Enteral Nutrition

Question 1

Once the enteral formula is opened, how long may it be stored in a refrigerator?

1: Up to 24 hours
2: Up to 36 hours
3: Up to 48 hours
4: Up to 72 hours

Answer 1

3: Up to 48 hours

Opened ready-to-feed formula may be stored in a refrigerator for up to 48 hours.

References:

Marian M, Carlson SJ. Enteral Formulations. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual, 2nd ed. Silver Spring, MD; A.S.P.E.N.; 2005:63-75.

Question 2

Which of the following is not an accepted means for estimating daily fluid requirements in enterally-fed adult patients?

1: 0.5 mL/kg/min
2: 35 mL/kg/day
3: 1500 mL/m2/24 hrs
4: 1 mL/kcal consumed

Answer 2

1: 0.5 mL/kg/min

Any of the following methods is intended to replace urine and insensible fluid losses in enterally fed adults: 35 mL water per kg body weight per day, 1500 mL water per m2 body surface area per day, or 1mL water per kcal consumed per day. 0.5 mL water per kg body weight per minute would grossly overestimate daily fluid requirements in any patient.

References:

Dickerson RN, Brown RO. Long-term nutrition support and the risk of dehydration. NCP. 2005;20:646-653.

Question 3

A 51.5 kg afebrile 55-year-old female with dysphagia is started on a standard 1.0 kcal/mL enteral formula with 85% water at 180 mL/hr over 10 hours nightly. Which of the following water flush regimens would best meet her daily estimated fluid requirements?

1: 0 mL
2: 60 mL every 8 hours
3: 90 mL every 8 hours
4: 120 mL every 8 hours

Answer 3

3: 90 mL every 8 hours

Daily fluid requirements in an afebrile, enterally fed patient can be estimated by using 35 mL/kg/d or 1 mL/kcal consumed. For this patient, daily estimated fluid requirements would approximate 1.8 L. The standard formula used is 85% water or provides 1.53 L water per day. The remainder may be given as a fluid bolus three times a day, this would equal 90 mL every 8 hours.

References:

Lord L, Harrington M. Enteral Nutrition Implementation and Management. In: Merritt, R, ed. A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed.Silver Spring, MD; A.S.P.E.N.; 2005:76-89.

Question 4

In studies comparing EN to PN in patients with severe acute pancreatitis, which of the following potential benefits of EN over PN has not been documented?

1: Decrease hospitalization length
2: Decrease mortality
3: Decrease trend of organ failure
4: Decrease infection rate

Answer 4

2: Decrease mortality

EN has been associated with a significant reduction in infectious morbidity, hospital length of stay, and a trend toward reduced organ failure when compared with PN. Results from individual studies suggest that EN in comparison to PN reduces oxidative stress, hastens resolution of the disease process, and costs less. A reduction in mortality has not been shown with the use of EN versus PN in severe acute pancreatitis. Insufficient data exist to determine whether EN improves outcomes over no artificial nutrition support.

References:

McClave SA, Chang WK, Dhaliwal R, Heyland DK. Nutrition Support in Acute Pancreatitis: A Systematic Review of the Literature. JPEN.2006;30:143-156

Question 5

Which of the following is NOT a perceived benefit of early enteral feeding in critically ill patients?

1: Prevents the occurrence of translocation of gut bacteria
2: Reduces atrophy of intestinal villae
3: Fewer infectious complications than PN-fed patients
4: Increases intestinal permeability

Answer 5

4: Increases intestinal permeability

Early appropriate enteral tube feeding may prevent the occurrence of bacterial translocation (the passage of bacteria across the intestinal wall), and preserve gut mucosal immunity. Lack of feeding via the gut during critical illness may lead to atrophy of intestinal villae, which could predispose the patient to translocation, increase gut permeability, and potentially increase the risk of infection. When early TF patients were compared to PN in injured patients, the PN patients had more infectious complications.

References:

Btaiche IF, Marik PE, Ochoa J, Martindale R, Salon JE. Nutrition in critical illness, including immunonutrition. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:263-270.

Question 6

Which of the following parameters is not useful in assessing the efficacy of enteral nutrition in pregnancy?

1: Maternal dry weight gain
2: Fetal growth
3: Urinalysis
4: Nitrogen balance

Answer 6

3: Urinalysis

Maternal weight gain and fetal growth are the most important factors in assessing the adequacy and efficacy of enteral tube feedings in pregnancy. Positive nitrogen balance is important in assessing provision of adequate protein. Although a urinalysis is routinely performed in pregnancy, results of this test are used to screen patients for ecclampsia and not efficacy of enteral nutrition.

