Duodenum

The duodenum is a portion of the small intestine that extends from the pylorus to the jejunum and transitions from a retroperitoneal structure to an intraperitoneal structure at the ligament of Treitz. Pancreatic and hepatic enzymes (bile) enter the second portion of the duodenum through the sphincter of Oddi. These enzymes work to neutralize acidic chyme and promote digestion. The duodenum is the primary site for absorption of iron, trace metals, and water-soluble vitamins.

Jejunum

The jejunum lies between the duodenum and ileum and comprises approximately half of the small bowel. Ninety percent of nutrients and 50% of water and electrolyte absorption is completed by the jejunum.

Ileum

The ileum connects the small intestine to the colon. Its functions include absorption of vitamin B₁₂ and bile salts and completion of any remaining nutrient absorption. The ileocecal valve is situated between the ileum and the colon. This valve delays entry of intestinal contents into the colon and prevents reflux of colon contents back into the small intestine.

Carbohydrates

Carbohydrates are consumed as disaccharides, oligosaccharides, and polysaccharides. These are digested, absorbed, and transported through the body primarily as glucose, which is the primary metabolic fuel.

Fats

A variety of lipids (fats) are consumed in the diet; the highest quantity is in the form of triglycerides. Dietary triglycerides are a major source of energy; they have a higher caloric density than the other macronutrients (i.e., carbohydrates and proteins). Adequate dietary lipids are needed to allow for the absorption of fat-soluble vitamins A, D, E, and K.

Protein

Dietary proteins are necessary for maintaining body proteins and increasing protein mass associated with growth. If dietary protein is inadequate, growth is retarded. Renal and liver disease, cancer, and infections are associated with loss of body proteins.

Indications for Parenteral Nutrition

PN is most often is used as a supportive rather than a definitive therapy for infants and children with complex illnesses and structural GI anomalies. Indications for the supportive use of PN in the neonatal period include: congenital GI anomalies requiring extensive resection of the small bowel, intestinal obstruction, and necrotizing enterocolitis. Beyond infancy, indications for PN include: severe malnutrition, acute pancreatitis, fulminant liver failure, inflammatory bowel disease, extensive burns, malabsorption syndromes, refractory anorexia nervosa, and other disorders causing intestinal failure (see the Intestinal Failure section in this chapter).

Parenteral Nutrition Solutions

PN solution consists primarily of glucose (as a source of carbohydrate), amino acids (as a source of protein), and fat emulsions. Dextrose provides 3.4   Kcal/g and constitutes 60% to 70% of the total PN caloric intake. Protein can be administered as Trophamine (recommended for infants younger than 1 year and for children with liver failure), or as Clinisol or Travasol (for children older than 1 year). Protein provides 4   Kcal/g and should constitute 14% to 20% of the total PN caloric intake. Fat emulsions (Intralipid) may be administered as a separate solution to provide a major source of calories (20% solution provides 2   Kcal/mL) and should constitute 30% to 50% of the total PN caloric intake. Providing adequate calories from fat (0.5   g/kg per day) prevents essential fatty acid deficiency states. Electrolytes, vitamins, minerals, and trace elements are added to these solutions to meet the child’s known nutritional requirements.

The PN orders are individually tailored to deliver appropriate amounts of fluid, nutrients, and electrolytes. The critically ill child’s fluid requirements often change and may differ from estimated maintenance fluid requirements. In addition, it may be necessary to alter electrolyte content based on the child’s clinical condition or changes in medications. For example, medications such as furosemide (Lasix) will increase the daily potassium requirements; if the furosemide dose is reduced, the child will require less supplementary potassium.

When PN is initiated, there is gradual titration of additives until goal calories are achieved. The goal calories should be determined by the healthcare provider in consultation with a dietitian or pharmacist.

Nursing Responsibilities

The nurse must closely monitor the child’s clinical appearance and fluid and electrolyte balance to prevent and detect complications of PN as soon as possible. This monitoring requires documentation of the quantity and content of the child’s fluid intake and output and evaluation of the child’s fluid and electrolyte status and daily weight. A sample monitoring schedule for children receiving PN is provided in Table 14-5.

Table 14-5 Sample Monitoring Schedule for Children Receiving Parenteral Nutrition: Must Be Tailored to Child’s Clinical Status

Monitoring	Frequency
General and Anthropometric Measurements
Vital signs	Every 4   hours, or more often as patient condition warrants
Weight	Daily
Strict intake and output	Constant
Caloric intake	Daily
Height	Weekly
Head circumference	Weekly (for children younger than 2 years)
Blood Sampling
Glucose	Initial + Daily until stable (more often in neonates)
Electrolytes	Initial + Daily until stable
BUN, Creatinine	Initial + Weekly
Ca2+/ionized calcium, , Mg2+	Initial + Weekly (, Mg2+should be checked daily if values not within reference range)
Alkaline phosphatase, AST, ALT	Initial + Weekly
Total and direct bilirubin	Initial + Weekly
Total protein, albumin	Initial + Weekly
Prealbumin	Initiation
Triglycerides, cholesterol	Weekly
Zinc, copper, selenium, manganese, iron	Monthly
Glucose point-of-care testing	When PN is abruptly discontinued, cycled, or if signs or symptoms of hypoglycemia or hyperglycemia suspected
CBC count with differential	When febrile
Blood culture	When febrile

ALT, Alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; Ca²⁺, calcium; CBC, complete blood count; Mg²⁺, magnesium; PN, parenteral nutrition; phosphorous.

Whenever the child receives concentrated glucose solutions, the nurse must verify that the fluid volume and content are appropriate for the child’s estimated daily requirements. Before every new bag of PN solution is infused, the nurse should confirm that the prepared solution is accurate and consistent with the order by checking the solution content against the provider’s original order. Reduction in the PN administration rate (e.g., if the intravenous [IV] catheter malfunctions or with the initiation of enteral feedings or feeding advancement) will reduce the child’s fluid, glucose, and electrolyte intake unless enteral feedings provide the difference.

Potential complications of PN include electrolyte abnormalities, infection, cholestasis leading to hepatic dysfunction, and hyperlipidemias (with triglyceride administration). In critically ill children, there is an association between hyperglycemia and organ dysfunction.³³

Because PN solution contains a high concentration of glucose, it provides an excellent medium for bacterial growth. When hanging a new bag of PN solution and tubing, the nurse must use strict aseptic technique to prevent line contamination. Many hospitals require that the entire tubing system (between PN solution and the patient, including infusion pump tubing) be changed every 24   hours to decrease the possibility of significant bacterial growth. The dressing over the catheter insertion site should be changed when it is no longer occlusive (per hospital policy), using sterile technique and an occlusive dressing. The nurse should assess the catheter insertion site for evidence of inflammation (erythema or exudate) and should report any abnormalities to the appropriate provider. Wound exudate should be cultured and sent for gram stain analysis as ordered (or per protocol). Nurses should be careful to follow the healthcare institutional policies and protocols to prevent central venous catheter-associated blood stream infections (see Chapter 22, Box 22-6 for further information).

Monitor the child’s temperature at least every 4   hours (or according to hospital PN policy). Blood cultures are typically ordered if the child’s temperature rises above 38.5°   C or if the child develops signs of infection. The child may be placed on empiric antibiotics until culture results are available. The antibiotics are then adjusted if the culture is positive and the bacterial sensitivities or susceptibilities support a change. Often the catheter is maintained during an attempt to clear an existing infection, because if the child requires long term PN it may be difficult to achieve and maintain venous access. Therefore existing access sites are salvaged if possible.

When PN is initiated, a low glucose concentration and a low rate of infusion are used, and then both are increased gradually so that the child’s insulin production can accommodate the glucose load. Once the PN infusion is established, providers should maintain the infusion at a uniform rate as ordered; it should not be decreased or increased, because hypoglycemia or hyperglycemia can result. Once goal calories are achieved, it may be appropriate to stop the PN for increasing time intervals, allowing intervals without the PN. When neonates or children are receiving high dextrose compositions, dosing may need to be decreased and increased (with a gradual decrease in rate of administration before and gradual increase after the off cycle) to prevent hypoglycemia or hyperglycemia. To discontinue PN, the glucose concentration and the rate should be weaned gradually.

When PN infusions are initiated, serum glucose measurements can be performed several times per day. Point-of-care glucose measurements may be performed every 4 to 8   hours in infants if unit or hospital policy allows such testing. The presence of either glucosuria or ketonuria should be reported to an on-call provider, and the child’s serum glucose level should be checked. Glucosuria usually indicates the presence of high serum glucose levels that exceed the renal threshold of 150 to 200   mg/dL blood.

If the PN catheter infiltrates or becomes occluded, providers should promptly insert a temporary IV catheter to continue glucose administration and avoid the development of hypoglycemia that could result from a sudden cessation of glucose infusion. Monitor the child closely for clinical evidence of hypoglycemia (e.g., lethargy, irritability, tremors, diaphoresis, tachycardia, headache, vomiting, dizziness, blurred vision) until the PN infusion is resumed. Point-of-care glucose measurements can be obtained from infants to rule out hypoglycemia. An additional source of IV glucose administration may be needed if the PN solution contains a dextrose concentration of greater than the maximum 12.5% dextrose solutions that can be infused peripherally.

Because serum magnesium, phosphate, and calcium levels may fall during PN therapy, providers will monitor the concentration of these elements at least weekly. Trace element deficiencies are more likely to develop with long-term PN therapy or when PN therapy is used in premature infants. The signs and symptoms of copper deficiency include anemia, neutropenia, loss of taste (obviously difficult to assess), and rash. Zinc deficiency can produce an erythematous maculopapular rash (called acrodermatitis enteropathica) over the face, trunk, and digits; poor wound healing; hair loss and loss of taste; and a functional ileus.⁶² A chromium deficiency can produce a diabetes-like syndrome.⁶²

Complications of the PN catheter may also develop. Cardiac arrhythmias can occur if the central venous catheter migrates into the heart, particularly into the right ventricle. Venous thrombosis can develop if a clot is allowed to form at the catheter tip. Superior vena caval thrombosis can complicate PN therapy, particularly in infants who require prolonged PN therapy. An air embolus can be caused by careless coupling of the IV line or stopcock.

Because the central venous PN catheter is inserted into a relatively large vein, a loose or cracked tubing connection can rapidly result in significant loss of blood (i.e., hemorrhage). It is important that the nurse check all tubing and catheter connections at least every hour. Because insertion of a central venous catheter creates risk of significant complications, the nurse must ensure that the catheter is secured in place with no possibility of dislodgement. If catheter misplacement or migration is suspected, a chest radiograph may be needed to verify placement (for further information, see Chapter 10).

Fat emulsions are typically piggybacked into the PN line just before the solution enters the vein. This practice evolved during the initial years of parenteral alimentation using fat emulsions and arose from a concern that prolonged contact between the PN amino acids and the lipids would cause emulsification of the fat and result in the production of fat emboli.

Administration of fat emulsion is contraindicated in neonates with jaundice. Lipid binds with albumin and will displace bilirubin, resulting in an increased risk of hyperbilirubinemia.

Children who receive prolonged PN frequently demonstrate abnormalities in liver function studies (i.e., elevation of the liver enzymes and bilirubin values). Many of these abnormalities are transient and resolve shortly after PN nutrition is discontinued; however, if these abnormalities are noted, the child should be weaned from the PN as clinically appropriate.

Cholestatic jaundice is a serious but incompletely understood complication of PN that is associated with periportal fibrosis, bile duct proliferation, and bile stasis. This complication contributes to morbidity and mortality in younger infants and children with short gut syndrome (SGS) following intestinal resection.¹⁰ The first sign of cholestatic jaundice is elevation in concentrations of liver enzymes (alanine aminotransferase [ALT] and aspartate aminotransferase [AST]). In addition, the bilirubin will begin to rise and the child may appear jaundiced; cholestasis is defined as a direct bilirubin greater than 2   mg/dL. Risk of cholestatic jaundice can be reduced by cycling and limiting lipid administration to 1   g/kg per day or using alternate day dosing of the fat emulsion. If cholestasis is present, treatment includes administration of ursodeoxycholic acid.

Etiology

The etiologies of intestinal failure can be categorized as congenital anomalies with bowel loss or resection (e.g., complicated gastroschisis, malrotation with volvulus, multiple intestinal atresias), postsurgical complications (e.g., NEC, trauma), dysmotility disorders (e.g., chronic intestinal pseudoobstruction, total intestinal Hirschsprung disease), inflammatory bowel disease (e.g., Crohn’s disease), and congenital enteropathies (e.g., microvillus inclusion disease, intestinal epithelial dysplasia, secretory diarrhea).

