Gut permeability in paediatric cardiac surgery

Risk factors and surgical outcomes in pediatric patients with congenital heart disease and ischemic colitis

INTRODUCTION

This study investigates risk factors and surgical outcomes in pediatric patients with congenital heart defects (CHD) who develop ischemic colitis (IC). Previous research indicates a higher IC risk in very low birth weight neonates with CHD.

METHODS

A retrospective analysis compared an IC-CHD group to a CHD-only group. Key variables included gestational age, birth weight, multiple pregnancies, prematurity, APGAR scores, cardiac and surgical characteristics, Aristotle-Score, and mortality rates. Surgical outcomes such as bowel resection and stoma procedures were also evaluated.

RESULTS

IC-CHD exhibited significantly lower gestational ages and birth weights, with higher rates of multiple pregnancies and prematurity. APGAR scores were notably lower. Cardiac and surgical data showed more frequent ECMO use and shorter cardiopulmonary bypass durations in the IC-CHD group. High rates of bowel resection highlighted severe gastrointestinal involvement. Mortality was significantly higher in IC-CHD with elevated Aristotle scores correlating with poorer outcomes.

CONCLUSION

Gestational age, birth weight, and initial health status are critical in predicting IC risk and surgical outcomes in pediatric patients with CHD. The significantly higher mortality and complex surgical needs in the IC-CHD group underscore the necessity for vigilant monitoring and tailored interventions. Development of targeted therapeutic strategies adjustment for confounding factors in future studies is needed.

Management of Hematochezia in Infants with Congenital Heart Disease Admitted to the Acute Care Cardiology Unit: A Multicenter Retrospective Pilot Study

OBJECTIVE

To assess the evaluation and prevalence of benign hematochezia (BH) vs necrotizing enterocolitis (NEC) in infants with congenital heart disease (CHD) <6 months old admitted to the acute care cardiology unit.

STUDY DESIGN

This was a multicenter retrospective review of patient characteristics and evaluation of all hematochezia events in patients with CHD <6 months admitted to acute care cardiology unit at 3 high-volume tertiary care centers from February 2019 to January 2021. NEC was defined by the Bell staging criteria. Patients with gastrointestinal disorders were excluded.

RESULTS

In total, 180 hematochezia events occurred in 121 patients; 42 patients had more than 1 event. In total, 61% of affected patients had single-ventricle physiology (38% hypoplastic left heart syndrome). Median age and weight at hematochezia were 38 days (IQR 24, 79) and 3.7 kg (IQR 3.2, 4.4). In total, 77% of hematochezia events were BH, and 23% were NEC. There were no surgical interventions for NEC or deaths from NEC. Those with NEC were significantly younger (34 vs 56 days, P < .01) and smaller (3.7 vs 4 kg, P < .01). Single-ventricle physiology was significantly associated with NEC. Initial bloodwork and diagnostic imaging at each center were assessed. There was no significant difference in white blood cell count or C-reactive protein in those with NEC compared with BH. Blood culture results were all negative.

CONCLUSIONS

The majority of infants with CHD with hematochezia have BH over NEC, although single-ventricle and surgical patients remain at greater risk. Infants <45 days are more vulnerable for developing NEC. Bloodwork was noncontributory in the identification of cardiac NEC. Expansion to a prospective study to develop a treatment algorithm is important to avoid overtreatment.

Intestinal Microbiota and Derived Metabolites in Myocardial Fibrosis and Postoperative Atrial Fibrillation

The high incidence of atrial fibrillation (AFib) following cardiac surgery (postoperative atrial fibrillation, POAF) relies on specific surgical features. However, in the setting of POAF, the role of the microbiome in the modulation of cardiac fibrosis is still not clear. This study aimed to analyze the effect of the microbiome and its main metabolic product (trimethylamine-N-oxide, TMAO) in the fibrosis of myocardial tissue, to investigate its role in POAF. Patients undergoing elective cardiac surgery with cardiopulmonary bypass, central atrio-caval cannulation and no history of AFib, were included. A fragment of the right atrium was analyzed for qualitative and mRNA-quantitative evaluation. A preoperative blood sample was analyzed with enzyme-linked immunosorbent assay (ELISA). A total of 100 patients have been included, with POAF occurring in 38%. Histologically, a higher degree of fibrosis, angiogenesis and inflammation has been observed in POAF. Quantitative evaluation showed increased mRNA expression of collagen-1, collagen-3, fibronectin, and transforming growth factor beta (TGFb) in the POAF group. ELISA analysis showed higher levels of TMAO, lipopolysaccharide and TGFb in POAF, with similar levels of sP-selectin and zonulin. TMAO ≥ 61.8 ng/mL (odds ratio, OR 2.88 [1.35-6.16], p = 0.006), preoperative hemoglobin < 13.1 g/dL (OR 2.37 [1.07-5.24], p = 0.033) and impaired right ventricular function (OR 2.38 [1.17-4.83], p = 0.017) were independent predictors of POAF. Also, TMAO was significantly associated with POAF by means of increased fibrosis. Gut microbiome product TMAO is crucial for myocardial fibrosis, which is a key factor for POAF. Patients in preoperative sinus rhythm who will develop POAF have increased genetic expression of pro-fibrotic genes and enhanced fibrosis in histological staining. Elevated TMAO level (≥61.8 ng/mL) is an independent risk factor for POAF.

