Outcome of neonatal necrotising enterocolitis: results of the BAPM/CDSC surveillance study, 1981-84

Noninvasive Tools to Predict Necrotizing Enterocolitis in Infants with Congenital Heart Diseases: A Narrative Review

BACKGROUND

Necrotizing enterocolitis (NEC) is the most frightening gastrointestinal emergency in newborns. Despite being primarily a disease of premature infants, neonates with congenital heart disease (CHD) are at increased risk of development. Acute and chronic hemodynamic changes in this population may lead to mesenteric circulatory insufficiency.

OBJECTIVES

In this narrative review, we describe monitoring tools, alone or in multimodal use, that may help in the early recognition of patients with CHD at major risk of NEC development.

METHODS

We focused on vital parameters, echocardiography, Doppler flowmetry, abdominal near-infrared spectroscopy (aNIRS), and abdominal ultrasound (aUS).

RESULTS

The number of studies on this topic is small and includes a wide range of patients' ages and types of CHD. Peripheral oxygen saturation (SpO2) and certain echocardiographic indices (antegrade and retrograde velocity time integral, cardiac output, etc.) do not seem to differentiate infants with further onset of NEC from those not developing it. Hypotensive events, persistent diastolic flow reversal in the descending aorta, and low mesenteric oxygen saturation (rsSO2) measured by aNIRS appear to occur more frequently in infants who later develop NEC. aUS may be helpful in the diagnosis of cardiac NEC, potentially showing air contrast tracked to the right atrium in the presence of pneumatosis.

CONCLUSIONS

This narrative review describes the current knowledge on bedside tools for the early prediction of cardiac NEC. Future research needs to further explore the use of easy-to-learn, reproducible instruments to assist patient status and monitor patient trends.

A role for neonatal bacteremia in deaths due to intestinal perforation: spontaneous intestinal perforation compared with perforated necrotizing enterocolitis

OBJECTIVE

To examine the relationship between intestinal perforations (caused by either spontaneous perforation (SIP) or necrotizing enterocolitis (NEC)) and the outcome "death due to intestinal perforation".

METHODS

Multivariable logistic regression analyses were used to compare infants <28 weeks' gestation with SIP (n = 32) and perforated-NEC (n = 45) for the outcome perforation-related death.

RESULTS

In univariate analyses the incidence of death due to perforation was higher among infants with perforated-NEC (36%) than infants with SIP (13%). However, infants with perforated-NEC were more likely to be older than 10 days and have bacteremia/fungemia with non-coagulase-negative staphylococci (non-CONS) organisms than infants with SIP. After adjusting for confounding the only variable that was significantly associated with mortality due to perforation was the presence of non-CONS bacteremia/fungemia at the onset of perforation.

CONCLUSIONS

The apparent association between death and perforated-NEC could be explained by the higher incidence of non-CONS bacteremia/fungemia among infants with perforated-NEC.

Developing routinely recorded clinical data from electronic patient records as a national resource to improve neonatal health care: the Medicines for Neonates research programme

Background

Clinical data offer the potential to advance patient care. Neonatal specialised care is a high-cost NHS service received by approximately 80,000 newborn infants each year.

Objectives

(1) To develop the use of routinely recorded operational clinical data from electronic patient records (EPRs), secure national coverage, evaluate and improve the quality of clinical data, and develop their use as a national resource to improve neonatal health care and outcomes. To test the hypotheses that (2) clinical and research data are of comparable quality, (3) routine NHS clinical assessment at the age of 2 years reliably identifies children with neurodevelopmental impairment and (4) trial-based economic evaluations of neonatal interventions can be reliably conducted using clinical data. (5) To test methods to link NHS data sets and (6) to evaluate parent views of personal data in research.

Design

Six inter-related workstreams; quarterly extractions of predefined data from neonatal EPRs; and approvals from the National Research Ethics Service, Health Research Authority Confidentiality Advisory Group, Caldicott Guardians and lead neonatal clinicians of participating NHS trusts.

Setting

NHS neonatal units.

Participants

Neonatal clinical teams; parents of babies admitted to NHS neonatal units.

Interventions

In workstream 3, we employed the Bayley-III scales to evaluate neurodevelopmental status and the Quantitative Checklist of Autism in Toddlers (Q-CHAT) to evaluate social communication skills. In workstream 6, we recruited parents with previous experience of a child in neonatal care to assist in the design of a questionnaire directed at the parents of infants admitted to neonatal units.

Data sources

Data were extracted from the EPR of admissions to NHS neonatal units.

Main outcome measures

We created a National Neonatal Research Database (NNRD) containing a defined extract from real-time, point-of-care, clinician-entered EPRs from all NHS neonatal units in England, Wales and Scotland (n = 200), established a UK Neonatal Collaborative of all NHS trusts providing neonatal specialised care, and created a new NHS information standard: the Neonatal Data Set (ISB 1595) (see http://webarchive.nationalarchives.gov.uk/±/http://www.isb.nhs.uk/documents/isb-1595/amd-32–2012/index_html; accessed 25 June 2018).

Results

We found low discordance between clinical (NNRD) and research data for most important infant and maternal characteristics, and higher prevalence of clinical outcomes. Compared with research assessments, NHS clinical assessment at the age of 2 years has lower sensitivity but higher specificity for identifying children with neurodevelopmental impairment. Completeness and quality are higher for clinical than for administrative NHS data; linkage is feasible and substantially enhances data quality and scope. The majority of hospital resource inputs for economic evaluations of neonatal interventions can be extracted reliably from the NNRD. In general, there is strong parent support for sharing routine clinical data for research purposes.

Limitations

We were only able to include data from all English neonatal units from 2012 onwards and conduct only limited cross validation of NNRD data directly against data in paper case notes. We were unable to conduct qualitative analyses of parent perspectives. We were also only able to assess the utility of trial-based economic evaluations of neonatal interventions using a single trial. We suggest that results should be validated against other trials.

