Management of Pediatric Intestinal Failure
Patients and families suffering from intestinal failure are exposed daily to physical, emotional, and fiscal burdens that result in an immeasurable amount of distress [1]. Intestinal failure occurs in these patients because of an inability of their bowel to meet fluid and/or nutritional needs required to sustain normal physiology and growth without parenteral nutritional support. In children, short-bowel syndrome (SBS) is the major cause of intestinal failure and results from both congenital disorders and extensive surgical resection. The common causes of SBS include intestinal atresia, abdominal wall defects (primarily gastroschisis), intestinal volvulus, long-segment Hirschsprung disease, complicated meconium ileus, and necrotizing enterocolitis (30% of cases and the most common cause).
Of all pediatric SBS, 80% occurs during the neonatal period. Data on the incidence and mortality related to SBS are sparse. A recent cohort of very low and extremely low birth weight neonates at 16 tertiary centers in the United States demonstrated incidences of SBS at 0.7% and 1.1%, respectively, although this excluded cases in term infants [2]. Given the increase in the overall number and survival of these at-risk patients, it is logical to assume that the overall number of pediatric SBS will continue to increase as well. Mortality in this population of patients occurs in a bimodal fashion, with the first peak corresponding to infants who undergo massive initial bowel resections and a later peak corresponding to complications of SBS, namely central venous catheter sepsis and intestinal failure–associated liver disease (IFALD). Survival rates for children with SBS have been quoted as 73% to 89%, with lower rates in patients requiring chronic total parenteral nutrition (TPN) [3–6].
Recently, the development of formal multidisciplinary programs has greatly improved the care provided to these patients by reducing both the morbidity and mortality associated with intestinal failure [7]. In general, these programs consist of gastroenterologists, pediatric surgeons, advanced care providers dedicated to intestinal rehabilitation, intestinal failure nutritionists, pharmacists with advanced training in parenteral nutrition (PN), and social workers. As intestinal rehabilitation centers care for children within their institutions as well as accepting numerous referrals both nationally and internationally, administrative support that provides these families and referring physicians easy access to the program is invaluable. This includes access to people who can help provide timely information on how to receive a consult and recommendations from the team, coordinate referrals and transport to the center, and provide continuity of care when they return home. After discharge, ongoing communication with the referring physicians and provision of detailed care plans can avoid many of the complications that contribute to the morbidity associated with intestinal failure.
The care of patients at risk for intestinal failure begins at birth for those with congenital problems and in the operating room for patients undergoing massive intestinal resection. Although the time course of intestinal adaptation predicts that many of these patients will eventually be able to obtain enteral autonomy, waiting for the few patients to declare themselves as having chronic intestinal failure misses an opportunity for prevention. Early treatment paradigms designed to minimize morbidity and establish early controlled feedings will likely benefit all patients at risk by reducing the overall need for parental nutritional support. Decisions made at this time should take into account several key points:
Assessment of the child with intestinal failure
A careful clinical assessment of the child with SBS is invaluable in gauging his or her overall status. Anthropometric data should be obtained frequently and compared with growth curves after adjustment for gestational age. Precise estimates of intake and output are important, as is monitoring of electrolytes, micronutrients, minerals, and trace elements (zinc, calcium, magnesium, copper, manganese, iron, chromium, selenium, and lead), especially in TPN-dependent children. If a surgical resection was performed at a referring institution, the location and type of stomas present is important both for planning reanastomosis and possibly introducing distal mucous fistula feeds. An estimate of the actual length of bowel remaining is helpful and should be recorded as a percentage of expected bowel length. The location and status of any existing central venous access sites should be assessed and a history of any catheter-related infections (CRIs) documented with culture and sensitivity data if available. Studies to evaluate the patency of central veins should be obtained in all patients, as vascular complications from long-term central venous access can limit the ability to provide PN and may be an indication for transplant evaluation.
Aggressive surgical strategies to reestablish intestinal continuity are beneficial in the management of children with intestinal failure. In patients with high stoma output, as commonly seen with proximal jejunostomies, correction of fluid and electrolytes in balance with enteral feeding is not achievable without the benefit of having the distal intestine in continuity. The presence of any defunctionalized loops of bowel should be noted and if possible they should be salvaged at the time of surgery. Before any attempt at reanastomosis, contrast studies should be performed to assess the anatomy of the remnant bowel and to help formulate a surgical plan.
Feeding strategies
The ultimate goal in treating children with SBS is a gastrointestinal tract that can meet the nutritional requirements sufficient to continue growth and normal physiology. This often requires continuous feeds to maximize the percentage of enteral feeds over a 24-hour period. Secure enteral access is required to meet this goal. As many of these patients have difficulty with gastric emptying, evaluating the ability of the patient to tolerate nasogastric (NG) feeds can provide very useful clinical information before placement of a gastric feeding tube (GT). In general, patients who tolerate NG feeds will also tolerate GT feeds. In cases of poor gastric emptying and high residuals, placement of a nasojejunal feeding tube (NJ) provides important additional clinical data regarding the ability of the bowel to tolerate enteral nutrition. If tolerated, placement of gastrojejunal feeding tubes (GJ) will allow distal feeding while simultaneously decompressing the stomach. This also provides a way to start oral feeds in patients with poor gastric motility, as the stomach remains vented. We typically avoid performing antireflux procedures in these patients unless their reflux is a limiting factor in the ability to feed via GJ tube.
