Long-term nutritional and clinical outcomes after serial transverse enteroplasty at a single institution

PURPOSE

Serial transverse enteroplasty (STEP) is a novel technique to lengthen and taper bowel in patients with intestinal failure. First described in 2003, initial data and reports have demonstrated favorable short-term outcomes, but there is limited published data on long-term outcomes of the procedure. Our aim was to assess clinical and nutritional outcomes after the STEP procedure.

METHODS

After obtaining institutional review board approval, we reviewed all records of patients (n = 16) who underwent the STEP procedure at our institution from February 2002 to February 2008. Patients were observed for a median time of 23 months (range, 1-71) postoperatively. Analyses of z scores for weight, height, and weight-for-height, and progression of enteral calories were performed using longitudinal linear models with random effects.

RESULTS

Of the 16 patients (10 male), the median age at time of surgery was 12 months (interquartile range, 1.5-65.0). The mean increase in bowel length was 91% +/- 38%. After the STEP procedure, patients had increased weight-for-age z scores of 0.03 units per month (P = .0001), height for age z scores of 0.02 units per month (P = .004), and weight-for-height z scores of 0.04 units per month (P = .02). Patients had improved enteral tolerance of 1.4% per month (P < .0001). Six patients (38%) transitioned off parenteral nutrition (median, 248 days). Long-term complications included catheter-related bacteremia (n = 5), gastrointestinal bleeding (n = 3), and small bowel obstruction (n = 1). Two patients ultimately underwent transplantation. There were no deaths.

CONCLUSIONS

In pediatric patients with intestinal failure, the STEP procedure improves enteral tolerance, results in significant catch-up growth, and is not associated with increased mortality.

Novel intravenous (13)C-methionine breath test as a measure of liver function in children with short bowel syndrome

Monitoring hepatic function in children with short bowel syndrome (SBS) and parenteral nutrition-associated liver disease (PNALD) is currently limited to conventional blood testing or liver biopsy. Metabolism of the stable isotope L[1-(13)C]methionine occurs exclusively in liver mitochondria and can be noninvasively quantified in expired breath samples. We hypothesized that the (13)C-methionine breath test ((13)C-MBT) could be a safe, noninvasive, and valid measure of hepatic mitochondrial function in children with SBS and PNALD.

METHODS

Baseline breath samples were collected in 8 children with SBS before intravenous administration of 2 mg/kg of L[1-(13)C]methionine. Six paired breath samples were obtained at 20-minute intervals. The (13)CO(2) enrichment was analyzed using isotope ratio mass spectrometry.

RESULTS

All 8 patients (5 males; mean age, 8.9 months) tolerated the (13)C-MBT without adverse events. Two patients underwent serial testing. One patient, tested before and after resolution of cholestasis, demonstrated increased cumulative percentage dose (4.7% to 6.6%) and area under the curve (AUC) (270-303). A second patient with progressive PNALD demonstrated decreased cumulative percentage dose (from 7.8% to 5.9%) and AUC (from 335 to 288).

CONCLUSION

The (13)C-MBT is a feasible, safe, and potentially clinically relevant measure of hepatic mitochondrial function in children with SBS and PNALD.

Preservation of intestinal motility after the serial transverse enteroplasty procedure in a large animal model of short bowel syndrome

INTRODUCTION

Serial transverse enteroplasty (STEP) has been shown to improve bowel function in short bowel syndrome. The effect of the STEP procedure on intestinal motility is not known, but some have hypothesized that it could disrupt bowel innervation and thus impair intestinal motility.

METHODS

Growing Yorkshire pigs (n = 7) underwent 3 operations at 6-week intervals: (1) reversal of 50 cm of jejunum, (2) 90% bowel resection +/- STEP to the proximal dilated bowel (4 STEP, 3 control), and (3) implantation of serosal strain gauges. At each operation, baseline and post-octreotide small intestinal motility was studied with continuously perfused manometry catheters using non-anticholinergic anesthesia. In addition, awake monitoring was performed using strain gauge analysis 1 week after the third operation. Characteristics of phase III of the migrating motor complex (MMC) were compared between and within groups using t test, chi(2), and analysis of variance, with significance set at P < .05.

RESULTS

Manometry data from the third surgery revealed no differences between groups or compared with baseline within groups for the presence and characteristics of phase III of the MMC. Specifically, the mean amplitude and frequency of phase III after octreotide, and both the mean baseline and mean octreotide-stimulated motility indices were equivalent. The duration of phase III after octreotide stimulation was significantly increased in the STEP animals, suggesting a potential benefit of the STEP procedure. Strain gauge analysis, performed in awake animals, confirmed no differences between the groups for basal and octreotide-stimulated characteristics of phase III of the MMC.

