Definition
Intestinal failure refers to the inability of a patient to sustain oneself via the enteral route.
Often, the loss of intestinal length due to surgical resection is referred to as either short gut syndrome or short bowel syndrome, although these terms exclude forms of intestinal failure in which intestinal length is normal but may not allow for proper absorption of nutrients.
Primary causes for intestinal failure in neonates include
Necrotizing enterocolitis: A multifactorial inflammatory condition of the GI tract that has a large spectrum of severity and the most severe form results in full-thickness bowel necrosis.
Intestinal atresia: Failure of part of the intestinal tract to completely form, causing an obstruction.
Gastroschisis: Full-thickness, typically right-sided, paraum- bilical abdominal wall defect and primarily has the intestines and stomach protruding through the defect in the amniotic fluid.
Omphalocele: Anterior abdominal wall defect at the base of the umbilical cord with herniation of intra-abdominal contents within sac made of the layers of the umbilical cord.
Midgut volvulus: A condition in which the intestines become twisted due to malrotation during fetal development.
Incidence
NEC is the most common cause of intestinal failure in infants and is diagnosed in roughly one to three per 1000 live births and the incidence increases to approximately 10% in infants of very low birthweight (<1500 g).
Pathophysiology
The exact etiology of NEC is not known.
Multiple processes can lead to an ischemic insult to the gastrointestinal mucosa.
Prematurity and low birthweight appear to be risk factors perhaps due to immaturity of the immune system and underdevelopment of the GI mucosal barrier.
Risk factors
In neonates, surgical resection necessitated by either congenital or acquired diseases represent the most common causes of intestinal failure, with necrotizing enterocolitis, gastroschisis, atresias, and midgut volvulus representing the most common causes of intestinal failure.
However, functional disorders of motility, such as long-segment Hirschsprung disease, and enterocyte disorders, such as intestinal epithelial dysplasia, may also be encountered in this age group.
Whatever the cause, the ultimate goal of treatment is to allow for normal growth while allowing for intestinal rehabilitation in the hopes that the patient will eventually be able to sustain himself/herself via the enteral route.
Clinical presentation
The clinical signs of NEC are nonspecific and overlap with neonatal sepsis.
The earliest signs include lethargy, abdominal distention, and vomiting.
More advanced disease may present with gross blood in the stool, vital sign instability, abdominal wall erythema, peritonitis.
Diagnosis
The diagnosis or NEC is often suspected when the triad of neutropenia, thrombocytopenia, and acidosis is identified.
In addition, plasma C-reactive protein and stool reducing substances may aid in the diagnosis; however, there are no specific lab studies that confirm the diagnosis of NEC.
Radiographic imaging with two-view abdominal radiographs will virtually always reveal generalized intestinal dilation consistent with ileus. Pneumatosis intestinalis is considered pathopneumonic, but may be only transiently evident even in severe forms. Advanced cases may demonstrate free air associated with perforation or the presence of portal venous gas.
Ultrasonography has been used to assist with identification of ascites, may help to assess segments of bowel for thinning or decreased perfusion, may demonstrate portal venous gas.
The Bell classification divides the disease into three stages: stage 1 = suspected disease, stage 2 = confirmed disease without need for surgical intervention, and stage 3 = severe gangrenous bowel requiring operation. Unfortunately, the ability to predict which infants will progress from stage 1 to stage 3 disease remains a problem with current diagnostic modalities.
The extent of bowel involvement may be focal, multisegmental, or panintestinal.
Management
Medical management
Nonoperative management for stage 1 and 2 disease includes cessation of enteral feedings, nasogastric decompression, and intravenous antibiotic therapy.
At this time, there are no predictive factors for progression and therefore serial physical examinations, repeated laboratory, and imaging studies are required.
Nutrition is provided parenterally.
Surgical management
In cases of bowel gangrene, surgical excision of necrotic bowel with preservation of viable bowel length is the goal.
Although there are reports of primary resection and bowel anastomosis, generally the distal bowel is brought out as an ostomy or simply transected with a surgical stapler to close the lumen and dropped back into the peritoneal cavity to be reassessed at a second look operation.
Some have advocated for primary peritoneal drainage as an alternative to surgical management. This therapy remains controversial, but likely has the highest rate of utility in patients that are too unstable to undergo surgical laparotomy.
Early developmental/therapeutic interventions
Prognosis
Mortality in infants with severe NEC with gangrene of bowel segments is reported at 35% in the first 90 days.
