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NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209 NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209
Carol Rees Parrish, MS, RDN, Series Editor
Enteral Nutrition in the Adult Short Bowel Patient:
A Potential Path to Central Line Freedom
Carol Rees Parrish Andrew P. Copland
Short bowel syndrome/intestinal failure (SBS/IF) is characterized by patients who have lost
absorptive surface area in the gut either due to structural (e.g. surgical) or functional (e.g. mucosal
disease) changes and demonstrate an inability to maintain both hydration and nutritional well-
being while eating and drinking a normal diet. While the use of enteral nutrition is part of primary
therapy in the pediatric SBS population, it is underutilized in adult patients trying to transition
off parenteral nutrition. Instead, adult SBS patients are sometimes left on chronic parenteral
hydration or nutrition. This article will address how one institution orchestrates an enteral
feeding trial in the adult SBS patient trying to achieve enteral autonomy from parenteral support.
INTRODUCTION
hort bowel syndrome/intestinal failure of vascular access are also significant. Effective
(SBS/IF) is best defined as an inability to and aggressive care of the SBS patient requires
Smaintain adequate nutrition and/or hydration a thoughtful approach to maximizing GI tract
through oral intake due to insufficient gut surface function and eliminating the need for parenteral
area either from surgical resection or a significantly support whenever possible.
defunctionalized bowel surface (e.g. radiation While enteral nutrition (EN) is widely used in
1-4
injury, etc.). Many patients require parenteral pediatric SBS patients in an attempt to transition
nutrition (PN) or hydration due to the severity from PN to enteral autonomy, it appears to be rarely
of malabsorption and/or dehydration present. used in adult SBS patients. Getting the most out
Not only does this pose significant lifestyle and of a shortened bowel means not only providing
financial challenges, but the medical risks of luminal nutrients to maximize absorption and the
catheter infection, thrombosis, and gradual loss adaptation process,5 but also means incorporating
creative strategies such as using the GI tract at a
Carol Rees Parrish MS, RDN Nutrition time when it would normally be in disuse (i.e.,
Support Specialist University of Virginia during sleep). This allows delivery of nutrients
Health System Digestive Health Center at a slower pace for gradual absorption without
Charlottesville, VA Andrew P. Copland, MD overwhelming the vulnerable GI tract. This article
Assistant Professor of Medicine Division of will address how one institution orchestrates an
Gastroenterology and Hepatology University EN trial in the adult SBS patient trying to achieve
of Virginia Health System Charlottesville, VA enteral autonomy from parenteral support.
36 PRACTICAL GASTROENTEROLOGY APRIL 2021
Enteral Nutrition in the Adult Short Bowel Patient
NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209 NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209
Adaptation Phase After Loss of Bowel SBS diet education materials for patients go to:
After a massive loss of bowel, the remaining bowel med.virginia.edu/ginutrition/patient-education.
attempts to boost absorption of nutrients and fluids
through hypertrophy of the villous mucosa. While Enteral Feeding Considerations
maximal adaptation is usually reached within in the Adult Short Bowel Patient
the first 6 months after resection, some bowel Available supportive evidence for using EN in
adaptation will continue for up to two years. During adult SBS patients with varying lengths of small
the adaptation phase, enteral nutrients directly bowel consists of case reports, case series and small
9-20
stimulate: observational studies.
• Enteral blood flow Feeding Route
• Epithelial cells Gastric delivery is favored over jejunal feeding, not
• Production of trophic hormones only to stimulate pancreaticobiliary secretions to
assimilate nutrients, but to encompass the greatest
• Pancreaticobiliary secretions amount of surface area for absorption and to
better regulate flow across the pylorus into the
In so doing, mucosal atrophy is prevented, small bowel. Jejunal feeding should be reserved
mucosal barrier function is preserved, and the for those patients with functional or mechanical
mucosal immune system is downregulated.5-7 gastric outlet obstruction, severe ongoing gastric
Recognizing that nutrients in the GI tract stimulate reflux, or anatomy that prevents gastric feeding.
this process is key to understanding intestinal However, this would only be appropriate in those
adaptation. To maximize intestinal adaptation, patients with adequate jejunal/ileal surface area
it is important to provide early introduction of below the jejunal feeding tube ports to absorb
whole, enterally delivered nutrients (either as infused nutrients.