References:

Frankenfield D. Pregnancy. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:343-348.

Question 7

Evidence exists to show which of the following enteral formulas to be most efficacious in a patient with diabetic gastroparesis?

1: Concentrated
2: Glutamine-supplemented
3: Hydrolyzed
4: Low fat

Answer 7

4: Low fat

Although gastroparesis may make tolerance of tube feeding difficult, most patients tolerate jejunal feeding when isotonic, rather than hypertonic or concentrated, formulas are used. Higher fat enteral formulas have been shown to decrease or delay gastric emptying. The use of hydrolyzed (vs. intact) formulas and formulas supplemented with glutamine have not been studied in diabetic gastroparesis.

References:

McMahon MM. Diabetes Mellitus. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:317-323.

Question 8

Lactose is a common ingredient in which type of enteral formula?

1: Semi-elemental formula
2: Standard adult formula
3: Standard infant formula
4: Elemental formula

Answer 8

3: Standard infant formula

Lactose is routinely used in standard infant formulation to mimic the carbohydrate found in human milk. Most adult medical nutritional products are lactose-free due to the prevalence of lactose intolerance in many populations and because lactase production may be decreased during illness.

References:

Marian M, Carlson SJ. Enteral Formulations. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual, 2nd ed. Silver Spring, MD; A.S.P.E.N.; 2005:63-75.

Question 9

Which of the following patient populations would most likely have difficulty tolerating a polymeric enteral formula?

1: Crohn’s disease
2: Intestinal lymphangiectasia
3: Gastroparesis
4: Celiac disease

Answer 9

2: Intestinal lymphangiectasia

Patients with intestinal lymphangiectasia have compromised lymphatic flow and increased pressure in the lymphatic system. Intestinal lymph flow and lymphatic pressure is increased during absorption of long-chain fats found in polymeric enteral formulas. This results in protein leakage into the intestinal lumen. A very low fat enteral formula (< 20 g) or a formula higher in medium-chain fats may relieve pressure in the lymphatic system and reduce protein losses. Patients with Crohn’s or celiac disease most often tolerate formulas with intact macronutrients. In severe cases refractory to medical management, trial of an elemental diet may be necessary. Patients with gastroparesis most often tolerate polymeric enteral formula fed into the jejunum. These patients should be kept NPO during initial enteral trials until tolerance to feeds is established.

References:

Parrish CR, Krenitsky J, Willcutts K, et al. Gastrointestinal Disease. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:508-539.

Question 10

In patients with pancreatitis, which of the following parameters would be LEAST important in predicting tolerance of enteral feedings?

1: Disease severity
2: Duration of NPO
3: Abdominal pain
4: Triglyceride level

Answer 10

4: Triglyceride level

The largest factor in determining tolerance of enteral nutrition in pancreatitis is disease severity as measured by APACHE II scores. Duration of NPO is also important as studies have shown poor tolerance in patients NPO for greater than or equal to 6 days prior to initiation of enteral feeding. Increasing abdominal pain is a clinical indication of enteral feeding intolerance in pancreatitis. Serum triglyceride levels are routinely used to measure tolerance of parenteral rather than enteral nutrition.

References:

Mascarenhas, MR, Divito D, McClave SA. Pancreatic disease. In Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual, 2nd ed. Silver Spring, MD; A.S.P.E.N.;2005; 211-230.

Question 11

Which of the following best describes the rationale for initiating specialized nutrition support?

1: It may be implemented in patients who cannot, should not, or will not eat adequately
2: It may be implemented in patients who are well nourished with an intact GI tract
3: It should be implemented on an emergency basis, regardless of patient’s hemodynamic status
4: It is commonly used to treat specific disease manifestations

Answer 11

1: It may be implemented in patients who cannot, should not, or will not eat adequately

Specialized nutrition support (SNS) may be implemented in patients who cannot, should not, or will not eat adequately and in whom the benefits of improved nutrition outweigh the risks. SNS should be implemented in patients who are malnourished or at significant risk for malnutrition. The initiation of SNS is not an emergency and should only be started when patients are hemodynamically stable. Only in relatively uncommon circumstances is SNS used to treat specific disease manifestations.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 12

Tube feedings can be effectively used in which of the following conditions?

1: Intractable nausea and vomiting
2: High output proximal fistula
3: Open peritoneal cavity
4: Short bowel syndrome (<50cm) without colon

Answer 12

3: Open peritoneal cavity

In an open peritoneal cavity, the peritoneum is left open and the viscera are protected with a temporary dressing until the abdomen can be closed. Enteral nutrition can be effectively used in patients requiring open peritoneal cavity management after laparotomy. Parenteral nutrition may not be necessary in this population. Nutritional goals and significant cost savings can be realized by using tube feedings. Parenteral nutrition should be used in patients with high output proximal fistula, intractable nausea and vomiting, and short bowel syndrome when the patient cannot be weaned off of parenteral nutrition.