CONCLUSIONS

These preliminary data suggest that the STEP procedure in a porcine model of short bowel syndrome does not interfere with baseline or hormonally stimulated motility within the small bowel. These findings further support the STEP procedure as a safe option for the surgical management of short bowel syndrome.

Clinical parameters do not adequately predict outcome in necrotizing enterocolitis: a multi-institutional study

OBJECTIVE

Necrotizing enterocolitis (NEC) remains a major cause of neonatal morbidity and mortality. Some infants recover uneventfully with medical therapy whereas others develop severe disease (that is, NEC requiring surgery or resulting in death). Repeated attempts to identify clinical parameters that would reliably identify infants with NEC most likely to progress to severe disease have been unsuccessful. We hypothesized that comprehensive prospective data collection at multiple centers would allow us to develop a model which would identify those babies at risk for progressive NEC.

STUDY DESIGN

This prospective, observational study was conducted at six university children's hospitals. Study subjects were neonates with suspected or confirmed NEC. Comprehensive maternal and newborn histories were collected at the time of enrollment, and newborn clinical data were collected prospectively, thereafter. Multivariate logistic regression analysis was used to develop a predictive model of risk factors for progression.

RESULT

Of 455 neonates analyzed, 192 (42%) progressed to severe disease, and 263 (58%) advanced to full feedings without operation. The vast majority of the variables studied proved not to be associated with progression to severe disease. A total of 12 independent predictors for progression were identified, including only 3 not previously described: having a teenaged mother (odds ratio, OR, 3.14; 95% confidence interval, CI, 1.45 to 6.96), receiving cardiac compressions and/or resuscitative drugs at birth (OR, 2.51; 95% CI, 1.17 to 5.48), and having never received enteral feeding before diagnosis (OR, 2.41; 95% CI, 1.08 to 5.52).

CONCLUSION

Our hypothesis proved false. Rigorous prospective data collection of a sufficient number of patients did not allow us to create a model sufficiently predictive of progressive NEC to be clinically useful. It appears increasingly likely that further analysis of clinical parameters alone will not lead to a significant improvement in our understanding of NEC. We believe that future studies must focus on advanced biologic parameters in conjunction with clinical findings.

Intestinal atresias: factors affecting clinical outcomes

BACKGROUND

Despite improvements in care, intestinal atresias are associated with prolonged hospitalization and occasionally mortality. Although each type of atresia is distinct, it is unclear which factors impact clinical course. This study seeks to identify predictors of untoward outcome.

METHODS

Neonates with duodenal, jejunal/ileal, and colonic atresia, treated at 1 institution from 1982 to 2005 were reviewed. Data were evaluated using nonparametric analysis of variance and logistic regression. Nonparametric data were expressed as medians with interquartile range (IQR).

RESULTS

A total of 132 infants were evaluated including 63 with duodenal, 60 with jejunal/ileal, and 9 with colonic atresias. Overall mortality was 7% with associated congenital anomalies identified as an independent risk factor (P = .01). Infants with associated anomalies were more likely to have low birth weight (2.3 +/- 0.8 vs 3.0 +/- 0.8 kg, P = .01), which further increased mortality risk. Atresia location did not affect mortality or length of stay; however it did impact the time to full enteral nutrition with jejunal atresia requiring longer than duodenal (17 [IQR, 9-40 days] vs 10 [IQR, 7-70 days]; P = .01).

CONCLUSION

Overall mortality from intestinal atresia is low and is not dependent on the location of obstruction. Infants with birth weight less than 2 kg and associated anomalies are at an increased risk for prolonged hospital stay and mortality.

High diagnostic yield of gastrointestinal endoscopy in children with intestinal failure

PURPOSE

Children with intestinal failure (IF) often have gastrointestinal (GI) symptoms, including bleeding, increased stool output, and feeding intolerance. The use of endoscopic assessment of these symptoms has not been previously reported. This report evaluates the diagnostic yield of GI endoscopy in the setting of IF.

METHODS

After institutional review board approval, we reviewed the medical records (including endoscopy, pathology and microbiology data) of patients with IF who underwent GI endoscopies between September 1999 and March 2007.

