to four days).

AUTHORS' CONCLUSIONS

The evidence available from randomised controlled trials suggests that delaying the introduction of progressive enteral feeds beyond four days after birth does not affect the risk of developing NEC in very preterm or very low birth weight infants, including growth-restricted infants. Delaying the introduction of progressive enteral feeds results in a few days delay in establishing full enteral feeds but the clinical importance of this effect is unclear. The applicability of these findings to extremely preterm or extremely low birth weight is uncertain. Further randomised controlled trials in this population may be warranted.

Expert consensus building using e-Delphi for necrotizing enterocolitis risk assessment

OBJECTIVE

To confirm content validity of GutCheck(NEC) , a risk index for necrotizing enterocolitis (NEC) and to determine the level of agreement among experts about NEC risk factors in premature infants.

DESIGN

Electronic Delphi method (e-Delphi).

SETTING

Online electronic surveys and e-mail communication supported by an interactive study website.

PARTICIPANTS

Nurses and physicians (N = 35) from four countries and across the United States who rated themselves as at least moderately expert about NEC risk.

METHODS

e-Delphi involved three rounds of surveys and qualitative thematic analysis of experts' comments. Surveys continued until criteria for consensus and/or stability were met.

RESULTS

Of 64 initial items, 43 were retained representing 33 risk factors (final GutCheck(NEC) Content Validity Index [CVI] = .77). Two broad themes about NEC risk emerged from 242 comments: the impact of individual physiologic vulnerability and variation in neonatal intensive care unit (NICU) clinicians' practices. Controversy arose over the impact of treatments on NEC, including probiotics, packed red blood cell (PRBC) transfusions, and patent ductus arteriosus (PDA) management using indomethacin.

CONCLUSION

GutCheck(NEC) achieved borderline content validity for a new scale. The e-Delphi process yielded a broad perspective on areas in which experts share and lack consensus on NEC risk. Future testing is underway to reduce the number of risk items to the most parsimonious set for a clinically useful risk tool and test reliability.

Slow advancement of enteral feed volumes to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

Early enteral feeding practices are potentially modifiable risk factors for necrotising enterocolitis in very preterm or very low birth weight (VLBW) infants. Observational studies suggest that conservative feeding regimens that include slowly advancing enteral feed volumes reduce the risk of necrotising enterocolitis. However, slow feed advancement may delay establishment of full enteral feeding and be associated with metabolic and infectious morbidities secondary to prolonged exposure to parenteral nutrition.

OBJECTIVES

To determine the effect of slow rates of enteral feed advancement on the incidence of necrotising enterocolitis, mortality and other morbidities in very preterm or VLBW infants.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 12), MEDLINE, EMBASE and CINAHL (to December 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of slow (up to 24 ml/kg/day) versus faster rates of advancement of enteral feed volumes upon the incidence of necrotising enterocolitis in very preterm or VLBW infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was performed using the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

We identified five randomised controlled trials in which a total of 588 infants participated. Few participants were extremely preterm, extremely low birth weight or growth restricted. The trials defined slow advancement as daily increments of 15 to 20 ml/kg and faster advancement as 30 to 35 ml/kg. Meta-analyses did not detect statistically significant effects on the risk of necrotising enterocolitis (typical risk ratio (RR) 0.97, 95% confidence interval (CI) 0.54 to 1.74) or all-cause mortality (RR 1.41, 95% CI 0.81 to 2.74). Infants who had slow advancement took significantly longer to regain birth weight (reported median differences two to six days) and to establish full enteral feeding (two to five days).

AUTHORS' CONCLUSIONS

The available trial data suggest that advancing enteral feed volumes at slow rather than faster rates does not reduce the risk of necrotising enterocolitis in very preterm or VLBW infants. Advancing the volume of enteral feeds at slow rates results in several days delay in regaining birth weight and establishing full enteral feeds but the long term clinical importance of these effects is unclear. The applicability of these findings to extremely preterm, extremely low birth weight or growth restricted infants is limited. Further randomised controlled trials in these populations may be warranted to resolve this uncertainty.

Mortality and intestinal failure in surgical necrotizing enterocolitis

BACKGROUND/PURPOSE

To examine whether as initial surgical intervention for necrotizing enterocolitis, primary peritoneal drainage as compared to primary laparotomy is associated with increased mortality or intestinal failure.

METHODS

Retrospective observational study of 240 infants with surgical necrotizing enterocolitis.

RESULTS

There was no difference concerning the composite outcome of mortality before discharge or survival with intestinal failure after adjusting for known covariates (Odds Ratio 1.73, 95% CI 0.88, 3.40). More surviving infants in the peritoneal drainage with subsequent salvage or secondary laparotomy had intestinal failure compared to those who received a peritoneal drain without subsequent laparotomy and survived (12% vs. 14% vs. 1%, p=0.015).

CONCLUSIONS

There is no difference between peritoneal drainage and laparotomy in infants with surgical necrotizing enterocolitis concerning the combined outcome of mortality or survival with intestinal failure. There is increased intestinal failure in surviving infants treated with peritoneal drain with either subsequent salvage or secondary laparotomy compared to peritoneal drainage alone.

Newer monitoring techniques to determine the risk of necrotizing enterocolitis

Necrotizing enterocolitis affects up to 10% of neonates who are born weighing less than 1500 g. It has a high rate of morbidity and mortality, and predicting infants who will be affected has so far been unsuccessful. In this article, a number of new methods are discussed from the literature to determine if any currently available techniques may allow for the identification of patients who are at increased risk for developing this potentially lethal disease.