Association of Early Postoperative Regional Oxygen Saturation Measures and Development of Necrotizing Enterocolitis in Neonates Following Cardiac Surgery

Necrotizing enterocolitis (NEC) is a relatively common complication in neonates with single ventricle physiology following heart surgery. Near-infrared spectroscopy (NIRS) is used to measure regional oxygen saturations in neonates in the postoperative period. We sought to investigate the association of somatic regional oxygen saturation (srSO2) and cerebral regional oxygen saturation (crSO2) in the early postoperative period and the subsequent development of NEC. We performed a retrospective cohort study of neonates who underwent cardiac surgery with cardiopulmonary bypass from October 2017 to September 2021 at the University of Virginia Children's Hospital. Values of srSO2 and crSO2 were captured over the first 48 h following surgery. 166 neonates were included and the median age at time of surgery was 8 days. NEC was diagnosed in 18 neonates following heart surgery with a median interval from surgery to diagnosis of 7 days. Neonates with single ventricle physiology had lower average crSO2 (62% vs 78%, p < 0.001), average srSO2 (72% vs 86%, p < 0.001), average crSO2 to srSO2 ratio (0.874 vs 0.913, p < 0.001), and an increased average srSO2-crSO2 difference (10% vs 8%, p = 0.03). Adjusting for single ventricle physiology, lower average crSO2 was associated with the development of definite NEC (modified Bell's criteria stage IIa and higher) (OR = 0.86, 95% CI 0.78-0.96, p = 0.007). Lower crSO2 values in the early postoperative period in neonates following cardiac surgery was associated with an increased risk in the subsequent development of NEC.

From heart to gut: Exploring the gut microbiome in congenital heart disease

Congenital heart disease (CHD) is a prevalent birth defect and a significant contributor to childhood mortality. The major characteristics of CHD include cardiovascular malformations and hemodynamical disorders. However, the impact of CHD extends beyond the circulatory system. Evidence has identified dysbiosis of the gut microbiome in patients with CHD. Chronic hypoxia and inflammation associated with CHD affect the gut microbiome, leading to alterations in its number, abundance, and composition. The gut microbiome, aside from providing essential nutrients, engages in direct interactions with the host immune system and indirect interactions via metabolites. The abnormal gut microbiome or its products can translocate into the bloodstream through an impaired gut barrier, leading to an inflammatory state. Metabolites of the gut microbiome, such as short-chain fatty acids and trimethylamine N-oxide, also play important roles in the development, treatment, and prognosis of CHD. This review discusses the role of the gut microbiome in immunity, gut barrier, neurodevelopment, and perioperative period in CHD. By fostering a better understanding of the cross-talk between CHD and the gut microbiome, this review aims to contribute to improve clinical management and outcomes for CHD patients.

Particular genomic and virulence traits associated with preterm infant-derived toxigenic Clostridium perfringens strains

Clostridium perfringens is an anaerobic toxin-producing bacterium associated with intestinal diseases, particularly in neonatal humans and animals. Infant gut microbiome studies have recently indicated a link between C. perfringens and the preterm infant disease necrotizing enterocolitis (NEC), with specific NEC cases associated with overabundant C. perfringens termed C. perfringens-associated NEC (CPA-NEC). In the present study, we carried out whole-genome sequencing of 272 C. perfringens isolates from 70 infants across 5 hospitals in the United Kingdom. In this retrospective analysis, we performed in-depth genomic analyses (virulence profiling, strain tracking and plasmid analysis) and experimentally characterized pathogenic traits of 31 strains, including 4 from CPA-NEC patients. We found that the gene encoding toxin perfringolysin O, pfoA, was largely deficient in a human-derived hypovirulent lineage, as well as certain colonization factors, in contrast to typical pfoA-encoding virulent lineages. We determined that infant-associated pfoA+ strains caused significantly more cellular damage than pfoA- strains in vitro, and further confirmed this virulence trait in vivo using an oral-challenge C57BL/6 murine model. These findings suggest both the importance of pfoA+ C. perfringens as a gut pathogen in preterm infants and areas for further investigation, including potential intervention and therapeutic strategies.

Clinical Characteristics and Potential Pathogenesis of Cardiac Necrotizing Enterocolitis in Neonates with Congenital Heart Disease: A Narrative Review

Neonates with congenital heart disease (CHD) are at an increased risk of developing necrotizing enterocolitis (NEC), an acute inflammatory intestinal injury most commonly associated with preterm infants. The rarity of this complex disease, termed cardiac NEC, has resulted in a dearth of information on its pathophysiology. However, a higher incidence in term infants, effects on more distal regions of the intestine, and potentially a differential immune response may distinguish cardiac NEC as a distinct condition from the more common preterm, classical NEC. In this review, risk factors, differentiated from those of classical NEC, are discussed according to their potential contribution to the disease process, and a general pathogenesis is postulated for cardiac NEC. Additionally, biomarkers specific to cardiac NEC, clinical outcomes, and strategies for achieving enteral feeds are discussed. Working towards an understanding of the mechanisms underlying cardiac NEC may aid in future diagnosis of the condition and provide potential therapeutic targets.

Immediate Post-operative Enterocyte Injury, as Determined by Increased Circulating Intestinal Fatty Acid Binding Protein, Is Associated With Subsequent Development of Necrotizing Enterocolitis After Infant Cardiothoracic Surgery