Conclusions

We show that it is possible to obtain research-standard data from neonatal EPRs, and achieve complete population coverage, but we highlight the importance of implementing systematic examination of NHS data quality and completeness and testing methods to improve these measures. Currently available EPR data do not enable ascertainment of neurodevelopmental outcomes reliably in very preterm infants. Measures to maintain high quality and completeness of clinical and administrative data are important health service goals. As parent support for sharing clinical data for research is underpinned by strong altruistic motivation, improving wider public understanding of benefits may enhance informed decision-making.

Future work

We aim to implement a new paradigm for newborn health care in which continuous incremental improvement is achieved efficiently and cost-effectively by close integration of evidence generation with clinical care through the use of high-quality EPR data. In future work, we aim to automate completeness and quality checks and make recording processes more ‘user friendly’ and constructed in ways that minimise the likelihood of missing or erroneous entries. The development of criteria that provide assurance that data conform to prespecified completeness and quality criteria would be an important development. The benefits of EPR data might be extended by testing their use in large pragmatic clinical trials. It would also be of value to develop methods to quality assure EPR data including involving parents, and link the NNRD to other health, social care and educational data sets to facilitate the acquisition of lifelong outcomes across multiple domains.

Study registration

This study is registered as PROSPERO CRD42015017439 (workstream 1) and PROSPERO CRD42012002168 (workstream 3).

Funding

The National Institute for Health Research Programme Grants for Applied Research programme (£1,641,471). Unrestricted donations were supplied by Abbott Laboratories (Maidenhead, UK: £35,000), Nutricia Research Foundation (Schiphol, the Netherlands: £15,000), GE Healthcare (Amersham, UK: £1000). A grant to support the use of routinely collected, standardised, electronic clinical data for audit, management and multidisciplinary feedback in neonatal medicine was received from the Department of Health and Social Care (£135,494).

Intestinal failure associated cholestasis in surgical necrotizing enterocolitis and spontaneous intestinal perforation

BACKGROUND

Surgery for necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) is often complicated by intestinal failure (IF) and intestinal failure associated cholestasis (IFAC).

OBJECTIVE

Assessment of incidence, predictors, and mortality associated with IFAC in surgically treated NEC and SIP.

METHODS

A retrospective observational study based on hospital records during 1986-2014 in the two largest Finnish neonatal intensive care units was performed. IFAC was defined as conjugated bilirubin >34 μmol/l (2.0 mg/dl) for ≥ two postoperative weeks while receiving parenteral nutrition (PN).

RESULTS

In total 225 patients underwent surgery for NEC (n = 142; 63%) or SIP (n = 83; 37%). Included were 57 survivors with ≥two weeks PN. Sixty-five (42%) patients developed IFAC. Two-year survival with IFAC was 80% and without IFAC 89% (p = 0.13). Of the 65 patients with IFAC, all eight with unresolved IFAC died in comparison to six of 57 (11%) whose IFAC resolved (p < 0.0001), while IFAC resolved in all survivors. Survival among patients with resolved IFAC was 89% and with unresolved IFAC (n = 8) 0%, (p < 0.0001). IFAC lasted for median 83 (IQR 45-120) days and correlated with the duration of PN (R2 = 0.16, p = 0.03), delay of starting enteral feeds (R2 = 0.12, p = 0.05) and PN lipid emulsion (RR = 1.0 (95% CI = 1.0-1.1) (p = 0.02). In multivariate logistic regression analysis, IFAC development associated with septicemias and reoperations.

CONCLUSIONS

42% of prematures who underwent surgery for NEC or SIP developed IFAC. Reoperations and septicemias increased the risk of IFAC. None of the patients with unresolved IFAC survived, but IFAC did not increase overall mortality.

TYPE OF STUDY

Retrospective prognosis study.

LEVEL OF EVIDENCE

Level II.

Outcomes of surgery for necrotizing enterocolitis and spontaneous intestinal perforation in Finland during 1986-2014

BACKGROUND

Necrotizing enterocolitis (NEC) and spontaneous intestinal perforation (SIP) are the most common abdominal surgical conditions in preemies. Associated mortality remains high and long periods of parenteral nutrition (PN) may be required. We assessed the developments in the outcomes of surgically treated NEC and SIP in the two largest Finnish neonatal intensive care units (NICU).

METHODS

Retrospective observational study based on hospital records during 1986-2014. Main outcome measures were three-month survival during 1986-2000 compared with 2001-2014 and predictors of mortality.

RESULTS

Included were 225 patients (NICU A 131 and NICU B 94) with NEC in 142 (63%) and SIP 83 (37%). The median birth weight (BW) (870 vs 900 g) and gestation age (GA) (27 vs 27 weeks, p = 0.96) were similar in NEC and SIP. Small intestine was affected in 85% of NEC and 76% of SIP patients (p = 0.12). In 5% of patients NEC was panintestinal. Median small intestinal loss was 25% in NEC and 4.0% in SIP (p < 0.001). Ileocecal valve was resected in 29% of NEC and 14% of SIP patients (p = 0.01). Enterostomy was performed in 78% of patients and primary anastomosis in 18%; 4% died of extensive NEC without definitive surgery. Overall survival was 74% (NEC 73%, SIP 77%, p = 0.48; NICU A 82%, NICU B 65%, p = 0.003). From 1986-2000 to 2001-2014 overall survival increased from 69 to 81% (p = 0.04). Treating NICU was the strongest predictor of survival, RR = 2.8 (95% CI = 1.4-5.1), p = 0.003.

CONCLUSIONS

Overall survival improved significantly from the early (1986-2000) to the late (2001-2014) study period. Strongest predictor of mortality was the treating neonatal intensive care unit.

LEVEL OF EVIDENCE

III.

Early hybrid approach and enteral feeding algorithm could reduce the incidence of necrotising enterocolitis in neonates with ductus-dependent systemic circulation

BACKGROUND

The reported incidence of necrotising enterocolitis in neonates with complex CHD with ductus-dependent systemic circulation ranges from 6.8 to 13% despite surgical treatment; the overall mortality is between 25 and 97%. The incidence of gastrointestinal complications after hybrid palliation for neonates with ductus-dependent systemic circulation still has to be defined, but seems comparable with that following the Norwood procedure.

