Jeremy G. Fisher

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.

Predictors of Enteral Autonomy in Children with Intestinal Failure: A Multicenter Cohort Study

OBJECTIVES In a large cohort of children with intestinal failure (IF), we sought to determine the cumulative incidence of achieving enteral autonomy and identify patient and institutional characteristics associated with enteral autonomy. STUDY DESIGN A multicenter, retrospective cohort analysis from the Pediatric Intestinal Failure Consortium was performed. IF was defined as severe congenital or acquired gastrointestinal diseases during infancy with dependence on parenteral nutrition (PN) >60 days. Enteral autonomy was defined as PN discontinuation >3 months. RESULTS A total of 272 infants were followed for a median (IQR) of 33.5 (16.2-51.5) months. Enteral autonomy was achieved in 118 (43%); 36 (13%) remained PN dependent and 118 (43%) patients died or underwent transplantation. Multivariable analysis identified necrotizing enterocolitis (NEC; OR 2.42, 95% CI 1.33-4.47), care at an IF site without an associated intestinal transplantation program (OR 2.73, 95% CI 1.56-4.78), and an intact ileocecal valve (OR 2.80, 95% CI 1.63-4.83) as independent risk factors for enteral autonomy. A second model (n = 144) that included only patients with intraoperatively measured residual small bowel length found NEC (OR 3.44, 95% CI 1.36-8.71), care at a nonintestinal transplantation center (OR 6.56, 95% CI 2.53-16.98), and residual small bowel length (OR 1.04 cm, 95% CI 1.02-1.06 cm) to be independently associated with enteral autonomy. CONCLUSIONS A substantial proportion of infants with IF can achieve enteral autonomy. Underlying NEC, preserved ileocecal valve, and longer bowel length are associated with achieving enteral autonomy. It is likely that variations in institutional practices and referral patterns also affect outcomes in children with IF.

Serious Congenital Heart Disease and Necrotizing Enterocolitis in Very Low Birth Weight Neonates

BACKGROUND Infants with serious congenital heart disease (CHD) appear to be at increased risk for necrotizing enterocolitis (NEC). This study aimed to quantify the incidence and mortality of NEC among very low birth weight (VLBW) neonates with serious CHD, and identify specific CHD diagnoses at the highest risk for developing NEC. STUDY DESIGN Data were prospectively collected on 257,794 VLBW (401 to 1,500 g) neonates born from 2006 to 2011 and admitted to 674 Vermont Oxford Network US centers. Entries were coded for specific CHD diagnoses and reviewed for completeness and consistency. Survival was defined as alive in-hospital at 1 year or discharge. RESULTS Of eligible neonates, 1,931 had serious CHD. Of these, 253 (13%) developed NEC (vs 9% in infants without CHD, adjusted odds ratio [AOR] 1.80, p<0.0001). Mortality for neonates with CHD and no NEC was 34%, vs 55% for those with CHD and NEC (p<0.0001). Both groups of CHD patients had higher mortality than infants with NEC without CHD (28%, p<0.0001). Although NEC mortality overall decreases with higher birth weight, mortality for NEC and CHD together does not. CONCLUSIONS The incidence of NEC is significantly higher in VLBW neonates when CHD is present. The mortality of CHD and NEC together is substantially higher than that with each disease alone. Infants with atrioventricular canal appear to have higher risk for developing NEC than other CHD diagnoses. In addition to providing benchmark incidence and mortality data, these findings may have utility in the further study of the pathophysiology of NEC.

