Update on Enteral Nutrition in Pediatric Intestinal Failure

It is always nice to see how other centers manage clinical problems.  In a recent review (J Pediatr 2014; 165: 1065-90) from Boston Children’s, the authors provide details on how they use enteral nutrition in pediatric intestinal failure (IF) patients.  Prior to reviewing their approach, the authors provide a few definitions:

  • “IF occurs when there is a reduction of functional intestinal mass necessary for adequate digestion and absorption for nutrient, fluid, and growth requirements, resulting in the need for intensive nutritional support.”
  • “IF resulting from extensive intestinal resection is termed SBS” (short bowel syndrome)

The authors also discuss intestinal adaptation and factors that predispose to improvement.  Enteral nutrition (EN) stimulates adaptation and ‘gut rest’ results in atrophy of intestinal mucosa.

Key points:

  • “Prompt initiation of enteral feeding after bowel resection has been shown to decrease the duration of hospitalization”
  • “The optimal choice for EN in infants with IF seems to be human milk…If human milk is unavailable, amino acid-based formulas have been associated with improved outcomes.”
  • If intact colon with ileocecal valve, supplementation with dietary fiber (e.g.. green beans) at 2 g/kg/d may be helpful.
  • In this population, there is a high prevalence of micronutrient deficiencies while on partial PN support, TPN (depending on availability of components), and when on exclusive enteral feedings.
  • “We commonly employ an approach that uses … continuous feeding at night and bolus feeding during the day.
  • Outcomes of IF are reviewed (noted in previous blog entry –see below). Citrulline can be useful predictor of enteral autonomy.

Feeding Advancement Principles -Figure 1:

When feeds are held, usually held for 8 hours and then restarted at 75% of previous rate

Stool output:

  • If <10 mL/kg/d or < 10 stools/d —->advance rate by 10-20 mL/kg/d
  • If 10-20 mL/kg/d or 10-12 stools/d —>no change
  • If >20 mL/kg/d or >12 stools/d  —->reduce or hold feeds

Ostomy output:

  • If 2 mL/kg/h —> advance rate by 10-20 mL/kg/d
  • If 2-3 mL/kg/h –>no change
  • If >3 mL/kg/h  –>reduce or hold feeds

Also suggested to reduce or holding feeds when/if:

  • signs of dehydration
  • stool reducing substances >1%
  • gastric aspirates > four times previous hour’s infusion rate

Oral feeds:

  • When developmentally appropriate, offer one hour’s worth of continuous feeds BID-TID after 5 days of continuous feeds.  Hold tube feeds during oral feeds.
  • More than an hour’s worth of oral feeds once infant has reached full volume of feeds by continuous route and gaining weight.

Take-home message: Outcomes of IF have improved.  This review provides one approach towards optimizing enteral nutrition.

Related blog posts:

 

Enteral Fish Oil and Intestinal Adaptation in Premature Infants

A provocative article (J Pediatr 2014; 165: 274-9) examines supplementation of enteral fat/fish oil in premature infants as a mechanism to reduce parenteral nutrition associated cholestasis (PNAC).  While the study’s limitations will prevent any dramatic conclusions, the article and associated editorial (pgs 226-27) do make several useful points.

Before discussing the limitations, the design of the study:

Infants were block randomized (block size of 8) into either a control group or treatment group.  While both groups received conventional PN, the treatment group received supplemental enteral fat as microlipid and fish oil after tolerating enteral feeds at 20 mL/kg/d.  Microlipid was started at 1 g/kg/d and advanced up to 2.5 g/kg/d; coinciding with microlipid increases, parenteral intralipid was decreased.  Fish oil was started at 0.2 g every 12 hours and was advanced to a maximum of 0.5 g every 6 hours.  The two fish oil products were Major Fish Oil 500 (Major Pharmaceuticals) and Rugby Sea Omega 50 (Rugby Laboratories).

The limitations include the following:

  • Small cohort of 18 patients in each arm
  • Due to the smell of fish oil, the study could not truly be blinded which introduces potential bias
  • Only 7 of the 36 patients could be considered to have short bowel syndrome as most of the infants had small amounts of intestine resected
  • Advancement of enteral feedings were halted if stoma output reached 20 mL/kg/d.  The editorialists note that 40 mL/kg/d would be more typical.  Thus, in both the treatment group and the control group, there was significant opportunity to reduce PN by more aggressive enteral nutrition advancement.