Objectives: 1 Measure serial serum intestinal fatty acid binding protein levels in infants undergoing cardiac surgery with cardiopulmonary bypass to evaluate for evidence of early post-operative enterocyte injury. 2 Determine the association between immediate post-operative circulating intestinal fatty acid binding protein levels and subsequent development of necrotizing enterocolitis. Design: Observational cohort study. Intestinal fatty acid binding protein was measured pre-operatively, at rewarming, and at 6 and 24 h post-operatively. Percent of goal enteral kilocalories on post-operative day 5 and episodes of necrotizing enterocolitis were determined. Multivariable analysis assessed for factors independently associated with clinical feeding outcomes and suspected/definite necrotizing enterocolitis. Setting: Quaternary free-standing children's hospital pediatric cardiac intensive care unit. Patients: 103 infants <120 days of age undergoing cardiothoracic surgery with cardiopulmonary bypass. Interventions: None. Results: Median pre-operative intestinal fatty acid binding protein level was 3.93 ng/ml (range 0.24-51.32). Intestinal fatty acid binding protein levels rose significantly at rewarming (6.35 ng/ml; range 0.54-56.97; p = 0.008), continued to rise slightly by 6 h (6.57 ng/ml; range 0.75-112.04; p = 0.016), then decreased by 24 h (2.79 ng/ml; range 0.03-81.74; p < 0.0001). Sixteen subjects (15.7%) developed modified Bell criteria Stage 1 necrotizing enterocolitis and 9 subjects (8.8%) developed Stage 2 necrotizing enterocolitis. Infants who developed necrotizing enterocolitis demonstrated a significantly higher distribution of intestinal fatty acid binding protein levels at both 6 h (p = 0.005) and 24 h (p = 0.005) post-operatively. On multivariable analysis, intestinal fatty acid binding protein was not associated with percentage of goal enteral kilocalories delivered on post-operative day 5. Higher intestinal fatty acid binding protein was independently associated with subsequent development of suspected/definite necrotizing enterocolitis (4% increase in odds of developing necrotizing enterocolitis for each unit increase in intestinal fatty acid binding protein; p = 0.0015). Conclusions: Intestinal fatty acid binding protein levels rise following infant cardiopulmonary bypass, indicating early post-operative enterocyte injury. Intestinal fatty acid binding protein was not associated with percent of goal enteral nutrition achieved on post-operative day 5, likely due to protocolized feeding advancement based on clinically observable factors. Higher intestinal fatty acid binding protein at 6 h post-operatively was independently associated with subsequent development of necrotizing enterocolitis and may help identify patients at risk for this important complication.

Alkaline Phosphatase Activity and Endotoxemia After Infant Cardiothoracic Surgery

OBJECTIVE

Infant cardiopulmonary bypass (CPB) increases intestinal permeability leading to endotoxemia. Alkaline phosphatase (AP) reduces endotoxin toxicity in vitro but its effects on endotoxemia in human disease are poorly understood. We assessed the association between serum AP activity and endotoxemia in infants undergoing CPB and determined the effect of ex vivo addition of AP on endotoxemia.

METHODS

Prospective cohort study of 62 infants ≤120 days of age undergoing CPB. AP activity and Endotoxin Activity Assay (EAA) were measured pre-operatively, during rewarming, and 24 h after cardiac intensive care unit admission. In 22 subjects, EAA was measured in pre-operative and rewarming whole blood samples with/without addition of 1,600 U/L of human liver AP.

RESULTS

AP activity decreased during CPB (mean decrease 94.8U/L; P < 0.0001). Median EAA was 0.41 pre-operation, rose to 0.52 (P < 0.05) during rewarming, and remained stably elevated at 24 h. Subjects with low pre-operative AP activity had significantly higher pre-operative (0.47 vs. 0.36; P < 0.05) and rewarming (0.59 vs. 0.43; P < 0.01) EAA with a trend toward higher EAA at 24 h (0.52 vs. 0.45; P = 0.12). Subjects with low rewarming AP activity showed similar differences that did not reach statistical significance. Ex vivo addition of human liver AP decreased pre-operative EAA by 29% (P < 0.001) and rewarming EAA by 51% (P < 0.0001).

CONCLUSION

Endotoxemia is common in infants undergoing CPB. Native AP activity and endotoxemia are inversely related and ex vivo addition of exogenous AP reduces whole blood EAA. Future research should evaluate AP as a therapy to reduce the harmful effects of endotoxemia following infant CPB.

Endotoxin Activity in Neonates Undergoing Cardiac Surgery: Cohort Study

BACKGROUND

Endotoxemia in pediatric cardiac surgical patients is poorly understood. The endotoxin activity assay (EAA) levels were examined in neonates undergoing cardiac surgery in order to assess their reference levels and their association with other pre-, intra-, and postoperative risk factors for gut hypoperfusion. We finally observed if refeeding was associated with modification of endotoxin levels.

METHODS

In a prospective cohort study, neonates undergoing surgery for correction or palliation were enrolled. Preterm birth, weight below 1.5 kg, the need for extracorporeal membrane oxygenation, and urgent surgery were exclusion criteria.

RESULTS

Among the 26 enrolled neonates, 12 underwent on-pump and 14 off-pump surgery, 22 received a preoperative infusion of prostaglandin E2. Overall, 11 patients were surgically corrected and 15 received a palliation. Endotoxin activity assay baseline levels were inversely correlated with age at surgery ( r = -.50, P = .006) and they increased to postoperative day2 ( P = .002). On-pump versus off-pump surgery ( P =.36) and surgical palliation with a Blalock-Taussig shunt versus correction ( P = .45) did not predict increase in EAA levels. Aortic clamping for coarctation repair was associated with the lowest levels ( P = .04). Systolic, mean, and diastolic pressures were associated with EAA levels ( r = -.55, P = .01; r = -.45, P = .02; r = -.37, P = .04, respectively). Endotoxin activity assay levels after refeeding were similar to baseline levels. Patients with abdominal distension and feeding intolerance showed higher median peak EAA levels (0.7, 0.66-1.11) than asymptomatic patients (0.53, 0.35-0.64; P = .01).

CONCLUSIONS

Endotoxin activity assay levels increase after elective neonatal surgery and are not modified by refeeding. High postoperative levels may predict feeding intolerance.