Mortality associated with laparotomy-confirmed neonatal spontaneous intestinal perforation: A prospective 5-year multicenter analysis

BACKGROUND Spontaneous intestinal perforation (SIP) has been recognized as a distinct disease entity. This study sought to quantify mortality associated with laparotomy-confirmed SIP and to compare it to mortality of laparotomy-confirmed necrotizing enterocolitis (NEC). METHODS Data were prospectively collected on 177,618 very-low-birth-weight (VLBW, 401-1500g) neonates born between January 2006 and December 2010 admitted to US hospitals participating in the Vermont Oxford Network (VON). SIP was defined at laparotomy as a focal perforation of the intestine without features suggestive of NEC or other intestinal abnormalities. The primary outcome was in-hospital mortality. RESULTS At laparotomy, 2036 (1.1%) neonates were diagnosed with SIP and 4076 (2.3%) with NEC. Neonates with laparotomy-confirmed SIP had higher mortality (19%) than infants without NEC or SIP (5%, P=0.003). However, laparotomy-confirmed SIP patients had significantly lower mortality than those with confirmed NEC (38%, P<0.0001). Mortality in both NEC and SIP groups decreased with increasing birth weight and mortality was significantly higher for NEC than SIP in each birth weight category. Indomethacin and steroid exposure were more frequent in the SIP cohort than the other two groups (P<0.001). CONCLUSIONS In VLBW infants, the presence of laparotomy-confirmed SIP increases mortality significantly. However, laparotomy-confirmed NEC mortality was double that of SIP. This relationship is evident regardless of birth weight. The variant mortality of laparotomy-confirmed SIP versus laparotomy-confirmed NEC highlights the importance of differentiating between these two diseases both for clinical and research purposes.

Nutritional outcomes in survivors of congenital diaphragmatic hernia (CDH)-factors associated with growth at one year.

BACKGROUND Malnutrition is prevalent among congenital diaphragmatic hernia (CDH) survivors. We aimed to describe the nutritional status and factors that impact growth over the 12-months following discharge from the pediatric intensive care unit (PICU) in this cohort. METHODS CDH survivors, who were discharged from the PICU from 2000 to 2010 with follow-up of at least 12months, were included. Nutritional intake, anthropometric, and clinical variables were recorded. Multivariable linear regression was used to determine factors associated with weight-for-age Z-scores (WAZ) at 12months. RESULTS Data from 110 infants, 67% male, 50% patch repair, were analyzed. Median (IQR) WAZ for the cohort was -1.4 (-2.4 to -0.3) at PICU discharge and -0.4 (-1.3 to 0.2) at 12-months. The percentage of infants with significant malnutrition (WAZ<-2) decreased from 26% to 8.5% (p<0.001). Patch repair (p=0.009), protein intake<2.3g/kg/day (p=0.014), and birth weight (BW)<2.5kg (p<0.001) were associated with lower WAZ at 12-months. CONCLUSIONS CDH survivors had a significantly improved nutritional status in the 12-months after PICU discharge. Patch repair, lower BW, and inadequate protein intake were significant predictors of lower WAZ at 12-months. A minimum protein intake in the PICU of 2.3g/kg/day was essential to ensure optimal growth in this cohort.

Necrotizing enterocolitis is associated with earlier achievement of enteral autonomy in children with short bowel syndrome.