References:
Corkins MR, Scolapio J. Diarrhea. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.:2005:203-210

Question 13

Which of the following is an indication to surgically place a jejunostomy feeding tube?

1: Hyperemesis gravidarum
2: Dysphagia
3: Gastroesophageal reflux
4: Diabetic gastroparesis

Answer 13

4: Diabetic gastroparesis

Gastroparesis is an indication for placing a jejunal feeding tube versus a percutaneous endoscopic gastrostomy (PEG) tube. The jejunal tube bypasses the stomach thus preventing postprandial nausea and vomiting during feeding. Research has not supported the need for surgical placement of a jeujunostomy tube in patients with hyperemesis gravidarum, gastroesophageal reflux, or dysphagia.

References:
A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 14

Which of the following is the most invasive method used to assist in placement of a nasoenteric feeding tube?

1: Corkscrew method
2: Direct fluoroscopic guidance
3: Endoscopic assistance
4: Pharmacologic stimulation

Answer 14

3: Endoscopic assistance

While all methods listed have a success rate of 80-95%, endoscopic placement is the most invasive technique. It requires placement of a larger instrument in addition to the feeding tube into the GI tract. Other types of methods used to assist in transpyloric placement of feeding tubes include pharmacologic stimulation of gastric peristalsis with erythromycin and metoclopramide, using a corkscrew method during inserting of the feeding tube, and direct fluoroscopic guidance.

References:
Gabriel SA, Ackermann RJ. Placement of nasoenteral feeding tubes using external magnetic guidance. JPEN. 2004;28:119-122.

Question 15

How long should T-fasteners be left in place after placing a gastrostomy or jejunostomy feeding tube laparoscopically or radiologically?

1: 4-5 days
2: 10-14 days
3: 21-24 days
4: 28-31 days

Answer 15

2: 10-14 days

There is no incision with gastrostomy or jejunostomy tubes placed laparoscopically or radiologically. Instead, T-fasteners are used to hold the stomach or small bowel in place against the abdominal wall. The external portion of the T-fastener is called a bumper. Typically four T-fasteners are used and remain in place for 10-14 days to allow a stoma tract to form. If removed sooner, displacement may occur. If kept in longer than 10 days, local skin infection and pain may result.

References:
Worthington PH, Reyen L. Equipment and formulas for enteral nutrition. In: Worthington, PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders; 2004:283-309.

Question 16

Which of the following is most characteristic of a skin-level device or a button for enteral feeding?

1: Can only be used with gastrostomies
2: Does not contain an antireflux valve
3: Can be capped at skin level when not in use
4: Can only be placed in the operating room

Answer 16

3: Can be capped at skin level when not in use

Skin-level, low-profile, or gastric button devices are alternatives to standard gastrostomy or jejunostomy tubes. Because they are less obtrusive, they have a minimal impact on body image. Skin level devices can be capped at skin level when not in use and contain an antireflux valve to prevent backflow of fluids. Physicians, nurses, or caregivers can exchange the device for a longer size if the patient grows or gains weight. Exchange or initial placement of the device does not have to be performed in the operating room since these devices are typically inserted in a well-established stoma tract.

References:
Worthington PH, Reyen L. Equipment and formulas for enteral nutrition. In: Worthington, PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders; 2004:283-309.

Question 17

What is the gold standard for determining proper position of a feeding tube placed at the bedside?

1: Radiographic confirmation
2: pH testing for acidity of aspirates
3: Aspiration of obvious gastric contents
4: Air sufflation and auscultation over the gastric bubble

Answer 17

1: Radiographic confirmation

Radiographic confirmation after insertion of a nasoenteric feeding tube is the best method (gold standard) for determining proper placement of a nasogastric tube. Although tube placement can be confirmed by air insufflation, ascultation and aspiration of gastric contents, these methods have been reported to result in false positives resulting in tube placement in the tracheobronchial tree.

Question 18

Which of the following is a CONTRAINDICATION to a percutaneous endoscopic jejunostomy tube?