METHODS

We reviewed the incidence of gastrointestinal complications in a series of 42 consecutive neonates with ductus-dependent systemic circulation, who received early hybrid palliation associated with a standardised feeding protocol.

RESULTS

The median age and birth weight at the time of surgery were 3 days (with a range from 1 to 10 days) and 3.07 kg (with a range from 1.5 to 4.5 kg), respectively. The median ICU length of stay was 7 days (1-70 days), and the median hospital length of stay was 16 days (6-70 days). The median duration of mechanical ventilation was 3 days. Hospital mortality was 16% (7/42). In the postoperative period, 26% of patients were subjected to early extubation, and all of them received treatment with systemic vasodilatory agents. Feeding was started 6 hours after extubation according to a dedicated feeding protocol. After treatment, none of our patients experienced any grade of necrotising enterocolitis or major gastrointestinal adverse events.

CONCLUSIONS

Our experience indicates that the combination of an "early hybrid approach", systemic vasodilator therapy, and dedicated feeding protocol adherence could reduce the incidence of gastrointestinal complications in this group of neonates. Fast weaning from ventilatory support, which represents a part of our treatment strategy, could be associated with low incidence of necrotising enterocolitis.

Incidence and enteral feed antecedents of severe neonatal necrotising enterocolitis across neonatal networks in England, 2012-13: a whole-population surveillance study

BACKGROUND

Necrotising enterocolitis is a neonatal gastrointestinal inflammatory disease with high mortality and severe morbidity. This disorder is growing in global relevance as birth rates and survival of babies with low gestational age improve. Population data are scant and pathogenesis is incompletely understood, but enteral feed exposures are believed to affect risk. We aimed to quantify the national incidence of severe necrotising enterocolitis, describe variation across neonatal networks, and investigate enteral feeding-related antecedents of severe necrotising enterocolitis.

METHODS

We undertook a 2-year national surveillance study (the UK Neonatal Collaborative Necrotising Enterocolitis [UKNC-NEC] Study) of babies born in England to quantify the burden of severe or fatal necrotising enterocolitis confirmed by laparotomy, leading to death, or both. Data on all liveborn babies admitted to neonatal units between Jan 1, 2012, and Dec 31, 2013, were obtained from the National Neonatal Research Database. In the subgroup of babies born before a gestational age of 32 weeks, we did a propensity score analysis of the effect of feeding in the first 14 postnatal days with own mother's milk, with or without human donor milk and avoidance of bovine-origin formula, or milk fortifier, on the risk of developing necrotising enterocolitis.

FINDINGS

During the study period, 118 073 babies were admitted to 163 neonatal units across 23 networks, of whom 14 678 were born before a gestational age of 32 weeks. Overall, 531 (0·4%) babies developed severe necrotising enterocolitis, of whom 247 (46·5%) died (139 after laparotomy). 462 (3·2%) of 14 678 babies born before a gestational age of 32 weeks developed severe necrotising enterocolitis, of whom 222 (48·1%) died. Among babies born before a gestational age of 32 weeks, the adjusted network incidence of necrotising enterocolitis ranged from 2·51% (95% CI 1·13-3·60) to 3·85% (2·37-5·33), with no unusual variation from the adjusted national incidence of 3·13% (2·85-3·42), despite variation in feeding practices. The absolute risk difference for babies born before a gestational age of 32 weeks who received their own mother's milk within 7 days of birth was -0·88% (95% CI -1·15 to -0·61; relative risk 0·69, 95% CI 0·60 to 0·78; number needed to treat to prevent one case of necrotising enterocolitis 114, 95% CI 87 to 136). For babies who received no compared with any bovine-origin products within 14 days of birth, the absolute risk difference was -0·65% (-1·01 to -0·29; relative risk 0·61, 0·39 to 0·83; number needed to treat 154, 99 to 345). We were unable to assess the effect of human donor milk as use was low.

INTERPRETATION

Early feeding of babies with their own mother's milk and avoidance of bovine-origin products might reduce the risk of necrotising enterocolitis, but the absolute reduction is small. Owing to the rarity of severe necrotising enterocolitis, international collaborations are needed for adequately powered preventive trials.

FUNDING

National Institute for Health Research.

Mortality and management of surgical necrotizing enterocolitis in very low birth weight neonates: a prospective cohort study

BACKGROUND

Necrotizing enterocolitis (NEC) is a leading cause of death in very low birth weight (VLBW) neonates. The overall mortality of NEC is well documented. However, those requiring surgery appear to have increased mortality compared with those managed medically. The objective of this study was to establish national birth-weight-based benchmarks for the mortality of surgical NEC and describe the use and mortality of laparotomy vs peritoneal drainage.

STUDY DESIGN

There were 655 US centers that prospectively evaluated 188,703 VLBW neonates (401 to 1,500 g) between 2006 and 2010. Survival was defined as living in-hospital at 1-year or hospital discharge.

RESULTS

There were 17,159 (9%) patients who had NEC, with mortality of 28%; 8,224 patients did not receive operations (medical NEC, mortality 21%) and 8,935 were operated on (mortality 35%). On multivariable regression, lower birth weight, laparotomy, and peritoneal drainage were independent predictors of mortality (p < 0.0001). In surgical NEC, a plateau mortality of around 30% persisted despite birth weights >750 g; medical NEC mortality fell consistently with increasing birth weight. For example, in neonates weighing 1,251 to 1,500 g, mortality was 27% in surgical vs 6% in medical NEC (odds ratio [OR] 6.10, 95% CI 4.58 to 8.12). Of those treated surgically, 6,131 (69%) underwent laparotomy only (mortality 31%), 1,283 received peritoneal drainage and a laparotomy (mortality 34%), and 1,521 had peritoneal drainage alone (mortality 50%).