Cost of morbidities in very low birth weight infants

OBJECTIVE

To determine the association between direct costs for the initial neonatal intensive care unit hospitalization and 4 potentially preventable morbidities in a retrospective cohort of very low birth weight (VLBW) infants (birth weight <1500 g).

STUDY DESIGN

The sample included 425 VLBW infants born alive between July 2005 and June 2009 at Rush University Medical Center. Morbidities included brain injury, necrotizing enterocolitis, bronchopulmonary dysplasia, and late-onset sepsis. Clinical and economic data were retrieved from the institution's system-wide data and cost accounting system. A general linear regression model was fit to determine incremental direct costs associated with each morbidity.

RESULTS

After controlling for birth weight, gestational age, and sociodemographic characteristics, the presence of brain injury was associated with a $12048 (P = .005) increase in direct costs; necrotizing enterocolitis, with a $15 440 (P = .005) increase; bronchopulmonary dysplasia, with a $31565 (P < .001) increase; and late-onset sepsis, with a $10055 (P < .001) increase. The absolute number of morbidities was also associated with significantly higher costs.

CONCLUSION

This study provides collective estimates of the direct costs incurred during neonatal intensive care unit hospitalization for these 4 morbidities in VLBW infants. The incremental costs associated with these morbidities are high, and these data can inform future studies evaluating interventions aimed at preventing or reducing these costly morbidities.

Evolution of in vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotising enterocolitis

BACKGROUND

We have previously reported evidence of in vitro sensitisation to cow's milk protein in peripheral blood mononuclear cells (PBMCs) in preterm infants with necrotising enterocolitis (NEC). In the present study, we document the changes in the PBMC responses to stimulation with mitogen (phytohaemagglutinin) and cow's milk proteins β-lactoglobulin (β-lg) and casein over time: from the acute presentation of NEC, to initial recovery (reinitiation of enteral feeds), to full recovery (full feeding).

METHODS

Of the 14 preterm infants recruited with acute NEC, 12 were followed until fully enterally fed (2 died during the acute phase). Cytokine secretion (interferon-γ [IFN-γ], interleukin 4, [IL-4], IL-10, and transforming growth factor-β1 [TGF-β1]) by PBMCs in response to stimulation by phytohaemagglutinin, β-lg, and casein was measured by enzyme-linked immunospot in the acute phase and subsequently at recovery and full recovery.

RESULTS

The high levels of cytokine secretion (IFN-γ, IL-4, IL-10, and TGF-β1) observed in response to β-lg and casein in the acute phase increased by a further 50% to 100% at recovery (P < 0.005). At full recovery (full feeding), however, IFN-γ, IL-4, and IL-10 secretion response had returned to, or below, acute-phase levels, whereas the augmented TGF-β1 response was maintained (P = 0.005 vs acute level). This response pattern was similar for casein, and did not appear to be influenced by the nature of the feed used following NEC (breast milk/formula/hydrolysed formula).

CONCLUSIONS

The evolution of the cytokine response profile in parallel with the clinical recovery from NEC is consistent with a putative role for TGF-β1 in regulation of inflammation, and possibly also oral tolerance.

Intestinal microcirculatory dysfunction and neonatal necrotizing enterocolitis

OBJECTIVE

Based on the observation that coagulation necrosis occurs in the majority of neonatal necrotizing enterocolitis (NEC) patients, it is clear that intestinal ischemia is a contributing factor to the pathogenesis of NEC. However, the published studies regarding the role of intestinal ischemia in NEC are controversial. The aim of this paper is to review the current studies regarding intestinal microcirculatory dysfunction and NEC, and try to elucidate the exact role of intestinal microcirculatory dysfunction in NEC.

DATA SOURCES

The studies cited in this review were mainly obtained from articles listed in Medline and PubMed. The search terms used were "intestinal microcirculatory dysfunction" and "neonatal necrotizing enterocolitis".

STUDY SELECTION

Mainly original milestone articles and critical reviews written by major pioneer investigators in the field were selected.

RESULTS

Immature regulatory control of mesentery circulation makes the neonatal intestinal microvasculature vulnerable. When neonates are subjected to stress, endothelial cell dysfunction occurs and results in vasoconstriction of arterioles, inflammatory cell infiltration and activation in venules, and endothelial barrier disruption in capillaries. The compromised vasculature increases circulation resistance and therefore decreases intestinal perfusion, and may eventually progress to intestinal necrosis.

CONCLUSION

Intestinal ischemia plays an important role through the whole course of NEC. New therapeutic agents targeting intestinal ischemia, like HB-EGF, are promising therapeutic agents for the treatment of NEC.

A three-dimensional mathematical and computational model of necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe disease that affects the gastrointestinal (GI) tract of premature infants. Different areas of NEC research have often been isolated from one another and progress on the role of the inflammatory response in NEC, on the dynamics of epithelial layer healing, and on the positive effects of breast feeding have not been synthesized to produce a more integrated understanding of the pathogenesis of NEC. We seek to synthesize these areas of research by creating a mathematical model that incorporates the current knowledge on these aspects. Unlike previous models that are based on ordinary differential equations, our mathematical model takes into account not only transient effects but also spatial effects. A system of nonlinear transient partial differential equations is solved numerically using cell-centered finite differences and an explicit Euler method. The model is used to track the evolution of a prescribed initial injured area in the intestinal wall. It is able to produce pathophysiologically realistic results; decreasing the initial severity of the injury in the system and introducing breast feeding to the system both lead to healthier overall simulations, and only a small fraction of epithelial injuries lead to full-blown NEC. In addition, in the model, changing the initial shape of the injured area can significantly alter the overall outcome of a simulation. This finding suggests that taking into account spatial effects may be important in assessing the outcome for a given NEC patient. This model can provide a platform with which to test competing hypotheses regarding pathological mechanisms of inflammation in NEC, suggest experimental approaches by which to clarify pathogenic drivers of NEC, and may be used to derive potential intervention strategies.