1: Gastroparesis
2: Partial gastrectomy
3: Refractory celiac disease
4: End-jejunostomy

Answer 18

4: End-jejunostomy

Jejunal feeding would be contraindicated in short bowel syndrome when only the jejunum is remaining. Delivery of formula in this situation will result in significant diarrhea and inability to absorb adequate calories for survival. In this situation parenteral nutrition or a PEG (percutaneous endoscopic gastrostomy) tube may become necessary. Gastroparesis is the primary indication for a percutaneous endoscopic jejunostomy (PEJ). A partial gastrectomy and refractory celiac disease would not be contraindications to jejunal feeding or to placement of a PEJ.

References:
A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 19

Compared to gastric feeding, small bowel feeding is associated with which of the following outcomes in critically ill patients?

1: Longer time to achieve target nutrition
2: Increased nutrient delivery
3: Increased gastroesophageal regurgitation
4: Increased rate of ventilator-associated pneumonia

Answer 19

2: Increased nutrient delivery

Based on a systematic review of studies comparing gastric and small bowel feeding methods, small bowel feeding is associated with reduced gastric residual volume and reflux, but adequately powered trials are not available to support prevention of aspiration pneumonia. Several studies document increased protein and energy delivery and a shorter time to target rate with small bowel feeding.

References:

Kattelmann KK, Hise M, Russell M, Charney P, Stokes M, Compher C. Preliminary evidence for a medical nutrition therapy protocol: enteral feedings for critically ill patients. J Am Diet Assoc. 2006;106(8):1226-1241.

Question 20

Which of the following surgically placed feeding tubes can result in a thoracic duct injury?

1: Witzel gastrostomy
2: Stamm gastrostomy
3: Cervical esophagostomy
4: Needle catheter jejunostomy

Answer 20

3: Cervical esophagostomy

Potential complications of a surgically placed cervical esophagostomy or cervical pharyngostomy include infection, hemorrhage, aspiration, thoracic duct injury, recurrent laryngeal nerve injury, permanent fistula, and inadvertent tube dislodgement. Thoracic duct injury is not a complication of a surgically placed jejunostomy or gastrostomy because anatomically the surgeon is not operating near the thoracic duct. Cervical esophagotomy and pharyngostomy are rarely used today as a result of improved surgical techniques for placement of feeding tubes.

References:

Vanek VW. Ins and outs of enteral access: Part 2-Long term access-esophagastomy and gastrostomy. NCP. 2003;18(1):50-74.

Question 21

During placement of a nasogastric feeding tube in an alert patient, which of the following is an appropriate step to avoid inadvertent tube placement into the airway?

1: Administer IV metoclopramide.
2: Keep patient NPO during insertion.
3: Position patient with head bent forward, chin toward the chest.
4: Measure distance from the tip of the patient’s nose to the earlobe and mark on tube with tape

Answer 21

3: Position patient with head bent forward, chin toward the chest.

After gathering the appropriate equipment for placing a nasogastric feeding tube, the procedure should be explained to the patient. To approximate the distance for insertion of tube into the stomach, the distance from the tip of the patient’s nose to the earlobe and then the xiphoid process should be measured and marked on the tube with tape. Sit and position the patient upright in a chair or raise the head of the bed as much as possible. This upright position reduces the risk of aspiration. After lubricating the tip of the tube, the most patent nostril should be selected to ensure unobstructed passage of the tube. Once the tube is inserted into the nostril, the patient should be positioned with head bent forward and chin toward the chest to reduce the possibility of tube entering airway. Offering sips of water or ice chips at this point stimulates reflexive swallowing to facilitate passage of tube into stomach. The tube should be advanced gently as patient swallows.

References:

Worthington PH, Reyen L. Equipment and formulas for enteral nutrition. In: Worthington, PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders; 2004:283-309.

Question 22

Which of the following methods is usually the most successful in the transpyloric placement of a nasoenteric feeding tube?

1: pH sensor tubes
2: Metoclopramide
3: Fluoroscopic placement
4: Weighted tube at bedside

Answer 22

3: Fluoroscopic placement

Both fluoroscopic and endoscopic placements have the highest percentage of successful transpyloric passage. Endoscopy can facilitate feeding tube placement in the small bowel, with a reported success rate of 90-95%. A disadvantage of fluoroscopic placement is that it requires changes in the patient’s body position, which may not be possible in critically ill patients. If bedside fluoroscopy is not available, patients must be transported to the radiology suite. Results with other placement methods including weighted tubes, pH sensor tubes, and use of metoclopramide are variable and less successful than fluoroscopic placement.

References:

Kirby DF, Opilla M. Enteral access and infusion equipment. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual 2nd ed. Silver Spring, MD: A.S.P.E.N.;2005:54-62.

Question 23

Which of the following is least likely to be problematic for placement of a percutaneous endoscopic gastrostomy (PEG) tube in a patient with liver disease?