In general, all at-risk patients for intestinal failure should be treated using protocols designed to minimize complications and enhance adaptation. Most of these patients will require initial support by PN. At our institution, we have established a lipid reduction protocol that limits the amount of fat to less than 1 g/kg/d in all at-risk patients and we have noted a dramatic decrease in the incidence of elevated direct bilirubin and liver enzymes. In select cases with ongoing elevation of liver enzymes and direct bilirubin, intravenous omega-3 fatty acids (Omegaven; Fresenius Kabi AG, Bad Homburg, Germany) appear to be beneficial [13]. Ongoing prospective studies are evaluating these 2 treatment options and should provide useful data in the near future to help establish data-driven practical guidelines regarding the use of these strategies.
Early initial feeds should be provided continuously using breast milk (mother’s or donor’s) for all infants when available. There are several studies that support the use of breast milk in this patient population for reducing complications associated with SBS [12]. This benefit is likely because of its high levels of immunoglobulin A, nucleotides, long-chain fats, growth factors, and free amino acids, including glutamine present in breast milk. In cases where protein allergies occur, when breast milk is not available, or in older patients, we initially provide an elemental amino acid–based formula.
Advancement of feeds is based on the lack of emesis and abdominal distention, the consistency and amount of stool output, and the presence of skin break down. When the patient experiences feeding intolerance, the feeds should be reduced rather than stopping and restarting all feeds, unless there is evidence of systemic illness or sepsis. In our opinion, the recurrent practice of starting and stopping feeds limits enteral stimulation of adaptation and makes it difficult to identify the amount of enteral feeds that these patients will tolerate. Fluid losses from stoma output and decompressing gastrostomy tubes in the case of jejunal feeds should be carefully measured and replaced mL:mL with an appropriate electrolyte solution. In cases where the stoma output approaches or exceeds 40 mL/kg/d, we consider adding 3% pectin to the formula and frequently use antidiarrheal and antisecretory medication. We do not decrease the rate of feeds in these patients unless there are issues with persistent fluid and electrolyte issues, usually identified by a decreased CO2 below 20 on serum chemistries. We do not check for the presence of reducing substances, as this does not provide useful clinical data in our opinion. One important reason to hold or limit feeds is the presence of skin or perineal breakdown. Local wound care in this population can be very difficult and benefits tremendously from established wound care programs.
Oral feedings in neonates with SBS are typically not begun until the patient is tolerating full continuous feedings. During this time, aggressive occupational and physical therapy are provided to help establish oral motor skills. Holding feeds for 1 hour and offering that omitted volume orally begins the transition from continuous feedings. Initially this is done daily or twice a day and then gradually increased. Parenteral nutrition should be decreased as enteral feeding volumes are increased. In general, we decrease by 1 mL/h for each 1-mL/h increase in enteral feeds. In cases of extremely low birth weight and very low birth weight infants, the inability to provide PN below rates of 2 mL/h and the overall limitation of total amount of fluid volume the patient may receive can make achieving the total amount of calories by enteral nutrition a challenge. In situations where early reestablishment of intestinal continuity is possible, we will opt for improved growth with PN rather than pushing or concentrating feeds until after surgery. It is important to recognize that the short-term goal is not to wean off PN, but rather to establish enteral nutrition with fluid and electrolyte balance that results in normal growth. Many of the complications of PN are greatly minimized when enteral feeding provides greater than 50% of the total needs. Morbidity associated with early weaning of PN such as poor weight gain and intestinal damage or bacteremia owing to high formula concentration or volume is outweighed by the risks of low-volume PN.
Predictors of outcome in intestinal failure
Several retrospective studies have tried to identify certain characteristics that may be useful in predicting outcomes in children with SBS and/or intestinal failure. Given the wide array of diagnoses that can lead to intestinal failure, it is difficult to isolate predictors of outcome, but there are some general trends (Table 1). The length of remaining bowel and its location are the most logical factors to use in predicting a patient’s course with intestinal failure. Neonates have an amazing capacity for adaptation, and this potential is increased in preterm infants [9]. Previous work has shown that patients with less than 10% of their predicted small-bowel length were less likely to wean from PN and they have a higher relative risk of death [5]. This fact makes accurate assessment of small-bowel length at the time of surgery critical for helping to plan a comprehensive treatment regimen and for anticipating complications. The remnant bowel should be measured and documented in the operative notes with each surgical procedure. Using a silk suture along the antimesenteric border of the bowel is a reasonable approach to obtain an accurate length [8].
Table 1 Factors associated with prognosis in intestinal failure