CONCLUSIONS

Fifty-two percent of VLBW neonates with NEC underwent surgery, which was accompanied by a substantial increase in mortality. Regardless of birth weight, surgical NEC showed a plateau in mortality at approximately 30%. Laparotomy was the more frequent method of treatment (69%) and of those managed by drainage, 46% also had a laparotomy. The laparotomy alone and drainage with laparotomy groups had similar mortalities, while the drainage alone treatment cohort was associated with the highest mortality.

Epidemiology and trends of necrotizing enterocolitis in Sweden: 1987-2009

OBJECTIVE

To investigate temporal, seasonal, and geographic variations in the incidence of necrotizing enterocolitis (NEC) and its relation to early infant survival in the Swedish population and in subgroups based on gestational age, birth weight, and gender.

METHODS

In the Swedish birth cohort of 1987 through 2009 all children with a diagnosis of NEC were identified in the National Patient Register, the Swedish Medical Birth Register, and the National Cause of Death Register. NEC incidence, early mortality, and seasonality were analyzed with descriptive statistics, Poisson regression, and auto regression.

RESULTS

The overall incidence of NEC was 3.4 in 10,000 live births, higher in boys than in girls (incidence rate ratio 1.22, 95% confidence interval 1.06-1.40, P = .005), with a peak in November and a trough in May, and increased with an average of ~5% a year during the study period. In most subgroups, except the most immature, an initial decrease was followed by a steady increase. Seven-day mortality decreased strongly in all subgroups over the entire study period (annual incidence rate ratio 0.96, 95% confidence interval 0.95-0.96, P < .001). This was especially marked in the most premature and low birth weight infants.

CONCLUSIONS

After an initial decrease, the incidence of NEC has increased in Sweden during the last decades. An association with the concurrent dramatically improved early survival seems likely.

Pediatric surgery and the human microbiome

Bold advances in the past decade have made it possible to carefully study the contributions of microbes to normal human development and to disease pathogenesis. The intestinal microbiota has been implicated in adult diseases ranging from obesity to cancer, but there have been relatively few investigations of bacteria in surgical diseases of infancy and childhood. In this review, we discuss how novel culture-independent approaches have been harnessed to profile microbes present within clinical specimens. Unique features of the pediatric microbiota and innovative approaches to manipulate the gut flora are also reviewed. Finally, we detail the contributions of gut microbes to 3 diseases relevant to pediatric surgeons: necrotizing enterocolitis, obesity, and inflammatory bowel disease. Current and future research regarding the pediatric microbiota is likely to translate to improved outcomes for infants and children with surgical diseases.

Necrotizing enterocolitis in neonates undergoing the hybrid approach to complex congenital heart disease

OBJECTIVE

To investigate the prevalence of necrotizing enterocolitis (NEC) in neonates undergoing the Stage I hybrid procedure for palliation of complex congenital heart disease (CHD). Neonates undergoing the Norwood surgery for hypoplastic left-heart syndrome have the highest risk for NEC of all CHD patients. The hybrid procedure is another palliative option for hypoplastic left-heart syndrome, but NEC in neonates undergoing this procedure has not been reported.

DESIGN

Retrospective chart review of 73 neonates who underwent the hybrid procedure for palliation of complex CHD. Demographic, perinatal, perioperative, clinical, and procedural data were collected. NEC was defined as modified Bell's Stage II and above.

SETTING

The cardiothoracic and neonatal intensive care units in a large free-standing children's hospital.

PATIENTS

All neonates who underwent the hybrid Stage I procedure for the palliation of complex CHD from April 2002 through April 2008.

MEASUREMENTS AND MAIN RESULTS

Seventy-three neonates were reviewed and 11.0% (eight of 73) developed NEC. Of the patients with NEC, 37.5% (three of eight) died and two patients required abdominal surgery. Earlier gestational age (< 37 wks), lower maximum dose of prostaglandin infusion, and unexpected readmission to the intensive care unit were statistically associated with NEC (p = .009, 0.02, and 0.04, respectively). No other demographic, perinatal, perioperative, clinical, or procedural variables were associated with the development of NEC in this patient population, including enteral feeding regimens, umbilical artery catheters, inotrope use, and average oxygen saturation and diastolic blood pressure.

CONCLUSIONS

The prevalence of NEC in patients undergoing the hybrid procedure is comparable to that reported for neonates undergoing the Norwood procedure. Earlier gestational age is a significant risk factor for NEC in patients who undergo the hybrid Stage I procedure. Multidisciplinary approaches to better understand abdominal complications and to develop feeding regimens in neonates undergoing the hybrid approach to complex CHD are needed to improve outcomes and decrease morbidities.

National prospective surveillance study of necrotizing enterocolitis in neonatal intensive care units

PURPOSE

There is scant epidemiological data on necrotizing enterocolitis (NEC), so we conducted a national study to characterize prevalence, surgical management, and mortality.

METHODS

A prospective cross-sectional survey was performed in the United Kingdom requesting data from 158 level 2 and 3 neonatal intensive care units (NICUs) during 2 winter and 2 summer months in 2005 to 2006; 51% of questionnaires were returned. Results are given as percentage with 95% confidence intervals.

RESULTS

(1) Period prevalence: 211 infants were diagnosed with NEC (45% Bell's stage I, 21% stage II, and 33% stage III) from a total of 10,946 NICU admissions, with a period prevalence of 2% (1.7-2.2). In infants less than 1000 g birth weight, the prevalence was 14% (12-16), and in less than 26 weeks of gestation, 14% (11-17). Prevalence decreased significantly with increasing birth weight (P < .0001) and increasing gestation (P < .0001). (2) SURGERY: 66 infants received surgical procedures; peritoneal drain in 13 (followed by laparotomy in 8) and in 53, laparotomy alone. (3) Mortality: 27 infants died with NEC of a total 283 deaths, thus, accounting for 9.5% of NICU mortality. Eight (30%) infants with NEC died without surgery.