1: Ascites
2: Coagulopathy
3: Gastric varices
4: Hepatitis B

Answer 23

Placement of a PEG tube in the face of portal hypertension is often not an option. The presence of ascites at the time of tube placement may prevent the gastric and abdominal walls from being in close proximity, this results in the inability of the trocar to pass through the stomach wall or in a poor seal between the abdominal and gastric wall, allowing the egress of ascetic fluid externally or the passage of the feeding formula into the peritoneal cavity. Thus, ascites is a relative contraindication for PEG placement. Providing tube feeding to a patient with liver disease should be considered if the patient is malnourished. Benefit has been shown in patients with cirrhosis receiving tube feeding for at least 3-6 weeks. Appropriate assessment of risks vs. benefits of tube feeding must be made regarding esophageal and gastric varices, coagulapathy, hepatic encephalopathy, ascites, and fulminant hepatic failure. The cause of liver failure does not affect the decision in placement of a PEG.

References:

Crippin JS. Is tube feeding an option in patients with liver disease? NCP. 2006;21:296-298.

Question 24

Which of the following is an advantage of a gastrostomy-placed feeding tube compared to a nasogastric feeding tube?

1: Reduced incidence of aspiration
2: Less nasal irritation
3: More successful delivery of calories
4: Reduced incidence of gastric perforation

Answer 24

2: Less nasal irritation

When enteral feeding is required for more than four weeks, gastrostomy feeding tubes are preferred. Since the nasal tract is bypassed, nasal irritation is avoided. Feeding through a gastrostomy tube does not reduce aspiration risk. Provided the nasal feeding tube does not become frequently displaced and occluded, the calories delivered by both methods are similar. Gastric perforation is greater with a gastrostomy placed tube than a nasal placed tube.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 25

Which of the following is a CONTRAINDICATION to percutaneous endoscopic gastrostomy tube placement?

1: Ascites
2: Partial gastrectomy
3: Obesity
4: Stroke

Answer 25

1: Ascites

Ascites is considered a contraindication to percutaneous endoscopic gastrostomy (PEG) placement because of the increased risk of peritonitis. Provided adequate transillumination is found during endoscopy, partial gastrectomy and obesity are not contraindications to placement. The stroke patient with dysphagia is the most common indication for PEG placement.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 26

Which of the following is NOT pre-procedure care of a patient undergoing placement of a percutaneous endoscopic gastrostomy tube?

1: Obtaining informed consent
2: Obtaining an abdominal X ray
3: Administering an antibiotic on call
4: Confirming normal INR

Answer 26

2: Obtaining an abdominal X ray

Informed consent from either the patient or power of attorney should be obtained before percutaneous endoscopic gastrostomy (PEG) placement. A dose of antibiotic, usually Cefazolin, should be given on call 30 minutes prior to placement to prevent local skin site infection. Patients should have an adequate platelet count and normal INR prior to placement to reduce the chance of bleeding. Patients with renal insufficiency also have a higher chance of bleeding. An abdominal X-ray is not indicated prior to placement.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 27

Which of the following is the preferred method of feeding tube placement when post pyloric feeding is required for less than 4 weeks?

1: Laparoscopic
2: Open surgical
3: Nasal jejunal tube
4: Percutaneous endoscopic jejunostomy

Answer 27

3: Nasal jejunal tube

Placement of a jejunal feeding tube via the open surgical route, laparoscopically, or endoscopically (PEJ) is not without risk. Risks include bleeding, anesthesia complication, bowel perforation, and infection. Although complications can occur with nasally placed tubes, they are much less common. If a feeding tube is required short term (i.e. less than 4 weeks), a nasally placed tube is the preferred method.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 28

What is the primary advantage of a direct percutaneous endoscopic placed jejunal tube versus a percutaneous endoscopic transgastric-placed jejunal tube?

1: Easier to place
2: Reduced incidence of bleeding
3: Reduced incidence of migration
4: Reduced incidence of gastric outlet obstruction

Answer 28

3: Reduced incidence of migration

Placement of a direct percutaneous endoscopic jejunostomy (PEJ) has less potential for migration or flipping back into the stomach compared to the percutaneous endoscopic transgastric jejunostomy (PEG-J) method. Although gastric outlet obstruction may occur more in the PEG-J method by virtue of it crossing the pylorus, this is not the primary advantage of using direct PEJ. Bleeding risk is no different between methods. The ability to place a PEG-J depends on the skill and training of the endoscopist.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 29

Which of the following types of enteral formulas is MOST likely to increase splanchnic blood flow in a critically ill patient?