Pathophysiology

Each child with intestinal failure is unique, because there are no absolute criteria for the amount and type of bowel needed to sustain absorption of nutrients for appropriate growth. The normal estimated bowel length at birth is 250 ± 40   cm.²² After the loss of a bowel segment, the intestine undergoes a process termed intestinal adaptation. As a general rule, infants can experience acceptable intestinal function 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.¹⁷ It is unlikely that children with less than 20   cm of remaining bowel will be able to grow and develop with enteral nutrition alone. Intestinal transplantation may offer hope to these patients.

Many children with SGS no longer have a functioning ileocecal valve; this results in more rapid intestinal transit and decreased absorption of nutrients. Small bowel distension results in stasis and bacterial overgrowth. Small bowel bacterial overgrowth can result in bacterial translocation and sepsis that contributes to morbidity and mortality in this patient population. For these reasons, enteral antibiotics, and most recently probiotics (bacteria administered to support healthy intestinal flora), are often prescribed for children with SGS to minimize small bowel bacterial overgrowth.

Intestinal adaptation is characterized by increasing intestinal mass, lengthening of villi, and improved absorption at the epithelial level.^10,22 This process allows for the remaining intestine to compensate for the loss of the bowel by increasing its surface area and functional abilities.¹⁰ Successful adaptation is described as the ability to achieve normal growth, fluid balance, and electrolyte concentration without PN.⁵³ The time frame required for adaptation is unclear and dependent on the etiology of the SBS and the functional state of the remaining bowel, although adaptation can occur over weeks to months.^10,22 Children have been transitioned to enteral feedings exclusively over periods as long as 8 years. There are a number of metabolic derangements that occur after loss of bowel that are summarized in Table 14-6.

Table 14-6 Metabolic Derangements and Consequences in Children with Short Gut Syndrome

From Cohran VC and Kocoshis SA: Short bowel. In Baker S, Baker R, David A, editors: Pediatric nutrition support, Sudburry, MA, 2007, Jones and Bartlett.

Management

The care of patients with intestinal failure includes complementary medical and surgical interventions with the goals of optimizing oral or enteral diet, PN prescription, treatment of bacterial overgrowth, and use of stool bulking agents. Surgical procedures include bowel lengthening procedures and intestinal transplantation.

In order for the bowel to adapt it must be fed; therefore initiation of early enteral feeding is paramount. Enteral feeding can start with a continuous infusion of nutrition administered through a nasogastric, gastrostomy, or transpyloric feeding tube. Appropriate fluid administration is as important as caloric intake. Many of these children will require 150% to 160% of maintenance fluid to remain hydrated. Once a continuous rate of feeding is tolerated, the time interval can be shortened and feedings can be consolidated if larger volumes are tolerated. Once a consolidated hourly feeding schedule is tolerated, the child can be advanced to bolus feeding.

Often 20   Kcal/ounce feedings are initiated and can be advanced to higher caloric density (to as high as 30   Kcal/ounce [1   Kcal/mL]) as tolerated. Usually these children are fed with casein hydrolysate formulas and elementary amino acid-based formulas such as Pregestimil (Mead Johnson, Evansville, IN), EleCare (Abbott Nutrition, Columbus, OH), and Neocate (Nutricia North America, Gaithersburg, MD) in infants and Peptamen Jr (Nestle Nutrition, North America, Minneapolis, MN) and Neocate Jr.(Nutricia North America, Gaithersburg, MD) in older children. These formula types are easier to digest and are less likely to trigger an immune response, so they will enhance bowel adaptation.¹⁰

The eventual goal of medical and surgical therapy is appropriate growth with enteral intake alone, without the need for PN. Promotion of oral food intake should be encouraged; many of these children will have an oral aversion.

When children are unable to achieve appropriate growth with enteral feedings, they may be considered surgical candidates for procedures to restore normal bowel diameter, lengthen the bowel, or both. The goals of surgical intervention include reducing stasis, improving motility, and increasing the effective mucosal surface area.²⁹ The most common short bowel procedures are the Bianchi, Kimura, and the serial transverse enteroplasty procedure.

The Bianchi procedure is the oldest procedure and involves a longitudinal incision to create two tubes to lengthen the bowel (Fig. 14-5). The Kimura procedure (Fig. 14-6) is an alternative procedure for patients with SGS and inadequate mesentery who are not candidates for the Bianchi procedure. The serial transverse enteroplasty (STEP) procedure augments bowel length by stapling dilated bowel in a zigzag fashion to achieve more effective bowel surface area (Fig. 14-7).

Fig. 14-5 The Bianchi intestinal lengthening procedure. The bowel is divided in a longitudinal plane to create two tubes, which after reanastomosis results in doubling of the intestinal length at the expense of halving the bowel wall circumference.

(From Warner BW: Short-bowel syndrome. In Grosfeld JL et al, editors: Pediatric surgery, ed 6, Philadelphia, 2006, Mosby.)

Fig. 14-6 The Iowa (Kimura) intestinal lengthening procedure. The antimesenteric bowel wall is pexed to the undersurface of the abdominal wall. A seromyotomy along the bowel wall and mechanical abrasion of the abdominal wall before pexing promote neovascularization of the antimesenteric bowel, based on the systemic-derived abdominal wall. Several months later, the bowel may be longitudinally divided into two limbs. The first is based on the systemic blood supply to the antimesenteric limb, and the other is based on the mesenteric blood supply. These two limbs are then reapproximated to double the intestinal length.

(From Warner BW: Short-bowel syndrome. In Grosfeld JL et al, editors: Pediatric surgery, ed 6, Philadelphia, 2006, Mosby.)

Fig. 14-7 The serial transverse enteroplasty procedure. Multiple fires of an anastomotic stapling device to alternating sides of the bowel wall result in decreased bowel caliber with an increased length of enteral nutrient transit.

(From Warner BW: Short-bowel syndrome. In Grosfeld JL et al, editors: Pediatric surgery, ed 6, Philadelphia, 2006, Mosby.)

With advances in surgical techniques and immunosuppressive therapy, intestine transplantation is successful as an isolated procedure and when combined with transplantation of other organs.⁵⁴ A major reason for the increased success of intestinal transplantation is the availability of more potent immunosuppressants such as tacrolimus (Prograf). The major limiting factor that prevents widespread use of transplantation is the lack of available organs for transplantation. Because children with less than 15   cm of bowel are not likely to tolerate enteral feeding and thrive, they should be referred to an intestinal rehabilitation and transplant program as soon as possible.

The ideal intestine donor has the same blood type, weighs within 10% of the recipient’s body weight, and is close in age to the recipient. All intestine recipients have a stoma to allow for bowel surveillance and access for endoscopy and biopsy. Figure 14-8 shows the technical details of isolated intestine transplant procedure and intestine transplant in combination with other organs.⁵⁴

Fig. 14-8 The three basic intestinal transplant procedures (the graft is shaded): Isolated intestine transplant, Intestine transplant combined with liver transplant, and multivisceral transplant. With the isolated intestine transplant, the venous outflow may be to the recipient portal vein (center), to the inferior vena cava (left), or to the superior mesenteric vein (right).

(From Reyes JD: Intestinal transplantation. Semin Pediatr Surg 15:228-234, 2006.)

The priorities of care for patients with liver-intestine failure (so-called “ABCs” of care) in the pediatric critical care unit include aeration, bowel integrity, and caloric or hydration requirements. As with any critical care patient, the nurse will assess and support the child’s airway, breathing, and circulation. Bowel integrity is initially assessed by evaluating the physical appearance of the stoma (normal stoma appears pink and moist) and enteric output. Initially caloric requirements are met with PN. Enteral feedings are initiated as soon as possible after the transplant.

Critical care goals are to support the patient to be hemodynamically stable, with adequate oxygenation and ventilation, free of requirement for mechanical ventilation support. Airway clearance and spontaneous ventilation may be ineffective as a result of the lengthy abdominal surgical procedure (and resultant need for anesthetic administration during the long procedure), visceral edema, and pain. With the postoperative resolution of coagulopathies, aggressive chest physiotherapy is initiated. Intestine recipients generally require mechanical ventilation longer than isolated liver recipients (see Liver Transplantation in Chapter 17), because intestine recipients typically are in poor health before the transplant and often have a precarious fluid balance. Additional challenges include open abdominal wounds and potential need for surgical reexploration for complications such as perforation or bleeding.

Complications of intestine transplant procedures include rejection, infection, and posttransplant lymphoproliferative 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 not usually a visual finding during endoscopy, and there are no known confirmatory laboratory tests. Endoscopy with biopsy is the gold standard.

Infection is a common complication following intestine transplant. Viral infection is the most threatening infection for the intestine recipient. Primary infections are typically more serious and occur when the recipient has had no previous exposure to a virus and becomes infected in the posttransplant period. A secondary infection represents reactivation of a previous latent virus.

The most common infecting organisms are cytomegalovirus and Epstein-Barr virus. For the isolated intestine recipient efforts are made to match the recipient and donor cytomegalovirus status. The donor-recipient serology relationship is important because prophylactic therapy is initiated based on viral titers.

Post-transplant lymphoproliferative disorder (PTLD) is one of the most underrated complications of immunosuppression. PTLD is the development of continually proliferating B-lymphocytes, presumably under the influence of Epstein-Barr virus. Diagnosis is made by clinical examination and histologic review. Clinical signs and symptoms include fever, lymphadenopathy, GI symptoms, and weight loss. If the biopsy specimen is diagnostic for PTLD, treatment includes holding or reducing immunosuppression and initiating IV antiviral therapy and immunoglobulin therapy (see Chapter 17 for additional information).

PTLD is a difficult complication to treat following intestine transplantation, because rejection can develop following withdrawal of immunosuppression. Therefore careful titration of immunosuppression is imperative to promote recovery, although the graft may be lost to preserve the child’s life.

Etiology and Pathophysiology

GI bleeding in children can result from inflammation of the intestine, congenital or acquired visceral or vascular anomalies, trauma, esophageal varices, ulcers, or coagulopathies. The incidence of acquired GI bleeding in critically ill children receiving mechanical ventilation has been reported to be as high as 51.8% in some series.^14,47 Identified risk factors include a pediatric risk of mortality 2 score of 10 or higher, operating room procedures longer than 3   hours, hepatic insufficiency, coagulopathy, respiratory failure, and high-pressure ventilator settings of greater than or equal to 25   cm H₂O.^14,47

Upper GI bleeding originates proximal to the ligament of Treitz. Causes include gastritis, peptic ulcer disease (from nonsteroidal antiinflammatory use and from Helicobacter pylori infection), esophageal or gastric varices, and vascular malformations.

Lower GI bleeding is the result of mucosal disruption distal to the ligament of Treitz and can be caused by Crohn’s disease, intussusception, or ischemic injury. Common causes of GI bleeding in children are listed in Table 14-7.

Table 14-7 Causes of Gastrointestinal Bleeding in Infants and Children

GI, Gastrointestinal.

Data from Arensman RM, Browne M, Madonna MB: Gastrointestinal bleeding. In Grosfeld JL et al, editors: Pediatric surgery, ed 6, Philadelphia, 2006, Mosby; Martin SA, Simone S: Gastrointestinal system: In Slota MC, editor: Core curriculum for pediatric critical care nursing, ed 2, St Louis, 2006, Mosby-Elsevier.

Microscopic bleeding may cause no symptoms and may be detectable only through analysis of GI secretions or feces. Significant GI bleeding may result in hypovolemia and low cardiac output, shock, and death (see also Shock, in Chapter 6). See the section on Gastrointestinal Bleeding in the Chapter 14 Supplement on the Evolve Website for additional information about the pathophysiology of GI hemorrhage.

Clinical Signs and Symptoms

The appearance of the child with GI bleeding varies considerably, and it is affected by the amount and rapidity of blood loss. Usually the child is brought to the provider’s office or emergency department for treatment after vomiting blood, passing black, tarry stools (melena), or passing bright red blood per rectum (hematochezia). Bright red vomitus indicates recent or ongoing upper GI hemorrhage, whereas coffee-ground vomitus indicates partial digestion of the blood.

The color and the source of the bleeding often help to identify the location of the bleeding. Bright red vomitus usually results from esophageal or gastric bleeding, and bright red blood in the stool results almost exclusively from rectal bleeding. Maroon, black, or tarry stool often indicates the presence of upper GI bleeding; the color derives from blood that is partially digested during passage through the bowel.

The patient with sudden, significant bleeding is more likely to demonstrate faintness, pallor, tachycardia, thready pulses, diaphoresis, thirst, apprehension, and other signs of acute blood loss. The child with gradual bleeding, however, may experience only weakness and faintness; the child may be aware of passing black stools, but may not know that significant blood loss has occurred.

The child with GI bleeding may have a normal systolic blood pressure, particularly in the recumbent position, despite significant intravascular volume loss and shock. Signs of decreased peripheral perfusion are usually the earliest signs of severe hemorrhage and include tachycardia; cool, pale, mottled skin; decreased peripheral pulses; and oliguria (urine output averaging less than 0.5-1.0   mL/kg per hour despite adequate fluid intake) or anuria.