Arginine and citrulline protect intestinal cell monolayer tight junctions from hypoxia-induced injury in piglets

BACKGROUND

Arginine (Arg) is deficient in the serum of the preterm neonate and is lower in those developing intestinal ischemia. We investigated whether Arg or its precursor, citrulline (Cit), protects intestinal tight junctions (TJs) from hypoxia (HX) and determined whether inducible nitric oxide (NO) plays a role.

METHODS

Neonatal piglet jejunal IPEC-J2 cell monolayers were treated with Arg or Cit, reversible and irreversible NO synthetase (NOS) inhibitors, and were exposed to HX. TJs were assessed by serial measurements of transepithelial electrical resistance (TEER), flux of inulin-fluorescein isothiocyanate, and immunofluorescent staining of TJ proteins.

RESULTS

We found that Arg and Cit were protective against HX-related damage. At the final time point (14 h), the mean TEER ratio (TEER as compared with baseline) for Arg + HX and Cit + HX was significantly higher than that for HX alone. Both Arg and Cit were associated with decreased inulin flux across hypoxic monolayers and qualitatively preserved TJ proteins. Irreversible inhibition of NOS blocked this protective effect. Lipid peroxidation assay showed that our model did not produce oxidant injury.

CONCLUSION

Arg and Cit, via a mechanism dependent on NO donation, protected intestinal epithelial integrity.

Intestinal alkaline phosphatase prevents the systemic inflammatory response associated with necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is the most common surgical emergency in neonates, with an incidence of 0.5-2.4 cases per 1000 live births and a mortality rate between 10% and 50%. Neonates affected by NEC develop a septic injury that is associated with increased risk of neurological impairment due to intraventricular bleeding and chronic lung disease. Intestinal alkaline phosphatase (IAP) is an endogenous protein that has been shown to inactivate the endotoxin lipopolysaccharide (LPS), and has recently been used successfully as an adjunct to treat sepsis in adult patients. We tested the hypothesis that systemic, exogenous IAP will mitigate the inflammatory response as measured by serum levels of proinflammatory cytokines in a rat model of NEC.

METHODS

Newborn Sprague-Dawley rats were divided into groups. Control pups were dam fed. NEC was induced by feeding formula containing LPS and exposure to intermittent hypoxia. NEC pups were given intraperitoneal injections of 4 or 40 glycine units (U) of IAP or placebo twice daily. Intestine and serum was collected for cytokine analysis as well as measurement of alkaline phosphatase activity.

RESULTS

Systemic IAP administration significantly increased serum alkaline phosphatase activity in a dose- and time-dependent fashion. The proinflammatory cytokines tumor necrosis factor α, interleukin 6, and interleukin 1β were significantly increased in NEC rats versus controls on days 2 and 3. Importantly, treatment with 40 U systemic IAP decreased these proinflammatory cytokines back to near-control levels.

CONCLUSIONS

Systemic IAP administration appears effective in mitigating the systemic inflammatory response associated with NEC, and may prove to be a valuable adjunctive treatment for NEC.

Carnitine deficiency in OCTN2-/- newborn mice leads to a severe gut and immune phenotype with widespread atrophy, apoptosis and a pro-inflammatory response

We have investigated the gross, microscopic and molecular effects of carnitine deficiency in the neonatal gut using a mouse model with a loss-of-function mutation in the OCTN2 (SLC22A5) carnitine transporter. The tissue carnitine content of neonatal homozygous (OCTN2^−/−) mouse small intestine was markedly reduced; the intestine displayed signs of stunted villous growth, early signs of inflammation, lymphocytic and macrophage infiltration and villous structure breakdown. Mitochondrial β-oxidation was active throughout the GI tract in wild type newborn mice as seen by expression of 6 key enzymes involved in β-oxidation of fatty acids and genes for these 6 enzymes were up-regulated in OCTN2^−/− mice. There was increased apoptosis in gut samples from OCTN2^−/− mice. OCTN2^−/− mice developed a severe immune phenotype, where the thymus, spleen and lymph nodes became atrophied secondary to increased apoptosis. Carnitine deficiency led to increased expression of CD45-B220⁺ lymphocytes with increased production of basal and anti-CD3-stimulated pro-inflammatory cytokines in immune cells. Real-time PCR array analysis in OCTN2^−/− mouse gut epithelium demonstrated down-regulation of TGF-β/BMP pathway genes. We conclude that carnitine plays a major role in neonatal OCTN2^−/− mouse gut development and differentiation, and that severe carnitine deficiency leads to increased apoptosis of enterocytes, villous atrophy, inflammation and gut injury.

Rising charges and costs for pediatric catheter ablation

INTRODUCTION

Catheter ablation has been shown to be effective for pediatric tachyarrhythmias, but the associated charges and costs have not been described in the recent era. Understanding such contemporary trends may identify ways to keep an effective therapy affordable while optimizing clinical outcomes.

METHODS

We used the 1997-2009 Kids' Inpatient Databases to examine trends in charges and costs for pediatric catheter ablation and identify determinants of temporal changes.