Alkaline Phosphatase in Infant Cardiopulmonary Bypass: Kinetics and Relationship to Organ Injury and Major Cardiovascular Events

OBJECTIVES

To determine the kinetics of alkaline phosphatase (AP) activity and concentration after infant cardiopulmonary bypass, including isoform-specific changes, and to measure the association between postoperative AP activity and major postoperative cardiovascular events, organ injury/dysfunction, and postoperative support requirements STUDY DESIGN: Prospective cohort study of 120 infants ≤120 days of age undergoing cardiopulmonary bypass. AP total and isoform-specific activity was assessed at 6 time points (preoperation, rewarming, 6, 24, 48, and 72 hours postoperation). Low AP activity was defined as ≤80 U/L. AP concentrations and biomarkers of organ injury/dysfunction were collected through 24 hours postoperation. Major cardiovascular events were defined as cardiac arrest, mechanical circulatory support, or death.

RESULTS

AP activity loss occurred primarily during the operation (median decrease 89 U/L; P < .0001) secondary to decreased bone and liver 2 isoforms. Activity declined through 24 hours in 27% of patients. AP activity strongly correlated with serum concentration (r = 0.87-0.91; P < .0001). Persistent low AP activity at 72 hours was associated independently with occurrence of a major cardiac event (OR 5.6; P < .05). Early AP activity was associated independently with subsequent vasoactive-inotropic score (P < .001), peak lactate (P < .0001), peak creatinine (P < .0005), N-terminal pro-brain natriuretic peptide (P < .05), and intestinal fatty acid binding protein (P < .005).

CONCLUSIONS

AP activity decreases during infant cardiopulmonary bypass and may continue to decrease for 24 hours. Activity loss is secondary to decreased bone and liver 2 isoform concentrations. Early low AP activity is associated independently with subsequent postoperative support and organ injury/dysfunction, and persistence of AP activity ≤80 U/L at 72 hours is associated independently with increased odds of major cardiovascular events.

Intestinal Barrier Maturation in Very Low Birthweight Infants: Relationship to Feeding and Antibiotic Exposure

OBJECTIVE

To test the hypothesis that feeding and antibiotic exposures affect intestinal barrier maturation in preterm infants, we serially measured intestinal permeability (IP) biomarkers in infants <33 weeks gestation (gestational age [GA]) during the first 2 weeks of life.

STUDY DESIGN

Eligible infants <33 weeks GA were enrolled within 4 days of birth in a prospective study of IP biomarkers (NCT01756040). Study participants received the nonmetabolized sugars lactulose/rhamnose enterally on study days 1, 8, and 15 and lactulose/rhamnose were measured in urine by high-performance liquid chromatography. Serum zonulin and fecal alpha-1-anti-trypsin, 2 other IP markers, were measured by semiquantitative Western blot and ELISA, respectively.

RESULTS

In a cohort of 43 subjects, the lactulose/rhamnose ratio was increased on day 1 and decreased over 2 weeks, but remained higher in infants born at ≤28 weeks of gestation compared with IP in infants born at >28 weeks of gestation. Exclusive breastmilk feeding was associated with more rapid maturation in intestinal barrier function. A cluster analysis of 35 subjects who had urine samples from all time points revealed 3 IP patterns (cluster 1, normal maturation: n = 20 [57%]); cluster 2, decreased IP during the first week and subsequent substantial increase: n = 5 [14%]); and cluster 3, delayed maturation: n = 10 [29%]). There were trends toward more prolonged antibiotic exposure (P = .092) and delayed initiation of feeding ≥4 days (P = .064) in infants with abnormal IP patterns.

CONCLUSIONS

Intestinal barrier maturation in preterm infants is GA and postnatal age dependent, and is influenced by feeding with a maturational effect of breastmilk feeding and possibly by antibiotic exposures.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01756040.

Gastrointestinal complications associated with the surgical treatment of heart disease in children

BACKGROUND/PURPOSE

The gastrointestinal system is prone to complications following heart surgery. We sought to determine the incidence and factors associated with gastrointestinal complication after cardiac surgery in children.

METHODS

A retrospective review of patients aged <16years that underwent cardiac surgery between 2009 and 2013. Primary outcome was occurrence of gastrointestinal complication within 30days. Multivariable logistic regression was performed to identify variables related to occurrence of gastrointestinal complication. Patients with gastrointestinal complication were matched with controls and postoperative lengths of stay compared.

RESULTS

Eight hundred eighty-one children underwent 1120 cardiac surgical procedures. At time of operation, 18% were neonates and 39% were infants. Cardiopulmonary bypass was used in 79%. Of 1120 procedures, 31 (2.8% [95% CI 2.0-3.9%]) had gastrointestinal complication. Necrotizing enterocolitis accounted for 61% of complications. Of patients with gastrointestinal complication, 87% survived to hospital discharge. Gastrointestinal complication was associated with preoperative co-morbidity (OR 2.2 [95% CI 1.02-4.8]) and univentricular disease (OR 2.5 [95% CI 1.1-5.5]). Neonates had the highest risk of gastrointestinal complication. Patients with gastrointestinal complications had longer hospital stays than controls (median difference, 13days [95% CI 3-43]).

CONCLUSIONS

Serious gastrointestinal complications are uncommon but associated with longer hospital stay. Neonates with univentricular disease and preoperative comorbidity are at highest risk.

TYPE OF STUDY

Prognosis study.

LEVEL OF EVIDENCE

II.

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.

Abdominal Problems in Children with Congenital Cardiovascular Abnormalities

BACKGROUND

Congenital cardiovascular abnormality is an important cause of morbidity and mortality in childhood. Both the type of congenital cardiovascular abnormality and cardiopulmonary bypass are responsible for gastrointestinal system problems.

AIMS

Intra-abdominal problems, such as paralytic ileus, necrotizing enterocolitis, and intestinal perforation, are common in patients who have been operated or who are being followed for congenital cardiovascular abnormalities. Besides the primary congenital cardiovascular abnormalities, ischemia secondary to cardiac catheterization or surgery contributes to the incidence of these problems.

STUDY DESIGN

Cross-sectional study.