Arterial constriction makes blood pressure measurement by cuff difficult or inaccurate, because automated oscillometric blood pressure cuffs may provide falsely high readings in the presence of shock with or without hypotension. The arterial waveform displayed from an indwelling arterial line usually is dampened in appearance, with a narrow pulse pressure.

Metabolic acidosis and a rise in serum lactate may be noted. Oxyhemoglobin desaturation may not be present or detected by pulse oximetry, because existing hemoglobin may be saturated with oxygen. The oximeter device may have difficulty detecting a signal if the child’s pulses are weak. The nurse should notify an on-call provider immediately of these findings, because the patient’s status is critical (see Chapter 6 for more information about recognition and treatment of shock).

Digested blood has a specific odor that may be noted on the patient’s breath even before the onset of melena or the first expulsion of hematemesis. This odor is qualitatively the same as that of melena, but it is usually fainter. To detect early evidence of GI bleeding, all GI fluids and stools of patients at risk should be tested for the presence of blood (hemoprotein). The presence of occult blood in gastric fluid may be determined with point-of-care (bedside) testing such as the use of Gastroccult (Beckman Coulter, Brea, CA).

During the first days of life, the Apt test (named for Leonard Apt) may be performed to distinguish between swallowed maternal blood and GI bleeding as a cause of blood in the newborn’s stool.⁴ The Apt test is performed by placing blood from the neonate on filter paper with 1% sodium hydroxide (a reagent that reacts with fetal hemoglobin).⁴ Maternal blood will appear rusty brown, whereas the neonate’s blood that contains fetal hemoglobin will remain pink or red.⁴ The pink or red color is a positive result, indicative of presence of blood from the neonate.

Management

The three phases of management of the child with GI bleeding are resuscitation, specific diagnosis, and specific treatment. A diagnostic algorithm for upper GI bleeding is presented in Fig. 14-9.

Fig. 14-9 Diagnostic algorithm for upper gastrointestinal (GI) hemorrhage. PPI, Proton pump inhibitor; PUD, peptic ulcer disease.

(From Arensman RM, Browne M, Madonna MB: Gastrointestinal bleeding. In Grosfeld JL, O’Neill JA, Coran AG, Fonkalsrud EW, editors: Pediatric surgery, ed 6, Philadelphia, 2006, Mosby.)

During resuscitation and replacement of intravascular volume, nursing observations may help to determine the source of the child’s bleeding. If saline lavage through a nasogastric tube reveals grossly bloody or red-tinged aspirate, ongoing upper intestinal bleeding is present. Nursing interventions during resuscitation of the child with GI bleeding are summarized in Box 14-1.

Proton pump inhibitors and histamine-2 receptor antagonists are the most commonly used pharmacologic agents to prevent the development of GI bleeding (Table 14-8). Although only a small number of critically ill children will develop gastric bleeding, the associated morbidity justifies the common practice of prophylaxis.

Upper GI endoscopy is indicated when bleeding is significant. It can be performed in the critical care unit and is the diagnostic procedure of choice. Push endoscopy is one method, and newer diagnostic tools include video capsule endoscopy. For diagnosis of small bowel bleeding, video capsule endoscopy can be a valuable diagnostic tool. A minute endoscope is embedded in a capsule that is swallowed. The capsule is propelled by peristalsis and captures images that are recorded on a hard drive attached to the patient’s belt.

Indications for urgent surgical intervention include the development of intestinal perforation (identified by the presence of free air on an abdominal radiograph) or severe hemorrhage unresponsive to blood replacement therapy. If GI bleeding is stopped effectively with medical management and after resuscitation is complete, further studies will be performed to determine the origin of the bleeding and whether the patient is stable. Surgical intervention may be required at that time.

Etiology

Bilirubin is the major byproduct of hemoglobin breakdown. Hyperbilirubinemia is an elevation in the level of total serum bilirubin (TSB); it results from an imbalance between bilirubin production and excretion. An increase in bilirubin production can result from increased red blood cell (RBC) breakdown (such as hemolysis or decreased RBC life span in the neonate), or impaired bilirubin excretion (such as decreased capacity for elimination in the neonate or cholestatic liver disease). This section addresses hyperbilirubinemia in the neonate; hyperbilirubinemia in the older child is included in the liver failure section.

When the neonate’s TSB is elevated, the bilirubin can cross the blood-brain barrier, causing acute bilirubin encephalopathy or the chronic form of bilirubin encephalopathy, kernicterus. Kernicterus is a yellow staining and brain tissue damage with degenerative lesions, resulting from central nervous system exposure to high concentrations of unconjugated bilirubin. Hyperbilirubinemia is commonly associated with prematurity, breast feeding, and other factors summarized in Box 14-2.

In the first week of life, it is estimated that approximately 60% of normal newborns will become clinically jaundiced.⁴² Newborns are now discharged from the hospital at approximately 24 to 48 hours after birth, before the typical TSB peak at 48 to 96 hours. As a result, hyperbilirubinemia is the most common reason for hospital readmission of the neonate. A sentinel event alert was issued by the Joint Commission in 2001, because an increased number of cases of kernicterus were being diagnosed in otherwise healthy newborns.

Pathophysiology

When RBCs reach the end of their 120-day life span, they normally are sequestered in the spleen. The cells are destroyed, and the heme portion of the hemoglobin molecule is oxidized, and bilirubin is formed. Bilirubin is bound to albumin in the plasma and taken up in the liver, where it is combined with a sugar through the action of the enzyme, bilirubin uridine diphosphate glucuronosyltransferase, making conjugated bilirubin.¹¹ Conjugated bilirubin is water soluble, it cannot cross the blood-brain barrier, and it is normally excreted in bile (Fig. 14-10). Free bilirubin, called unconjugated (indirect) bilirubin, is lipid soluble and not water soluble. Because unconjugated bilirubin is thought to diffuse freely into the brain, high concentrations of this form of bilirubin may be neurotoxic and cause kernicterus.

Fig. 14-10 The pathophysiology of neonatal hyperbilirubinemia.

(From Colletti JE, et al: An emergency medicine approach to neonatal hyperbilirubinemia. Emerg Med Clin N Am 25:1117-1135, 2007.)

Increased TSB concentrations can result from an elevation in conjugated or unconjugated bilirubin. An elevation in the level of conjugated bilirubin is known as direct hyperbilirubinemia. It most commonly results from biliary tree obstruction or liver disease, although it also may occur with metabolic disorders, sepsis, meningitis, or drug reactions.

Elevation of unconjugated bilirubin levels is known as indirect hyperbilirubinemia. It most commonly occurs as a result of excessive bilirubin production in the neonatal period. Premature and critically ill neonates bind bilirubin less effectively than do healthy infants, so indirect hyperbilirubinemia is common among premature neonates. In addition, it can result from impaired transport of bilirubin caused by hypoxia, acidosis or the administration of albumin-binding drugs that displace bilirubin from the albumin. Impaired hepatic uptake of bilirubin also may cause indirect hyperbilirubinemia.

Kernicterus is yellow (bilirubin) staining of the basal ganglia in the brain of neonates with severe jaundice. Although the precise mechanisms responsible for the entry of bilirubin into the brain are not known, disruption of the blood brain barrier from increased permeability (e.g., caused by hyperosmolarity or severe asphyxia), prolonged transit time (e.g., caused by increased central venous pressure [CVP]), or increased blood flow (e.g., caused by hypercarbia and acidosis) are thought to be contributory.⁶³

Jaundice (icterus) can usually be detected when the child’s TSB level exceeds 3.0 to 5.0   mg/dL (normally it is less than 1.5   mg/dL). Jaundice is characterized by the accumulation of yellow pigment in the skin and other tissues. In the skin, the jaundice is apparent with digital blanching. Jaundice is usually evident first in the sclera and then progresses in a cephalocaudal distribution. The urine color may become brown as the result of the urinary excretion of conjugated bilirubin. In addition, the stools may become gray or acholic, indicating the absence of normal fecal elimination of bilirubin. Clinical signs that the jaundice is pathologic include persistently elevated direct bilirubin level, dark urine, and acholic stools. Infants with these signs should be evaluated for liver disease.

The neurotoxic sequelae of hyperbilirubinemia are the most worrisome, and a grading for acute bilirubin encephalopathy has been proposed. The earliest signs may include alteration in the tone of extensor muscles (hypotonia or hypertonia), retrocollis (backward arching of the neck), opisthotonus (backward arching of the trunk), and a poor suck.³ The early symptoms may intensify and be accompanied by a shrill cry and unexplained irritability alternating with lethargy.³ Therapy at this stage may prevent advancement of symptoms. Cessation of feeding, irritability, seizures, and altered mental status are later symptoms of acute bilirubin encephalopathy. The final stage is kernicterus and may be irreversible with the development of cerebral palsy, deafness or hearing loss, and impairment of upward gaze. Kernicterus has a significant mortality (at least 10%) and long-term morbidity (at least 70%), and most cases are reported in infants with TSB greater than 20   mg/dL.²⁸

Noninvasive (transcutaneous) bilirubin measurements can be obtained with newer instruments. Published data suggest that in most infants the measurements are within 2 to 3   mg/dL of serum measurements and can replace TSB measurements in most cases.² In infants undergoing phototherapy, this measurement is not reliable and should not be used.

It is possible to measure serum levels of total bilirubin and direct (or conjugated) bilirubin. Current recommendations caution against inferring the indirect (unconjugated) bilirubin from the TSB, because the difference between the total and direct bilirubin is not constant. Current guidelines recommend that providers evaluate the TSB level⁶³; the higher the TSB, the greater the risk of bilirubin encephalopathy. Treatment is indicated for infants with bilirubin levels in excess of 20   mg/dL.

Management

If direct hyperbilirubinemia is present, the nurse should be alert for the appearance of additional signs of liver disease or decreased hepatic function. Additional diagnostic tests are indicated (these tests are reviewed in greater detail in the section, Liver Failure, later in this chapter).

Indirect hyperbilirubinemia is observed most commonly during the neonatal period, and it often complicates the care of premature infants. Neonatal indirect hyperbilirubinemia is treated with phototherapy, pharmacologic agents, or exchange transfusions to avoid kernicterus.

The current American Academy of Pediatrics (AAP) recommendations for phototherapy are based on age and TSB levels (see Evolve Fig. 14-1 in the Chapter 14 Supplement on the Evolve Website to view a graphic representation of recommended therapies based on infant age and total serum bilirubin concentration). Prophylactic phototherapy is often instituted for neonates weighing less than 1500   g. Although exclusive breast feeding can contribute to high TSB levels, the AAP recommends that breast feeding be continued with 10 to 12 feedings recommended per day, plus administration of supplementary intravenous fluid to treat dehydration.²

Phototherapy converts bilirubin to a water-soluble form that can be excreted without glucuronidation. Phototherapy units contain day lights, fluorescent tubes, fiberoptic light, and halogen bulbs. The effectiveness of phototherapy is determined by the type of light, the infant’s distance to the light, and the amount of exposed body surface area. Light emitted at a wavelength in the blue-green spectrum of 425 to 495   nm is thought to be most effective because of the optical qualities of bilirubin and the skin. The AAP recommends the use of special blue fluorescent lamps or light-emitting diodes.^41,42

The infant is unclothed while receiving phototherapy to expose maximum surface area. Remove the diaper if the TSB levels are approaching exchange transfusion level. Place protective eye shields over the infant’s closed eyes, because the light can injure the retina. Exposure of body surface area may be enhanced in low-birth weight infants by placing a fiberoptic pad under the infant. Unless serum bilirubin levels are critically elevated, phototherapy should be interrupted briefly several times each day. During these interruptions the eye patches should be removed, and the infant (if condition allows) should be wrapped and held to provide comforting tactile and visual stimulation.

The infant’s insensible water loss may be increased during phototherapy, so accurate measurement of fluid intake and output is required and weights should be recorded daily. Discuss evidence of excessive fluid loss or inadequate fluid intake with the responsible provider immediately. Neonates receiving phototherapy often develop diarrhea, which can contribute to fluid loss and nutritional compromise.

The infant receiving phototherapy should be turned frequently, and pressure points should be gently massaged. The phototherapy light must be turned off while blood specimens are obtained. If the blood specimens are exposed to light (especially phototherapy), then the bilirubin may be oxidized, thus altering the measured serum bilirubin levels in the blood samples and rendering them inaccurate.

Long-term sequelae of phototherapy are not known. Known complications include potential disruption of maternal infant bonding and possible eye injuries. Transient skin bronzing can occur in infants with cholestasis, although the cause of this bronzing is not clear.