RESULTS

There were 7,130 discharges for catheter ablation in the sample. Mean age at ablation was 12.1 ± 0.2 years. Patients with congenital heart disease (CHD) made up 10% of the sample. Complications occurred in 8% of discharges. Mean total charges rose 219% above inflation (from $23,798 ± 1,072 in 1997 to $75,831 ± 2,065 in 2009). From 2003 to 2009, costs rose 25% (from $20,459 ± 780 in 2003 to $25,628 ± 992 in 2009). Charges for ablation increased markedly relative to surgical procedures, but with a similar slope to other catheter-based interventions. Multivariable analysis revealed that year (P < 0.0001), payer (P = 0.0002), CHD (P < 0.0001), valvular heart disease (P = 0.0004), cardiomyopathy (P = 0.0009), hospital region (P < 0.0001), length of stay (P < 0.0001), and complications (P < 0.0001) predicted increased charges. The same factors also predicted increased costs. Charges and costs varied considerably by region, particularly for high-volume centers (P < 0.0001).

CONCLUSIONS

Charges and costs for pediatric catheter ablation increased relative to other procedures and significantly outstripped inflation. Further study of complications, length of stay, and regional differences may help control rising costs while maintaining quality of care.

Probiotics and necrotizing enterocolitis: finding the missing pieces of the probiotic puzzle

Necrotizing enterocolitis (NEC) is one of the leading causes of death in the neonatal intensive care unit. Morbidity and mortality rates significantly increase with decreases in gestational age and birth weight. Strong evidence suggests probiotic prophylaxis may significantly decrease the incidence of NEC and should therefore be incorporated into the standard of care for preterm infants. However, debate still remains because of limitations of completed studies. The purpose of this review was to provide an overview of the controversies regarding probiotic use in preterm infants and to shed light on the practical considerations for implementation of probiotic supplementation.

Paneth cells and necrotizing enterocolitis: a novel hypothesis for disease pathogenesis

Current models of necrotizing enterocolitis (NEC) propose that intraluminal microbes destroy intestinal mucosa and activate an inflammatory cascade that ends in necrosis. We suggest an alternate hypothesis wherein NEC is caused by injury to Paneth cells (PCs) in the intestinal crypts. PCs are specialized epithelia that protect intestinal stem cells from pathogens, stimulate stem cell differentiation, shape the intestinal microbiota, and assist in repairing the gut. Our novel model of NEC uses neonatal mice and ablates PCs followed by enteral infection. We contrast this model with other animal examples of NEC and the clinical disease. Selective destruction of PCs using dithizone likely releases tumor necrosis factor-α and other inflammatory mediators. We propose that this event produces inflammation in the submucosa, generates platelet-activating factor, and induces a coagulopathy. The role of PCs in NEC is consistent with the onset of disease in preterm infants after a period of PC-related maturation, the central role of PCs in crypt-related homeostasis, the anatomic location of pneumatosis intestinalis close to the crypts, and the proximity of PCs to occluded blood vessels that cause coagulation necrosis of the intestinal villi. We offer this hypothesis to promote new thoughts about how NEC occurs and its potential prevention.

[Short bowel syndrome in children: a diagnosis and management update]

Short bowel syndrome (SBS) refers to the sum of the functional alterations that are the result of a critical reduction in the length of the intestine, which in the absence of adequate treatment, presents as chronic diarrhea, chronic dehydration, malnutrition, weight loss, nutriment and electrolyte deficiency, along with a failure to grow that is present with greater frequency during the neonatal period. The aim was to carry out a review of the literature encompassing the definition and the most frequent causes of SBS, together with an understanding of its physiopathology, prognostic factors, and treatment. An Internet search of PubMed articles was carried out for the existing information published over the last 20 years on SBS in children, using the keywords "short bowel syndrome". From a total of 784 potential articles, 82 articles were chosen for the literature review. The treatment of patients presenting with SBS is quite a challenge and therefore it is necessary to establish multidisciplinary management with a focus on maintaining optimal nutritional support that covers the necessities of growth and development and at the same time provides a maximum reduction of short, medium, and long-term complications. The diagnosis and treatment of a child with SBS require a team of professionals that are experts in gastroenterologic, pediatric, and nutritional management. The outcome for the child will be directly related to opportune management, as well as to the length of the intestinal resection and the presence or absence of the ileocecal valve.

Interleukin 8 correlates with intestinal involvement in surgically treated infants with necrotizing enterocolitis

PURPOSE

The aim of this study was to test the predictive value of interleukin (IL) 8 in the assessment of intestinal involvement in necrotizing enterocolitis (NEC).

METHODS

Forty infants with surgically treated NEC were classified into 3 groups based on intestinal involvement during laparotomy: focal (n = 11), multifocal (n = 16), and panintestinal (n = 13). Preoperatively obtained serum levels of IL-8, C-reactive protein, white blood cell count, and platelet count were correlated with intestinal involvement using logistic regression models.

RESULTS

Interleukin 8 correlated significantly with intestinal involvement in infants with surgically treated NEC (odds ratio, 1.74; confidence interval, 1.27-2.39; P < .001). An exploratory IL-8 cutoff value of 449 pg/mL provided a specificity of 81.8% and sensitivity of 82.8% to discriminate focal from multifocal and panintestinal disease. An IL-8 cutoff value of 1388 pg/mL provided a specificity of 77.8% and a sensitivity of 76.9% to discriminate panintestinal disease from focal and multifocal disease.

CONCLUSIONS

To our knowledge, this is the first study to demonstrate a significant correlation of IL-8 with intestinal involvement in advanced NEC in a large patient population. Our results indicate that IL-8 may be a promising biomarker for assessing intestinal involvement in infants with advanced NEC.

Effect of breast milk on hospital costs and length of stay among very low-birth-weight infants in the NICU

PURPOSE

Care of the very low-birth-weight (VLBW) infant is associated with prolonged hospitalization and increased hospital costs. Specific complications of prematurity, including necrotizing enterocolitis (NEC), late-onset sepsis (LOS), and feeding intolerance, contribute to increased cost and length of hospitalization in this population. The provision of breast milk to VLBW infants has been associated with decreased incidence of NEC and LOS as well as fewer days required to achieve full enteral feedings. The purpose of this study was to determine the impact of breast milk on length of hospitalization and hospital costs among VLBW infants in the neonatal intensive care unit (NICU).

