GASTROINTESTINAL SYSTEM
E. Complications and Outcomes 1. Rejection
when the PT is less than 17 seconds. Aspirin decreases platelet aggregation. Dipyridamole (Persantine) is a platelet adhesion inhibitor.
Dextran decreases blood viscosity and platelet adhesiveness. Heparin may be used as a prophy- lactic anticoagulant.
e. Other commonly used medications include immunosuppressive therapy (see
“Pharmacology” section earlier in this chapter) and drugs for infection prophylaxis. Broad- spectrum IV antibiotics are given periopera- tively. Co-trimoxazole (Bactrim) is prescribed indefinitely for Pneumocystis carinii, nocar- dia, and toxoplasmosis prophylaxis. Nystatin (Mycostatin) is an antifungal agent used for thrush prophylaxis.
E. Complications and Outcomes
INTESTINAL FAILURE/SHORT GUT/INTESTINE TRANSPLANTATION ■ 577
b. Acquired conditions include NEC (see
“Necrotizing Enterocolitis” section) and trau- matic injuries.
3. Other indications include intestinal dysmotility (e.g., intestinal pseudoobstruction, aganglionosis) and enterocyte absorptive impairment (microvillus inclusion disease and tufting enteropathy), or dis- ease-associated loss of absorption.
B. Pathophysiology
1. Each infant- or child-rendered short gut is unique as successful intestinal adaptation is dependent on the type and length of bowel segment present.
a. At birth, the normal estimated bowel length is 250 ± 40 cm (Goulet, Ruemmele, Lacaille, &
Colomb, 2004).
b. Infants can experience acceptable intesti- nal adaptation with less than 15 cm of intestine if the ileocecal valve is intact, and with 30 to 45 cm of intestine if the ileocecal valve is absent or does not function (Fishbein & Matsumoto, 2006).
c. Intestinal adaptation occurs by increasing existing bowel surface area and functional abili- ties over a period of weeks to many months and is dependent on the etiology of the SBS and the functional state of the remaining bowel.
d. Intestinal adaptation is characterized by increasing intestinal mass, lengthening of villi, and improved absorption at the epithelial level.
e. Successful adaptation is described as the ability to achieve normal growth, fluid balance, and electrolyte levels without PN.
2. There are a multitude of mechanisms that con- tribute to malabsorption, including acid hypersecre- tion, rapid intestinal transit, and loss of surface area and impaired residual bowel with bacterial over- growth and bile acid wasting.
C. Clinical Presentation
1. History. Most children younger than the age of 1 year are rendered short gut from a congenital anomaly or NEC. History is variable as there are both congenital and acquired etiologies with vari- ous disease trajectories.
2. Physical Examination. Specific exam consider- ation includes careful monitoring of growth param- eters, signs and symptoms of liver dysfunction
(see “Liver Failure” section specifically findings with cholestasis), integrity of central venous access, and skin integrity of diapered patients as excess secretion of bile acids may result in a severe diaper rash.
3. Diagnostic Tests
a. An upper GI series with small bowel follow through may be done to determine bowel length and evaluate bowel caliber, if bowel lengthening procedure is being considered.
b. A breath hydrogen test can be performed to evaluate for bacterial overgrowth.
c. Although endoscopy is not indicated for this reason, if done, a culture of duodenal fluid can be obtained to evaluate for bacterial overgrowth.
4. Clinical Course
a. Trajectory is variable depending on etiol- ogy, remaining bowel, and retained function.
D. Patient Care Management
1. Preventive Care. Optimize the medical and sur- gical management of neonates with congenital disorders to promote intestinal adaptation and bowel salvage with the goal of optimizing the enteral diet, PN prescription, treatment of bacterial overgrowth, administration of antacids and antise- cretory agents, and use of antidiarrheal (stool bulk- ing) agents.