RESULTS

Twenty-seven patients underwent 61 GI endoscopies: 34 esophagogastroduodenoscopies, 17 colonoscopies, 7 flexible sigmoidoscopies, and 3 ileoscopies. Indications for endoscopy, which were not mutually exclusive, included chronic diarrhea (39%, n = 24), GI bleeding (36%, n = 22), suspected bacterial overgrowth (36%, n = 22), and suspected peptic disease (15%, n = 9). Based on gross endoscopic appearance, histopathology, or microbiology, 43 (70%) procedures yielded abnormalities. These included infectious (20%, n = 12), anatomical (18%, n = 11), peptic (15%, n = 9), allergic (15%, n = 9), and other (2%, n = 1) findings. Eleven (73%) of 15 duodenal cultures grew a spectrum of 17 bacterial species. Overall, 24 (89%) of 27 patients had gross endoscopic, histopathologic, or microbiologic abnormalities.

CONCLUSIONS

In pediatric patients with IF, diagnostic upper and lower GI endoscopies yield high rates of abnormalities and can help guide clinical management.

Improved survival in a multidisciplinary short bowel syndrome program

PURPOSE

Pediatric short bowel syndrome (SBS) remains a management challenge with significant mortality. In 1999, we initiated a multidisciplinary pediatric intestinal rehabilitation program. The purpose of this study was to determine if the multidisciplinary approach was associated with improved survival in this patient population.

METHODS

The Center for Advanced Intestinal Rehabilitation includes dedicated staff in surgery, gastroenterology, nutrition, pharmacy, nursing, and social work. We reviewed the medical records of all inpatients and outpatients with severe SBS treated from 1999 to 2006. These patients were compared to a historical control group of 30 consecutive patients with severe SBS who were treated between 1986 and 1998.

RESULTS

Fifty-four patients with severe SBS managed by the multidisciplinary program were identified. Median follow-up was 403 days. The mean residual small intestinal length was 70 +/- 36 vs 83 +/- 67 cm in the historical controls (P = NS). Mean peak direct bilirubin was 8.1 +/- 7.9 vs 9.0 +/- 7.4 mg/dL in controls (P = NS). Full enteral nutrition was achieved in 36 (67%) of 54 patients with severe SBS vs 20 (67%) of 30 patients in the control group (P = NS). The overall survival rate, however, was 89% (48/54), which is significantly higher than in the historical controls (70%, 21/30; P < .05).

CONCLUSIONS

A multidisciplinary approach to intestinal rehabilitation allows for fully integrated care of inpatients and outpatients with SBS by fostering coordination of surgical, medical, and nutritional management. Our experience with 2 comparable cohorts demonstrates that this multidisciplinary approach is associated with improved survival.

Defect size determines survival in infants with congenital diaphragmatic hernia

OBJECTIVES

Congenital diaphragmatic hernia is a significant cause of neonatal mortality. The objective of this study was to evaluate the clinical factors associated with death in infants with congenital diaphragmatic hernia by using a large multicenter data set.

METHODS

This was a prospective cohort study of all liveborn infants with congenital diaphragmatic hernia who were cared for at tertiary referral centers belonging to the Congenital Diaphragmatic Hernia Study Group between 1995 and 2004. Factors thought to influence death included birth weight, Apgar scores, size of defect, and associated anomalies. Survival to hospital discharge, duration of mechanical ventilation, and length of hospital stay were evaluated as end points.

RESULTS

A total of 51 centers in 8 countries contributed data on 3062 liveborn infants. The overall survival rate was 69%. Five hundred thirty-eight (18%) patients did not undergo an operation and died. The defect size was the most significant factor that affected outcome; infants with a near absence of the diaphragm had a survival rate of 57% compared with infants having a primary repair with a survival rate of 95%. Infants without agenesis but who required a patch for repair had a survival rate of 79% compared with primary repair.

CONCLUSIONS

The size of the diaphragmatic defect seems to be the major factor influencing outcome in infants with congenital diaphragmatic hernia. It is likely that the defect size is a surrogate marker for the degree of pulmonary hypoplasia. Future research efforts should be directed to accurately quantitate the degree of pulmonary hypoplasia or defect size antenatally. Experimental therapies can then be targeted to prospectively identify high-risk patients who are more likely to benefit.

First report of the international serial transverse enteroplasty data registry: indications, efficacy, and complications

BACKGROUND

Serial transverse enteroplasty (STEP) is a novel surgical therapy for short bowel syndrome and is being used with increasing frequency worldwide. Because no single center is likely to obtain sufficient experience for meaningful analysis, we created the International STEP Data Registry to allow for larger, multicenter patient accrual and followup. This report describes patient characteristics, operative parameters, and early results of STEP in the first 38 patients enrolled in the International STEP Data Registry.

STUDY DESIGN

After IRB approval, data were entered online through password-protected enrollment and followup forms. Patient and procedural characteristics were analyzed. Pre- and postoperative small bowel length and enteral feeding tolerance were compared with the paired t-test.