food or polymeric formula). Whole nutrients help
maximize the functional workload of the intestinal Continuous vs. Bolus Enteral Infusion
epithelium which drives intestinal adaptation (think Pump feeding is preferred to bolus feeding to
use it or lose it). Utilizing the gut overnight may present nutrients slowly over time to maximize
have the added benefit of avoiding overstimulation nutrient contact and saturation of mucosal receptors
of the bowel by presenting nutrients slowly via a resulting in overall improved absorption per unit
1
pump maximizing uptake at the brush border. length of small bowel. Delivery of EN via a pump
It is absolutely critical in caring for the newly is vastly slower than the slowest/smallest amount
minted SBS patient to allow time for adaptation of food or fluid taken orally; consider: 60mL/
before committing a patient to “long-term or hour = 1mL/minute (a teaspoon [5mL] infused
PERMANENT TPN.” Patients may see significant over 5 minutes). Several studies have shown
improvements in bowel function as the adaptation improved outcomes (nutrient absorption, weight
window closes which could facilitate weaning of gain, less diarrhea, less divalent cation loss), with
previously necessary parenteral support. As with continuous infusion in both pediatric and adult SBS
any post-op GI patient, oral/enteral nutrients populations.4,13-16,18,21,22 In the patient consuming
should be started as soon as feasible, to initiate a short bowel diet over the course of the day,
the intestinal adaption process, even if oral intake is nocturnal pump feedings over 8-12 hours at night
not sufficient, or needs to be kept to a minimum to have the advantage of using the GI tract when there
prevent high output. Oral intake enlists the cephalic is no competition for the mucosal receptors, leaving
phase of digestion activating salivary glands and nutrients their very own contact time. For those
stimulation of epidermal growth factor secretion who want to infuse during the day and tolerate
and other trophic agents in saliva that also may the increased daytime enteral workload, an enteral
2,8
play a role in adaptation. Finally, oral intake backpack can be used to carry the infusion pump
is a very important component in the quality of so patients can continue their normal activities as
life of our patients. For our institution’s written desired (“infuse and cruise” as it were).
PRACTICAL GASTROENTEROLOGY APRIL 2021 37
Enteral Nutrition in the Adult Short Bowel Patient
NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209
Enteral Product Selection metabolism generates useful free fatty acids.
In the early studies of enteral feeding in pediatric However, patients with concurrent small intestinal
SBS, elemental or semi-elemental formulas were bacterial overgrowth may find that fiber exacerbates
often used based on the assumption that the injured, gas and distension. This can be worsened in some
shortened intestinal tract needed help to absorb patients by the addition of fructo-oligosaccharides
25,26
nutrients by having them partially or fully broken (FOS) in some of the enteral products.
down. While there is evidence in animal studies As enteral formulas are known to be relatively
that more complex nutrients promote adaptation, low in sodium content, SBS patients with end
human studies have been small, hence clear benefit jejunostomies or ileostomies may need additional
27
of polymeric vs. elemental formulas is not available salt added directly to their EN prior to infusion
13,14,20,23,24
at this time. Elemental-type formulas tend if they do not get enough salt in their diet. Those
to be more osmotic and costly. The whole nutrients with a colon should not need this as even a small
in polymeric formulas also provide the necessary colon segment avidly absorbs sodium from the gut.
5
“workload” to maximally stimulate adaptation. Finally, there may be a few patients who only
See Table 1 for a comparison of various standard need hydration rather than additional nutrition
polymeric vs. elemental-type formulas. support. Oral rehydration infused over time via
Fiber-containing products may be useful in a gastrostomy tube may effectively hydrate and
28
those SBS patients with a colon segment as colon allow freedom from the risks of a central line.
