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Patients should be assessed for the appropriate timing and route for

nutrition support.

Case 37-1 (Questions 1, 2)

The type of tube placement and site of formula delivery are determined

by several factors.

Case 37-2 (Question 1)

Formula selection is based on nutrient requirements, fluid restrictions,

and the extent

of impaired digestion and absorption.

Case 37-2 (Questions 2–5)

The administration regimen for feeding is influenced by the feeding

route, formula selected, and duration of feeding.

Case 37-2 (Questions 6–8)

Although the preferred route for nutrition intervention in critical illness is

enteral,

the ideal formula composition remains unresolved.

Case 37-3 (Questions 1–4)

Macronutrient content should be considered when selecting an enteral

formula for patients with diabetes.

Case 37-4 (Question 1)

Appropriate monitoring is essential to recognize and prevent

complications associated with enteral nutrition.

Case 37-4 (Question 2)

Medication administration through a feeding tube requires selection of

appropriate dosage forms and proper preparation.

Case 37-4 (Question 3)

Feeding tube occlusion is a common problem influenced by medicationrelated

and nonmedication-related factors.

Case 37-4 (Question 4)

Patients must meet strict criteria for Medicare coverage of home enteral

nutrition.

Case 37-5 (Question 1)

Diarrhea in patients receiving enteral nutrition is multifactorial, including

both

tube-feeding-related and nontube-feeding-related causes.

Case 37-6 (Question 1)

Enteral nutrition refers to nutrition provided via the gastrointestinal (GI) tract.

However, because the term is commonly used, enteral nutrition (EN) is synonymous

with delivery of nutrients into the GI tract by tube (e.g., nasogastric or jejunostomy

feeding). Tube feeding allows continued use of the GI tract when one or more steps

in the normal process of obtaining nutrients from oral intake are disrupted. Table 37-

1 lists functional anatomic units of the GI tract along with major steps occurring in

preparing nutrients for absorption and examples of conditions potentially impairing

each region. Chewing or swallowing may be completely disrupted, but some

digestive and absorptive function must remain for tube feeding to be a viable option.

PATIENT SELECTION AND ROUTE OF FEEDING

CASE 37-1

QUESTION 1: G.W., a 59-year-old woman, 5 feet 2 inches tall, 88 kg, was brought to the emergency

department (ED) last night complaining of severe left-sided upper abdominal pain. Tests performed in the ED

were consistent with acute pancreatitis. G.W. was admitted to the hospital and has “nothing by mouth” (NPO)

orders in her chart. The gastroenterology service has seen her and scheduled an endoscopic retrograde

cholangiopancreatography (ERCP) for tomorrow. A nutrition support consult was ordered. G.W. is currently

receiving intravenous (IV) 5% dextrose/0.9% sodium chloride with KCl 20 mEq/L at 125 mL/hour. She is also

receiving hydromorphone via a patient-controlled analgesia (PCA) pump.

G.W. has been experiencing crampy upper right quadrant pain on and off for about 3 weeks and saw her

primary care physician a week ago. She is allergic (rash) to sulfa. She was told that her symptoms are

consistent with gallbladder inflammation; surgery will be necessary if her symptoms continue or the pain

worsens. In addition, her doctor said blood pressure and glucose control “needed improvement” and mentioned

it might be because her weight was up 8 pounds. She quit smoking 6 months ago; she frequently drinks one

glass of wine with dinner.

Laboratory values this morning are as follows:

Sodium, 139 mEq/L

Potassium, 3.8 mEq/L

Blood urea nitrogen (BUN), 10 mg/dL

Serum creatinine (SCr), 0.8 mg/dL

Glucose, 175 mg/dL

Albumin, 3.4 g/dL

Amylase, 705 units/L (down from 1,200 units/L in the ED)

Lipase, 698 units/L (down from 1,198 in the ED)

Triglycerides, 185 mg/dL

White blood cells (WBC), 12.7 × 10

3

/μL

Hemoglobin (Hgb), 12.4 g/dL

Hematocrit (Hct), 37.3%

C-reactive protein (CRP), 2.2 mg/dL

Does G.W. require nutritional intervention at this time? When should nutrition intervention be considered for

G.W.?