The duration of phototherapy required is affected by the TSB level, the cause of the hyperbilirubinemia, and the infant’s age. For infants readmitted for phototherapy during the first days of life, the treatment is usually discontinued when TSB levels reach 13 to 14   mg/dL. It is not uncommon for infants to experience a rebound increase in TSB level of 1 to 2   mg/dL when the therapy is discontinued.⁴¹

With the aggressive and early use of phototherapy and pharmacologic intervention, exchange transfusions are not often required. Exchange transfusions are most often used for infants with a hemolytic cause of hyperbilirubinemia. Exchange transfusion should be performed only in a pediatric or neonatal critical care unit with appropriate hemodynamic monitoring and resuscitation capabilities.

Pharmacologic options for treatment of hyperbilirubinemia include the administration of gamma globulin for hemolytic disease, possible use of tin-mesoporphyrin, and reduction of medications that bind albumin, if possible. For infants with isoimmune hemolytic disease, IV gamma globulin should be administered at a dose of 0.5 to 1   g/kg over 2   hours if TSB levels continue to rise despite phototherapy or if the TSB level is within 2 to 3   mg/dL of exchange transfusion levels.

There is some evidence to support administration of a drug that inhibits the production of heme oxygenase (the precursor to bilirubin development) to prevent hyperbilirubinemia. This drug is not yet approved by the U.S. Food and Drug Administration. Drugs that bind with serum albumin (ceftriaxone, sulfonamides, oxacillin, gentamicin, diazepam, furosemide, hydrocortisone, and digoxin) are avoided if possible, because they may displace serum bilirubin from albumin, thereby increasing the concentration of free bilirubin and the risk of bilirubin diffusion across the blood brain barrier.

Etiology

Portal hypertension is an increase in portal venous pressure above 5 to 10   mmHg. It is caused by obstruction to the normal flow of blood through the portal venous system, the liver sinusoids, or the hepatic vein from the mesenteric vascular bed (small and large intestine, stomach, spleen, and pancreas).⁶¹ It may be caused by (1) obstruction of the portal vein or its immediate tributaries (this is a form of extrahepatic or prehepatic portal hypertension), (2) an increase in vascular resistance within the liver that occurs secondary to fibrosis of the liver (this form is called intrahepatic or hepatocellular portal hypertension), or rarely (3) obstruction of hepatic venous outflow into the inferior vena cava (this is a form of suprahepatic or posthepatic portal hypertension).

Children can develop extrahepatic portal hypertension as a result of thrombosis of the portal vein. Most portal vein thrombosis is idiopathic in origin. It may also be congenital in origin, it may result from the use of umbilical venous catheters during the newborn period, or it may result from a hypercoagulable disease state.

Intrahepatic portal hypertension can complicate any form of chronic liver disease, including neonatal or childhood hepatitis, biliary atresia, congenital hepatic fibrosis, or liver disease secondary to infection or metabolic diseases (e.g., alpha1-antitrypsin deficiency). Suprahepatic portal hypertension may be caused by inferior vena cava (IVC) obstruction, hepatic vein occlusion, thrombosis from Budd-Chiari syndrome, or stenosis of the hepatic vein orifice.⁶¹

Pathophysiology

Portal venous blood flows into liver sinusoids. Because these sinusoids offer more resistance to blood flow than normal capillaries, pressure in the portal vein is normally higher than the CVP. If flow through the liver is obstructed, pressure in the portal vein and the splenic and mesenteric circulations may increase rapidly.

Anything that obstructs blood flow within the portal venous system, liver, or inferior vena cava can produce portal hypertension. Thrombosis of the portal vein will cause a significant rise in pressure in the portal vein proximal to the clot. Fibrosis of the liver compresses and distorts liver architecture and blood vessels; this will increase the resistance to blood flow through the liver and elevate portal venous pressure. Any obstruction to the flow of blood through the hepatic vein and into the IVC can increase sinusoidal pressure and distend the liver sinusoids with blood. If this obstruction is severe or chronic, resistance to the flow of blood into those sinusoids will increase and portal hypertension will result.

The three major physiologic complications of portal hypertension are: congestion of the splenic and mesenteric circulations, the development of collateral vessels, and sequestration of blood in the splanchnic circulation (the blood vessels from the gut and spleen that normally drain into the portal vein). When portal vein pressure increases, blood flow from the splanchnic circulation is impeded; this results in the pooling of blood in the splanchnic circulation. Because the splanchnic circulation consists of the mesenteric and splenic veins, splenic congestion and enlargement will result.

Hypersplenism and stasis of blood in the spleen cause damage to or sequestration of the formed elements of the blood, producing anemia, thrombocytopenia, and neutropenia. Engorgement of mesenteric vessels may cause mesenteric vein thrombosis or mesenteric infarction.

Impedance to portal blood flow and hypertension in the portal and splanchnic circulation promote the formation of collateral vessels between the systemic and portal circulations and the IVC, or other major central veins (Fig. 14-11). Major collateral vessels form from the portal vein, along the stomach and esophagus to the intercostal veins, in the paraumbilical veins (causing enlarged abdominal wall vessels), and around the rectum and anus (in the hemorrhoidal veins). Submucosal veins of the esophagus often enlarge and form collateral vessels between the portal venous system and vena cava. These enlarged veins often protrude into the esophagus and are known as esophageal varices.

Fig. 14-11 Varices related to portal hypertension. Portal vein, its major tributaries, and the most important shunts (collateral veins) between the portal and caval systems.

(From Monahan FD, Sands JK, Neighbors M, Marek JF, Green-Nigro CJ: Hepatic problems. In Phipps’ medical-surgical nursing: health and illness perspectives, ed 8, St Louis, 2007, Mosby.)

Clinical Signs and Symptoms

Splenomegaly is often one of the first clinical signs of portal hypertension in children. Children with portal hypertension may also have ascites, markedly dilated superficial abdominal veins (caput medusae), and hypoalbuminemia.

If esophageal varices are present, sudden, severe esophageal and GI bleeding may occur without warning (see Gastrointestinal Bleeding, earlier in this chapter) with the onset of hematemesis, melena, or hematochezia. The bleeding from esophageal varices can be complicated by high variceal pressure and associated thrombocytopenia, so it may be particularly difficult to control.

The mortality rate for patients with bleeding esophageal varices was previously high; however, current treatment with vasopressin and somatostatin, correction of coagulopathy, endoscopic sclerotherapy and ligation (banding), and balloon tamponade (with a Sengstaken-Blakemore tube) are generally effective in controlling bleeding in children.⁵⁵ Balloon tamponade requires skilled personnel and is reserved for uncontrollable bleeding in larger patients.

The diagnosis of portal hypertension can be confirmed with ultrasound examination and assessment of the splenic or hepatic veins with vascular mapping. In some centers, computed tomography (CT) angiograms are performed to assess the existing vasculature. Liver function tests and a liver biopsy can be performed to determine the cause or extent of the primary disease in children with intrahepatic portal hypertension.

Management

Bleeding from esophageal varices is a life-threatening complication of portal hypertension. The goals of initial management are to maintain intravascular volume and systemic perfusion and to stop active bleeding (Box 14-3). For patients with portal hypertension from intrahepatic causes, there is a higher mortality when the initial bleeding episode is associated with liver dysfunction, malnutrition, and coagulopathy.

If bleeding from esophageal varices persists after correction of coagulopathies and volume resuscitation, a continuous IV infusion of vasopressin or somatostatin analog (octreotide acetate) can be initiated (see Table 14-8).

Alternative therapies for the treatment of bleeding esophageal varices that can be performed once acute bleeding is controlled include endoscopic sclerotherapy or band ligation in larger patients. These techniques require the expertise of a gastroenterologist or a pediatric surgeon and can be performed at the bedside using sedation or anesthesia.

During endoscopic sclerotherapy, the endoscopist injects a sclerosing agent such as 5% ethanolamine, 1 to 1.5% tetradecyl sulfate, or 5% sodium morrhuate either into or around bleeding esophageal varices.⁵⁵ The resulting edema and thrombosis stops bleeding in most patients (Fig. 14-12). Esophageal varices can be obliterated completely with repeated injections at 2 to 4-week intervals, thus preventing recurrent episodes of bleeding. Potential complications of this technique include exacerbation of bleeding, esophageal stricture, and esophageal perforation.⁴³

Fig. 14-12 Techniques of injection sclerotherapy.

(From Terblanche J, Burroughs AK, Hobbs EKF. Controversies in the management of bleeding esophageal varices. N Engl J Med 320:1393-1398, 1989.)

A pediatric Sengstaken-Blakemore tube (Fig. 14-13) can be inserted at the onset of the bleeding. Although this tube is usually effective in controlling bleeding, it is used infrequently because the complication rate is high. The tube must be inserted by skilled, experienced personnel, and the child typically requires arterial pressure monitoring and airway control with endotracheal intubation. Complications include pulmonary aspiration, discomfort, and pressure necrosis of the distal esophagus. When a Sengstaken-Blakemore tube is used, bedside providers should constantly monitor the tube function, placement, and integrity. In many instances bleeding reoccurs after the tube is removed. See the Chapter 14 Supplement on the Evolve Website, Portal Hypertension, Management, for additional information on The Sengstaken-Blakemore Tube.

Fig. 14-13 Positioning of a Sengstaken-Blakemore tube.

(From Given B, Simmons S: Gastroenterology in clinical nursing, ed 4, St Louis, 1984, Mosby.)

Surgery to decompress the hypertensive portal system may be necessary if life-threatening variceal bleeding recurs, although these procedures are most successful in children who are older than 10 years, when veins are of larger size. These procedures reduce the portal venous pressure by shunting portal blood flow directly into the IVC, bypassing the scarred liver or thrombosed portal vein.

The Rex shunt is an option for surgical correction of extrahepatic portal vein obstruction. The word Rex refers to the anatomic name of the portion of the liver to which the blood is shunted. The Rex shunt uses an autologous vein, most commonly the left jugular vein; this vessel extends from the superior mesenteric vein to the left branch of the portal vein.¹³ To prevent clotting of the shunt, heparin is initially provided. When oral intake is tolerated, anticoagulation therapy is transitioned to baby aspirin and dipyridamole (Persantine). The duration of this anticoagulation is variable, and is determined by the size of the child, the size of the graft, and the presence of any hypercoagulable conditions. For further information, readers are referred to websites about this procedure (e.g., http://www.childrensmemorial.org/depts/siragusa/transplant-surgery/rex-shunt.aspx)

Additional shunting procedures include the splenorenal shunt and the mesocaval shunt. The most popular shunting procedure performed in children is the distal splenorenal shunt, which results in anastomosis of the splenic vein to the left renal vein (Fig. 14-14). An alternative procedure, the mesocaval shunt, is occasionally performed; it redirects blood from the obstructed mesenteric system to the patent intrahepatic system.

Fig. 14-14 Distal splenorenal shunt. The lesser sac is entered, and the splenic vein is dissected off the interior border of the pancreas, ligating and dividing small pancreatic branches. The left renal vein is then found and mobilized, preserving the gonadal and adrenal branches. The splenic vein is divided close to the confluence with the superior mesenteric artery (SMA) and anastomosed end to side with the left renal vein. The vein should lie in a smooth curve to avoid kinking. The coronary and gastroepiploic veins are ligated and divided. Blood flows from the gastric and esophageal varices via the short gastric veins, across the spleen, and into the splenic vein. The spleen is also decompressed in this fashion while portal flow to the liver is preserved.

(From Superina R: Portal hypertension. In Grosfeld JL et al, editors: Pediatric surgery, ed 6, St Louis, 2006, Mosby).

A potential postoperative complication of the shunting procedure is thrombosis of the anastomotic vessel and recurrence of the portal hypertension. The mesocaval shunt diverts some blood from the splanchnic circulation, reducing flow to the liver. As a result, the shunt may reduce liver detoxification of some circulating toxins, such as nitrogenous substances. The nurse must monitor for the development of hepatic encephalopathy (see discussion under Liver Failure later in this chapter).

Nursing interventions during acute episodes of GI bleeding secondary to portal hypertension are summarized earlier in this chapter (see Gastrointestinal Bleeding). Intervention for the treatment of ascites is presented in the following section.

Etiology

Ascites is the accumulation of free fluid in the peritoneal cavity. It can result from diffuse inflammation of the peritoneal surface such as occurs with peritonitis, or it can be associated with increased portal capillary pressure resulting from cirrhosis, severe congestive heart failure, or other obstructive vascular conditions. Ascites may also be associated with diseases that result in sodium and water retention with decreased plasma colloid osmotic pressure (e.g., nephrotic syndrome). In children, significant ascites is caused most often by liver disease, severe congestive heart failure, infection, or nephrotic syndrome. Chylous ascites may occur in newborns and may be acquired in older infants and children.

Pathophysiology

Ascites results from the exudation of fluid from the surface of the liver, bowel, or peritoneum. This fluid enters the abdominal cavity instead of the mesenteric or portal venous system if any of the following conditions is present: (1) obstruction to flow between the mesenteric or portal vein and the IVC, (2) extremely high CVP, (3) low serum albumin, or (4) presence of proteinaceous fluid in the peritoneal cavity.