SUBJECTS

A total of 80 infants weighing less than 1500 g, born prior to 32 weeks' gestation and who remained in the home hospital until discharge.

DESIGN

This descriptive comparative study examined cost of hospitalization and length of stay between 2 groups of VLBW premature infants fed either exclusively formula (n = 40) or at least 50% breast milk (n = 40) during their hospitalization.

METHODS

A retrospective chart review was used to collect information concerning patient demographics, discharge information, and nutritional variables. Information regarding hospital costs was obtained from the hospital's patient accounting office.

MAIN OUTCOME MEASURES

Independent t tests were used to compare demographic data, length of hospitalization, and cost of care between the 2 groups.

PRINCIPAL RESULTS

No statistically significant differences in length of stay or cost of care were found between infants fed at least 50% breast milk and those who were exclusively formula fed. Descriptive data concerning length of stay and cost of care for VLBW infants and those infants weighing less than 1000 g are presented.

CONCLUSION

This article presents a descriptive comparative study on the effect of providing at least 50% breast milk feedings compared with formula feeding on days to discharge and cost of hospitalization in VLBW infants in the NICU. It also provides information concerning cost of care and length of stay in VLBW and infants weighing less than 1000 g.

A.S.P.E.N. clinical guidelines: nutrition support of neonatal patients at risk for necrotizing enterocolitis

BACKGROUND

Necrotizing enterocolitis (NEC) is one of the most devastating diseases in the neonatal population, with extremely low birth weight and extremely preterm infants at greatest risk.

METHOD

A systematic review of the best available evidence to answer a series of questions regarding nutrition support of neonates at risk of NEC was undertaken and evaluated using concepts adopted from the Grading of Recommendations, Assessment, Development and Evaluation working group. A consensus process was used to develop the clinical guideline recommendations prior to external and internal review and approval by the A.S.P.E.N. Board of Directors. RESULTS/ CONCLUSIONS: (1) When and how should feeds be started in infants at high risk for NEC? We suggest that minimal enteral nutrition be initiated within the first 2 days of life and advanced by 30 mL/kg/d in infants ≥ 1, 000 g. (Weak) (2) Does the provision of mother's milk reduce the risk of developing NEC? We suggest the exclusive use of mother's milk rather than bovine-based products or formula in infants at risk for NEC. (Weak) (3) Do probiotics reduce the risk of developing NEC? There are insufficient data to recommend the use of probiotics in infants at risk for NEC. (Further research needed.) (4) Do nutrients either prevent or predispose to the development of NEC? We do not recommend glutamine supplementation for infants at risk for NEC (Strong). There is insufficient evidence to recommend arginine and/or long chain polyunsaturated fatty acid supplementation for infants at risk for NEC. (Further research needed.) (5) When should feeds be reintroduced to infants with NEC? There are insufficient data to make a recommendation regarding time to reintroduce feedings to infants after NEC. (Further research needed.).

Randomized controlled trial of slow vs rapid enteral feeding advancements on the clinical outcomes of preterm infants with birth weight 750-1250 g

OBJECTIVE

To evaluate the effect of slow vs rapid rates of advancement of enteral feed volumes on the clinical outcomes in preterm infants with 750-1250 g birth weight.

STUDY DESIGN

A total of 92 stable neonates 750-1250 g and gestational age <32 weeks were randomly allocated to enteral feeding advancement of 20 mL/kg/d (n = 46) or 30 mL/kg/d (n = 46). The primary outcome was days to reach full enteral feeding, defined as 180 mL/kg/d. Secondary outcomes included rates of necrotizing enterocolitis (NEC) and culture-proven sepsis, days of parenteral nutrition (PN), length of hospital stay, and growth end points.

RESULTS

Neonates in the rapid-feeding advancement group achieved full enteral volume of feedings earlier than the slower advancement group. They received significantly fewer days of PN, exhibited a shorter time to regain birth weight, and had a shorter duration of hospital stay. The incidence of NEC and the number of episodes of feeding intolerance were not significantly different between the groups, whereas the incidence of culture-proven late-onset sepsis was significantly less in infants receiving a rapid feeding advancement. Excluding infants who were small for gestational age at birth, the incidence of extrauterine growth restriction was significantly reduced in the rapid-advancement group at 28 days and at hospital discharge.

CONCLUSION

Rapid enteral feeding advancements in 750-1250 g birth weight infants reduce the time to reach full enteral feeding and the use of PN administration. Rapid-advancement enteral feed also decreases extrauterine growth restriction with improved short-term outcomes for these high-risk infants.

Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common acquired gastrointestinal disease of premature neonates and is a serious cause of morbidity and mortality. NEC is one of the leading causes of death in neonatal intensive care units. Surgical treatment is necessary in patients whose disease progresses despite medical therapy. Surgical options include peritoneal drainage and laparotomy, with studies showing no difference in outcome related to approach. Survivors, particularly those requiring surgery, face serious sequelae.

Necrotizing enterocolitis risk: state of the science

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

The ProPrems trial: investigating the effects of probiotics on late onset sepsis in very preterm infants

Background

Late onset sepsis is a frequent complication of prematurity associated with increased mortality and morbidity. The commensal bacteria of the gastrointestinal tract play a key role in the development of healthy immune responses. Healthy term infants acquire these commensal organisms rapidly after birth. However, colonisation in preterm infants is adversely affected by delivery mode, antibiotic treatment and the intensive care environment. Altered microbiota composition may lead to increased colonisation with pathogenic bacteria, poor immune development and susceptibility to sepsis in the preterm infant.