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Table 37-1

Functional Units of the Gastrointestinal Tract

Functional Unit Major Steps Conditions/Diseases Disrupting Function

Mouth and

oropharynx

Chew and lubricate food;

swallow; taste

Amyotrophic lateralsclerosis, muscular dystrophy,

severe RA, CVA, end-stage Parkinson disease,

paralysis, coma. Anorexia due to other disease: cardiac

or cancer cachexia, renal failure and uremia, liver

failure, neurologic disease.

Esophagus Transport food to the stomach Esophageal ulcer, cancer, obstruction, or fistula;

esophagectomy; CVA.

Stomach Hold food for mixing and

grinding; add acid and enzymes;

release chyme to small bowel;

osmoregulation

Severe gastritis or ulceration, gastroparesis, gastric

outlet obstruction, gastric cancer, severe

gastroesophageal reflux.

Duodenum Osmoregulation; neutralize

stomach acid

Severe duodenal ulcer or fistula; cancer: gastric or

pancreatic; surgical resection or bypass of the

duodenum: Whipple-type procedures.

Small bowel: jejunum

and ileum

Digestion; absorption Enterocutaneous fistula, severe enteric infection,

malnutrition, malabsorption, Crohn disease, celiac

disease, ileus and dysmotility syndrome.

Pancreas Secretion of digestive enzymes Pancreatitis, pancreatic cancer, pancreatic injury,

pancreatic fistula.

Colon Absorb fluid; ferment soluble

fiber and unabsorbed

carbohydrate; absorb water

Ulcerative colitis, Crohn disease, colon cancer,

colocutaneous fistula, colovaginal fistula, diverticulitis,

colitis of any etiology, colon surgery.

CVA, cerebrovascular accident; RA, rheumatoid arthritis.

Patients generally are considered at risk for nutrient depletion and associated

increased morbidity and mortality when intake is less than 50% to 75% of

requirements for 5 to 7 days acutely or when weight loss exceeds 5% or more in 1

month, 7.5% or more in 3 months, or 10% or more of pre-illness weight within a 6-

month period.

1,2 For adequately nourished patients, specialized nutrition support is

generally not warranted when support will be needed for fewer than 7 to 10 days.

3

Undernourished patients require nutritional intervention sooner. See Chapter 35,

Basics of Nutrition and Patient Assessment, for further information on malnutrition.

G.W. was adequately nourished before admission based on her weight for height and

serum albumin. She has weight gain per the clinic visit, although edema should be

ruled out as a cause, and has been NPO for less than 24 hours. Nutrition support is

not warranted at this time. However, once the ERCP has been completed, the need

for nutrition intervention should be reassessed. If G.W. must remain NPO for a week

or more, nutritional intervention would be warranted. Obesity does not preclude the

need for nutritional intervention.

CASE 37-1, QUESTION 2: What route of nutrition intervention would be most appropriate for G.W. if she

cannot restart her diet in a timely manner?

Routes of nutrition intervention may include modified oral diet, including oral

supplements or altered consistency diets (e.g., thickened liquids, pureed foods), EN

by tube, or parenteral nutrition (PN). Tube feeding is considered the route of choice

in patients with a functional GI tract in whom oral nutrient intake is contraindicated

or is insufficient to meet estimated needs.

3 Other than potential “gallstone”

pancreatitis, G.W. is expected to have a functional GI tract. The ERCP and pain

symptoms will help determine whether G.W. will remain NPO or have a diet started.

It appears her pancreatitis is improving based on decreasing amylase and lipase

values. For patients with severe acute pancreatitis, Society of Critical Care Medicine

(SCCM) and American Society for Parenteral and Enteral Nutrition (ASPEN)

Critical Care (SACC) guidelines recommend initiation of EN as soon as volume

resuscitation is complete.

4 For patients such as G.W. with mild-to-moderate acute

pancreatitis, symptoms typically resolve before nutrition intervention is necessary.

When symptoms are prolonged and nutrition support is required, EN is the preferred

route of nutrition support because EN may reduce the inflammatory response and

decrease complications.

4–6

EN may be appropriate for patients with the disorders listed in Table 37-1,

depending on the extent to which normal intake, transport, digestion, and absorption

of nutrients are impaired. Clinical circumstances, not specific diagnoses, should be

the

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