METHODS

In this study, we aimed to screen the intra-abdominal problems seen in patients with congenital cardiovascular abnormalities who had undergone surgical or angiographical intervention(s). Patients with congenital cardiovascular abnormalities who had been treated medically or surgically between 2000 and 2014 were analyzed retrospectively in terms of intra-abdominal problems. The patients' demographic data, type of congenital cardiovascular abnormalities, the intervention applied (surgical, angiographic), the incidence of intra-abdominal problem(s), the interventions applied for the intra-abdominal problems, and the results were evaluated.

RESULTS

Fourteen (Group I) of the 76 patients with congenital cardiovascular abnormalities diagnosis were operated due to intra-abdominal problems, and 62 (Group II) were followed-up clinically for intra-abdominal problems. In Group I (10 boys and 4 girls), 11 patients were aged between 0 and 12 months, and three patients were older than 12 months. Group II included 52 patients aged between 0 and 12 months and 10 patients older than 12 months. Cardiovascular surgical interventions had been applied to six patients in Group I and 40 patients in Group II. The most frequent intra-abdominal problems were necrotizing enterocolitis and intestinal perforation in Group I, and paralytic ileus in Group II. Seven of the Group I patients and 22 of the Group II patients died. The patients who died in both groups had more than three congenital cardiovascular abnormalities in the same patient, and 80% of these patients had been operated for congenital cardiovascular abnormalities.

CONCLUSION

The gastrointestinal system is involved in important complications experienced by patients with congenital cardiovascular abnormalities. The mortality rate was higher in operated patients due to gastrointestinal complications. Gastrointestinal complications are more frequent in patients with cyanotic anomalies. The presence of more than one congenital cardiovascular abnormality in a patient increased the mortality rate.

Splanchnic near-infrared spectroscopy and risk of necrotizing enterocolitis after neonatal heart surgery

Infants with critical congenital heart disease, especially patients with a single-ventricle (SV) physiology, are at increased risk for the development of necrotizing enterocolitis (NEC). Decreased splanchnic oxygen delivery may contribute to the development of NEC and may be detected by regional oximetry (rSO2) via splanchnic near-infrared spectroscopy (NIRS). This prospective study enrolled 64 neonates undergoing biventricular (BV) repair or SV palliation for CHD and monitored postoperative splanchnic rSO2 before and during initiation of enteral feedings to determine whether changes in rSO2 are associated with risk of NEC. Suspected or proven NEC was observed in 32 % (11/34) of the SV subjects and 0 % (0/30) of the BV subjects (p = 0.001). Compared with the BV subjects, the SV palliated subjects had significantly lower splanchnic rSO2 before and during initiation of enteral feedings, but the groups showed no difference after correction for lower pulse oximetry (SpO2) in the SV group. The clinical parameters were similar among the SV subjects with and without NEC except for cardiopulmonary bypass times, which were longer for the patients who experienced NEC (126 vs 85 min; p = 0.03). No difference was observed in splanchnic rSO2 or in the SpO2-rSO2 difference between the SV subjects with and without NEC. Compared with the patients who had suspected or no NEC, the subjects with proven NEC had a lower average splanchnic rSO2 (32.6 vs 47.0 %; p = 0.05), more time with rSO2 less than 30 % (48.8 vs 6.7 %; p = 0.04) at one-fourth-volume feeds, and more time with SpO2-rSO2 exceeding 50 % (33.3 vs 0 %; p = 0.03) before feeds were initiated. These data suggest that splanchnic NIRS may be a useful tool for assessing risk of NEC, especially in patients with an SV physiology.

Necrotising enterocolitis in infants with congenital heart disease: the role of enteral feeds

OBJECTIVE

Necrotising enterocolitis is a rare, though catastrophic complication that may occur in term newborns with congenital heart disease. There is considerable controversy regarding the factors that lead to necrotising enterocolitis in this population. We sought to determine the incidence of necrotising enterocolitis among term and near-term newborns with congenital heart disease, focusing on the relationship of enteral feeding to this complication.

METHODS

In this retrospective study, we identified the incidence of necrotising enterocolitis among 1551 newborns admitted to our cardiac intensive care unit between July 1, 2002 and July 1, 2010. In order to understand the impact of enteral feeding upon the development of necrotising enterocolitis, we undertook a nested 2:1 matched case-control analysis to compare feeding patterns in an age- and lesion-matched control population.

RESULTS

Necrotising enterocolitis developed in 45 term or near-term infants (3%). The majority of these cases, 27 (60%), occurred in the post-operative period after the introduction of enteral feeds. This subgroup was used for matched analysis. There were no differences in enteral feeding patterns among the patients who developed necrotising enterocolitis and their matched controls. The overall mortality rate for patients who developed necrotising enterocolitis was 24.4% (11 out of 45).

CONCLUSIONS

Despite numerous advances in the care of infants with congenital heart disease, necrotising enterocolitis remains a significant source of morbidity and mortality. In these infants, there is no clear relationship between enteral feeding patterns and the development of necrotising enterocolitis in the post-operative period. The benefits of graduated feeding advancements to avoid the development of necrotising enterocolitis remain unproven.

Factors associated with peptide-based formula prescription in a pediatric intensive care unit

OBJECTIVES

There is no evidence-based consensus on the use of peptide-based formulas for critically ill children. The present study aimed to identify the factors associated with the choice of peptide-based formulas in the first enteral nutrition prescription for critically ill children and to compare the direct costs of the enteral formulas used in a pediatric intensive care unit.

METHODS

In a prospective study, children admitted to the intensive care unit and receiving tube feeding for ≥48 hours were evaluated. The potential exposure variables for the use of peptide-based formulas as the first nutrition prescription were age, sex, malnutrition, sepsis/septic shock, fasting period >2 days, use of α-adrenergic drugs before initiating first diet, and the revised Pediatric Index of Mortality score. A direct cost comparison of prescribed formulas was performed.