PURPOSE Necrotizing enterocolitis (NEC) remains one of the most common underlying diagnoses of short bowel syndrome (SBS) in children. The relationship between the etiology of SBS and ultimate enteral autonomy has not been well studied. This investigation sought to evaluate the rate of achievement of enteral autonomy in SBS patients with and without NEC. METHODS Following IRB approval, 109 patients (2002-2014) at a multidisciplinary intestinal rehabilitation program were reviewed. The primary outcome evaluated was achievement of enteral autonomy (i.e. fully weaning from parenteral nutrition). Patient demographics, primary diagnosis, residual small bowel length, percent expected small bowel length, median serum citrulline level, number of abdominal operations, status of the ileocecal valve (ICV), presence of ileostomy, liver function tests, and treatment for bacterial overgrowth were recorded for each patient. RESULTS Median age at PN onset was 0 weeks [IQR 0-0]. Median residual small bowel length was 33.5 cm [IQR 20-70]. NEC was present in 37 of 109 (33.9%) of patients. 45 patients (41%) achieved enteral autonomy after a median PN duration of 15.3 [IQR 7.2-38.4]months. Overall, 64.9% of patients with NEC achieved enteral autonomy compared to 29.2% of patients with a different primary diagnosis (p=0.001, Fig. 1). Patients with NEC remained more likely than those without NEC to achieve enteral autonomy after two (45.5% vs. 12.0%) and four (35.7% vs. 6.3%) years on PN (Fig. 1). Logistic regression analysis demonstrated the following parameters as independent predictors of enteral autonomy: diagnosis of NEC (p<0.002), median serum citrulline level (p<0.02), absence of a jejunostomy or ileostomy (p=0.013), and percent expected small bowel length (p=0.005). CONCLUSIONS Children with SBS because of NEC have a significantly higher likelihood of fully weaning from parenteral nutrition compared to children with other causes of SBS. Additionally, patients with NEC may attain enteral autonomy even after long durations of parenteral support.

Extraluminal distraction enterogenesis using shape-memory polymer

PURPOSE Although a few techniques for lengthening intestine by mechanical stretch have been described, they are relatively complex, and the majority involve placement of an intraluminal device. Ideally, techniques applicable to humans would be easy to perform and extraluminal to avoid the potential for mucosal injury. This study of distraction enterogenesis used an extraluminal, radially self-expanding shape-memory polymer cylinder and a simple operative approach to both elongate intestine and grow new tissue. METHODS Young Sprague Dawley rats (250-350 g) underwent Roux-en-Y isolation of a small intestinal limb and were divided in three groups: no further manipulation (Control 1, C1); placement of a nonexpanding device (Control 2, C2); or placement of a radially expanding device by the limb (Experimental, Exp). For C2 and Exp animals, the blind end of the limb was wrapped around the radially expanding cylindrical device with the limb-end sutured back to the limb-side. Bowel length was measured at operation and at necropsy (14 days) both in-situ and ex-vivo under standard tension (6g weight). Change in length is shown as mean ± standard deviation. A blinded gastrointestinal pathologist reviewed histology and recorded multiple measures of intestinal adaptation. The DNA to protein ratio was quantified as a surrogate for cellular proliferation. Changes in length, histologic measures, and DNA:protein were compared using analysis of variance, with significance set at P<0.05. RESULTS The length of the Roux limb in situ increased significantly in Exp animals (n=8, 29.0 ± 5.8mm) compared with C1 animals (n=5, -11.2 ± 9.0mm, P<0.01). The length of the Roux limb ex vivo under standard tension increased in the Exp group (25.8 ± 4.2mm) compared with the C2 group (n=6, -4.3 ± 6.0, P<0.01). There were no differences in histologic measures of bowel adaptation between the groups, namely villous height and width, crypt depth, crypt density, and crypt fission rate (all P ≥ 0.08). Muscularis mucosal thickness was also not different (P=0.25). There was no difference in DNA:protein between groups (P=0.47). CONCLUSION An extraluminally placed, radially expanding shape-memory polymer cylinder successfully lengthened intestine, without damaging mucosa. Lack of difference in muscularis thickness and a constant DNA:protein ratio suggests that this process may be related to actual growth rather than mere stretch. This study demonstrated a simple approach that warrants further study aiming at potential clinical applicability.