Table 1. Fat Content of Elemental, Semi-Elemental and Low Fat Enteral Formulas
Formula Calories/ g Fat/ % MCT g fat/ g fat/ mOsm/
mL Liter 1000 kcal 2000 kcal Liter
Elemental
Peptamen® 1.0 39 70 39.0 78 270
Peptamen 1.5® 1.5 56 70 37.3 74.6 550
Peptamen AF 1.2® 1.2 54 50 45 90 390
Peptamen Intense 1.0 HP® 1.0 38 50 38 76 345
Perative® 1.3 37.3 40 28.6 57.2 385
Vital 1.0® 1.0 38.1 47 38.1 76.2 411
Vital AF 1.2® 1.2 54 45 29 58 459
Vital 1.5® 1.5 57.1 47 38 76 610
® 50 46.4 419
Vital HP 1.0 23.2 23.2
Vivonex RTF® 1.0 11.6 40 11.6 23.2 630
Vivonex T.E.N. Powder 1.0 3 0 3 6 630
Vivonex Plus Powder 1.0 25 0 25 50 650
Standard Polymeric
® 19 52 340
Promote 1.0 26 26
Replete® 1.0 34 20 34 68 300
Isosource 1.0 HP® 1.2 40 20 32 64 330
Osmolite 1.5® 1.5 49 19 32 64 525
Nutren 1.5, unflavored® 1.5 60 20 40 80 530
38 PRACTICAL GASTROENTEROLOGY APRIL 2021
Enteral Nutrition in the Adult Short Bowel Patient
NUTRITION ISSUES IN GASTROENTEROLOGY, SERIES #209
Blended Whole Food Formulas fat polymeric formula: Replete @ 110mL/hr
In a small study of 10 pediatric patients with x 6 cans. While this dropped his total daily
intestinal failure (80% with colon in continuity), EN calories from 2250kcal to 1500kcal, it also
transition from an elemental to a commercial reduced the total fat content from 84g to 50g/
blended formula (Compleat Pediatric®) resulted day; his weight stabilized at 120 lbs and he
in more formed stools and appropriate weight gain experienced a decrease in his 24-hour stool
24
after one year. output, demonstrating improved absorption
on less total fat.
Lower Fat Formulas Might be Worth a Try Be wary of exchanging medium chain
in Some Patients (especially those with a colon) triglycerides (MCT) for long chain triglycerides
In general, avoid restricting fat intake because of the (LCT). Too much MCT can overwhelm a SBS
caloric density fat provides. However, some patients patient's ability to passively absorb it and still
with SBS have significant fat malabsorption, result in significant fat malabsorption. In our
which may be worsened by a coexisting bile salt experience, the use of MCTs should be reserved
insufficiency, or the increasingly more common for SBS patients with colon in continuity, and then
pancreatic exocrine asynchrony from altered upper only if clear clinical benefit is demonstrated in an
gut anatomy such as a Roux en y gastric bypass. individual patient.
Using a lower total fat formula in these cases may In a patient with SBS, lower osmolality
improve overall absorption, particularly in patients products may be helpful, but this benefit is often
with colon in continuity. Case in point: minimal given the extensive dilution effect of both
baseline gastric and intestinal secretions with any
32 year-old male with history of SBS due to gastric formula infused. The bottom line is any
necrotizing enterocolitis as an infant (~ 30cm enteral product that clearly drives stool/ostomy
proximal SB anastomosed to ~ 50cm of distal output above what is tenable for an individual
colon); transferred to the adult service when patient is not sustainable.
he was 24 years of age. Therapy at that time Additionally, poorly absorbed osmoles are
included: PN, nocturnal semi-elemental EN via significant contributors to diarrhea in any patient,
gastrostomy tube, and an oral short bowel diet especially patients with SBS. Liquid medications
(followed fairly well). His usual body weight containing sugar alcohols (see Table 2) and enteral
fluctuated for years between 95-105 lbs (height products containing FOS have been shown to
25,26,29
4’ 10”). After numerous central line septic increase stool volume.
episodes, he was transitioned off PN to daily
nocturnal IV fluids/electrolytes alone (he could Who Needs an Enteral Feeding Trial?
not hydrate himself without), nocturnal EN, Once out of the adaptation phase, every SBS
and optimized oral SBS diet and fluids during patient that is PN-dependent as well as every SBS
the day. When teduglutide became available, patient that is struggling with nutrition/hydration
he was started on it in an effort to get him off on oral intake alone, should be considered for novel
IV fluids. His weight increased over time to approaches to maximize current function of their
an all-time high of 124 lbs (goal weight was GI tract.
110 lbs., but patient started working out and Although there are some patients that have a
wanted to weigh 120 lbs.). Urine and stool low probability of success, there is no downside
output averaged 900-1100mL (never a kidney to trying to liberate a patient from PN or IV fluids
stone), and 1500-2000mL, respectively. Given and central line access. Situations that may be
his weight gain, and the fact it was over goal, considered relative “contraindications” are high
®
it was decided to switch him from Peptamen output fistula on maximum medication therapy
1.5 @ 110mL/hr x 6 cans for years to a lower (antidiarrheals, antisecretory, etc.), chronic
dysmotility, chronic obstruction, and severe
practicalgastro.com (> 2000mL/day) diarrhea output.
(continued on page 46)
PRACTICAL GASTROENTEROLOGY APRIL 2021 39
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