CONCLUSIONS

Prevalence of NEC in the United Kingdom is high and comparable to published series in other countries from the 1990s. There may be a hidden mortality in patients who do not receive surgery.

Redefining the role of intestinal microbes in the pathogenesis of necrotizing enterocolitis

Neonatal necrotizing enterocolitis (NEC) remains an important cause of morbidity and mortality among very low birth weight infants. It has long been suspected that intestinal microbes contribute to the pathogenesis of NEC, but the details of this relationship remain poorly understood. Recent advances in molecular biology and enteric microbiology have improved our ability to characterize intestinal microbes from infants with NEC and from healthy unaffected newborns. The lack of diversity within the neonatal intestine makes it possible to study gut microbial communities at a high level of resolution not currently possible in corresponding studies of the adult intestinal tract. Here, we summarize clinical and laboratory evidence that supports the hypothesis that NEC is a microbe-mediated disorder. In addition, we detail recent technologic advances that may be harnessed to perform high-throughput, comprehensive studies of the gut microbes of very low birth weight infants. Methods for characterizing microbial genotype are discussed, as are methods of identifying patterns of gene expression, protein expression, and metabolite production. Application of these technologies to biological samples from affected and unaffected newborns may lead to advances in the care of infants who are at risk for the unabated problem of NEC.

A systematic review of serologic tests in the diagnosis of necrotizing enterocolitis

BACKGROUND

Although many serologic markers have been suggested for diagnosis of necrotizing enterocolitis, there is little consensus on which of these is potentially clinically useful. Our aims were (i) to systematically review circulating markers that are potentially useful in the diagnosis of NEC and (ii) to compare the relative performance of each serologic marker of NEC by pooling estimates of marker accuracies and presenting their combined diagnostic accuracies.

METHODS

We undertook a systematic review of the literature to identify studies that reported serologic markers at the time of diagnosis of necrotizing enterocolitis. Where possible, we constructed 2-by-2 tables of diagnostic accuracy from each article, if 2 or more studies investigated the same test, their results were meta-analyzed by pooling estimates of sensitivity, specificity, likelihood ratio for positive index test (LR+), likelihood ratio for negative index test (LR-), diagnostic odds ratio, and their corresponding 95% confidence intervals.

RESULTS

Twenty-five articles provided information on serology at the time of diagnosis of necrotizing enterocolitis. Of these, it was possible to construct diagnostic accuracy tables from 16 articles and to combine data from studies that used C-reactive protein, intestinal fatty acid binding protein, and platelet-activating factor. Of these C-reactive protein was a sensitive but nonspecific marker for necrotizing enterocolitis, whereas platelet-activating factor and intestinal fatty acid binding protein were both sensitive and specific.

CONCLUSIONS

Most serologic markers of necrotizing enterocolitis have been used in too few studies to evaluate their use. Of those tests that have been tested repeatedly, platelet-activating factor and intestinal fatty acid binding protein are potentially useful, although their use must be further tested in larger prospective studies.

Low mortality in necrotizing enterocolitis associated with coagulase-negative Staphylococcus infection

The aim of this study was to correlate the clinical course of necrotizing enterocolitis (NEC) with infection by coagulase-negative Staphylococcus at the onset of the illness. Records of all newborn infants developing NEC between January 1998 and December 2001 were reviewed. NEC was classified according to the criteria of Bell et al. Numeric variables were described by standard statistical methods. Comparisons between subgroups were performed by parametric statistical tests. Forty-four patients developed NEC stage II (n = 25) or III (n = 19). The incidence was 0.024% of live births in the hospital, and the mortality rate was 9%. The main risk factor was prematurity (84%). Only one-fourth of the patients had gastric residuals. A platelet count of <100,000 cells/mm3 occurred only in grade III NEC. Blood cultures were positive in 34% of the patients. The predominant organism (73%) was coagulase-negative Staphylococcus (CoNS). Neither Clostridium nor Bacteroides species were isolated. Stage II patients were maintained nothing per os (NPO) for 9 +/- 3 days and received antibiotics for 10 +/- 3 days. All of the stage III patients required an operation. In one-third of them, primary peritoneal drainage was initially performed but all required further operative procedures. We report a low incidence and mortality rate of necrotizing enterocolitis. Thrombocytopenia is confirmed as a marker of severity. Positive blood cultures for CoNS may explain, at least in part, the low mortality reported.

The neonatal intestinal vasculature: contributing factors to necrotizing enterocolitis

Based on the demonstration of coagulation necrosis, it is clear that intestinal ischemia plays a role in the pathogenesis of necrotizing enterocolitis (NEC). Intestinal vascular resistance is determined by a dynamic balance between vasoconstrictive and vasodilatory inputs. In the newborn, this balance heavily favors vasodilation secondary to the copious production of endothelium-derived nitric oxide (NO), a circumstance which serves to ensure adequate blood flow and thus oxygen delivery to the rapidly growing intestine. Endothelial cell injury could shift this balance in favor of endothelin (ET)-1-mediated vasoconstriction, leading to intestinal ischemia and tissue injury. Evidence obtained from animal models and from human tissue collected from infants with NEC implicates NO and ET-1 dysregulation in the pathogenesis of NEC. Strategies focused on maintaining the delicate balance favoring vasodilation in the newborn intestinal circulation may prove to be useful in the prevention and treatment of NEC.

Doppler flow velocimetry in the superior mesenteric artery on the first day of life in preterm infants and the risk of neonatal necrotizing enterocolitis

OBJECTIVE

The purpose of this work was to relate Doppler indices of splanchnic perfusion and vascular resistance to the risk of developing necrotizing enterocolitis.

METHODS

We conducted a prospective cohort study with analysis of Doppler flow velocity waveforms of splanchnic vessels on the first day of life. Clinical management and diagnosis of necrotizing enterocolitis were performed blind to the Doppler results in a tertiary NICU on 64 eligible preterm neonates admitted for intensive care. We measured necrotizing enterocolitis using an objective diagnostic classification.