Probiotics are live microorganisms, which when administered in adequate amounts confer health benefits on the host. Amongst numerous bacteriocidal and nutritional roles, they may also favourably modulate host immune responses in local and remote tissues. Meta-analyses of probiotic supplementation in preterm infants report a reduction in mortality and necrotising enterocolitis. Studies with sepsis as an outcome have reported mixed results to date.

Allergic diseases are increasing in incidence in "westernised" countries. There is evidence that probiotics may reduce the incidence of these diseases by altering the intestinal microbiota to influence immune function.

Methods/Design

This is a multi-centre, randomised, double blinded, placebo controlled trial investigating supplementing preterm infants born at < 32 weeks' gestation weighing < 1500 g, with a probiotic combination (Bifidobacterium infantis, Streptococcus thermophilus and Bifidobacterium lactis). A total of 1,100 subjects are being recruited in Australia and New Zealand. Infants commence the allocated intervention from soon after the start of feeds until discharge home or term corrected age. The primary outcome is the incidence of at least one episode of definite (blood culture positive) late onset sepsis before 40 weeks corrected age or discharge home. Secondary outcomes include: Necrotising enterocolitis, mortality, antibiotic usage, time to establish full enteral feeds, duration of hospital stay, growth measurements at 6 and 12 months' corrected age and evidence of atopic conditions at 12 months' corrected age.

Discussion

Results from previous studies on the use of probiotics to prevent diseases in preterm infants are promising. However, a large clinical trial is required to address outstanding issues regarding safety and efficacy in this vulnerable population. This study will address these important issues.

Trial registration

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN012607000144415

The product "ABC Dophilus Probiotic Powder for Infants^®", Solgar, USA has its 3 probiotics strains registered with the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ - German Collection of Microorganisms and Cell Cultures) as BB-12 15954, B-02 96579, Th-4 15957.

The risk of necrotizing enterocolitis after indomethacin tocolysis

BACKGROUND

Postnatal indomethacin is reportedly associated with an increased incidence of necrotizing enterocolitis (NEC) in preterm infants. Because indomethacin readily crosses the placenta, we hypothesized that antenatal indomethacin (AI) would increase the risk for NEC in preterm infants.

OBJECTIVE

The goal of this study was to explore the association between AI and NEC in preterm infants.

METHODS

Medical records of preterm infants, 23 to 32 weeks' gestational age, without major congenital anomalies, were reviewed. Maternal and neonatal data were abstracted. Association of AI within 15 days before delivery (predictor variable) and classification of NEC according to modified Bell's stage 2a or higher in the first 15 days after delivery (early NEC [primary outcome variable]) was explored by using bivariate analyses, multivariate logistic regression, and propensity score analysis.

RESULTS

Of 628 eligible infants, 63 received AI and 28 developed early NEC. AI exposure was significantly associated with multiple gestation, race, antenatal corticosteroids and magnesium sulfate, lower birth weight and gestational age, umbilical arterial catheter placement, respiratory distress syndrome, postnatal vasopressors and antibiotics, patent ductus arteriosus, sepsis, NEC, intraventricular hemorrhage, and mortality. On multivariate logistic regression controlling for covariates, AI was significantly associated with early NEC (adjusted odds ratio: 7.193 [95% confidence interval: 2.514-20.575]; number needed to harm: 5). The results remained significant when analyses were repeated using AI exposure within 5 days before delivery as a predictor variable; on analyses stratified according to gestational age; and on propensity score analysis.

CONCLUSIONS

AI was associated with NEC in preterm infants in the first 15 days of life in this study, as were multiple other clinical factors.

Altered intestinal microcirculation is the critical event in the development of necrotizing enterocolitis

PURPOSE

The pathophysiology of necrotizing enterocolitis (NEC) includes prematurity, enteral feeds, hypoxia, and hypothermia. We hypothesized that vasoconstriction of the neonatal intestinal microvasculature is the essential mechanistic event in NEC and that these microvascular changes correlate with alterations in mediators of inflammation.

METHODS

Sprague-Dawley rat pups were separated into groups by litter. Necrotizing enterocolitis was induced in experimental groups, whereas control animals were delivered vaginally and dam fed. Neonatal pups underwent intravital videomicroscopy of the terminal ileum with particular attention to the inflow and premucosal arterioles. Reverse transcriptase-polymerase chain reaction was performed to evaluate for messenger RNA of mediators of inflammation.

RESULTS

Necrotizing enterocolitis animals demonstrated statistically significant smaller inflow and premucosal arterioles than control animals (P < .05). Necrotizing enterocolitis animals had an altered intestinal arteriolar flow with a distinct "stop-and-go" pattern, suggesting severe vascular dysfunction. Reverse transcriptase-polymerase chain reaction confirmed elevation of Toll-like receptor 4 (P = .01) and high-mobility group box protein 1 (P = .001) in the ileum of animals with NEC.

CONCLUSION

Intestinal arterioles were significantly smaller at baseline in animals with NEC compared with controls, and expression of inflammatory mediators was increased in animals with NEC. This represents a novel method of defining the pathophysiology of NEC and allows real-time evaluation of novel vasoactive strategies to treat NEC.

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.

The NFKB1 (g.-24519delATTG) variant is associated with necrotizing enterocolitis (NEC) in premature infants

OBJECTIVE

While it is known that gene-environment interactions contribute to necrotizing enterocolitis (NEC) pathogenesis, characterization of genetic risk-factors that can predict NEC in preterm infants remains nascent. We hypothesized that altered intestinal immune responses arising from sequence variation in the toll-like receptor (TLR) pathway genes contribute to NEC susceptibility.