With these limitations in mind, there authors were able to show that supplemental fat (with fish oil) was associated with less parenteral intravenous lipid, and reduced conjugated bilirubin prior to anastomosis.  However, there was no significant difference in PN duration.  Growth parameters were similar prior to anastomosis, but improved in the treatment group after anastomosis.

In the editorial, it is noted that “enteral feeding with a high-fat diet has been demonstrated to enhance structural features of resection-associated adaptation, the underlying mechanisms for this phenomenon are still presently unknown.”

Take-home message: Enteral fat/fish oil supplementation helped decrease parenteral intravenous lipids in this study.  More broadly, advancing enteral nutrition by accepting higher ostomy outputs is likely the best strategy to avoid PNAC and other PN-associated complications.

Related blog posts:

 

Don’t Forget to Check Urine Sodium

In patients with short bowel syndrome and excessive ostomy losses, salt depletion is associated with failure to thrive.  An easy way to screen for this is checking a “spot” urine sodium level; a urine sodium <10 mmol/L is too low.  While this has been recognized in infants for a long time, a recent case report shows that this can be an issue for older children (up to 19 years) as well (Nutr Clin Pract 2014 vol. 29 no. 397-401 -thanks to Kipp Ellsworth’s twitter feed for this reference & link: http://goo.gl/TkjKyd).

The authors conclusion: “We advise that patients of all ages with high stoma output have routine urine sodium levels checked, particularly in the setting of weight loss or poor gain. Furthermore, instances of TBSD [total body salt depletion] should be treated with sodium supplementation.”

Missing ingredients in TPN -Case Report

Recently one of my radiology colleagues, Dr. Laura Hayes, put together (lead author) a presentation (poster) for an upcoming meeting.  The main focus of the presentation is a TPN-dependent toddler who presented with refusal to walk due to copper deficiency.

Attached is a link to the presentation: TPN Copper.  This link is a power point presentation with numerous radiographs and even bone scan images.

Key points:

  • All TPN components except dextrose have been in periods of shortage over the last few years.
  • TPN-dependent patients may not be receiving all the needed components and their physicians may not have been notified of the specific shortage(s).
  • Copper deficiency leads to reduced activity of numerous enzymes important for function of bone, blood, skin, nervous system and hair.
  • Subperiosteal hemorrhage leads to the periosteal thickening seen in this case and is associated with the bone pain our patient experienced.
  • Increased losses of bilious fluid can increase the risk of copper deficiency due to the excretion of copper in bile.
  • Other TPN-related deficiencies reviewed include thiamine deficiency (Wernicke’s encephalopathy), Vitamin D deficiency (Rickets), and Vitamin C deficiency (Scurvy).

Another recent case report:

Oestreich AE, Cole CR. Vigorous periosteal reaction secondary to copper deficiency in an infant on total parenteral nutrition. (2013) Pediatr Radiol 43:1411-1413.

Related Blog Posts:

More STEP Experience

A retrospective review of all serial transverse enteroplasty (STEP) procedures from Omaha provides more data on long-term outcomes (J Pediatr 2014; 164: 93-8).  In total 51 patients underwent a total of 68 STEP procedures.  Underlying bowel diseases: NEC (n=8), Gastroschisis (n=29), Intestinal Atresia (n=11), and Volvulus (n=4).  Median length prior to STEP: 30 cm.

Results:

  • Median bowel length gain of 54% (median 51 cm) was noted with first STEP.
  • Median age of 1 year at first STEP
  • Parenteral caloire requirement decreased to median <20 kcal/kg/day at 1 year post-op
  • Longer length gains had higher risk of stricture formation.  Six strictures developed which occurred in the first 22 procedures in the series.  Subsequently, the authors state that they have not reduced the luminal diameter below 2 cm at any point.
  • 7 children underwent transplantation; 60% of non-transplanted children were enterally independent.  The authors note that “no child has gone on to transplant following a STEP procedure since August 2009.”
  • 48 of 51 children are alive at a median of 39 months of followup.

Bottomline: The authors philosophy is that the STEP should create uniformity of luminal diameter as the first priority rather than increased length.  Based on their experience, there appears to be a learning curve to optimizing outcomes with STEP procedures.