Recurrence of NEC occurs in approximately 5% of infants at a median of 37 days following the primary episode. Generally, recurrent episodes are stage 1 disease and managed nonoperatively.
Short bowel syndrome occurs in 23% of infants with NEC and is the most serious complication of NEC. Generally, when the length of bowel of small bowel remnant is less than 30 cm, the remnant intestine is unable to adequately absorb nutrients and requires TPN supplementation.
With comprehensive treatment programs, 2-year survival for these patients is over 70%, with some centers reporting 100% survival at 2 years.
Definition
Intestinal failure or short bowel syndrome is defined as the inability to absorb all needed nutrients from the remnant bowel length. This is likely to be permanent after 60 days of TPN dependence.
Incidence
Approximately 23% of infants suffering NEC develop short bowel syndrome and require chronic long-term TPN therapy.
Pathophysiology
Resection of bowel length removes intestinal mucosal absorptive surface area.
Risk factors
The most important risk factor contributing to permanent TPN dependence in patients with short bowel syndrome is remnant bowel length.
Permanent TPN dependence is usually needed in infants with <30 cm of remnant small bowel with the ileocecal valve and entire colon or <50 cm of small intestine with some portion of the colon.
Clinical presentation
The infant with short bowel syndrome will develop diarrhea and diaper rash due to high volume and acidic stool output when enteral feeding is introduced after an episode of NEC.
The high volume of stool losses may often be mistaken for urine in the diaper due to excessive water content. This may lead to inadequate volume replacement and dehydration, renal insufficiency, and/or electrolyte disturbance.
Management
These patients require a multidisciplinary approach that includes input from neonatologists, primary pediatricians, gastroenterologists, pediatric surgeons, speech therapists, dieticians, and enterostomal therapists.
Unfortunately, most of the medical issues associated with intestinal failure will not have been resolved by the time of discharge from the NICU and often require long-term medical management for months or years. Thus, the need for coordination between inpatient medical personnel, outpatient providers, and families is imperative.
Specific management strategies are discussed below, as they are ongoing postdischarge from the NICU.
Developmental interventions
Physical therapy
Central hypotonia is common due to length of time in supine, nonswaddled positioning, as well as surgical history.
Physical therapy services should be initiated as soon as the infant is stable.
Speech/occupational/feeding therapy
Nonnutritive sucking and oral stimulation should be started early, as infants with SBS often require supplemental or continuous tube feedings through discharge.
Oral aversions are common in these infants.
Discharge issues
Families of these patients will be expected to care for central venous catheters, administer TPN on a daily basis, manage either gastrostomy or gastrojejunostomy tubes, run tube feeds via these tubes, care for stomas, and give multiple other medications to their baby. As such, early, comprehensive discharge planning is imperative for a successful transition to the home environment.
Teaching
Nursing staff should begin teaching caregivers well in advance of the expected discharge date.
Checklists of skills that need to be mastered can be helpful in planning education.
Parents should meet with therapists and dietician prior to discharge.
Most neonates with intestinal failure will not have reached the goal of tolerated full feeds via the oral route by the time they are discharged home from the NICU, so oral feeding skills and plans for advancing should be taught.
Other in-home therapies such as physical therapy and speech therapy may also be arranged for these babies to continue to progress developmentally. Parents should learn exercises to work on postdischarge prior to going home.
Prior to discharge, a rooming-in period for caregivers will also allow for families to practice these skills while an RN is close by to offer assistance and clarification.
Monitoring, equipment training, home nursing
Parents should understand the importance of monitoring feeding tolerance and hydration status.
Patient resource managers or discharge planners also play an integral role in ensuring that all needed supplies are available in the home environment and home health nursing is arranged.
Once discharged from the hospital, home health nurses provide invaluable help in continuing to educate the family about a baby’s care.
Equipment such as IV or feeding pumps are often different than the machines used in the hospitals, so parents may need retraining on new machines.
Safety
Car seat safety test.
Parents must understand proper infection control measures when caring for a central line. They must also understand symptoms of an infection and the importance of immediately seeking medical care when present.
A safety plan should be in place for fevers, dehydration, etc.
Discharge care conference
Multidisciplinary care meetings that include the family can help define the specific needs of the patient and family, as well as allow practitioners to assess the family’s readiness for taking on the complex care of the infant.