MATERIALS AND METHODS

Very low birth weight (VLBW) infants were recruited prospectively in a multi-center, cohort study involving collection of blood samples along with collation of clinical information. DNA obtained from blood samples was used to genotype nine single nucleotide polymorphisms (SNPs) in eight TLR pathway genes by single-base extension. Prevalence of the variant allele was compared between cases and controls using Fisher's exact test.

RESULTS

In our cohort of 271 infants, 15 infants (5.6%) developed NEC, and five died from it. Infants with NEC were less mature (P < 0.001), and were more likely to be African-American (P = 0.007). SNPs in the TLR2, TLR4, TLR5, TLR9, IRAK1, and TIRAP genes were not associated with NEC. The NFKB1 (g.-24519delATTG) variant was present in all infants with NEC but only in 65% of infants without NEC (P = 0.003), while the NFKBIA (g.-1004A>G) variant was present in 13.3% of infants with NEC but in 49% of infants without NEC (P = 0.007). After correcting for multiple comparisons, the NFKB1 and NFKBIA variants remained associated with NEC (P < 0.05).

CONCLUSIONS

These data suggest that TLR genetic variants can alter susceptibility to NEC in VLBW infants and support the hypothesis that genetically programmed differences in the innate immune response contribute to NEC pathogenesis.

Review of the Relationships Between Maternal Characteristics and Preterm Breastmilk Immune Components

The immune properties of breastmilk are the most effective preventative means of reducing infant mortality through both passive and active immunity. Breastmilk for term infants has been linked to decreased incidence of respiratory and ear infections and gastrointestinal distress. This protection is even more important for the preterm infant. Prematurity is one of the leading causes of infant death in the United States. Hospitalized infant outcomes associated with consumption of breastmilk are shorter length of stay and decreased incidence of nosocomial infections and necrotizing enterocolitis (NEC). The presence of nosocomial infections and necrotizing enterocolitis increases risk of preterm mortality and morbidity as well as healthcare expenditures. However, breastmilk immunological components such as secretory immunoglobulin A, lactoferrin (LFT), and cytokines provide a framework of immunity that, in conjunction with nutritional support, significantly improves neonatal health. The relationship between maternal characteristics and breastmilk immune properties is central to further the understanding of the impact of breastmilk on preterm infant morbidity and mortality. The purpose of this article is to review the numerous immune components in breastmilk, the moderators of the immune components, and the relevance of these components to preterm/infant health. Exploration of the complexity of breastmilk immune components may direct future development of interventions to improve and sustain the immunological benefits of preterm breastmilk.

Delayed introduction of progressive enteral feeds to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

The introduction of progressive enteral feeds for very low birth weight (VLBW) infants is often delayed for several days or longer after birth due to concern that earlier introduction may not be tolerated and may increase the risk of necrotising enterocolitis (NEC). However, delaying enteral feeding could diminish the functional adaptation of the gastrointestinal tract and prolong the need for parenteral nutrition with its attendant infectious and metabolic risks.

OBJECTIVES

To determine the effect of delayed introduction of progressive enteral feeds on the incidence of NEC, mortality and other morbidities in VLBW infants.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2010, Issue 4), MEDLINE (1966 to December 2010), EMBASE (1980 to December 2010), CINAHL (1982 to December 2010), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of delayed (more than four days' postnatal age) versus earlier introduction of progressive enteral feeds on the incidence of NEC, mortality and other morbidities in VLBW infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis were performed in accordance with the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

We identified five randomised controlled trials (RCT) in which a total of 600 infants participated. The trials defined delayed introduction as later than five to seven days after birth and early introduction as less than four days after birth. Two of the trials, in which a total of 488 infants participated, only recruited growth-restricted infants with Doppler ultrasound evidence of abnormal fetal circulatory distribution or flow. Meta-analyses did not detect statistically significant effects on the risk of NEC [typical relative risk 0.89, 95% confidence interval (CI) 0.58 to 1.37] or all cause mortality (typical relative risk 0.93, 95% CI 0.53 to 1.64). Infants who had delayed introduction of enteral feeds took significantly longer to establish full enteral feeding (reported median difference three days).

AUTHORS' CONCLUSIONS

Current trial data do not provide evidence that delayed introduction of progressive enteral feeds reduces the risk of NEC in VLBW infants. Delaying the introducing of progressive enteral feeds results in several days delay in establishing full enteral feeds but the clinical importance of this effect is unclear. Further RCTs are needed to give more precise estimates of the effect of delaying the introduction of enteral feeds on clinical outcomes in VLBW infants.

Probiotics for prevention of necrotizing enterocolitis in preterm infants

BACKGROUND

Necrotizing enterocolitis (NEC) and nosocomial sepsis are associated with increased morbidity and mortality in preterm infants. Through prevention of bacterial migration across the mucosa, competitive exclusion of pathogenic bacteria, and enhancing the immune responses of the host, prophylactic enteral probiotics (live microbial supplements) may play a role in reducing NEC and associated morbidity.

OBJECTIVES

To compare the efficacy and safety of prophylactic enteral probiotics administration versus placebo or no treatment in the prevention of severe NEC and/or sepsis in preterm infants.

SEARCH STRATEGY

For this update, searches were made of MEDLINE (1966 to October 2010), EMBASE (1980 to October 2010), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2010), and abstracts of annual meetings of the Society for Pediatric Research (1995 to 2010).

SELECTION CRITERIA

Only randomized or quasi-randomized controlled trials that enrolled preterm infants < 37 weeks gestational age and/or < 2500 g birth weight were considered. Trials were included if they involved enteral administration of any live microbial supplement (probiotics) and measured at least one prespecified clinical outcome.

