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  1. Describe the etiology, pathophysiology, clinical presentation, patient needs, and principles of management for:

    • Acute gastrointestinal bleeding

    • Liver failure

    • Acute pancreatitis

    • Bowel ischemia

    • Bowel obstruction

    • Bariatric (gastric bypass surgery)

  2. Identify nutritional requirements for enterally fed critically ill patients.

  3. List important interventions to decrease the risk for aspiration pneumonia during enteral feeding.


Acute Gastrointestinal Bleeding

Upper GI Bleeding

Bleeding from the upper gastrointestinal (GI) tract is a medical emergency associated with morbidity, mortality, and costly care. Prompt and decisive treatment is essential to improve outcomes. Upper GI bleeding is 4 times more common than lower GI bleeding. An acute upper GI bleed is suspected when patients present with syncope, hypotension, or abdominal tenderness, and report melanic stool, hematochezia, and blood or coffee-ground emesis. In addition to anemia, laboratory values typically show an elevation of the blood urea nitrogen (BUN) to creatinine ratio (> 20:1). Although bleeding stops spontaneously in 80% to 90% of cases, patients presenting with sudden blood loss are at risk for hypotension, decreased tissue perfusion, and reduced oxygen-carrying capability. Many organ systems may be adversely affected.

Acute upper GI bleeding has a mortality of 6% to 15% and a high rate of reoccurrence. Many patients with bleeds are rebleeding from a previous upper GI tract lesion. A poor prognosis with upper GI bleeding is associated with age above 65, shock, overall poor health, active bleeding at the time of presentation, elevated creatinine or transaminases, onset of bleeding during hospitalization, and initial low hematocrit. Death is typically not a direct result of blood loss, but is related to age and comorbidities.

Lower GI bleeding

In contrast to upper GI bleeding, lower GI bleeding is defined as bleeding that originates distal to the ligament of Treitz and unlike upper GI bleeding has a lower morbidity and mortality. In fact, the bleeding resolves spontaneously in the vast majority of patients and the mortality rate is less than 5%. Distinguishing upper versus lower GI bleeding by origin is an important consideration because a rapid upper GI bleed may present as the presence of blood in the lower GI tract.

Lower GI bleeding is a common disorder in older adults and may be associated with a host of conditions including infection, hemorrhoids, cancer, diverticulitis, or vascular anomaly. Regardless of the source, lower GI bleeding typically presents as hematochezia. Bleeding sources within the left side of the colon often result in the presence of bright red blood whereas those from the right colon may be mixed with stool and present as a darker shade of red.

Etiology, Risk Factors, and Pathophysiology

A variety of abnormalities within the GI tract can be the source of upper GI bleeding (Table 14-1).

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