Also noted: J Pediatr 2013; 163: 1692-6.  Retrospective study of prospectively collected data from 178 children with regard to micronutrient deficiency among intestinal failure patients transitioning to enteral feeds. Figures 1 and 2 along with Table 2 provide the prevalence of micronutrient deficiency while receiving supplemental parenteral nutrition (PN) and while on full enteral nutrition (FEN).  Iron deficiency was most common in both situations with prevalence of 84% and 61% respectively. With the exception of folate (0%), all of the vitamins and micronutrients had fairly high rates of deficiency.  While on FEN defiencies were  the following:

  • Vitamin A 19%
  • Vitamin B12 6.5%
  • Vitamin D 30%
  • Vitamin E 6%
  • Copper 8%
  • Iron 61%
  • Selenium 4%
  • Zinc 23%

A recent post on The Pediatric Nutritionist blog provides a suggested approach to the monitoring of vitamins and micronutrients based on the need for parenteral nutrition and on the need to consider inflammatory markers in the interpretation of these lab values: The Importance of Nutrition Lab Monitoring Protocols Featuring …

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What helps kids poop?

While there are a number of answers to the above title, the answer that I’m looking for is physical activity (JPGN 2013; 57: 768-74).

With regard to the referenced study, a large prospective birth-cohort study (n=347 participants) in Rotterdam showed that preschool children with increased physical activity had about 1/3rd less frequency of functional constipation in the fourth year of life.  Activity measurements at the age of 2 years were accomplished by wearing ActiGraph accelerometers during 1 weekday and 1 weekend day.  Additionally, children who had physical activity of 60 min/day at age 4 had about 1/2 the likelihood of having functional constipation.  There are several limitations to the study; reduced activity and constipation could both be present in some individuals as a consequence of personality or psychologic attributes rather than physical activity having a causal relationship in causing constipation.

Bottomline: Another good reason to encourage physical activity –it might help with regular bowel habits.

Also, on a separate note, a recent blog post by Kipp Ellsworth is a useful reference for lab monitoring (micronutrients and vitamins) in children with short bowel syndrome:

Blog | The Pediatric Nutritionist | Covering the world of infant, child …

Related blog entries:

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Rehabilitation for Short Bowel Syndrome

As noted in several blog posts, there have been some important advances in the care of short bowel syndrome (SBS)/intestinal failure (IF) patients which have resulted in improved outcomes.  A recent review of 28 children with ≤20 cm of small bowel has been published (J Pediatr 2013; 163: 1361-6, editorial 1243) and provides tangible evidence of these changes.

This retrospective study reviewed the charts of these children managed at Omaha’s intestinal rehabilitation program.  7 patients had NEC, 6 intestinal atresia, 6 had gastroschisis, 3 omphalocele, 5 had malrotation, and 1 patient had vascular disease.

Key results:

  • 27 survived (96%)
  • 14 (50%) had at least one lengthening procedure; in this cohort, bowel lengthening was not associated with a greater rate of adaptation than native bowel.
  • 13/27 (48%) achieved parenteral nutrition independence (“nutritional autonomy”) with their native bowel.
  • Predictors of “successfully rehabilitated” patients: intact colon and ileocecal valve
  • All patients had improvements in lowering PN requirements, total bilirubin, and growth z-scores.
  • Serum transaminase levels did not improve in the nonrehabilitated patients

The main medical treatments at IRP include use of agents for control of bacterial overgrowth, reducing gastric acid production, lipid minimization, promotility and antimotility agents (eg. loperamide), and ethanol locks.  The editorial comments on the “poor results” for surgical intervention, “particularly among those with ultra-short bowel.” This may be due to ‘marginal motility, ischemia, severe wall thickening, or due to adhesions.’

With regard to ethanol locks, the editorial supports them but states, “the main factor in prevention [of line infections] has been maintaining a consistent and strict protocol for catheter care.”

Previous related blog entries:

Drug Shortages and Selenium Deficiency

If you participate in the care of patients who are dependent on parenteral nutrition, then you are familiar with frequent component drug shortages.  Generally, attempts to manage these shortages involve rationing and targeting those with the greatest need.  In one institution, this was not effective in preventing biochemical deficiency of selenium (JPEN 2013; DOI 10.1177/0148607113486005).  Thanks to Kipp Ellsworth for this reference.

The authors describe five pediatric patients who were completely dependent on parenteral nutrition due to intestinal failure.  During a 9-month shortage of intravenous selenium, all five who were previously selenium replete had deficiency identified (level <20 ng/mL).