1: High fat
2: High carbohydrate
3: High fiber
4: High osmolarity

Answer 29

1: High fat

Feeding the critically ill patient is challenging, especially when they are receiving pressors and are being actively resuscitated. Knowing the characteristics of enteral formulas that have the greatest effect on blood flow to the bowel can be beneficial when choosing the formula that best meets the patient’s nutritional needs. Research has shown that blood flow to the bowel is maximized with use of high fat formulas over high carbohydrate formulas. An isotonic (low osmolarity), fiber-free formula is ideally recommended for patients at high risk for intestinal ischemia as adequate bowel perfusion is necessary for tolerance of high fiber, high osmolarity feedings.

References:

McClave S. Feeding the Hypotensive Patient: Does Enteral Feeding Precipitate or Protect against Ischemic Bowel? NCP. 2004;18:294-296.

Question 30

Hospital-prepared enteral nutrition formulas should be stored at what temperature?

1: 4° C (39.2° F)
2: 6° C (42.8° F)
3: 8° C (46.4° F)
4: 10° C (50.0° F)

Answer 30

1: 4° C (39.2° F)

To prevent microbial growth and contamination, hospital prepared formulas should be stored at 4° C (39.2° F). The danger zone for food contamination falls between 4.44 and 60 degrees Celsius (40 and 140 degrees Fahrenheit).

References:

Russell MK, Andrews MR, Brewer CK, et al. Standards for specialized nutrition support: Adult hospitalized patients. NCP. 2002;17:384-391.

Question 31

An isotonic formula has an osmolality of

1: 150 mOsm/kg.
2: 300 mOsm/kg.
3: 450 mOsm/kg.
4: 600 mOsm/kg

Answer 31

2: 300 mOsm/kg.
The osmolality of gastrointestinal secretions is approximately 300 mOsm/kg. A formula that is isotonic would have the same osmolality of gastrointestinal secretions.

References:

Parrish CR, Krenitsky J, Willcutts K, et al. Gastrointestinal Disease. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:508-539.

Question 32

Which of the following best describes the initiation of a hypertonic formula for gastric feeding?

1: Formula can safely be initiated at full strength at a low rate
2: Formula should be diluted to an isotonic formula and initiated at goal rate
3: Formula should be co-administered with an anti-diarrheal agent
4: Formula should be switched to an isotonic formula at a low rate

Answer 32

1: Formula can safely be initiated at full strength at a low rate

Research has failed to show a benefit to diluting enteral formulations, and the act of dilution may increase the rate of feeding intolerance by creating an environment that supports microbial growth. Dilution of enteral formulas during initiation may also result in a long period of inadequate nutrition. Hypertonic formulas should therefore be initiated at full strength at a low rate and advanced as tolerated.

References:

Marian M, McGinnis C. Overview of Enteral Nutrition. In: Gottschlich MM, ed. The A.S.P.E.N. Nutriton Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD; A.S.P.E.N.; 2007:187-208.

Question 33

Which of the following medications has NOT been shown to lead to diarrhea in a patient receiving enteral nutrition?

1: Sorbitol elixirs
2: Alpha-2 adrenergic agonists
3: Antibiotics
4: Magnesium-containing preparations

Answer 33

2: Alpha-2 adrenergic agonists
Drugs may cause diarrhea due to hypertonicity, increased susceptibility to infectious enteritis, or direct laxative action. Sorbitol elixirs, antibiotics, and magnesium-containing preparations have all been associated with the development of diarrhea in tube fed patients. High osmolality of tube feeding, rapid bolus technique or significantly compromised albumin levels have also been cited. Alpha-2 adrenergic agonists, such as clonidine, have been shown to have significant antimotility effects and often prolong instead of reduce intestinal transit time.

References:

Malone AM, Seres DS, Lord L. Complications of Enteral Nutrition. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:246-263.

Question 34

Tube feeding with a standard enteral formula is often held before and after administration of all the following medications EXCEPT

1: Theophylline
2: Nitroglycerin
3: Ciprofloxacin
4: Phenytoin

Answer 34

2: Nitroglycerin

Question 35

Which of the following alterations to the enteral formula most often reduces the risk for physical interaction between the formula and medications?

1: Switch to a free amino acid enteral formula
2: Add fiber to the enteral formula
3: Reduce fat content of the enteral formula
4: Increase total free water in the enteral formula

Answer 35

1: Switch to a free amino acid enteral formula

The presence of complex proteins (caseinates, soy, whey) in enteral formulas has been shown to lead to physical interaction (precipitation, curdling, clumping) with several medications. Switching to a hydrolyzed or free amino acid enteral formula may improve compatibility with medications administered during enteral feeding. The addition of fiber may increase risk for physical drug interaction. The fat or water content of the enteral formula does not seem to affect the risk of physical interaction with drugs, however high fat formulas may alter drug absorption through delayed gastric emptying.