RESULTS

Of 291 patients included, 85 (29.2%) were given peptide-based formulas in the first nutrition prescription. This choice was independently associated with malnutrition (odds ratio [OR] 2.94; 95% confidence interval [CI] 1.60%-5.39%; P < 0.01), fasting period >2 days (OR 3.46; 95% CI 1.93%-6.20%; P < 0.01), and use of α-adrenergic drugs (OR 2.32; 95% CI 1.24%-4.31%; P < 0.01). Peptide-based formula costs were up to 10 times higher than standard polymeric formula costs.

CONCLUSIONS

The choice of peptide-based formula as the first enteral nutrition prescription is associated with the greater severity of patients' clinical status-patients receiving α-adrenergic drugs, those who are malnourished, and those with longer fasting periods. These prescriptions engender costs higher than those associated with standard polymeric formula.

Bone quality and nutritional status in children with congenital heart defects

The aim of this study was to evaluate bone quality and nutritional status in children with congenital heart defects (CHDs) using quantitative ultrasound. A cross-sectional study was designed. A population-based sample of 75 children with CHD (age: 0--6yr) from the Department of Pediatric Cardiology at the National Cardiology Institute "Ignacio Chávez" was compared with 106 healthy children during 2009. Weight and height were determined in both groups; bone status was measured at the radius and tibia as speed of sound (SOS). Nutritional status was defined according to the Waterloo and Gómez index. Chi-square test, Student's t-test, and analysis of variance were used to determine the statistical differences. A linear regression analysis adjusted by age, weight, height, type of CHD, and birth weight was made. Both groups were similar in sex distribution, prematurity, and birth weight. Acyanotic cardiopathy with increased pulmonary flow was the most frequent (61.3%). Prevalence of malnutrition was higher in CHD group compared with healthy children (p<0.001), and radius SOS was lower in children with CHD compared with healthy children (3484±180 vs 3575±159m/s, respectively; 95% confidence interval: 39.8--143; p=0.001). A positive correlation was found between CHD and reduced SOS in the adjusted linear regression model, r²=0.455 (p<0.001). Children with CHD have lower SOS radius values compared with healthy children, suggesting reduced bone quality regardless of the nutritional status.

Effects of regional analgesia on stress responses to pediatric surgery

Invasive surgery induces a combination of local response to tissue injury and generalized activation of systemic metabolic and hormonal pathways via afferent nerve pathways and the central nervous system. The local inflammatory responses and the parallel neurohumoral responses are not isolated but linked through complex signaling networks, some of which remain poorly understood. The magnitude of the response is broadly related to the site of injury (greater in regions with visceral pain afferents such as abdomen and thorax) and the extent of the trauma. The changes include alterations in metabolic, hormonal, inflammatory, and immune systems that can be collectively termed the stress response. Integral to the stress responses are the effects of nociceptive afferent stimuli on systemic and pulmonary vascular resistance, heart rate, and blood pressure, which are a combination of efferent autonomic response and catecholamine release via the adrenal medulla. Therefore, pain responses, cardiovascular responses, and stress responses need to be considered as different aspects of a combined bodily reaction to surgery and trauma. It is important at the outset to understand that not all components of the stress response are suppressed together and that this is important when discussing different analgesic modalities (i.e. opioids vs regional anesthesia). For example, in terms of the use of fentanyl in the infant, the dose required to provide analgesia (1-5 mcg·kg(-1)) is less than that required for hemodynamic stability in response to stimuli (5-10 mcg·kg(-1)) (1) and that this in turn is less than that required to suppress most aspects of the stress response (25-50 mcg·kg(-1)) (2). In contrast to this considerable dose dependency, central local anesthetic blocks allow blockade of the afferent and efferent sympathetic pathways at relatively low doses resulting in profound suppression of hemodynamic and stress responses to surgery.

Non-invasive markers of gut wall integrity in health and disease

The intestinal mucosa is responsible for the absorption of nutrients from the lumen and for the separation of the potentially toxic luminal content (external environment) from the host (internal environment). Disruption of this delicate balance at the mucosal interface is the basis for numerous (intestinal) diseases. Experimental animal studies have shown that gut wall integrity loss is involved in the development of various inflammatory syndromes, including post-operative or post-traumatic systemic inflammatory response syndrome, sepsis, and multiple organ failure. Assessment of gut wall integrity in clinical practice is still a challenge, as it is difficult to evaluate the condition of the gut non-invasively with currently available diagnostic tools. Moreover, non-invasive, rapid diagnostic means to assess intestinal condition are needed to evaluate the effects of treatment of intestinal disorders. This review provides a survey of non-invasive tests and newly identified markers that can be used to assess gut wall integrity.

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.

Mediastinitis in pediatric cardiac surgery: Prevention, diagnosis and treatment

In spite of advances in the management of mediastinitis following sternotomy, mediastinitis is still associated with significant morbidity. The prognosis is much better in pediatric surgery compared to adult surgery, but the prolonged hospital stays with intravenous therapy and frequent required dressing changes that occur with several therapeutic approaches are poorly tolerated. Prevention includes nasal decontamination, skin preparation, antibioprophylaxis and air filtration in the operating theater. The expertise of the surgical team is an additional factor that is difficult to assess precisely. Diagnosis is often very simple, being made on the basis of a septic state with wound modification, while retrosternal puncture and CT scan are rarely useful. Treatment of mediastinitis following sternotomy is always a combination of surgical debridement and antibiotic therapy. Continued use of numerous surgical techniques demonstrates that there is no consensus and the best treatment has yet to be determined. However, we suggest that a primary sternal closure is the best surgical option for pediatric patients. We propose a simple technique with high-vacuum Redon's catheter drainage that allows early mobilization and short term antibiotherapy, which thus decreases physiological and psychological trauma for patients and families. We have demonstrated the efficiency of this technique, which is also cost-effective by decreasing intensive care and hospital stay durations, in a large group of patients.