RESULTS

When adjusted for gestational age at birth, the following indices of the Doppler flow velocity wave form in the superior mesenteric artery were significantly predictive of the risk of necrotizing enterocolitis: end-diastolic velocity, mean velocity, and pulsatility index. The association between necrotizing enterocolitis and Doppler velocimetry indicative of high vascular resistance was independent of a range of other factors and comorbidities (race, mode of delivery, umbilical arterial catheter, growth restriction, patent ductus arteriosus, jaundice, respiratory distress syndrome, mechanical ventilation, and hypotension).

CONCLUSIONS

We concluded that neonates with high resistance patterns of blood flow velocity in the superior mesenteric artery on the first day of life are at increased risk of developing necrotizing enterocolitis.

Jejunal blind loop 10 years after neonatal necrotizing enterocolitis

A 10-year-old girl presented with abdominal distension and vomiting due to a jejunojejunal bowel fistula, forming a blind loop. This was related to neonatal necrotizing enterocolitis (NEC) in her first few weeks of life, which was followed by apparently a full recovery. We would like to raise awareness of possible long-term gastrointestinal sequelae in children who have had NEC.

Neonatal necrotizing enterocolitis: diagnosis, management, and pathogenesis

The diagnosis of neonatal necrotizing enterocolitis is one of great concern to pediatric and neonatal clinicians. Intravenous access remains an integral part of the medical and surgical management of infants with this diagnosis, and the infusion nurse is intimately involved in the care of these patients. This article discusses the definition of necrotizing enterocolitis, presents current knowledge regarding its basic pathophysiology, and identifies common and rare sequelae of this oftentimes devastating disease of premature infants. Medical and surgical management goals of therapy are described. This overview will aid the infusion nurse in caring for these patients.

Epidemiology of neonatal necrotising enterocolitis: a population-based study

We examined the birthweight-, gender- and race-specific incidence as well as the biodemographic and clinical correlates of necrotising enterocolitis (NEC) in a well-defined six-county perinatal region in upstate New York. We conducted a retrospective, 8-year population-based survey to identify all cases of proven NEC (modified Bell stage II and above) in the area's regional neonatal intensive care unit (NICU). The denominator used to calculate the incidence was obtained from the Statewide Planning Research Cooperative System. Incidence was expressed as cases per 1000 live births. A total of 85 documented cases of proven NEC was identified in a six-county perinatal region that experienced 117 892 live births during the 8-year period. The average annual incidence was 0.72 cases per 1000 live births [95% CI 0.57, 0.87 per 1000 live births]. The highest incidence of NEC occurred among infants weighing 750-1000 g at birth and declined with increasing birthweight. The urban county had a 1.53 times higher risk of NEC than rural counties [95% CI 0.9, 2.6]. The overall incidence of NEC for non-Hispanic blacks was significantly greater than that for non- Hispanic whites (2.2 vs. 0.5 cases per 1000 live births, P = 0.00). The differences remained statistically significant even after correction for birthweight. Most cases (93%) in this series were preterm (gestational age <37 weeks). Only two patients were never fed before the diagnosis of NEC was confirmed. Positive blood cultures were documented in 27% of the cases with a predominance of Gram-negative enteric micro-organisms. NEC remains an important health problem especially for preterm infants and the non-Hispanic black population.

Outcome of very premature infants with necrotising enterocolitis cared for in centres with or without on site surgical facilities

OBJECTIVE

To determine if the presence of a neonatal surgical facility on site has any effect on mortality and morbidity of very premature infants with necrotising enterocolitis (NEC).

DESIGN AND SETTING

Retrospective review of infants of less than 29 weeks gestation cared for in the seven perinatal centres in New South Wales.

PATIENTS

Between 1992 and 1997, 605 infants were cared for in two centres with in house surgical facilities (group 1) and 1195 in five centres where transfers were required for surgical management (group 2).

RESULTS

Although use of antenatal steroids was significantly lower in group 1 centres than group 2 centres (74% v. 85% respectively), and the incidence of hyaline membrane disease, pneumothorax, and NEC was higher, mortality was identical (27%). Fifty two (9%) infants in group 1 and 72 (6%) in group 2 of comparable perinatal characteristics and CRIB (Clinical Risk Index for Babies) scores developed radiologically or pathologically proven NEC. The overall mortality of infants with NEC in group 1 was lower but this was not statistically significant (27% v. 35%). Significantly more infants with NEC in group 1 had surgery (69% v. 39%). There were fewer postoperative deaths in group 1 and more deaths without surgery in group 2. The duration of respiratory and nutritional support and hospital stay for the survivors were similar in the two groups. In a multivariate analysis, shorter gestation was the only factor associated with mortality in infants with NEC; the presence of in house surgical facilities was not.

CONCLUSIONS

There were no significant differences in outcome of premature infants with NEC managed in perinatal centres with or without on site surgical facilities. Early transfers should be encouraged. This finding may have implications for future planning of facilities for neonatal care.

Prognostic factors of mortality in newborns with necrotizing enterocolitis submitted to exploratory laparotomy

PURPOSE

The aim of this study was to identify and assess mortality predictive factors in newborns with necrotizing enterocolitis (NEC) requiring emergency exploratory laparotomy.

METHODS

A prospective study of 91 newborns with NEC submitted to exploratory laparotomy was conducted. Clinical outcomes were death and survival 60 days after surgery. Nine variables were analyzed: weight at birth, gestational age, intrauterine growth, sex, gas in the portal vein at abdominal x-ray, pneumoperitoneum, extent of the disease, operative strategies, and extension of bowel resection. Univariate and multivariate analyses were performed to identify mortality predictors.

RESULTS

Mean weight at birth was 1,676 +/- 634.8 g, and mean gestational age was 34 +/- 2.8 weeks. Thirty-nine newborns (42.9%) presented intrauterine growth retardation. Operative techniques included bowel resection with enterostomy (80 patients), bowel resection with primary anastomosis (10 patients), and decompressive enterostomy (1 patient). Six deaths occurred caused by co-existing disease. NEC-related mortality rate was 46.15% (42 of 91).