References:

Rollins CJ. Drug-Nutrient Interactions. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:340-359.

Question 36

Drugs in microencapsulated bead, enteric-coated granule or pellet form are most effectively administered through feeding tubes when mixed with

1: orange juice.
2: gingerale.
3: oral electrolyte solution.
4: warm water.

Answer 36

1: orange juice.

An acidic juice such as orange juice can reduce the risk of beads, pellets, or granules sticking to the tube. After administration, a 30-mL warm water flush may then be used to clear the tube of the acidic juice-drug mixture. Mixing drugs with carbonated beverages such as gingerale may be problematic. The use of water or an oral electrolyte solution to administer granules may cause them to become sticky and adhere to the tube, thereby increasing the risk for feeding tube occlusion.

References:

Rollins CJ. Drug-Nutrient Interactions. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:340-359

Question 37

Which of the following feeding formulas is most likely to be contaminated?

1: Pasteurized
2: Blenderized
3: Ready to feed
4: Ready to hang

Answer 37

2: Blenderized

A study that implemented the hazard analysis critical control points (HACCP) system improved the microbial quality of the feedings. Blenders used to reconstitute feedings were found to be the main source of bacterial contamination.

References:

Oliviera MH, Bonelli R, Aidoo KE, et al. Microbiological quality of reconstituted enteral formulations used in hospitals. Nutrition. 2000;16:729-733.

Question 38

Which of the following best describes the absorption of small peptides and free amino acids contained in hydrolyzed enteral formulas?

1: The majority of small peptides and amino acids are absorbed through active transport across the gastric mucosa
2: Free amino acid absorption occurs more rapidly than an equivalent mixture of small peptides
3: Small peptide formulations have a higher osmolality and thereby less efficient absorption than free amino acid formulas
4: Although absorption may differ, there are no established clinical advantages to the use of small peptide over free amino acid formulas or vice-versa.

Answer 38

4: Although absorption may differ, there are no established clinical advantages to the use of small peptide over free amino acid formulas or vice-versa.

The protein found in elemental or fully hydrolyzed enteral formulas is mostly in free amino acid form whereas the protein in semi-elemental or partially hydrolyzed formulas is mainly in small peptide form. The majority of small peptides and free amino acids are absorbed through active transport across the lumen of the small intestine. Small peptides are generally absorbed faster than free amino acids. Free amino acid formulas have a higher osmolality than small peptide formulas, which may adversely affect absorption in several patient populations. However, in those patients studied, there appear to be no clinical differences or advantages between the use of small peptides or free amino acid enteral formulations.

References:

Young LS, Kearns LR, Schoepfel SL. Protein. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach-The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:71-87.

Question 39

The use of enteral formulas with intact protein has been shown to be as effective as use of free amino acid-based formulas in promoting remission of

1: Crohn’s disease.
2: gastrointestinal cancer.
3: pancreatitis.
4: hepatic encephalopathy

Answer 39

1: Crohn’s disease.

Intact proteins and free amino acids were equally effective in promoting remission in a randomized, double-blind study of patients with Crohn’s disease. Intact proteins may help maintain intestinal integrity and promote bowel adaptation in patients with intestinal failure and/or multiple bowel resections. The usefulness of enteral formulas with intact proteins or amino acids in promoting remission in patients with gastrointestinal cancer has not been studied. Both intact proteins and free amino acid-based enteral formulas appear to stimulate pancreatic secretion more than formulas with small peptides. Fat-free or high medium chain triglyceride enteral formulas are more likely to promote remission than polymeric formulas in patients with pancreatitis. Branched-chain amino acids, rather than intact peptides, have been used to promote remission in refractory hepatic encephalopathy.

References:

Verma S, Brown S, Kirkwood B, et al. Polymeric versus elemental diet as primary treatment in active Crohn’s disease: a randomized, double-blind trial. Am J Gastroenterol. 2000;95(3):735-739.

Question 40

Which of the following patients is most likely to benefit from immunonutrition?