RESULTS

Between September 1, 2004, and April 30, 2006, 19 centers from 3 countries enrolled 38 patients. Median followup from STEP procedure to analysis was 12.6 months (range 0 to 66.9 months). Indications for STEP were short bowel syndrome (SBS, n=29), bacterial overgrowth (n=6), and neonatal atresia (n=3). Mean small intestine length was substantially increased in all groups (68+/-44 cm versus 115+/-87 cm, p < 0.0001, n=27). Notable complications included intraoperative staple line leak (n=2), bowel obstruction (n=2), and fluid collection or abscess (n=3). Late outcomes included progression to transplantation (n=3) and mortality (n=3). For the short bowel syndrome cohort, enteral tolerance was notably increased from 31%+/-31% to 67%+/-37% of calories (p < 0.01, n=21).

CONCLUSIONS

STEP has been performed at multiple centers with minimal complications and encouraging outcomes. Indications for the procedure have broadened beyond short bowel syndrome to include bacterial overgrowth and neonatal intestinal obstruction with dilated proximal intestine. Continued accrual and followup of patients in the International STEP Data Registry will elucidate the longterm safety and efficacy of the procedure, with the goal of improved patient selection and operative timing.

The second STEP: the feasibility of repeat serial transverse enteroplasty

BACKGROUND

Serial transverse enteroplasty (STEP) lengthens and tapers dilated bowel. Redilation of the STEP segment occurs in some patients with intestinal failure. The feasibility of a repeat STEP procedure in a pig model is evaluated.

METHODS

Six pigs underwent reversal of an intestinal segment distal to the ligament of Treitz. At 6-week intervals after reversal, each animal had 2 STEP procedures on the bowel proximal to the reversed segment. Necropsy was performed up to 6 weeks after repeat STEP.

RESULTS

Bowel length increased by 11.3 +/- 3.9 cm and bowel diameter decreased from a mean of 5.3 +/- 0.8 to 1.8 +/- 0.4 cm (P < .0001) after the first STEP. After repeat STEP, bowel length increased by 16.7 +/- 13.3 cm (P < .01), and the bowel was tapered from a mean of 5.4 +/- 0.9 to 2.2 +/- 0.4 cm (P < .01). Five pigs did well after repeat STEP, and 1 pig had early necropsy for bowel obstruction. None had histologic evidence of bowel ischemia in the repeat STEP segment.

CONCLUSIONS

A second STEP operation is feasible in a pig model and may be considered to optimize bowel length and function in select patients with intestinal failure.

The effect of insulin infusion upon protein metabolism in neonates on extracorporeal life support

OBJECTIVE

Critically ill neonates on extracorporeal life support (ECLS) demonstrate elevated rates of protein breakdown that, in turn, are associated with increased morbidity and mortality. This study sought to determine if the administration of the anabolic hormone insulin improved net protein balance in neonates on ECLS.

METHODS

Twelve parenterally fed neonates, on ECLS, were enrolled in a randomized, prospective, crossover trial. Subjects were administered a hyperinsulinemic euglycemic clamp and a control saline infusion. Protein metabolism was quantified using ring-D5-phenylyalanine and ring-D2-tyrosine stable isotopic infusions. Statistical comparisons were made by paired sample t tests (significance at P < 0.05).

RESULTS

Serum insulin concentration increased 20-fold during insulin infusion compared with saline infusion control (P < 0.0001). Protein breakdown was significantly decreased during insulin infusion compared with controls (7.98 +/- 1.82 vs. 6.89 +/- 1.03 g/kg per day; P < 0.05). Serum amino acid concentrations were significantly decreased by insulin infusion (28,450 +/- 9270 vs. 20,830 +/- 8110 micromol/L; P < 0.02). Insulin administration tended to decrease protein synthesis (9.58 +/- 2.10 g/kg per day vs. 8.60 +/- 1.20; P = 0.05). For the whole cohort, insulin only slightly improved net protein balance (protein synthesis minus protein breakdown) (1.60 +/- 0.80 vs. 1.71 +/- 0.89 g/kg per day; P = 0.08). In neonates receiving > or =2 g/kg per day of dietary amino acids insulin significantly improved net protein balance (2.17 +/- 0.34 vs. 2.40 +/- 0.26 g/kg per day; P < 0.01).

CONCLUSIONS

Insulin effectively decreases protein breakdown in critically ill neonates on ECLS. However, this is associated with a significant reduction in plasma amino acids and a trend toward decreased protein synthesis. Insulin administration significantly improves net protein balance only in those ECLS neonates in whom adequate dietary protein is provided.