Non-invasive markers of gut wall integrity in health and disease

The intestinal mucosa is responsible for the absorption of nutrients from the lumen and for the separation of the potentially toxic luminal content (external environment) from the host (internal environment). Disruption of this delicate balance at the mucosal interface is the basis for numerous (intestinal) diseases. Experimental animal studies have shown that gut wall integrity loss is involved in the development of various inflammatory syndromes, including post-operative or post-traumatic systemic inflammatory response syndrome, sepsis, and multiple organ failure. Assessment of gut wall integrity in clinical practice is still a challenge, as it is difficult to evaluate the condition of the gut non-invasively with currently available diagnostic tools. Moreover, non-invasive, rapid diagnostic means to assess intestinal condition are needed to evaluate the effects of treatment of intestinal disorders. This review provides a survey of non-invasive tests and newly identified markers that can be used to assess gut wall integrity.

Enteral feeding algorithm for infants with hypoplastic left heart syndrome poststage I palliation

BACKGROUND

Infants with hypoplastic left heart syndrome (HLHS) experience a high incidence of growth failure in the postoperative period following stage I palliation. Because of an increased risk of necrotizing enterocolitis in this population, clinicians may be reluctant to initiate early enteral feedings. Published guidelines for initiating and advancing enteral feedings in this population are limited.

OBJECTIVE

To test the safety and efficacy of an enteral feeding algorithm in infants with HLHS following stage I palliation.

DESIGN

Single-center, prospective case series with historical comparisons.

SETTING

Pediatric cardiovascular intensive care unit in tertiary care children's hospital.

PATIENTS

The study group consisted of consecutive patients > or =35 wks gestational age and weight > or =2 kg admitted to our cardiac intensive care unit over an 18-month period following stage I palliation of HLHS (n = 36). Excluded were nonsurvivors, patients supported on extracorporeal membrane oxygenation or those with a history of NEC or fetal intervention. These data were compared with a similar cohort of patients admitted to the cardiac intensive care unit over an 18-month period before the implementation of the feeding algorithm (n = 27).

INTERVENTION

A feeding algorithm was implemented in the study group in the postoperative period for initiation and advancement of enteral nutrition.

MEASUREMENTS AND MAIN RESULTS

The median duration of total parenteral nutrition was significantly higher in the control group (116 vs. 51 hrs; p = 0.03) compared with the study group. The median time to achieve recommended daily allowance of calories defined as 108 kcal/kg per day was significantly reduced in the study group (9 vs. 13 days; p = 0.01). Despite the rapid advancement of enteral feedings on the algorithm, there was no incidence of NEC in the study group compared with 11% in the control group.

CONCLUSION

The use of an enteral feeding algorithm is a safe and effective means of initiating and advancing enteral nutrition in infants with HLHS following stage I palliation.

Lower weight-for-age z score adversely affects hospital length of stay after the bidirectional Glenn procedure in 100 infants with a single ventricle

OBJECTIVE

Poor growth has been described in infants with a single ventricle; however, little is known regarding its effect on surgical outcomes. We sought to assess the effect of nutritional status at the time of the bidirectional Glenn procedure on short-term outcomes.

METHODS

We performed a retrospective case series of children who underwent the bidirectional Glenn procedure at our institution between January 2001 and December 2007. Anthropometric measurements were recorded at the time of neonatal admission and the bidirectional Glenn procedure. Data from preoperative echocardiograms and cardiac catheterization were recorded. The primary outcome variable was length of hospital stay.

RESULTS

Data on 100 infants were included for analysis. Age at the time of the bidirectional Glenn procedure was 5.1 months (range, 2.4-10 months). The median weight-for-age z score at birth was -0.4 (range, -2.6 to 3.2), and by the time of the bidirectional Glenn procedure, it had decreased to -1.3 (range, -3.9 to 0.6). In multivariable modeling longer postoperative hospital stays were predicted by lower weight-for-age z score (P = .02), younger age (P < .001), being fed through a gastrostomy tube (P = .01), and undergoing concomitant aortic arch reconstruction (P < .001) at the time of the bidirectional Glenn procedure.

CONCLUSIONS

There is suboptimal weight gain between neonatal discharge and the bidirectional Glenn procedure. A lower weight-for-age z score and younger age at the time of the bidirectional Glenn procedure affects length of hospital stay independent of hemodynamic or echocardiographic variables.

New Insight in Loss of Gut Barrier during Major Non-Abdominal Surgery

Background

Gut barrier loss has been implicated as a critical event in the occurrence of postoperative complications. We aimed to study the development of gut barrier loss in patients undergoing major non-abdominal surgery.

Methodology/Principal Findings

Twenty consecutive children undergoing spinal fusion surgery were included. This kind of surgery is characterized by long operation time, significant blood loss, prolonged systemic hypotension, without directly leading to compromise of the intestines by intestinal manipulation or use of extracorporeal circulation. Blood was collected preoperatively, every two hours during surgery and 2, 4, 15 and 24 hours postoperatively. Gut mucosal barrier was assessed by plasma markers for enterocyte damage (I-FABP, I-BABP) and urinary presence of tight junction protein claudin-3. Intestinal mucosal perfusion was measured by gastric tonometry (P_rCO₂, P_r-aCO₂-gap). Plasma concentration of I-FABP, I-BABP and urinary expression of claudin-3 increased rapidly and significantly after the onset of surgery in most children. Postoperatively, all markers decreased promptly towards baseline values together with normalisation of MAP. Plasma levels of I-FABP, I-BABP were significantly negatively correlated with MAP at ½ hour before blood sampling (−0.726 (p<0.001), −0.483 (P<0.001), respectively). Furthermore, circulating I-FABP correlated with gastric mucosal P_rCO₂, P_r-aCO₂-gap measured at the same time points (0.553 (p = 0.040), 0.585 (p = 0.028), respectively).