When blood passes through any capillary bed, the amount of fluid filtered out of the capillaries (the vascular space) is determined by pressure gradients across the capillary bed (from the arterial to the venous end and between the intravascular and the extravascular or interstitial space) and the difference in oncotic pressure between the intravascular and extravascular spaces. Under normal circumstances these factors, known as Starling’s capillary forces, favor a small amount of net fluid filtration (flow into the extravascular or interstitial space) at the arterial end of the capillary bed and reabsorption of most of the fluid (flow back into the vascular space or capillary) at the venous end of the capillary bed. The slight tendency for fluid to filter out of the capillary as the result of capillary hydrostatic pressure is balanced almost exactly by the oncotic pressure normally exerted by plasma (intravascular) proteins, so that a near equilibrium exists between fluid filtration and reabsorption. A rise in venous hydrostatic pressure, an increase in extravascular (interstitial) oncotic pressure (e.g., caused by leak of protein from the vascular space), or a fall in intravascular oncotic pressure (hypoalbuminemia) can destroy the capillary equilibrium and produce a net loss of fluid from the vascular space to the extravascular space. This net loss of fluid to the extravascular space in the abdominal cavity results in ascites.

When hepatic and portal venous blood flow is obstructed, such as in cirrhosis of the liver, venous capillary and hepatic sinusoidal pressures rise. Initially the veins and sinusoids expand to accommodate larger quantities of blood. Eventually, however, as the capillary hydrostatic pressure rises, fluid begins to exude from the surface of the liver into the peritoneal cavity. Because liver sinusoids are far more permeable than normal capillaries, both fluids and proteins leak into the abdominal cavity. Once a sufficient quantity of proteins is present in the abdominal cavity, the extravascular colloid osmotic (oncotic) pressure rises, drawing more fluid from the vascular space into the abdominal cavity.

Congestive heart failure may produce ascites if the CVP rises sufficiently. Initially, hepatic venous and sinusoidal pressures rise, and the veins and sinusoids expand to accommodate a greater blood volume. This venous congestion causes one of the earliest signs of congestive heart failure in children—hepatomegaly (see Congestive Heart Failure in Chapter 8). If the CVP continues to rise, the liver’s storage capacity for blood is exceeded, and fluids and proteins will exude into the abdominal cavity, creating ascites.

Children with nephrotic syndrome or hypoalbuminemia demonstrate a low plasma oncotic pressure. This low oncotic pressure enhances net fluid filtration from the vascular space, even if capillary pressure remains low. Hypoalbuminemia usually produces generalized edema, including ascites.

Peritoneal inflammation results in the formation of protein-rich ascitic fluid. The presence of this fluid in the peritoneal cavity creates an increase in extravascular colloid osmotic pressure, drawing more fluid from the vascular space into the abdominal cavity (ascites).

Spontaneous bacterial peritonitis occurs in children with ascites from cirrhosis.³⁵ Chylous ascites develops secondary to lymphatic obstruction at the level of the cisterna chyli or above.

Clinical Signs and Symptoms

Ascites usually develops gradually and is frequently unnoticed by the child or parents unless it is associated with other symptoms of the primary disease. Clothing may be perceived as too tight around the waist, and belts must be loosened as weight gain occurs and abdominal girth increases. Peripheral, ankle, and presacral edema may not be present unless hypoalbuminemia develops. If the ascites results from inferior vena caval, portal, or abdominal venous obstruction or a high CVP, superficial abdominal veins will be distended and visible on the surface of the abdomen (caput medusae).

The child’s abdomen will be visibly distended. The abdominal girth should be measured every 4   hours, and more often if the patient’s condition changes, to allow for monitoring of the severity of the ascites. The abdomen is generally dull to percussion, indicating the presence of fluid. Ascitic fluid will collect in dependent areas of the abdominal cavity, so the location of the area of dullness may change when the patient changes position; this is called shifting dullness.

If the child is cooperative and a second observer is present, it may be possible to elicit a fluid wave during palpation of the abdomen. The first observer places a hand firmly on the midline of the child’s abdomen. The second observer places one hand along one side of the child’s abdomen and, with the second hand, sharply taps the other side of the child’s abdomen. If significant amounts of free peritoneal fluid are present, both observers feel a “wave” of fluid transmitted from one side of the abdomen to the other. The first observer’s midline hand will rise when the fluid wave passes the midline.

Patients with ascites demonstrate a wide variety of fluid and electrolyte imbalances. Hypoalbuminemia may result from the primary disease or from a loss of protein into the ascitic fluid. Protein synthesis also is decreased if liver function is impaired. If the child has cirrhosis, antidiuretic hormone levels are elevated because the liver does not inactivate the antidiuretic hormone; this causes water retention and may produce a dilutional hyponatremia. In addition, aldosterone is not inactivated by the cirrhotic liver, so both water and sodium retention increase. Hypokalemia may result from aldosterone excess or from potassium loss caused by administered diuretics.

If significant fluid accumulates in the child’s abdomen, it can impede diaphragm excursion. The child will demonstrate tachypnea with shallow breaths and may develop atelectasis. Providers should monitor for signs of respiratory distress, because assistance may be needed, using mechanical ventilation.

With the accumulation of large amounts of ascitic fluid, the child may develop a hydrothorax or accumulation of fluid in the thorax. This fluid most commonly enters the right chest, although bilateral hydrothoraces may develop. The child with a hydrothorax demonstrates dyspnea, increased respiratory effort (retractions and nasal flaring), and tachypnea. Breath sounds over the area of fluid usually are decreased, although the observer simply may note a change in the pitch of breath sounds caused by transmission of breath sounds from other areas of the chest through the pleural fluid.

If the ascites is secondary to liver, cardiovascular, or renal disease, then the child will exhibit signs of the primary disease and the ascites. For further information, see the appropriate sections in this chapter (e.g., Liver Failure), in Chapter 8 (Congestive Heart Failure) and in Chapter 13 (Acute Renal Failure).

The child with ascites may be extremely self-conscious about the abdominal distention. These children often complain of a sensation of “fullness” in the abdomen, and they may be anorexic. Nutritional weight loss may be masked by the weight gain produced by ascites.

Management

Ideally, healthcare providers should identify and treat the cause of the ascites before it is severe and produces respiratory compromise. Nurses should carefully measure fluid intake and output for any child at risk for the development of ascites. Weigh the child at the same time of day with the same scale and technique to detect small weight changes. Measure the child’s abdominal girth frequently if ascites is developing or worsening.

Strict fluid and possibly sodium restriction are often required in the treatment of severe ascites. Administration of diuretics will necessitate close monitoring of fluid and electrolyte balance. The nurse must carefully monitor systemic perfusion during diuresis to prevent compromise in intravascular volume and systemic perfusion.

If a CVP catheter is placed in the child with an obstruction or compression of the IVC, it is important to know the location of the tip of the catheter in relation to the obstruction or compression. If the catheter tip is distal to the IVC obstruction or compression (e.g., catheter tip located in femoral vein in the child with severe ascites), the IVC pressure measured at that point will not reflect right atrial pressure. If possible, the tip of the catheter should be advanced beyond any area of obstruction (e.g., to the junction of the IVC and right atrium) if the central venous catheter pressure measurements are to be used to evaluate intravascular volume and cardiac preload.

If oral feedings are permitted, hard candy may be given to older children to assuage thirst and provide some glucose intake during periods of fluid restriction. An effort must be made to make meals palatable. Small, frequent feedings usually are better tolerated than infrequent, larger ones because gastric distention increases the sensation of abdominal fullness. If possible, allow the older child to plan disbursement of the restricted fluid intake during the day.

The child may develop lower lobe atelectasis from the pressure of abdominal fluid on the diaphragm and resultant shallow breathing. To prevent atelectasis, encourage the child to sit upright, rather than recline, and to remain as ambulatory as possible. Ambulation and use of incentive spirometry or bubbles may prevent atelectasis; chest physical therapy will be needed if pneumonia or atelectasis develops. If the child develops signs of respiratory distress, elevate the head of the bed to maximize diaphragm movement. Infants can be placed in an infant seat, and older children may prefer to sit at the side of the bed, leaning forward over a bedside table. Use pulse oximetry and titrate oxygen administration during episodes of respiratory distress.

Most cases of chylous ascites resolve without surgical intervention. The goal of treatment is to reduce lymphatic flow. For mild cases, reduce enteral fat intake with or without the use of medium chain triglyceride. Some patients require a period of no enteral intake and PN. In others, the addition of somatostatin will be effective. Palliative procedures to reduce fluid include decompression with paracentesis or placement of an intraabdominal drain and thoracentesis. After paracentesis, monitor the child closely for complications such as hypotension (large shifts of intravascular volume) and bacterial peritonitis.³⁵ Surgical decompression using a peritoneal-jugular shunt may necessary.

Etiology

Bowel obstruction can be mechanical or functional in origin, and it can occur anywhere along the length of the GI tract. Mechanical obstruction is a physical barrier that blocks the lumen of the GI tract, so that peristaltic contractions are unable to propel GI contents forward. Four main causes of mechanical bowel obstruction are: (1) congenital GI malformations (e.g., duodenal atresia, annular pancreas), (2) intraluminal obstruction (e.g., foreign body, stool, bezoars [masses of organic or inorganic material—often swallowed material—trapped in the gastrointestinal system]), (3) intramural lesions within the bowel wall (e.g., tumors, Crohn’s disease, webs), and (4) extramural causes (e.g., bowel adhesions, hernias, intestinal volvulus).³²

A functional obstruction, also called an ileus, occurs when the motor function or peristalsis of the GI tract is impaired, creating a stasis of bowel contents. Functional obstruction can develop after abdominal surgery (i.e., postoperative ileus) but can be related to sepsis, medications (e.g., opioids), trauma, head injury, pneumonia, and metabolic imbalances.

Clinical Signs and Symptoms

Clinical signs and symptoms vary depending on the location of the obstruction, the type of obstruction (mechanical or functional), and whether the obstruction is complete or partial. Presentation can be acute with signs of peritonitis (e.g., volvulus) or subtle and chronic with incomplete or recurring bouts of obstruction (e.g., intussusception).

When obstruction develops, bowel proximal to the obstruction becomes distended by a collection of air and fluids. Distal bowel collapses from a lack of intraluminal content. Proximal obstructions create a relatively larger amount of bowel collapse, and physical findings can include a scaphoid or sunken abdomen.

An obstruction in the lower GI tract will result in more bowel distention and, consequently, more abdominal distension. Clinical findings include a rounded, distended, and tympanic abdomen with bowel loops that may be visible and palpable. If the bowel obstruction is mechanical, bowel sounds will be present and often are high pitched and tinkling in character, because the peristaltic waves continue to propel contents against the obstruction. Pain is initially mild, but increases in severity and often corresponds with peristalsis.

Functional obstructions are referred to as the silent abdomen, because there is lack of peristaltic activity. Pain associated with a functional obstruction is constant and increases in intensity as the bowel becomes further dilated. In cases of obstruction associated with compromised intestinal perfusion such as volvulus, pain results from ischemia and is continuous with escalating intensity.

Obstructions may be complete or partial and intermittent. Complete obstruction stops all progression of bowel contents, but patients will evacuate distal contents before all output ceases. Many patients with complete obstruction will develop bowel ischemia.⁴⁶ Patients with partial or intermittent obstructions will pass some air and liquid stool (diarrhea and flatus).

Vomiting is a common symptom of both mechanical and functional bowel obstruction. The character and frequency of vomiting may provide clues to the location of the obstruction. Higher obstructions result in more rapid onset and more frequent episodes of vomiting. With lower obstructions there is more space to accommodate the accumulation of air and fluid, so there is typically a longer time before the onset of vomiting. Vomiting is typically a late sign of a lower obstruction and is preceded by bowel and abdominal distension.

Emesis typically is described as nonbilious (yellow) or bilious (green) in color. Vomiting associated with obstruction proximal to the sphincter of Oddi will more likely be nonbilious, because the expelled fluids have not yet mixed with bile excreted at the sphincter. Bilious emesis usually represents an obstruction occurring beyond the sphincter of Oddi and is regarded as a hallmark sign of a probable surgical emergency that requires rapid investigation and treatment.

Abdominal plain radiographs are the first choice for diagnostic imaging when bowel obstruction is suspected. The normal bowel gas pattern includes a paucity of air in the small bowel, but air is normally visible in the colon and rectum (Fig. 14-15, A). With obstruction, bowel proximal to the obstruction dilates as air and fluid accumulate, causing air fluid levels that are visible in the abdominal plain radiographs (Fig. 14-15, B). The colon and rectum have little or no air, so they may not be visible. The more distal the obstruction, the higher the visible air fluids levels (Fig. 14-15, C). With complete obstruction a paucity of air is visible distal to the obstruction and a cutoff point maybe evident. It is difficult to differentiate between large and small bowel obstruction on the basis of plain abdominal radiographs in infants.