Preservation of Biochemical Liver Function With Low-Dose Soy-Based Lipids in Children with Intestinal Failure Associated Liver Disease

Objectives: Intestinal failure–associated liver disease (IFALD) contributes to significant morbidity in pediatric patients with intestinal failure (IF); however, the use of parenteral nutrition (PN) with a fish oil–based intravenous (IV) emulsion (FO) has been associated with biochemical reversal of cholestasis and improved outcomes. Unfortunately, FO increases the complexity of care: because it can be administered only under Food and Drug Administration compassionate use protocols requiring special monitoring, it is not available as a 3-in-1 solution and is more expensive than comparable soy-based IV lipid emulsion (SO). Because of these pragmatic constraints, a series of patient families were switched to low-dose (1 g kg−1 day−1) SO following biochemical resolution of cholestasis. The present study examines whether reversal of cholestasis and somatic growth are maintained following this transition. Methods: The present study is a chart review of all children with IFALD who switched from FO to SO following resolution of cholestasis. Variables are presented as medians (interquartile ranges). Comparisons were performed using the Wilcoxon signed-rank test. Results: Seven patients ages 25.9 (16.2–43.2) months were transitioned to SO following reversal of cholestasis using FO. At a median follow-up of 13.9 (4.3–50.1) months, there were no significant differences between pretransition and post-transition serum alanine and aspartate aminotransferases, direct bilirubin, and weight-for-age z scores. Because of recurrence of cholestasis, 1 patient was restarted on FO after 4 months on SO. Conclusions: Biochemical reversal of IFALD and growth were preserved after transition from FO to SO in 6 of 7 (86%) patients. Given the challenges associated with the use of FO, SO may be a viable alternative in select patients with home PN.

Metabolic bone disease in pediatric intestinal failure patients: Prevalence and risk factors ☆ ☆☆

PURPOSE Patients with intestinal failure (IF) are known to have impaired absorption of nutrients required for maintenance of skeletal mass. Rates and risk factors of low bone mineral density (BMD) are unknown in pediatric IF patients. METHODS Following IRB approval, patients with IF having undergone DXA scans were identified and laboratory, clinical, and nutritional intake variables were recorded. Low BMD was defined by a z-score of less than or equal to -2.0. Univariate followed by multivariable regression analysis was performed. RESULTS Sixty-five patients underwent a total of 99 routine DXA scans. Twenty-seven (41%) had vitamin D deficiency, 22 (34%) had low BMD, and nineteen (29%) had a history of fractures. Variables noted to be associated with low BMD (p<0.1) on univariate analysis were considered for multivariable regression. Multivariable regression identified WAZ and serum calcium levels (p<0.05) as independent predictors of low BMD z-score. None of the other evaluated factors were associated with the risk of low BMD. Low BMD was not associated with risk of fractures. CONCLUSION There is a significant incidence of low BMD in children with IF. WAZ and lower serum calcium levels are associated with risk of low BMD. Additional long term prospective studies are needed to further characterize the risk factors associated with low BMD.

Operative indications in recurrent ileocolic intussusception

BACKGROUND Air-contrast enema (ACE) is standard treatment for primary ileocolic intussusception. Management of recurrences is less clear. This study aimed to delineate appropriate therapy by quantifying the relationship between recurrence and need for bowel resection, pathologic lead points (PLP), and complication rates. METHODS After IRB approval, a single institution review of patients with ileocolic intussusception from 1997 to 2013 was performed, noting recurrences, outcomes, and complications. Fishers exact and t-tests were used. RESULTS Of 716 intussusceptions, 666 were ileocecal. Forty-four underwent bowel resection, with 29 PLPs and 9 ischemia/perforation. Recurrence after ACE occurred in 96 (14%). Recurrence did not predict PLP (P=0.25). Recurrence (≥3) was associated with higher resection rate (P=0.03), but not ischemia/perforation (P=0.75). ACE-related complications occurred in 4 (0.5%) patients. Successful initial ACE had 98% negative predictive value for resection and PLP (e.g., after successful ACE, 2% had resections, 2% PLP). After failed initial ACE, 36% received resection, and 23% had PLP (P<0.001). CONCLUSIONS Recurrence is associated with a greater risk of resection but not PLP or ACE-complication. Failed ACE is associated with increased risk for harboring PLP and receiving resection. ACE should be the standard treatment in recurrent intussusception, regardless of number of recurrences.