After these deficiencies were identified, the patients were placed on Multitrace-5 (MTE-5).  This multivitamin contains 20 mcg/mL of selenium.  While patients prior to the shortage typically received 50-75 mcg/day, after instituting MTE-5, they received 10-26 mcg/day.  Nevertheless, this helped prevent any clinical evidence of deficiency.  In patients with selenium deficiency, there is an increased risk of cardiomyopathy, chronic illness, and death.

The authors note that their preference is to individually dose the specific trace elements and that MTE-5 can contribute to elevated levels of manganese and chromium with long-term usage.

Related blog links:

Related references:

  • -Gastroenterol 2009; 137: S61-S69.
  • -J Pediatr 2011; 159: 39.

Fish Oil, IFALD, and Liver Fibrosis

While there has been a lot of enthusiasm for the use of fish oil as a potential breakthrough for intestinal failure-associated liver disease, this has been based largely on the use of surrogate markers of liver disease and based on comparisons with the historical use of conventional intravenous lipids.  The latter problem has been discussed before on this blog (see links below).

A recent study begins to address the issue of surrogate markers by reinforcing the viewpoint that improvements in bilirubin and aminotransferases may not translate into improvement in liver fibrosis or other clinically-meaningful outcomes (JPGN 2013; 56: 364-69).  A previous pediatric study (J Pediatr 2010; 156: 327-31) showed failure of regression of hepatic fibrosis in 2 children receiving FOE therapy.

In this study, the authors sequentially examined 6 children on fish-oil lipid emulsions (FOE) who underwent multiple liver biopsies.  In this cohort, 5 of 6 children had gastroschisis and the mean gestational age was 35 weeks.  Median intestinal (small bowel) length beyond the ligament of Treitz was 26 cm and most children retained about 2/3rds of their colon.  Liver biopsies were obtained at the time of other open abdominal operations (eg. serial transverse enteroplasty, stoma takedown).

Key results:

  • Liver fibrosis persisted in 2 cases, progressed in 3 cases, and regressed in 1 case.
  • Histology and biochemistries indicated improvement in cholestasis and inflammation.
  • One patient has weaned off parenteral nutrition, two patients underwent isolated small bowel transplantation due to recurrent line infections, and three patients receive 25-40% of their calories parenterally.

The biggest limitation of this study besides the small number of enrolled patients was the relatively short  time period that was studied.  Only one patient who was studied had data reported for FOE more than 36 weeks.  The oldest age of any patient at the time of their last biopsy was 131 weeks old.

Take-home points:

  • “There is no direct evidence to support any one [proposed theoretical benefit of FOE] as clinically meaningful as yet.”
  • “Lipid minimization strategies are also effective in reducing cholestasis.”
  • “Many of the biopsies taken right at the time of FOE initiation” showed significant fibrosis which “speaks to how quickly fibrosis can develop.” One child had stage 2 fibrosis at 14 weeks of life.
  • “The biochemical resolution of cholestasis is at best a weak surrogate marker ..for…enteral independence and overall survival.”  “These findings make a strong case for early referral of children with short bowel syndrome to specialized intestinal rehabilitation centers.”

Related blog posts:

Copper in Cholestasis

More data indicate that copper levels in infants receiving parenteral nutrition are usually not affected by cholestasis (JPEN 2013; 37: 92-96).

A retrospective study reviewed all patients younger than 1 year who had copper levels measured between 1999-2009 at Riley Hospital for Children.  Inclusion criteria: parenteral nutrition for at least 50% of caloric needs and cholestasis (direct bilirubin >2 mg/dL).

Key findings:

  • 26 of 28 patients had gastrointestinal disorders.  82% were receiving standard parenteral nutrition (PN) dose of copper (20 mcg/kg/day).
  • Only one elevated copper level was found in a child with congenital heart disease.
  • 46% (n=13) of cholestatic infants had low copper levels.  Three of theses infants had no copper in their PN.
  • There was no correlation between bilirubin level and measured copper values.

Bottomline:

Measure copper values periodically in patients requiring parenteral nutrition.  Most patients, even cholestatic patients, will require standard dosing but some will need less and some more.

Additional References:

  • -JPGN 2010; 50: 650-54.  n=28.  (only 2 had elevated Cu). Typical Cu supplementation in HAL did not lead to significant increase in Cu toxicity or worsening of liver disease in cholestatic infants.  Study prompted by single infant who developed Cu deficiency/anemia.
  • -Clin Gastro & Hepatol 2004; 2: 1074. Two patients with Cu deficiency after bariatric surgery
  • -JPGN 2000; 31: 102-111. (review)