Fig. 14-15 A, Normal gas pattern. Typical caliber of bowel with air seen throughout the intestine, including the rectum. B, Bowel obstruction with severely dilated bowel and air fluid levels in the left lower quadrant. The bowel distension extends to below the diaphragm on the left side. C, Multiple air fluid levels are present with a paucity of air in the lower abdominal quadrants. This radiograph is consistent with bowel obstruction.

Management

Mechanical obstruction is more likely to require surgical intervention. Functional obstruction is often managed with supportive measures such as bowel rest, nasogastric tube decompression, and pharmacologic interventions (e.g., neostigmine, metoclopramide, naloxone, erythromycin).

Placement of a nasogastric or orogastric tube can create a route for bowel decompression, although recent data calls into question the need for nasogastric decompression in all patients with obstruction. If a tube is inserted, low intermittent suction is often used to remove pooled fluid and air and reduce distension. To maintain fluid balance, the child will likely require additional intravascular fluids (typically isotonic crystalloids) to replace those lost through GI suction.

Bowel obstruction is often associated with dehydration caused by a lack of oral fluid intake and recurrent vomiting. Vomiting expels both fluids and electrolytes, contributing to dehydration and electrolyte imbalance. Distention reduces the ability of the bowel to reabsorb water and electrolytes, further increasing fluid and electrolyte losses. Alkalosis with low chloride and elevated serum bicarbonate is commonly observed with a high obstruction, such as pyloric stenosis.

Abdominal distension can produce respiratory compromise. Increasing intraabdominal pressure compromises diaphragm excursion and can contribute to respiratory distress. Raising the head of the bed can help to maximize diaphragm excursion, decrease the work of breathing, and improve oxygenation and ventilation.

Surgery is often required for the management of bowel obstruction and may be required on an emergent basis to avoid loss of bowel. Emergent surgery is indicated in the setting of complete obstruction (e.g., midgut volvulus, unsuccessful reduction of intussusception, incarcerated hernia) or when the patient demonstrates signs of bowel ischemia and peritonitis. Patients without clinical signs of septic shock, peritonitis, or bowel ischemia can be treated safely with nasogastric decompression and fluid resuscitation before surgical intervention. Partial obstructions can be treated initially with decompression that may resolve the obstruction.⁴⁶

Etiology

NEC is an acquired disease of unknown origin that develops during the neonatal period. NEC typically occurs in premature low-birth weight newborns (<1500   g), but cases have been described in term babies.⁶⁰ Infants with NEC develop necrotic lesions in the GI tract, most commonly in the ileum and colon. The necrosis may be superficial and only detectable microscopically, or it may be transmural and involve both the small and large intestines. Mild disease may be completely reversible, but infants with extensive involvement may not survive or may be rendered as short gut with subsequent intestinal failure following surgical resection of the affected bowel.

A large number of epidemiologic factors have been associated with the development of NEC. The majority (more than 90%) of patients are premature neonates (less than 36 weeks’ gestation), who have received enteral nutrition. Newborns with low-flow states, such as patent ductus arteriosus or congenital heart disease (especially in infants with left ventricular outflow tract lesions), are at risk.^20,60 NEC can also develop following repair of gastroschisis. Further discussion of the etiology can be found in the Chapter 14 Supplement on the Evolve Website, Specific Diseases, Necrotizing Enterocolitis.

Pathophysiology

The pathophysiology of NEC is poorly understood but includes: intestinal ischemia, distension, colonization by pathogenic bacteria, subsequent bacterial translocation, and intestinal necrosis and perforation. The proposed inciting mechanisms are schematically presented in Fig. 14-16. The initiating injury in NEC is disruption of the intestinal mucosal epithelium; this disruption can result from a variety of mechanisms, most likely hypoxia or an infection. Most cases occur after the second week of life following bacterial colonization of the intestine.²⁵ See the Chapter 14 Supplement on the Evolve Website, Necrotizing Enterocolitis, for additional information about the role of enteral feeding in the development of NEC.

Fig. 14-16 Pathophysiology of necrotizing enterocolitis.

(From Lin PW, Stoll BJ: Necrotizing enterocolitis. Lancet 368:1271-1283, 2006.)

Pneumatosis intestinalis, a radiologic hallmark of well-established NEC, is the accumulation of extraluminal gas in the submucosal intestinal tissue following the invasion of intestinal bacterial flora. It is postulated that progressive infiltration of the mucosa and bowel wall with gram-negative or gram-positive bacteria leads to more extensive tissue inflammation and destruction from activated neutrophils, producing a vasoconstrictive response, with progression to necrosis, and perforation.²⁵

Clinical Signs and Symptoms

The classic clinical presentation of infant NEC includes the symptom group of abdominal tenderness, abdominal distension, hemepositive stools (or other gross or occult signs of GI bleeding), and ileus (decreased bowel sounds and increased gastric residual volume following tube feeding). Abdominal distension is the most commonly observed symptom.²⁵ Bilious vomiting after feeding also may be noted.

Signs of clinical deterioration in the child with NEC include apnea and bradycardia, lethargy, temperature instability, decreased urine output, further abdominal distension and discoloration of the abdominal wall. The wide range of symptoms in NEC has led to a clinical categorization or Bell’s staging of the condition.⁶ Symptoms and factors utilized in this staging include the infant’s history (and risk factors), nonspecific manifestations of distress, and specific gastrointestinal and radiographic clinical indicators (Box 14-4). Recently, a modification of Bell’s staging has been proposed to include histologic findings of each stage.²¹

Management

Preventative interventions currently under investigation include: antenatal glucocorticoid administration, preferential use of breast milk, use of a standardized feeding regimen, restricting water intake without compromising hydration, and the use of probiotics (i.e., live microorganisms that may confer health benefits when administered in adequate amounts) and immunoglobulin A and arginine supplementation.^37,49,60

If NEC is identified in its early stages and prompt medical treatment is provided, 30% to 50% of affected infants will improve without surgical intervention.²⁵ Once the diagnosis of NEC is suggested, enteral feedings are discontinued and a nasogastric or orogastric tube is passed for gastric drainage and decompression. Umbilical artery or venous catheters are discontinued. The infant will require administration of IV fluid therapy, including PN and appropriate IV antibiotics for both gram-negative and gram-positive organisms. Blood, urine, and sputum cultures should be sent before initiation of antibiotic therapy.

During the early stages, nursing interventions include monitoring of vital signs (including blood pressure), measuring abdominal girth and fluid intake and output (including weighing of all stools), evaluating daily weight, and testing all stools for blood.

The nurse must monitor the infant’s systemic perfusion closely. Signs of poor systemic perfusion include tachycardia, tachypnea, decreased intensity of peripheral pulses, coolness of extremities, pallor or mottled color, and a urine output of less than 0.5-1.0   mL/kg per hour. Hypotension may be only a late sign of cardiovascular compromise. Infants require aggressive fluid resuscitation (typical bolus volume is 10   mL/kg, repeated as needed), with administration of blood products as needed. Thrombocytopenia may develop secondary to gram-negative sepsis.

The infant with sepsis may develop hypothermia and lethargy rather than fever and irritability. If significant bowel edema or free peritoneal fluid is present, the infant may demonstrate evidence of third spacing of fluid, including signs of hypovolemia (inadequate circulating blood volume as the result of loss of fluid into the bowel wall or peritoneum). Additional signs include tachycardia, decreased intensity of peripheral pulses, hypotension, peripheral vasoconstriction, lactic acidosis, oliguria, and anuria.

Surgical intervention is indicated if the infant demonstrates evidence of intestinal perforation, erythema of the abdominal wall, persistent metabolic acidosis, or clinical deterioration that is unresponsive to vigorous medical management (Box 14-5).^39,51 Surgical options include laparotomy with the resection of the affected bowel and creation of stomas or the placement of a peritoneal drain. See the Chapter 14 Supplement on the Evolve Website, Necrotizing Enterocolitis, for information about treatment with a peritoneal drain.

During surgery, necrotic bowel is resected, although attempts are made to salvage as much viable intestine as possible. A second operation may be performed to maximize the amount of retained bowel (the salvaged intestine is checked again for evidence of viability). The creation of an ileostomy or a jejunostomy permits the minimum possible amount of bowel resection and allows the distal, involved intestine a period of rest. This approach has afforded the highest survival.

These infants often require short-term postoperative mechanical ventilation. Parenteral nutrition (PN) is also necessary until oral feedings are resumed (see sections on Care of the Child after Abdominal Surgery and Parenteral Nutrition, earlier in this chapter).

Postoperative complications include rendering the infant as short gut and the development of intestinal obstruction. Late obstruction can result from stricture, most commonly in the colon (sigmoid colon); it may develop in up to one third of infants undergoing operative intervention and may also develop in infants who are managed medically. Infants rendered as short gut may be candidates for intestinal transplantation (see Intestinal Failure).

Etiology

Biliary atresia (BA) is an inflammatory obstruction of the extrahepatic bile ducts with progressive inflammation of intrahepatic bile ducts. The atresia can involve isolated segments of the bile duct system or the entire biliary tree including the gallbladder. The progressive inflammation leads to fibrosis, with eventual bridging fibrosis and cirrhosis. There are two types of BA: the embryonic (fetal) form and the perinatal or acquired form. The embryonic form is usually associated with other congenital anomalies (e.g., polysplenia, cardiac anomalies, malrotation). Eighty percent of patients with biliary atresia in Western countries have the perinatal or acquired form of the disease, in which infants born with a patent hepatobiliary system develop progressive obstruction.⁴⁰ Precipitating factors include viral, toxic, vascular or immune mediators.⁴⁰

Pathophysiology

Obstruction of the biliary tree prevents bile drainage from the liver into the duodenum. The accumulation of bile in the liver causes direct (conjugated) hyperbilirubinemia. Cirrhosis may develop despite early diagnosis and surgical palliation.

Clinical Signs and Symptoms

Infants with BA exhibit persistent jaundice and direct (conjugated) hyperbilirubinemia during the first 2 months of life. Acholic or gray-colored stools indicate a lack of bile drainage in the GI tract, and dark-colored urine indicates increased bilirubin in the urine. In older children, a high serum bilirubin can cause pruritus. If the BA is not diagnosed within approximately the first month of life, signs of progressive liver disease (e.g., malabsorption of fats and fat-soluble vitamins, poor growth, rickets, hypoproteinemia) may develop. Cirrhosis will be associated with signs and symptoms of portal hypertension (see Portal Hypertension, earlier in this chapter).

An ultrasound examination may reveal a small noncontractile gallbladder, or the gallbladder is not visualized.¹⁸ A radionuclide hepatoiminodiacetic scan will detect movement of a radioactive tracer. The injected tracer is filtered by the liver, which adds it to the bile, so that the tracer normally flows through the bile ducts into the gallbladder and finally into the small intestine. In infants with BA there is no detectable excretion of the isotope into the small intestine.¹⁸ A liver biopsy may reveal bile duct proliferation and portal tract fibrosis, which suggest the diagnosis.

Management

Surgical palliation with the Kasai (portoenterostomy procedure) should be planned and discussed with the parents when diagnostic testing is underway, because surgery should be performed as soon as possible after the diagnosis to optimize postsurgical outcome. In the Kasai procedure, the atretic segments are resected, and a segment of jejunum is sewn between the liver and the duodenum to facilitate bile drainage (see Evolve Fig. 14-2 for an illustration of the Kasai procedure in the Chapter 14 Supplement on the Evolve Website). If successful bile drainage can be achieved, the prognosis for these patients is relatively good. The best outcomes are achieved in infants younger than 2 months of age.

When there is significant fibrosis or cirrhosis at the time of operation, the prognosis is poor, even after the Kasai procedure. These patients will demonstrate progressive liver failure postoperatively and will require liver transplantation (see Chapter 17, Overview of Solid Organ Transplantation).

Nursing interventions for the child undergoing a portoenterostomy procedure include postoperative laparotomy care (see Care of the Child after Abdominal Surgery, earlier in this chapter). Postoperative complications include infection (e.g., cholangitis), alteration in fluid and electrolyte balance, portal hypertension, and progression to liver failure. The risk of postoperative liver failure is increased if significant liver damage (scarring) is present at the time of surgery. Additional nursing interventions are those appropriate for the care of the child with liver failure (see Liver Failure, later in this chapter).