CONCLUSIONS

Two variables, intrauterine growth retardation, and diffuse bowel involvement, were predictive of mortality according to both univariate and multivariate analyses. Site of bowel involvement seems to be important mortality predictors in infants with NEC requiring surgery. The size of our population did not allow statistical analysis of this relationship. Further studies should focus on examining this aspect.

Necrotizing enterocolitis in neonates with congenital heart disease: risk factors and outcomes

OBJECTIVE

Necrotizing enterocolitis (NEC) is primarily a disease of the premature infant. Among children born at term, however, congenital heart disease may be an important predisposing factor for this condition. To determine risk factors for NEC in patients with congenital heart disease, we conducted a case-control study of neonates with cardiac disease admitted to the cardiac intensive care unit at our center during the 4-year period from January 1995 to December 1998.

METHODS

Cardiac diagnosis and age at admission were analyzed for association with NEC among the 643-patient inception cohort. Demographic, preoperative, and operative variables were recorded retrospectively in 21 neonates with congenital heart disease who developed NEC and 70 control neonates matched by diagnosis and age at admission. Using parametric and nonparametric analysis, cases and controls were compared with respect to previously identified risk factors for NEC.

RESULTS

Among the entire cohort of 643 neonates with heart disease admitted to the cardiac intensive care unit, diagnoses of hypoplastic left heart syndrome (odds ratio [OR] = 3.8 [1.6-9.1]) and truncus arteriosus or aortopulmonary window (OR = 6.3 [1.7-23.6]) were independently associated with development of NEC by multivariable analysis. In the case-control analysis, earlier gestational age at birth (36.7 +/- 2. 7 weeks vs 38.1 +/- 2.3 weeks), prematurity (OR = 3.9 [1.2-12.5]), highest dose of prostaglandin >0.05 microg/kg/minute (OR = 3.9 [1. 2-12.5]), and episodes of low cardiac output (meeting specific laboratory criteria) or clinical shock (OR = 6.5 [1.8-23.5]) correlated with the development of NEC. Earlier gestational age and episodes of low output were the only factors that remained significantly associated with NEC by multivariable analysis. Although there was no difference in hospital mortality between patients with and without NEC, mean hospital stay was significantly longer in those who developed NEC (36 +/- 22 days vs 19 +/- 14 days).

CONCLUSIONS

The risk of NEC in neonates with congenital heart disease is substantial. Factors associated with an elevated risk of NEC in infants with heart disease include premature birth, hypoplastic left heart syndrome, truncus arteriosus, and episodes of poor systemic perfusion or shock. Heightened suspicion is warranted in newborns with these risk factors.

Circulating pro- and counterinflammatory cytokine levels and severity in necrotizing enterocolitis

OBJECTIVES

To evaluate the relationship between the severity of necrotizing enterocolitis (NEC) and circulating concentrations of proinflammatory cytokines interleukin (IL)-1beta and IL-8 and counterinflammatory cytokines IL-1 receptor antagonist (IL-1ra) and IL-10. These cytokines have been associated with bowel injury or inflammation and may be released more slowly or later than previously examined cytokines. Also, to determine if any one of these cytokines will predict the eventual severity of NEC when measured at symptom onset.

METHOD

Serial blood samples at onset, 8, 24, 48, and 72 hours were obtained from newborn infants with predefined signs and symptoms of NEC. Normal levels were defined from weight-, gestation-, and age-matched controls. Concentrations of the four cytokines were determined by enzyme-linked immunosorbent assay and compared throughout the time period by stage of NEC, using sepsis as a co-factor. Mean concentrations of each cytokine at onset were compared with the controls. Threshold values were obtained with the best combination of high sensitivity and high specificity for defining stage 1 NEC or for diagnosing stage 3 NEC at onset.

RESULTS

There were 12 cases of stage 1, 18 cases of stage 2, and 6 cases of stage 3 NEC included in the study, as well as 20 control infants. Concentrations of IL-8 and IL-10 were significantly higher in infants with stage 3 NEC from onset through 24 hours compared with infants with less severe NEC. At onset, concentrations of all four cytokines were significantly higher in stage 3 NEC. To identify, at onset, the infants with a final diagnosis of stage 3 NEC, an IL-1ra concentration of >130 000 pg/mL had a sensitivity of 100% and a specificity of 92%. At 8 hours, an IL-10 concentration of >250 pg/mL had a sensitivity of 100% and a specificity of 90% in identifying stage 3 NEC in infants with symptoms suggestive of NEC at onset.

CONCLUSIONS

The severity of NEC and its systemic signs and symptoms are not due to a deficiency of counterregulatory cytokines. In fact, mean concentrations of IL-1ra in NEC are higher than what has been reported in other populations. The cytokines IL-8, IL-1ra, and IL-10 are released later or more slowly after a stimulus and may be more useful in identifying, within hours of symptom onset, which infant will develop significant NEC.

Assessing the effect of disease on nutrition of the preterm infant

OBJECTIVE

To review existing data on nutritional requirements of extremely low birth weight (ELBW) and very low birth weight (VLBW) preterm infants (those who weigh < 1000 g and 1000-1500 g at birth, respectively), and the effects of diseases on these nutritional requirements.

DATA SOURCES

A literature search was conducted on applicable articles related to nutritional requirements of preterm ELBW and VLBW infants and the effects of diseases in these infants on their nutritional and metabolic requirements.

DATA SYNTHESIS

The literature was analyzed to determine nutritional requirements of preterm ELBW and VLBW infants, to select the most common diseases that have significant and important effects on nutrition and metabolism in these infants, and to make recommendations about diagnostic and therapeutic approaches to nutritional problems as affected by diseases in ELBW and VLBW infants.

CONCLUSIONS

Many diseases unique to preterm infants, either directly or by enhancing the effects of stress on the metabolism of such infants, provide important changes in the nutrient requirements. The overriding observation from all studies, however, is that ELBW and VLBW preterm infants are underfed during the early postnatal period and that this condition, combined with additional stresses from various diseases, increases the risk of long-term neurological sequelae. The value of achieving a specific body composition and growth weight is less certain. There remains a critical need for determining the right quality as well as quantity of nutrients for these infants.