Conclusions/Significance

This study shows the development of gut barrier loss in children undergoing major non-abdominal surgery, which is related to preceding hypotension and mesenterial hypoperfusion. These data shed new light on the potential role of peroperative circulatory perturbation and intestinal barrier loss.

Autoimmune gastritis and parietal cell reactivity in two children with abnormal intestinal permeability

Autoimmune gastritis is characterised by lymphocytic infiltration of the gastric submucosa, with loss of parietal and chief cells and achlorhydria. Often, gastritis is expressed clinically as cobalamin deficiency with megaloblastic anaemia, which is generally described as a disease of the elderly. Here, we report on two prepubertal children who developed autoimmune gastritis. One child developed autoimmune gastritis as part of a polyglandular autoimmune disease from a family with polyglandular autoimmune disease type II (PGA type II) and the other as part of a classic "thyro-gastric cluster," which may have been triggered by emotional trauma. Both children presented with normal small bowel biopsies, with abnormal gut permeability, which subsequently resolved. These patients are among the youngest reported to date. The immune systems targetted the gastric parietal cell autoantigens (ATP4A and ATP4B) in both children, similar to the elderly. The study of children with autoimmune gastritis and their families may provide additional insights into the disease's pathogenesis and may also lead to the identification of inheritable factors influencing susceptibility. This report underlines the necessity to screen paediatric patients with organ-specific autoimmune diseases for co-existent conditions. Children with polyglandular autoimmune disease are at particularly high risk.

Postoperative course in the cardiac intensive care unit following the first stage of Norwood reconstruction

The medical records of all patients born between 1 September, 2000, and 31 August, 2002, and undergoing the first stage of Norwood reconstruction, were retrospectively reviewed for details of the perioperative course. We found 99 consecutive patients who met the criterions for inclusion. Hospital mortality for the entire cohort was 15.2%, but was 7.3%, with 4 of 55 dying, in the setting of a "standard" risk profile, as opposed to 25.0% for those with a "high" risk profile, 11 of 44 patients dying in this group. Extracorporeal membrane oxygenation was utilized in 7 patients, with 6 deaths. Median postoperative length of stay in the hospital was 14 days, with a range from 2 to 85 days, and stay in the cardiac intensive care unit was 11 days, with a range from 2 to 85 days. Delayed sternal closure was performed in 18.2%, with a median of 1 day until closure, with a range from zero to 5 days. Excluding isolated delayed sternal closure, and cannulation and decannulation for extracorporeal support, 24 patients underwent 33 cardiothoracic reoperations, including exploration for bleeding in 12, diaphragmatic plication in 4; shunt revision in 4, and other procedures in 13. The median duration of total mechanical ventilation was 4.0 days, with a range from 0.7 to 80.5 days. Excluding those who died, the median total duration of mechanical ventilation was 3.8 days, with a range from 0.9 to 46.3 days. Reintubation for cardiorespiratory failure or upper airway obstruction was performed in 31 patients. Postoperative electroencephalographic and/or clinical seizures occurred in 13 patients, with 7 discharged on anti-convulsant medications. Postoperative renal failure, defined as a level of creatinine greater than 1.5 mg/dl, was present in 13 patients. Eleven had significant thrombocytopenia, with fewer than 20,000 platelets per microl, and injury to the vocal cords was identified in eight patients. Risk factors for longer length of stay included lower Apgar scores, preoperative intubation, early reoperations, reintubation and sepsis, but not weight at birth, genetic syndromes, the specific surgeon, or the duration of surgery. Although mortality rates after the first stage of reconstruction continue to fall, the course in the intensive care unit is remarkable for significant morbidity, especially involving the cardiac, pulmonary and central nervous systems. These patients utilize significant resources during the first hospitalization. Further studies are necessary to stratify the risks faced by patients with hypoplasia of the left heart in whom the first stage of Norwood reconstruction is planned, to determine methods to reduce perioperative morbidity, and to determine the long-term implications of short-term complications, such as diaphragmatic paresis, injury to the vocal cords, prolonged mechanical ventilation, and postoperative seizures.

Gut permeability in neonates after a stage 1 Norwood procedure

OBJECTIVE

Intestinal mucosal ischemia can occur during and after cardiac surgery. Severe decreases in mucosal perfusion may be a causative factor for postoperative mortality or complications such as necrotizing enterocolitis. Mesenteric perfusion is challenged preoperatively due to an imbalance between the systemic and pulmonary circulations and challenged intraoperatively due to hypothermic circulatory arrest. We have investigated gut permeability in seven patients undergoing stage 1 of the Norwood procedure, applying the dual sugar permeability test with L-rhamnose and lactulose.

DESIGN

Seven patients with hypoplastic left heart syndrome: clinical presentation, gut permeability findings, and outcome.

SETTING

A 10-bed mixed pediatric intensive care unit in a university hospital.

PATIENTS

Seven patients admitted for postoperative care after cardiac surgery.

INTERVENTIONS

Determination of gut permeability with the dual sugar permeability test using lactulose and rhamnose. Intestinal permeability was measured after induction of anesthesia and 12 and 24 hrs later.

MEASUREMENTS AND MAIN RESULTS

: All patients had abnormal lactulose/rhamnose ratios. One patient, who had a lactulose/rhamnose ratio 12 hrs after surgery of 2.3 (46-times normal), developed necrotizing enterocolitis postoperatively and died 3 days after surgery.

CONCLUSIONS

Gut permeability as assessed by the dual sugar permeability test is abnormal in patients with hypoplastic left heart syndrome before and after surgery. Lactulose/rhamnose ratios 46 times the normal value reflect a highly permeable small intestine. This may be a sign of a low output state and may help to identify patients at risk of developing necrotizing enterocolitis.