Etiology

Hepatitis, or inflammation of the liver, is most commonly caused by viral illness. Other causes include autoimmune liver disease, toxins, and idiopathic neonatal hepatitis. Six etiologically and immunologically distinct viruses are known to cause hepatitis: hepatitis A, B, C, D, E, and G. Hepatitis that is not type A, B, or type C is referred to as non-A–non-B–non-C hepatitis and is a diagnosis of exclusion in fulminant hepatic failure when other serologic markers are negative. Other classifications of hepatitis and common viruses that can cause hepatitis are listed in Box 14-6. Idiopathic neonatal hepatitis is considered a distinct form of hepatitis and is not thought to be caused by a virus, but is a histologic descriptive term of giant cell hepatitis.

Pathophysiology

Viral hepatitis causes the destruction of liver cells and results in hepatic inflammation, necrosis, and autolysis. Changes occur diffusely throughout the liver, and the liver structure may be distorted. Regeneration of cells begins as soon as damaged ones are removed by phagocytosis. Most patients with nonneonatal forms of hepatitis recover with minimal residual damage. Unfortunately the hepatitis viruses mutate, and reinfection of the host can occur.

Fulminant hepatitis with accompanying hepatic encephalopathy may occur during the course of the viral illness (see Liver Failure, later in this chapter) and chronic hepatitis and cirrhosis may develop with chronic disease (HBV and HCV). An additional concern is that chronically infected patients can develop hepatocellular carcinoma (HCC).

Clinical Signs and Symptoms

The symptoms of viral hepatitis vary depending on the inciting virus. Many children have no apparent signs or symptoms, and the disease is often diagnosed when a child is tested for the disease after a parent is diagnosed with the disease.

General symptoms include flulike symptoms, fever, fatigue, nausea, vomiting, anorexia, abdominal pain (particularly right upper quadrant), diarrhea, and muscle soreness. Jaundice, producing yellow sclera and dark colored urine, is a later symptom that often triggers consultation with a healthcare provider. Jaundiced children will have elevated bilirubin and liver transaminases (AST and ALT).

Management

All healthcare providers should practice standard precautions when handling any patient’s body fluids (e.g., blood, urine, saliva, any wound or fluid drainage) and feces. There is no well-established treatment for the eradication of viral hepatitis. Medical treatment and nursing care is directed toward the relief of discomfort and maintenance of adequate nutrition and hydration.

If the child is eating, it is important to offer small, frequent tasty and nutritious meals. Typically hepatitis requires no dietary restrictions. Special treats, such as milk shakes, can provide fluid and calories without the appearance of a meal; therefore they may be appetizing to a child with anorexia or nausea. Antiemetics may be required if nausea prevents adequate nutrition.

Patients and families should be educated about the contagious nature of the disease and preventative measures. Family members should be vaccinated against HAV and HBV if not previously immunized. If known exposure has occurred, it may be appropriate to administer immunoglobulin preparations for HAV and HBV. Patients should be advised to eliminate exposure to hepatotoxic drugs, including alcohol.

In some affected patients, progression of liver damage occurs and cirrhosis develops; this indicates a poor prognosis for long-term survival without transplantation (see Liver Failure in this chapter and in Chapter 17, Overview of Solid Organ Transplantation).

Etiology

Liver failure can be acute in children, but it is most often the end stage of chronic liver disease. Liver failure in children with chronic liver disease and disease progression is often termed pediatric end stage liver disease. Patients in the late stages of chronic liver failure will begin to demonstrate the complications of acute severe liver failure (e.g., acute encephalopathy). This condition is termed acute on chronic failure.

Acute necrosis of a previously normal liver is often termed fulminant hepatic failure (FHF). FHF is defined as the development of hepatic encephalopathy within 8 weeks of diagnosis without previous evidence of liver disease.

Acute liver failure (ALF) usually occurs as the result of a toxin exposure, viral illness, or unrecognized diagnoses (e.g., Wilson’s disease). Other causes of ALF in previously normal children include idiosyncratic reactions to anesthetics, antibiotics, and chemotherapeutic agents. Ingestion of drugs or toxins such as acetaminophen (as may occur with therapeutic dosing or overdose), pesticides, cleaning compounds, or some plant alkaloids also can produce ALF.

Several causes of liver disease, including hepatitis and BA are addressed elsewhere in this chapter (see Biliary Atresia and Hepatitis sections). Other causes of liver disease in neonates and infants include genetic disorders such as Caroli’s disease, tyrosinemia type 1, alpha-1 antitrypsin deficiency, and Alagille syndrome. Reye’s syndrome was caused by an abnormal accumulation of fat in the liver and typically presented as a form of ALF. Following a published description of an association between aspirin administration to children with primary varicella or influenza (viral syndrome) and the development of Reye’s syndrome, the use of aspirin in children has been nearly abolished and this disorder is rarely seen.

Wilson’s disease is an autosomal recessive disorder that results in excessive accumulation of copper in the liver. Treatment includes administration of D-penicillamine and dietary restriction of copper; however, some patients will exhibit ALF and will require liver transplantation.

Nonalcoholic fatty liver disease has become the most common cause of liver disease in children in developed countries.^34,36 This diagnosis is considered in children with mild to moderate elevation in ALT and AST levels with a body mass index in the 95th percentile or higher. The diagnosis is confirmed by liver biopsy, which reveals the accumulation of droplet fat in the hepatocytes in a child with no alcohol exposure.³⁶ Treatment goals include identification and treatment of obesity, alleviation of risk factors such as insulin resistance, and avoidance of factors that may worsen the liver disease (e.g., exposure to hepatotoxic drugs and alcohol).³⁶ There are no standard treatment regimens available, although lipid-lowering drugs, metformin, and vitamin E have been studied.^34,36

Pathophysiology

The liver performs hundreds of synthetic, metabolic, and excretory functions, including drug detoxification, synthesis of protein and clotting factors, conversion of ammonia to urea, and phagocytosis with Kupffer cells. Liver failure produces both an accumulation of substances normally removed by the liver and a lack of substances normally manufactured by the liver. Although liver functions are fairly well preserved until 80% to 90% of liver function is lost, liver failure can contribute to multiorgan dysfunction. Major organ dysfunction with ALF includes the development of hepatic encephalopathy, coagulopathy, and hepatorenal syndrome.

Clinical Signs and Symptoms

Signs of chronic liver disease in the child with acute failure include sequelae of portal hypertension with ascites and dilation of superficial abdominal veins (caput medusae), xanthoma formation, clubbing of the nails, gynecomastia, skin ecchymosis, palmar erythema, and spider angiomas. Jaundice is often present. The child frequently appears malnourished, and scratch marks and scabs may be visible signs of itching triggered by the pruritus.

Early signs of hepatic encephalopathy include poor school performance, forgetfulness and malaise. Neurologic signs of hepatic encephalopathy include tremors, incoordination, muscle twitching, and violent movements. The classic early symptom of hepatic encephalopathy is a peculiar flapping tremor known as asterixis. It can be elicited by asking an older child to stretch the arms straight out and dorsiflex the hand. The child will be unable to maintain the hyperextended position of the hand and will develop coarse bursts of twitching movements at the wrist (see Chapter 11 for further information about encephalopathy).

A staging of hepatic encephalopathy is described in Box 14-7, and children with acute failure can progress to stage 4 (coma) in a period as short as 1 or 2 days. Progressive encephalopathy is indicated by a decreased level of consciousness. Cerebral edema can produce increased intracranial pressure (see Chapter 11 for further information regarding the recognition and management of increased intracranial pressure).

Liver failure produces many hematologic, coagulation, and serum chemistry derangements. Both the intrinsic and extrinsic clotting cascades are affected (see Chapter 15). An ominous laboratory constellation for the child with ALF is markedly elevated liver transaminases (>1000 IU/L with a trend to normal values once few functioning hepatocytes remain to release enzymes) with a rising prothrombin time. Decreased production of serum clotting factors by the liver causes a prolonged prothrombin time, manifested by ecchymosis or petechiae and increased bleeding from puncture sites or from mucosal irritation.

The child’s serum direct bilirubin, transaminases, alkaline phosphatase, and ammonia level are usually elevated. Serum albumin levels may be normal in the setting of FHF because the half-life of albumin is 21 days; it may be low with acute or chronic disease. Anemia, leukopenia, hypoglycemia, hypokalemia, and hypocalcemia will develop in the presence of significant hepatic necrosis.

Clinical signs of hepatorenal syndrome include abrupt oliguria and azotemia, often without apparent precipitating factors such as infection, sepsis, or shock. Diagnostic criteria in adults include a creatinine greater than 1.5   mg/dL (or 24-hour creatinine clearance less than 40   mL/min); absence of shock, infection, or fluid losses; no improvement in renal function after withdrawal of diuretics and expansion of intravascular volume with plasma expander (adult receives 1.5   L, child receives 20   mL/kg boluses); proteinuria less than 500   mg/day; and no evidence of parenchymal or obstructive renal disease.²³ Additional laboratory findings include a normal urinalysis, hyponatremia (despite the renal retention of sodium, the serum sodium falls because there is relatively greater renal absorption of water), and hypokalemia (see the discussion of Acute Renal Failure and Acute Kidney Injury in Chapter 13).

If the cause of the hepatic failure has not been identified, diagnostic studies will be performed immediately. These studies include extensive toxicology screening (for evidence of alcohol, drug, or chemical ingestion), liver function studies, hepatitis serologies, ultrasound examination to evaluate vessels, and possible liver biopsy (Table 14-11). Although a liver biopsy can be performed in the presence of significant coagulopathy, a coagulation profile should be obtained and significant coagulopathy corrected before the biopsy. Viral, bacteriologic, and fungal blood cultures also may be ordered.

Table 14-11 Common Liver Function Tests and Changes with Liver Failure

Data from Huether SE: Structure and function of the digestive system. In McCance KL, Huether SE, editors: Pathophysiology: the biologic basis for disease in adults and children, ed 6, St Louis, 2010, Mosby; Custer JW: Blood chemistries and body fluids. In Custer JW, Rau RE, editors: The Harriet Lane Handbook, ed 18, St Louis, 2009, Mosby-Elsevier; Values for blood clotting functions from Aquino J: Hematology. In Custer JW, Rau RE, editors: The Harriet Lane Handbook, ed 18, St Louis, 2009, Mosby-Elsevier.

Management

All children who are critically ill require planned nursing assessment and support of all body systems. The child with liver failure with multiorgan failure is no exception. Careful monitoring for respiratory cardiac, neurologic, and renal function is often more important than monitoring the child’s liver function. The focus of the following information is on clinical assessment and prevention of the complications of liver failure and encephalopathy. Figure 14-17 is an overview of care considerations for the child with end stage liver disease.

Fig. 14-17 Optimizing care for the child with end-stage liver disease. Critically ill children with end-stage liver disease have multiple complex medical issues that must be addressed adequately to achieve optimal healthy outcomes.

(From Leonis MA, Balistreri WF: Evaluation and management of end-stage liver disease in children. Gastroenterology 143:1741-1751, 2008.)

The principal problems of the child with liver failure include any or all of the following: alteration in neurologic function, respiratory insufficiency, blood loss, changes in intravascular and interstitial fluid balance, compromised nutritional status, renal dysfunction, electrolyte or acid-base imbalance, increased risk of infection, decreased activity level, and patient and family anxiety.

Until liver function returns, treatment of the child with liver failure is primarily supportive. During the acute phase the most important goal of therapy is the prevention of major complications, such as increased intracranial pressure, respiratory failure, hemorrhage, fluid and electrolyte imbalances, and renal failure. Nutritional support and prevention of the complications of chronic liver failure, such as portal hypertension, are also important. The presence and severity of associated encephalopathy and intracranial hemorrhage often have the greatest effect on the child’s survival.

Etiology

Pancreatitis in children is relatively rare. Causes are diverse and can be categorized as nonobstructive, obstructive, or inflammatory. Nonobstructive causes predominate and include blunt abdominal trauma, typically caused by bicycle handle bar injuries and motor vehicle crashes. Nonobstructive pancreatitis is also associated with several medications, including didanosine, azathioprine, mercaptopurine, L-asparaginase, and valproic acid.⁵²

Up to one third of cases of pancreatitis result from obstructive disorders in the biliary or pancreatic duct, with cholelithiasis being the most common. Cholelithiasis is frequently associated with hemolytic disorders, including spherocytosis, beta-thalassemia, and sickle cell disease. Inflammatory causes of pancreatitis include mumps, ulcerative colitis, mononucleosis, HIV, and cystic fibrosis. Hereditary pancreatitis is another cause of obstructive pancreatitis and is often recurrent.

Pathophysiology

When pancreatic acinar cells are damaged, they release and activate digestive enzymes, triggering an inflammatory process referred to as autodigestion. The inflammatory cascade causes edema, ischemia, and necrosis. When the autodigestion-inflammation affects structures surrounding the pancreas, multiorgan failure can result.

Acute pancreatitis refers to a single inflammatory episode. When this process resolves, the pancreas is left with no residual effects. With recurrent episodes, morphologic changes in the pancreas begin to interfere with exocrine and endocrine functions, resulting in chronic pancreatitis.