Bacterial contaminated breast milk and necrotizing enterocolitis in preterm twins

A pair of preterm twins developed fatal necrotizing enterocolitis (NEC) in association with Staphylococcus epidermidis septicaemia after receiving contaminated expressed breast milk (EBM). S. epidermidis NEC can be associated with severe bowel inflammation, high morbidity and mortality. Breast milk is the most suitable nutrient for preterm infants but EBM should undergo regular screening for bacterial overgrowth. We urge caution before administering EBM found to be heavily contaminated with S. epidermidis to preterm infants.

[Necrotizing enterocolitis: symptomatology, diagnosis and therapeutic consequences]

Within a 6-year period ten patients with necrotizing enterocolitis (grade II-III; Bell) have been treated at the University Hospital, Göttingen. The following NEC incidences were calculated: birth weight < 1000 g: 2.4% (3/123); 1000-1500 g: 0.6% (2/308); 1501-2000 g: 0.7% (3/436); > 3000 g: approximately 0.006% (2/30,000 live births). In all patients onset of necrotizing enterocolitis (NEC) was associated with typical clinical symptoms such as abdominal distension, feeding problems, bloody stools. Only four out of ten patients had positive blood tests of various inflammatory parameters when diagnosed (C-reactive protein, neutrophil count, I/T-ratio). However, increased CRP levels were observed in all patients during the course of the disease (maximum levels: day 2-4 after diagnosis). During primarily conservative therapeutic management only one out of ten patients developed bowel perforation (day 6 after diagnosis) and immediate surgical treatment was carried out. In addition, in three patients who acquired strictures with obstruction of the colon, elective surgery was performed at a postnatal age of 51-77 days. All patients survived NEC without longterm sequelae. We conclude that a primarily conservative therapeutic regimen-whenever perforation and gangrene are absent-may be an alternative to early surgical intervention in NEC.

Epidemiology of necrotizing enterocolitis

The descriptive epidemiology of necrotizing enterocolitis (NEC) is presented. Areas addressed include incidence, race, sex, age of onset, mortality rates, and endemic versus epidemic disease. Both descriptive and case control studies are reviewed to uncover clues relevant to the causes, pathogenesis, and prevention of NEC.

Epidemiology of necrotizing enterocolitis

The descriptive epidemiology of necrotizing enterocolitis (NEC) is presented. Areas addressed include incidence, race, sex, age of onset, mortality rates, and endemic versus epidemic disease. Both descriptive and case control studies are reviewed to uncover clues relevant to the causes, pathogenesis, and prevention of NEC.

Interdisciplinary treatment of necrotizing enterocolitis and spontaneous intestinal perforations in preterm infants

From January 1986 to December 1992, 13 patients with necrotizing enterocolitis (NEC) (Grade II-III; Bell) were treated. The incidence was highest in the very immature infants with birth weight < 1000 g: 6/148 (4%). From onset, NEC was associated with clinical symptoms such as abdominal distension, bloody stools, retained gastric contents and septicemia. Indications of inflammation were seen in only 6 out of 13 patients at the time of diagnosis. No complications were seen in 10 patients during the acute phase. Two infants developed a bowel perforation and another one a gangrene. Immediate surgery was performed. In three other infants, elective surgery was performed because of colonic strictures. Twelve (92%) patients survived NEC. Five other VLBW infants developed spontaneous perforations of the bowel. The clinical presentation, laboratory and radiological findings differed greatly from those with NEC. Four infants survived. A primarily conservative therapeutic regime with close cooperation between the surgeon and pediatrician may be an alternative to early surgical intervention in NEC.

Neonatal complications of extreme prematurity in mechanically ventilated infants

Previous data have suggested that neonatal complications amongst preterm ventilated infants increase with decreasing gestational age and thus are likely to be greatest among ventilated infants of less than 28 weeks gestational age. The aim of this study was to test that hypothesis, thus we report the neonatal complications of 175 extremely preterm mechanically ventilated infants (gestational age less than or equal to 28 weeks). Of the infants 152 were ventilated because of respiratory distress syndrome (RDS) or respiratory distress of severe prematurity, 41% of these infants died. Amongst infants with RDS or respiratory distress of extreme prematurity, mortality was significantly increased in infants of gestational age less than or equal to 24 weeks and birth weight less than or equal to 1000 g. In this group 20% developed a pneumothorax, and mortality was inversely related to gestational age. In infants with RDS, 43% developed a periventricular haemorrhage and 37% were still oxygen-dependent at 28 days of age; neither of these complications was significantly related to birth weight or gestational age. Of infants with RDS 38% developed a patent ductus arteriosus and 16% developed retinopathy of prematurity. These data suggest that even amongst very immature infants there has been an impressive reduction in the neonatal complications of mechanical ventilation.

Necrotizing enterocolitis in a perinatal centre

Thirty-five neonates developed radiologically proven necrotizing enterocolitis (NEC) over a 40 month period. They were 28 +/- 2 weeks gestation, and weighted 1094 +/- 411 g at birth. Eighteen infants (51%) required surgery and three (8.5%) died. The incidence was 6.7% in the very low birthweight (VLBW) infants. A large proportion of NEC (60%) presented beyond 10 days of life. An inverse relationship between gestation and age of onset was observed. The age of presentation was 22 +/- 13 days (range 10-53 days) for the 18 infants less than or equal to 28 weeks compared with 7 +/- 5 days for those over 28 weeks (P less than 0.01). Five NEC infants had bacteraemia which occurred 2-7 days prior to gastrointestinal symptoms of NEC, and four were staphylococcal. Compared with infants controlled for gestation, there was no significant differences observed in perinatal events or feeding history. We concluded that an immature gastrointestinal system is vulnerable to NEC even beyond the early neonatal period.