Growth and nutritional status in infants with short-bowel syndrome after the serial transverse enteroplasty procedure

BACKGROUND & AIMS

The aim of this study was to describe the long-term nutritional outcomes of 4 patients with short bowel syndrome (SBS) who underwent a newly described bowel-lengthening procedure, the serial transverse enteroplasty (STEP) procedure.

METHODS

We performed a retrospective review of the medical records of 4 children who underwent STEP at 1 center. The primary outcome measure was the percentage of total dietary energy received by the enteral route before and after STEP. Other outcome measures were weight and height Z scores and body composition, as measured by arm anthropometric values.

RESULTS

Four children with SBS were identified, all of whom had been dependent on parenteral nutrition since birth. The mean preoperative follow-up period was 234 days (range, 63-502 days), and the mean postoperative follow-up period was 362 days (range, 252-493 days). By using model-based mean estimates, the mean enteral nutrition intake was 48% preoperatively vs 62% postoperatively (P = .02). The model mean weight for age Z score increased by .7 SDs postoperatively (P = .01), and the model mean weight for height increased by .6 SDs (P < .0001). The percent standard mid-upper-arm circumference increased by 13.1% postoperatively (P = .03), and the percent standard triceps skinfold increased by 24.5% postoperatively (P < .0001).

CONCLUSIONS

The STEP procedure was associated with improved growth and body composition among 4 children with SBS in the face of a decreasing need for parenteral nutrition. Among patients with refractory SBS and dilated small intestine, the STEP procedure is associated with improved clinical and nutritional outcomes in the first year after surgery.

Real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery

OBJECTIVES

Given the demonstrated benefit of euglycemia in critically ill patients as well as the risk for hypoglycemia during insulin infusion in children, we sought to validate a subcutaneous sensor for real-time continuous glucose monitoring in pediatric patients during and after cardiac surgery.

METHODS

Children up to 36 months of age who were undergoing cardiac bypass surgery were recruited. After anesthetic induction, a continuous glucose-monitoring system sensor (CGMS, Medtronic Minimed, Northridge, CA) was inserted subcutaneously. Sensors remained in place for up to 72 hours. Arterial blood glucose was measured intermittently in the central laboratory (Bayer Rapidlab 860, Tarrytown, NY). Sensor data, after prospective calibration with 6-hourly laboratory values using the proprietary Medtronic Minimed Guardian RT algorithm, were compared with all laboratory glucose values. Statistical analysis was performed to test whether sensor performance was affected by body temperature, inotrope dose, or body-wall edema.

RESULTS

Twenty patients were enrolled in the study for a total of 40 study days and 246 paired sensor and laboratory glucose values. Consensus error grid analysis demonstrated that 72.0% of sensor value comparisons were within zone A (no effect on clinical action), and 27.6% of comparisons were within zone B (altered clinical action of little or no effect on outcome), with a mean absolute relative deviation of 17.6% for all comparisons. One comparison (0.4%) was in zone C (altered clinical action likely to affect outcome). No significant correlations were found between sensor performance and body temperature, inotrope dose, or body-wall edema. All patients tolerated the sensors well without bleeding or tissue reaction.

CONCLUSIONS

Guardian RT real-time subcutaneous blood glucose measurement is safe and potentially useful for continuous glucose monitoring in critically ill children. Subcutaneous sensors performed well in the setting of hypothermia, inotrope use, and edema. These sensors facilitate identifying and following the effects of interventions to control blood glucose.

Anesthesia and analgesia during and after surgery in neonates

BACKGROUND

Historically, the use of anesthetics and analgesics in neonates and infants has been based on extrapolations from studies performed in adults and older children. Over the past 20 years, there has been a growing body of research on the clinical pharmacology and clinical outcomes of these agents in neonates and infants.

OBJECTIVE

This article summarizes clinical pharmacology and clinical outcomes studies of opioids, opioid antagonists, sedative-hypnotics, nonsteroidal anti-inflammatory drugs and acetaminophen, and local anesthetics in neonates and infants to highlight gaps in the available knowledge, review some concerns about study design, and identify drugs that should receive high priority for future study.

METHODS

Relevant studies were identified through a search of MEDLINE and a review of textbooks, conference proceedings, and abstracts. The available literature was subjected to expert committee-based review.

CONCLUSIONS

There is a growing body of information on analgesic and anesthetic pharmacokinetics, pharmacodynamics, and clinical outcomes in neonates and infants, permitting safe and effective use in some clinical settings. Major gaps in knowledge persist, however. Future research may involve a combination of clinical trials and preclinical studies in suitable infant animal surrogate models.