Clinical Signs and Symptoms

Classic symptoms of pancreatitis in children are abdominal pain, nausea, vomiting, and anorexia. Symptom severity varies from mild abdominal pain to signs and symptoms of severe shock and end organ failure. Abdominal pain is typically the most intense in the epigastrium. Because the pancreas is retroperitoneal, back and flank pain are also common. Movement increases the intensity of the pain, so patients often lie still and are hesitant to move. Eating usually triggers or increases the pain and can induce vomiting that may be bilious. Pain may increase in intensity after vomiting occurs, because vomiting increases intraductal pressures producing further obstruction of pancreatic secretions.

Physical findings may include a bluish discoloration around the umbilicus (Cullen’s sign) or in the flanks (Turner’s sign), signifying hemorrhagic pancreatitis. Ascites may also be present.

Amylase and lipase are enzymes derived from pancreatic acinar cells; elevated levels aid in the diagnosis of pancreatitis. Amylase levels typically peak approximately 48   hours after the onset of pancreatitis and may remain elevated for as long as 4 days. Amylase levels may be elevated by other more common diseases, but levels typically do not reach those found in pancreatitis. Because amylase is produced by the salivary glands, levels can also increase with head and mouth trauma. Amylase isoenzymes are helpful in separating acute pancreatitis from other diseases that cause a rise in amylase, such as injury to the main salivary gland. Lipase is more specific to pancreatic injury than amylase, and it can remain elevated for as long as 14 days. Serum enzyme levels are diagnostic for pancreatitis if they are at least threefold greater than normal ranges. The severity of the rise of these enzymes does not correlate with the extent of pancreatic injury.

Metabolic complications of acute pancreatitis include lipid abnormalities, hypocalcemia, hyperglycemia and metabolic acidosis.¹² Hypocalcemia is observed in approximately 15% of patients with pancreatitis and develops when extensive fat necrosis occurs. Approximately 25% of patients with acute pancreatitis demonstrate hyperglycemia, because damaged pancreatic tissue releases less insulin than normal. The white blood cell count and differential are frequently normal, whereas the hematocrit reflects hemoconcentration secondary to dehydration.

A variety of radiologic studies are useful for detecting pancreatic abnormalities. Ultrasound examination is often the study of choice to evaluate pancreatic size and contour and to evaluate the progress of pancreatic or biliary obstruction in small, thin subjects. CT scans allow evaluation of the presence and extent of pancreatic necrosis, inflammation, ascites, and gallstones. Magnetic resonance cholangiopancreatography provides more accurate information about duct integrity.

Endoscopic retrograde cholangiopancreatography (ERCP) is both diagnostic and therapeutic, but is also the most invasive of these studies. When a pancreatic duct abnormality is detected during the study, procedures such as a sphincterotomy at the sphincter of Oddi, stent placement, and stone removal can be performed. This study is not advised during the acute phase of pancreatitis, because it may worsen the condition.

Management

The two goals of management of pancreatitis are to minimize causative factors and provide meticulous supportive care. Supportive care includes taking steps to decrease the production of digestive enzymes: the child should receive PN and should receive no enteral feeding (i.e., nothing by mouth or nasogastric tube). Octreotide acetate can be used to suppress GI hormones that stimulate pancreatic secretion.

Because the pain associated with pancreatitis can be severe, parenteral analgesia with narcotics or nonsteroidal antiinflammatory agents is generally required (see Chapter 5). The use of morphine and other opiate derivatives is theoretically less desirable in patients with pancreatitis, because these medications increase spasm of the sphincter of Oddi and may cause additional pain.

Shock is the leading cause of death in patients with acute fulminant pancreatitis.¹⁹ Nurses must closely monitor the child’s vital signs, systemic perfusion, and evidence of fluid balance, including CVP and urine output. Fluid shifts can cause severe abdominal distension that hinders diaphragm excursion. Close monitoring of respiratory status (oxygenation, ventilation, aeration, and respiratory effort) is required.

Surgical intervention may be necessary in cases of pancreatic trauma with fracture of the pancreas and disruption of the pancreatic duct. Surgery may also be necessary for patients with familial pancreatitis.

Etiology and Pathophysiology

Toxic megacolon is a term for acute toxic colitis with dilation of the colon that is often present in patients with ulcerative colitis. It is almost always a complication of pancolitis. Pathologic analysis reveals acute inflammation involving all layers of the colon, with variable amounts of necrosis and degeneration.

Clinical Signs and Symptoms

The diagnosis of megacolon is based on clinical history, physical examination, and radiologic studies. Fever, acute abdominal pain, and abdominal distention are the primary symptoms of toxic megacolon. Other symptoms include rectal bleeding, and vomiting. Because high dose corticosteroids are used for treatment of IBD, fever may not be present.

If bowel perforation occurs, physical findings include abdominal distension, hypoactive bowel sounds, and peritoneal signs (e.g., rebound tenderness, abdominal rigidity, pain with movement). The diagnosis of toxic megacolon is confirmed by the presence of marked dilation (greater than 6   cm) of the colon on a single flat-plate radiograph of the abdomen.

Management

Goals of treatment include: reduction of colon distension, correction of fluid and electrolyte imbalances and treatment of toxemia. Medical management includes discontinuation of oral intake and provision of IV fluids, initiation of nasogastric suction, and administration of systemic antibiotics. Intravenous steroids are administered to patients with IBD.

The child requires PN because oral feeding is contraindicated for several days. Complications of high-dose systemic steroids can develop, including leukocytosis, decreased immunologic defenses and diabetes. Continued steroid administration can cause bone demineralization with resultantvertebral collapse or aseptic necrosis of the femoral heads. Steroids also cause redistribution of body fat, especially in the face (Cushingoid changes), neck, and posterior shoulder area.

When the child is admitted to the critical care unit with the diagnosis of toxic megacolon, the healthcare team should explain the possibility and details of surgery to both the patient and the family. This ensures that the child and family are prepared if a bowel perforation occurs and the child requires urgent surgical intervention.

If toxic megacolon does not resolve with supportive medical therapy or if bowel perforation occurs, emergency surgery is required. Colectomy with an ileostomy will be performed. The child requiring a colectomy should receive careful preoperative preparation, including explanation and demonstration of ileostomy appliances. This preparation should be given a high priority, even when time is limited before the surgery.

Etiology

In children, diarrhea is most often the result of a viral or bacterial organism (Table 14-12). Rotavirus is the most common inciting pathogen worldwide in children younger than 5 years.^5,48 Two live oral rotavirus vaccines (Rota Teq, Merck, Sharp and Dohme, Merck Incorporated, Whitehouse, NJ; and Rotarex, GlaxoSmithKline, Research Triangle Park NC), have been approved by the Food and Drug Administration for use in the United States, and current recommendations are to immunize all children for rotavirus starting at 2 months of age.^1,48

Clostridium difficile is a common cause of antibiotic-associated diarrhea. This gram-positive organism is part of the normal GI bacterial flora, but antibiotics and some other medications and conditions can disrupt normal bacterial flora and allow some organisms to grow unchecked. Hospitalized children at risk for C. difficile disease include those receiving antimicrobial agents. Additional conditions that increase risk for this organism include recent abdominal surgery, presence of a feeding tube, and decreased stomach acidity from the administration of histamine type 2 antagonists and proton pump inhibitors.⁵⁰ Medications that increase GI motility (e.g., docusate [Colace], polyethylene glycol [MiraLax]) can also cause diarrhea.

Milk intolerance and dietary changes, such as changing formula and introducing new foods, can lead to diarrhea. Often children with failure to thrive are fed with concentrated formulas (up to 30   Kcal/ounce), and they may develop diarrhea from the hyperosmolar formulas and overfeeding. Some disease processes, including inflammatory bowel disease and Hirschsprung disease, may increase risk for colitis that can be life threatening.

Pathophysiology

Acute diarrhea alters the GI tract and can lead to dehydration. Dehydration is present when the total output of all fluids and electrolytes exceeds the total fluid intake. Dehydrated patients are deficient in both fluids and electrolytes. Dehydration is classified according to severity, based on clinical examination, and according to effects on the serum sodium and osmolality (see Dehydration and Hypovolemia in Chapter 12).

Clinical Signs and Symptoms

All children with diarrhea and dehydration will have a history of inadequate fluid intake and excessive fluid loss. The child may be febrile and usually is irritable and looks ill; there may or may not be associated vomiting. Initial clinical signs produced by dehydration can be difficult to separate from those produced by meningitis, because both can include a history of fever and irritability. However, a careful examination will reveal signs of dehydration, including sunken eyes, dry mucous membranes, and a sunken fontanelle in infants. The child will be tachycardic, and signs of compensated or hypotensive shock may be present. For further information, see Shock in Chapter 6 and Dehydration and Hypovolemia in Chapter 12.

The characteristics of the diarrhea stool can vary depending on the pathogen (see Table 14-12). If there is blood or mucous in the stool, stool studies should be obtained. The stool should be sent to identify stool pH, presence of reducing substance, presence of white blood cells, and C. difficile toxin and to check for ova and parasites and perform culture and sensitivity studies.

Initial diagnostic studies typically include evaluation of a serum chemistry panel and a complete blood cell count. Once the serum sodium concentration is determined, the estimate of the severity of dehydration (based initially on clinical examination alone) is modified as needed. Often these children have a metabolic acidosis, which may be evident from the low carbon dioxide level on the chemistry panel.

Management

The goals of the treatment of dehydration include restoration and maintenance of intravascular volume and systemic perfusion, and correction of abnormal serum electrolytes. If shock is present a urinary catheter is placed to enable continuous evaluation of urine production. Urine output should average approximately 0.5-1.0   mL/kg per hour. If urine output does not improve despite the presence of adequate systemic perfusion, notify an on-call provider immediately, because renal failure may be present (see Acute Renal Failure and Acute Kidney Injury in Chapter 13).

Treatment of dehydration requires replacement of the fluid deficit and any ongoing losses, and provision of maintenance fluid requirements. Regardless of the type of dehydration present, moderate or severe dehydration requires establishment of reliable vascular (IV or intraosseous) access. Children with mild dehydration may be able to replenish fluid losses with oral rehydration solutions, offered in small increments of 5-30   mL.

The child with moderate to severe dehydration will require IV fluid resuscitation with initial boluses (20   mL/kg) of isotonic crystalloids such as normal saline or Ringer’s lactate. Fluid boluses are repeated until systemic perfusion improves, with normalization of vital signs and urine output. Monitor the child’s systemic perfusion and continue fluid resuscitation as long as signs of shock are present.

It is important to monitor the child’s response throughout therapy. If the shock is corrected and rehydration is successful, systemic perfusion, neurologic function, acid-base and electrolyte balance, and urine output should all improve (for further information, see Shock in Chapter 6 and Dehydration and Hypovolemia in Chapter 12).

Children with diarrhea from a bacterial cause require contact isolation until antibiotic therapy is complete. When diarrhea has a viral cause, contact isolation is maintained until the symptoms resolve. Contact isolation must be enforced with meticulous attention to hand washing, because most of these organisms are contagious and are a frequent cause of healthcare-acquired infection.

Obtain an accurate weight as soon as possible after admission. This weight measurement can be helpful in determining the severity of dehydration and evaluating the patient’s response to therapy. Weight measurements are most reliable if the child is weighed using the same scale and technique at the same time every day. The nurse should carefully record intake and output and notify the on-call provider if the child’s urine output is less than the 0.5 to 1   mL/kg hour.

Monitor the child’s temperature throughout therapy. Young infants should be resuscitated under a warmer to prevent cold stress. If the infant is profoundly hypothermic, it may be necessary to warm resuscitation fluids before administration.

Treatment becomes supportive as diarrhea resolves. Initially, when stools are frequent and watery, the child receives nothing by mouth and maintenance fluid requirements are provided intravenously. The irritated GI tract requires a period of rest, followed by the gradual resumption of oral feedings with oral electrolyte solutions. Once stool output has decreased and the child is no longer vomiting, clear liquids are offered and enteral feeding can be advanced slowly as tolerated to an age-appropriate diet. If diarrhea resumes during diet advancement, the child should be placed back on a clear diet or the last tolerated intake.

Although the majority of acute diarrhea episodes are caused by viral pathogens, antimicrobial agents are administered for some bacteria or culture-proven parasitic infections. For culture-positive C. difficile infection, the causative antibiotic is discontinued if possible, and a 7-day oral course of metronidazole (Flagyl) is provided.⁵⁰ Oral vancomycin can also be administered to patients who cannot tolerate metronidazole or any adolescent patients who are breastfeeding or pregnant.⁵⁰

For the child who is experiencing concomitant vomiting and diarrhea, ondansetron (Zofran) can help with symptom control. For children with mild dehydration, the medication can be administered orally in the form of an oral disintegrating tablet; IV administration is recommended for children with moderate or severe dehydration.