2. Direct Care
a. Monitor stool and urine output.
i. Stool output should be replaced for out- put greater than 40 mL/kg/d. Most common replacement fluid is RL 0.5 mL:mL or mL:mL.
b. Use enteral and PN nutrition.
i. Fluid requirements are upwards of 100 to 200 mL/kg/d.
ii. Caloric requirements are 100 to 150 kcal/kg/d.
iii. EN promotes adaptation and BM is pre- ferred with an associated shorter duration of PN dependence. If maternal or banked BM is not available, elemental hydrolyzed formu- las are preferred. Duocal or microlipids may be used as caloric supplements.
iv. PN prescriptions should minimize intr- alipids (0.5 gm/kg/d adequate to prevent
essential fatty acid deficiency) levocarnitine should be added, trace elements manipulated (limit copper and selenium; remove manga- nese and chromium), glucose infusion rate should be optimized and wean or cycle PN as feasible. Alternative lipid formulations are being used that minimize the inflammatory effect on the liver, minimizing and reversing cholestatic changes. Unfortunately, avail- able products are expensive and not FDA approved (Omegaven and Smoflipid 20%
[soya oil, medium-chain triglyceride, olive oil, and fish oil]).
c. Use oral and enteral rehydration solutions as needed and may augment IV fluids as stool replacement, which may be added to enteral feedings.
d. Treat bacterial overgrowth with the cycling of antibiotics to prevent resistance. Metronidazole (Flagyl), sulfamethoxazole (Bactrim), and rifax- imin (Xifaxin) are commonly used.
e. Antacid therapy is prescribed to minimize acid hypersecretion.
f. Administer antisecretory and antidiar- rheal/bulking medications as prescribed (e.g., Imodium [loperamide] or Catapres [clonidine];
see “Pharmacology” section). Clonidine is most commonly used for children to slow ostomy effluence. Products to slow gastric motility (pec- tin and Benefiber) may be prescribed.
g. Bowel-lengthening surgical procedures.
i. Bowel-lengthening procedures are con- sidered for dilated loops of bowel (>2 cm) or complications from the dilated bowel loops (e.g., bacteremia from bacterial intestinal translocation or intolerance of enteral feed- ing advances).
ii. The Bianchi procedure is the oldest pro- cedure and involves a longitudinal incision to create two tubes to lengthen the bowel that are reconnected to create a longer, narrower single-lumen intestinal segment. The Kimura procedure is an alternative procedure for chil- dren with SGS and inadequate mesentery who are not candidates for the Bianchi proce- dure. The serial transverse enteroplasty pro- cedure augments bowel length and peristalsis by stapling dilated bowel in a zigzag fashion to achieve a greater mucosal absorptive sur- face area and decreased bowel diameter.
h. Intestinal transplantation is considered for children experiencing complications of PN, including liver failure, loss of greater than
two or more venous access devices, recurrent central-line catheter infections, and recurrent severe dehydration. The ideal intestine donor has the same blood type, weighs within 10%
of the recipient’s body weight, and is of simi- lar age as the recipient. All intestine recipients have a stoma to allow for bowel surveillance and access for endoscopy and biopsy. See Figure 7.3 for the common intestinal transplant pro- cedures. Postop care for the intestine recipient is summarized in Table 7.14. Complications of intestine transplant procedures include rejec- tion, infection, and posttransplant lymphopro- liferative disease (PTLD). Signs and symptoms of intestinal graft rejection include a pale or dusky stoma, an increase or decrease in enteric output, abdominal pain, and guaiac- positive output. Postoperative endoscopic biopsies of the transplanted bowel are made through the child’s stoma on a routine and as-needed basis.
Rejection is usually diagnosed with endoscopy and biopsy the gold standard.
3. Supportive Care. Children with intestinal failure should be referred to an intestinal rehabilitation team, which is usually composed of a gastroenter- ologist with specific expertise, advanced practice nurse, nutritionist, surgeon, social worker, and speech therapist.
E. Outcomes
1. PN-induced cholestasis is a possible complication of intestinal failure in patients with resultant con- comitant liver and intestinal failure. Cholestasis or a bilirubin level greater than 2 mg/dL occurs in 40% to 60% of children with intestinal failure (Sondheimer et al., 1998) and contributes to the greatest morbidity and mortality for these children.
a. Measures to reduce the incidence of cholestasis i. PN manipulations with cycling, lipid minimization, and limiting and/or remov- ing trace elements.
ii. EN with the promotion of breastmilk as optimal.
iii. Decrease central line infection rates with antibiotic and ethanol locks. Ethanol locks are incompatible with heparin and should be instilled for 2 to 4 hours.
iv. Cycle enteral antibiotics to treat bowel bacterial overgrowth.
b. Success for these children is defined by liberation from PN and normal growth and development.