The impact of prenatal bowel dilation on clinical outcomes in neonates with gastroschisis

PURPOSE

In fetuses with gastroschisis, the importance of ultrasonographic bowel dilation remains controversial. The outcome of patients with gastroschisis with and without prenatal bowel dilation is reported.

METHODS

From 2000 to 2004, 27 neonates with gastroschisis were followed at a single center. Thirteen patients had prenatal ultrasonographic bowel dilation (diameter, > or =6 mm; range, 6-35 mm). Outcomes of those with and without dilation were compared using 2 sample t tests and logistic regression.

RESULTS

Time to initiation of enteral nutrition varied significantly between groups (20.4 +/- 11.7 days vs 12.5 +/- 4.3 days, P < .05). A trend toward a reduced rate of primary closure was seen in those with dilation (23% vs 50%, P = .06). No significant difference was found when considering mortality, gestational age, time in the intensive care unit (ICU), time on parenteral nutrition, or length of stay. Prenatal bowel dilation, a longer ICU stay, and later gestational age independently predicted readmission for bowel obstruction (P < .001).

CONCLUSION

Infants with gastroschisis and prenatal bowel dilation were significantly slower to initiate enteral feeding and tended to have a reduced incidence of primary closure. This did not translate into increased mortality, time on parenteral nutrition, time in the ICU, or length of stay. However, dilation was associated with readmission for bowel obstruction.

Serial transverse enteroplasty enhances intestinal function in a model of short bowel syndrome

OBJECTIVE/SUMMARY BACKGROUND DATA: Serial transverse enteroplasty (STEP) is a new intestinal lengthening procedure that has been shown to clinically increase bowel length. This study examined the impact of the STEP procedure upon intestinal function in a model of short bowel syndrome.

METHODS

Young pigs (n=10) had a reversed segment of bowel interposed to induce bowel dilatation. Five pigs underwent a 90% bowel resection with a STEP procedure on the remaining dilated bowel while 5 served as controls and had a 90% bowel resection without a STEP procedure. Determinations of nutritional status, absorptive capacity, and bacterial overgrowth were conducted 6 weeks after resection. Statistical comparisons were made by 2-sample t test (significance at P<0.05).

RESULTS

The STEP procedure lengthened the bowel from 105.2+/-7.7 cm to 152.2+/-8.3 cm (P<0.01). The STEP animals showed improved weight retention compared with controls (mean, -0.5%+/-1.8% body weight versus -17.6%+/-1.5%, P<0.001). Intestinal carbohydrate absorption, as measured by d-Xylose absorption and fat absorptive capacity as measured by serum vitamin D and triglyceride levels, were increased in the STEP group versus controls. Serum citrulline, a marker of intestinal mucosal mass, was significantly elevated in the STEP pigs compared with controls. None of the STEP animals but 4 of 5 control animals were noted to have gram-negative bacterial overgrowth in the proximal bowel.

CONCLUSIONS

STEP improves weight retention, nutritional status, intestinal absorptive capacity, and serum citrulline levels in a porcine short bowel model. A salutary effect upon bacterial overgrowth was also noted. These data support the use of this operation in short bowel syndrome.

The route of lipid administration affects parenteral nutrition-induced hepatic steatosis in a mouse model

BACKGROUND

The etiology of parenteral nutrition (PN)-associated hepatic injury remains unresolved. Recent studies have suggested that the intravenous (IV) lipid emulsion administered with PN may contribute to PN-associated hepatic injury. We therefore examined whether the route of lipid administration would affect the development of PN-associated liver injury in a previously established animal model of PN-induced hepatic steatosis.

METHODS

Mice were fed ad libitum PN solution as their only nutritional source for 19 days with lipid supplementation by either the enteral or the IV route. Control mice received chow alone, and a final group received enteral PN solution without lipid supplementation.

RESULTS

All mice gained equivalent weight during the study. Mice receiving PN alone or PN with IV lipid developed severe histologic liver damage that was not seen in control mice or in mice receiving PN with enteral lipid. Liver fat content as measured by magnetic resonance spectroscopy was significantly lower in the control and enteral lipid groups when compared with mice receiving PN alone or with IV lipid. Mice receiving enteral lipid had significantly lower levels of serum aspartate aminotransferase and alanine aminotransferase compared with animals receiving PN alone.

CONCLUSIONS

These data provide preliminary evidence that lipid administered through the enteral route protects against PN-associated hepatic injury in an animal model.