DATA COLLECTION AND ANALYSIS

Standard methods of the Cochrane Collaboration and its Neonatal Group were used to assess the methodologic quality of the trials, data collection and analysis.

MAIN RESULTS

Sixteen eligible trials randomizing 2842 infants were included. Included trials were highly variable with regard to enrollment criteria (i.e. birth weight and gestational age), baseline risk of NEC in the control groups, timing, dose, formulation of the probiotics, and feeding regimens. Data regarding extremely low birth weight infants (ELBW) could not be extrapolated. In a meta-analysis of trial data, enteral probiotics supplementation significantly reduced the incidence of severe NEC (stage II or more) (typical RR 0.35, 95% CI 0.24 to 0.52) and mortality (typical RR 0.40, 95% CI 0.27 to 0.60). There was no evidence of significant reduction of nosocomial sepsis (typical RR 0.90, 95% CI 0.76 to 1.07). The included trials reported no systemic infection with the probiotics supplemental organism. The statistical test of heterogeneity for NEC, mortality and sepsis was insignificant.

AUTHORS' CONCLUSIONS

Enteral supplementation of probiotics prevents severe NEC and all cause mortality in preterm infants. Our updated review of available evidence supports a change in practice. More studies are needed to assess efficacy in ELBW infants and assess the most effective formulation and dose to be utilized.

Slow advancement of enteral feed volumes to prevent necrotising enterocolitis in very low birth weight infants

BACKGROUND

The major modifiable risk factors for necrotising enterocolitis (NEC) in very low birth weight (VLBW) infants relate to enteral feeding practices. Observational studies suggest that conservative feeding regimens that include slowly advancing enteral feed volumes reduce the risk of NEC. However, slow feed advancement may delay establishment of full enteral feeding and so be associated with metabolic and infectious morbidities secondary to prolonged exposure to parenteral nutrition.

OBJECTIVES

To determine the effect of slow rates of enteral feed advancement on the incidence of NEC, mortality and other morbidities in VLBW infants.

SEARCH STRATEGY

We used the standard search strategy of the Cochrane Neonatal Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2010, Issue 4), MEDLINE (1966 to December 2010), EMBASE (1980 to December 2010), CINAHL (1982 to December 2010), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that assessed the effect of slow (up to 24 ml/kg/day) versus faster rates of advancement of enteral feed volumes upon the incidence of NEC in VLBW infants.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was performed in accordance with the standard methods of the Cochrane Neonatal Review Group.

MAIN RESULTS

We identified four randomised controlled trials in which a total of 496 infants participated. Few participants were extremely low birth weight or growth restricted. The trials defined slow advancement as daily increments of 15 to 20 ml/kg and faster advancement as 30 to 35 ml/kg. Meta-analyses did not detect statistically significant effects on the risk of NEC (typical relative risk 0.91, 95% confidence interval 0.47 to 1.75) or all cause mortality (typical relative risk 1.43, 95% confidence interval 0.78 to 2.61). Infants who had slow rates of feed volume advancement took significantly longer to regain birth weight [reported median difference 2 to 6 days] and to establish full enteral feeding [reported median difference 2 to 5 days].

AUTHORS' CONCLUSIONS

Current data do not provide evidence that slow advancement of enteral feed volumes reduces the risk of NEC in VLBW infants. Increasing the volume of enteral feeds at slow rather than faster rates results in several days delay in regaining birth weight and establishing full enteral feeds but the long term clinical importance of these effects is unclear. Further randomised controlled trials are needed to determine how the rate of daily increment in enteral feed volumes affects clinical outcomes in VLBW infants.

Impact of very low birth weight infants on the family at 3 months corrected age

BACKGROUND

Very low birth weight infants (VLBW, <1500 g) have increased impact on families compared to term infants. However, there is limited research examining this impact in the first months post-discharge.

AIM

To determine maternal, neonatal, and infant characteristics associated with greater impact on the family at 3 months corrected age in VLBW infants. It was hypothesized that social/environmental and medical risk factors would be associated with higher impact.

STUDY DESIGN

Maternal, neonatal, and infant data were collected prospectively. Parents completed the Impact on Family, Family Support, and Family Resource Scales. Associations between characteristics and impact scores were analyzed by t-test and Pearson's correlation. Regression models for each impact score identified significant risk factors for impact.

SUBJECTS

152 VLBW infants born February 28, 2007 to September 5, 2008 who had a follow-up evaluation at 3 months corrected age.

OUTCOME MEASURE

Impact on family.

RESULTS

Siblings in the home, neonatal medical risk factors, longer hospitalization, more days on ventilator or oxygen, lower gestational age, lower social support, and poorer family resources were associated with increased impact. Multivariate analyses identified siblings in the home, poorer family resources, lower gestational age, and oxygen requirement at 3 months as the most important predictors of impact.

CONCLUSIONS

Social/environmental and medical risk factors contribute to impact on family. Families with identified risk factors should receive support services to assist them in coping with the burden of caring for a VLBW infant.

Monitoring technologies in the neonatal intensive care unit: implications for the detection of necrotizing enterocolitis

Necrotizing enterocolitis is the most common and fulminant gastrointestinal disease affecting neonates. Its pathogenesis is heterogeneous and not clearly understood. Early detection could prevent some of the devastating consequences of this disease, but currently there is no noninvasive method of reliable early-stage detection. Here, we review various noninvasive monitoring technologies that have already been employed or show promise for early detection. Each method may have an important role after its technical difficulties are resolved. These are discussed in detail as they relate to various aspects of the putative pathophysiology of this devastating disease.