Intestinal Failure with Dr. Brad Warner

Intestinal failure is an umbrella term for when the small intestine is unable to absorb or digest enough nutrition to support the patient entirely by oral or enteral feeding.

The intestine of a newborn or fetus doubles in length in the last trimester of gestation.

For a neonate with an ileocecal valve and entire colon, 10 to 15 centimeters of small intestine is a ballpark figure for potential salvageability.

Without the colon and ileocecal valve, at least 15 to 20 centimeters of small intestine would be needed for potential salvageability in neonates.

In adult studies, adults with less than 50 centimeters of intestine have about 40% mortality after 5 to 10 years.

According to Pediatric Intestinal Failure Research Consortium data, approximately 25% of children with short gut syndrome die, 25% need a transplant, and 50% can wean off TPN.

The most common causes of death in intestinal failure include liver failure, septic episodes from central line or bacterial overgrowth, variceal bleeding from liver disease, and loss of IV access.

Intestinal adaptation in humans probably takes place over about a year or two after small bowel resection.

Stool outputs of up to 40 cc per kilo per day are acceptable when advancing enteral feeding; beyond that threshold, enteral feeding should be reduced.

The most common causes of short gut syndrome are necrotizing enterocolitis, gastroschisis, midgut volvulus, and atresias, with trauma and inflammatory bowel disease further down the list.

For TPN, the goal is about 100 to 120 calories per kilo per day for total calories, with about 50% from glucose and the remainder from fat and protein.

TPN should provide about 2 to 3 grams of protein per kilo per day and about 2 to 3 grams of fat per kilo per day.

Babies should gain about 20 to 30 grams a day, which approximates in utero weight gain for a newborn.

Lipid reduction strategy involves reducing fat from 2-3 g/kg/day given daily down to about 1 g/kg/day delivered twice or three times a week, which has been effective in reducing TPN-associated cholestasis.

Omegaven is a fish oil-based fat containing primarily omega-3 fatty acids that are anti-inflammatory, in contrast to soybean-based intralipid which contains pro-inflammatory omega-6 fatty acids.

SMOF lipid contains soybean-based lipid (essential fatty acids), medium chain triglycerides (more easily digested), olive oil, and fish oil, and has recently been FDA approved in the United States.

Breast milk is the best choice for neonates because it contains proper fat composition plus growth factors such as epidermal growth factor and insulin-like growth factors that promote adaptation.

Complex formulas fed enterally may stimulate adaptation better than elemental formulas because they cause secretion of enterotrophic hormones to a greater extent.

There is a threshold percentage of enteral calories that prevents the onset of TPN-related liver damage, though the exact number is unknown; 90% enteral feeding carries far less risk than 10% enteral feeding.

Surgical intervention should be considered when patients regress in enteral tolerance (e.g., tolerating 50% enteral a month ago but now down to 20%), when there are multiple episodes of sepsis with abdominal distention and dilated bowel loops, or when the child develops jaundice.

Dilated bowel loops greater than 4 to 5 centimeters in diameter, combined with failure to advance enteral feeds or regression, is an indication for surgical intervention.

Less than 5 to 10% of patients with over 100 centimeters of intestine should require TPN, suggesting an underlying motility or mucosal problem if they remain TPN-dependent.

The STEP (serial transverse enteroplasty) procedure has emerged as the most commonly performed lengthening operation because it is easier to perform with less risk of injuring the mesenteric blood supply.

The Bianchi procedure takes advantage of the bifurcating blood supply to the bowel wall, allowing longitudinal division to create two tubes of bowel, effectively doubling the length.

STEP procedures can redilate and require redo operations, and outcomes are not as good when a STEP needs to be redone compared to never needing a redo.

A Bianchi can be performed first, then a STEP can be done later if needed, but a Bianchi cannot be done after a STEP has been performed (unless the STEP was inadequate).

Tapering should be considered for children with dilated bowel who have at least 90 to 100 centimeters of intestinal length.

Teduglutide (GLP-2 analog) has been shown in randomized prospective trials in adults to reduce TPN requirements by about 1 to 2 liters per week.

Growth hormone and glutamine combinations have been administered to patients, but results are primarily mixed and it hasn't been a huge advance in weaning TPN.

Current survival for small bowel transplant is about 50 to 60% at 5 years, with one-year survivals now above 70 to 80%.

The intestine is an immunogenic organ filled with white cells and macrophages that mount a huge graft-versus-host response, requiring industrial strength immunosuppression that increases risk for malignancies and infections.

Ethanol locks for central lines have significantly reduced the number of sepsis episodes in patients with short gut syndrome who have Broviac catheters.

Multidisciplinary teams including pharmacists, nutritionists, surgeons, GI doctors, ID specialists, and interventional radiologists improve survival in intestinal failure patients, as demonstrated in series from Boston, Michigan, and Texas.