The role of enteral nutrition in the reversal of parenteral nutrition-associated liver dysfunction in infants

BACKGROUND

Liver dysfunction in children dependent on parenteral nutrition (PN) is well established, and the extent of hyperbilirubinemia has been shown to correlate with morbidity and mortality. The aim of this study was to assess whether increasing provisions of enteral nutrition can improve PN-associated hyperbilirubinemia over time.

METHODS

A retrospective review was conducted on infants in our institution's Short Bowel Syndrome Clinic from 1999 to 2004. Inclusion criteria included PN duration more than 1 month, serum direct bilirubin more than 3 mg/dL while on PN, and tolerance of full enteral nutrition with eventual discontinuation of PN. Paired t tests were used for statistical analyses.

RESULTS

Twelve infants were identified with a PN duration of 5 +/- 1 months. Five patients underwent liver biopsy while on PN, and histological evidence of cholestasis was found on all specimens. Peak total and direct bilirubin levels were 10.5 +/- 1.9 and 7.0 +/- 1.6 mg/dL, respectively, and occurred at time of PN discontinuation. Only 2 patients had improvement in serum bilirubin levels before initiation of full enteral nutrition. After initiation of full enteral nutrition and discontinuation of PN, all patients achieved permanent normalization of bilirubin levels by 4 months (P < .05) after a 1-month plateau phase. Alkaline phosphatase levels approached reference range within this time but were not significant.

CONCLUSION

These data demonstrate for the first time that although PN-dependent infants can achieve normalization of marked hyperbilirubinemia with enteral nutrition, the improvement in liver function usually begins only after full enteral nutrition is tolerated and PN is withdrawn. These findings support the aggressive weaning of PN to enteral nutrition in infants with short bowel syndrome.

The first use of live continuous glucose monitoring in patients on extracorporeal life support

BACKGROUND

Evidence suggests that glycemic control provides clinical benefit to critically ill patients. The Extracorporeal Glucose Monitoring System (EGMS), Medtronic Minimed, Northridge, CA) has been developed to measure real-time, continuous blood glucose concentrations in patients on extracorporeal bypass. This pilot study reports the first in vitro and in vivo evaluations of EGMS in an extracorporeal circuit.

METHODS

In an in vitro study, three EGMS sensors were inserted in a neonatal extracorporeal circuit. Circuit blood glucose levels were altered by saline dilution and dextrose infusion. EGMS sensors were then inserted into the venous return limb of the extracorporeal circuit in a cohort of six critically ill infants on extracorporeal life support (ECLS). Continuous glucose measurements were compared with laboratory and bedside glucose values at predefined intervals. Linear regression analyses and the Clarke error grid were constructed to analyze device accuracy.

RESULTS

All three in vitro EGMS sensors recorded real-time data without interruption for 48 h. EGMS glucose measurements closely correlated with reference levels (R (2) = 0.93). EGMS glucose values demonstrated an approximate 7-10 min lag while glucose concentrations were rapidly changing. Eight EGMS devices were inserted into six neonates on ECLS on day of life 6 +/- 3. EGMS correlated well with laboratory glucose (R2 = 0.61) and bedside glucose during a hyperinsulinemic euglycemic clamp (R2 = 0.78). On the Clarke error grid, 98% of readings were within zones A and B using laboratory glucose as reference, and 100% were within zones A and B using bedside glucose measurements. Blood glucose range during the in vitro study was 19-295 mg/dL and during the in vivo study was 80-257 mg/dL.

CONCLUSIONS

This pilot study suggests that EGMS is a reliable tool for measuring continuous blood glucose in critically ill patients connected to an extracorporeal circuit, although important limitations exist. Potential applications of this technology include intensive glucose monitoring in patients on ECLS, cardiopulmonary bypass, and renal replacement therapy.

Serial transverse enteroplasty is associated with successful short-term outcomes in infants with short bowel syndrome

BACKGROUND

The serial transverse enteroplasty (STEP) has been shown to improve nutritional indices in an animal model of short bowel syndrome. The aim of this study was to review short-term surgical and nutritional outcomes in the first cohort of infants to undergo the STEP procedure at our institution.

METHODS

All patients who underwent the STEP procedure during a 26-month period from February 2002 to March 2004 were reviewed. Paired t tests were used for comparisons between values pre-STEP and post-STEP (P < .05 deemed significant). Data are expressed as mean and range.

RESULTS

The STEP was performed on 5 patients, including 1 newborn. The STEP was used as a primary lengthening operation in 4 patients. Intestinal length was significantly increased in all patients with 18 (10-26) stapler applications. There were no perioperative complications and no evidence of intestinal leak or obstruction on routine postoperative contrast study. Nutritional follow-up was available on 3 subjects at 17 (11-26) months post-STEP. Percentage of enteral nutrition was significantly increased in these subjects (P < .05). One subject was fully weaned from total parenteral nutrition 6 weeks after the STEP, and bilirubin in another patient with profound cholestasis who had been listed for liver-small bowel transplant normalized after the STEP. An additional patient, with established cirrhosis before operation, underwent successful liver-small bowel transplantation 8 months after intestinal lengthening.

CONCLUSION

The STEP procedure is a simple bowel-lengthening procedure with promising early surgical and nutritional outcomes. Further data from a multicenter registry are needed to demonstrate its long-term efficacy.

Assessment of cysteine synthesis in very low-birth weight neonates using a [13C6]glucose tracer

BACKGROUND/PURPOSE

Cysteine is an amino acid necessary for the synthesis of all proteins, the antioxidant glutathione, and the neuromodulator taurine. Whether cysteine is an essential amino acid for premature neonates remains controversial. Using a [13C6]glucose precursor in very-low-birth weight (VLBW) premature neonates, we measured the 13C content of cysteine in hepatically derived apolipoprotein (apo) B-100 and in the plasma to determine whether cysteine synthesis occurs and to relate minimum synthetic capacity to neonatal maturity.

METHODS

Twelve VLBW premature neonates (birth weight, 907 +/- 274 [SD] g; gestational age, 26.8 +/- 2.4 weeks) were studied on day of life 7.8 +/- 4.2 while on total parenteral nutrition (TPN) for 5.6 +/- 4.5 days. A 4-hour intravenous infusion of [13C6]glucose was administered. Blood samples were obtained immediately before and at the end of the infusion. Isotopic enrichment of cysteine was determined by gas chromatography/mass spectrometry. Analysis of variance, Student's t test, and linear regression were used for comparisons.

RESULTS

The 13C isotope ratio of apo B-100-derived cysteine after the [13C6]glucose infusion was significantly higher than baseline (18.57 +/- 0.38 [SEM] vs 17.54 +/- 0.25 mol%, P < .05). The 13C isotope ratio of plasma cysteine was also significantly higher than baseline (17.36 +/- 0.25 vs 16.91 +/- 0.16 mol%, P < .05). When expressed as a product/precursor ratio, the mole percent above baseline of [13C]apo B-100 cysteine/[13C6]glucose correlated with birth weight (r = 0.74, P < .01).

CONCLUSIONS

Very low-birth weight neonates are capable of cysteine synthesis as evidenced by incorporation of 13C label into hepatically derived apo B-100 cysteine and plasma cysteine from a glucose precursor. The minimum capacity for intrahepatic cysteine synthesis appears to be directly proportional to the maturity of the neonate and may impact the capabilities of VLBW neonates to counteract oxidative stresses such as bronchopulmonary dysplasia and necrotizing enterocolitis.

Intravenous insulin decreases protein breakdown in infants on extracorporeal membrane oxygenation

BACKGROUND/PURPOSE

Infants requiring extracorporeal membrane oxygenation (ECMO) have the highest rates of protein catabolism ever reported. Recent investigations have found that such extreme protein breakdown is refractory to conventional nutritional management. In this pilot study, the authors sought to use the anabolic hormone insulin to reduce the profound protein degradation in this cohort.

METHODS

Four parenterally fed infants on ECMO were enrolled in a prospective, randomized, crossover trial. Subjects were administered an insulin infusion using a 4-hour hyperinsulinemic euglycemic clamp followed by a control saline infusion on consecutive days in random order. Whole-body protein flux and breakdown were quantified using a primed continuous infusion of the stable isotope L-[1-13C]leucine. Statistical analyses were performed using paired t tests.

RESULTS

Serum insulin levels were increased 15-fold during the insulin clamp compared with the saline control (407 +/- 103 v 26 +/- 12 microU/mL; P <.05). During the insulin infusion, infants had decreased rates of total leucine flux (214 +/- 25 v 298 +/- 38 micromol/kg/h; P <.05) and leucine flux derived from protein breakdown (156 +/- 40 v 227 +/- 54 micromol/kg/h; P <.05) when compared with saline control. Overall, insulin administration produced a 32% reduction in protein breakdown (P <.05).

CONCLUSIONS

In this pilot study, the anabolic hormone insulin markedly reduced protein breakdown in critically ill infants on ECMO. Because elevated protein breakdown correlates with mortality and morbidity, the administration of intravenous insulin may ultimately have broad applicability to the metabolic management of critically ill infants.