1: Septic trauma patient
2: Trauma patient with isolated orthopedic injuries
3: Medical intensive care unit patient
4: Trauma patient with abdominal and torso injuries

Answer 40

4: Trauma patient with abdominal and torso injuries

The efficacy of immune-enhancing enteral therapy has been studied in a wide variety of patient populations. The strength of the evidence from several randomized prospective trials suggests that immunonutrition improves clinical outcome, lowers infectious complications, and shortens intensive care unit (ICU) lengths of stay in critically injured patients with blunt and penetrating trauma involving two or more body systems. The role of immunonutrition in medical ICU patients is unclear. At least two studies have shown an increase in mortality in medical ICU patients who have received immunonutrition. Although the composition of various immune-enhancing enteral formulas is not consistent, the four most commonly used immunonutrients are: glutamine, arginine, nucleotides, and omega-3 fatty acids. A growing body of evidence raises concern about possible negative effects of high arginine formulas in patients with sepsis. Therefore, immunonutrition is not advocated for trauma patients with sepsis.

References:

Consensus recommendations from the U.S. summit on immune-enhancing enteral therapy. JPEN. 2001;25(S):S61-S62.

Question 41

Which of the following would be the most appropriate tube feeding formula for a patient with extensive second and third degree burns?

1: High fat
2: High nitrogen
3: Concentrated
4: High fiber

Answer 41

2: High nitrogen

As part of the stress response, patients with burns exhibit increased breakdown of lean muscle tissue as a preferred source of energy. They also lose protein from open wounds. Therefore, patients with burns require increased intake of protein until significant wound healing is achieved.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 42

Length of stay and postoperative infection rates have been shown to DECREASE in surgical patients receiving tube-feeding formulas enriched with

1: arginine.
2: nucleotides.
3: ascorbic acid.
4: branched-chain amino acids.

Answer 42

1: arginine.

A meta analysis of 22 randomized trials with 2419 patients found that patients receiving tube feeding high in arginine had a decreased length of stay and lower infection rates than those receiving formulas that were not as high in arginine.

References:

Heyland DK, Novak F, Drover J, et al. Should immunonutrition become routine in critically ill patients? A systematic review of the evidence. JAMA. 2001;286;944-953.

Question 43

The enteral formula for individuals with pulmonary disease requiring mechanical ventilation should always be

1: based on individual tolerance and needs.
2: low fat, high carbohydrate.
3: fluid concentrated, low fat.
4: high fat, low carbohydrate.

Answer 43

1: based on individual tolerance and needs

Results demonstrating whether a high fat enteral formula offers a clinical advantage to the patient with pulmonary disease are inconclusive. When considering use in the hospitalized, mechanically ventilated patient, it is important to keep in mind potential disadvantages. Potential side effects of a high fat formula include delayed gastric emptying, the potential limitation in the availability of CHO and increased cost. A modified lipid/CHO formula may be beneficial in the ambulatory patient setting where nutritional repletion and weight gain are desired goals. Data supporting the routine use of a high fat enteral formula in hospitalized patients with pulmonary dysfunction are limited. It is suggested that this type of formula be reserved for patients with marginal respiratory reserve (severely malnourished) or who fail to wean from mechanical ventilation despite prevention of overfeeding. Severely malnourished ambulatory COPD patients who need repletion are more likely to benefit from a high fat formula than a similar normally nourished patient.

References:

Malone, A. The use of specialized enteral formulas in pulmonary disease, NCP. 2004;19:557-562.

Question 44

Modular products are added to the tube-feeding regimen to

1: prevent bacteria translocation.
2: increase the respiratory quotient.
3: increase calorie and protein content.
4: alter the ratio of vitamins to minerals.

Answer 44

3: increase calorie and protein content.

Modular products that provide either intact fat, carbohydrate, protein, amino acids, or micronutrients are used to alter the macronutient proportions of existing formulas or add an amino acid or micronutrient for a patient with unusual needs.

References:

Fussell ST, Enteral formulations. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice: A Clinical Guide. 2nd Ed. Philadelphia, PA: Saunders; 2005:188-200.

Question 45

Early commencement of enteral feeding has been suggested to benefit ICU patients, reducing infectious complications, length of hospital stay and even possibly reducing mortality. Which group of patients might be at significant risk from early enteral feeding?

1: Post surgical patients whose surgery involved the gastrointestinal tract
2: Post surgical patients who have experienced a significant blood loss during surgery and who have a poor urine output postoperatively
3: Trauma patients with head trauma that may include a fractured base of skull
4: Patients admitted with acute pancreatitis

Answer 45

2: Post surgical patients who have experienced a significant blood loss during surgery and who have a poor urine output postoperatively

Feeding a patient before hemodynamic stability has been achieved may increase the risk of intestinal ischaemia. Blood perfusion of the gut may be compromised in a patient who is still requiring high doses of vasopressor drugs to maintain blood pressure. Enteral feeding should be delayed until fluid resuscitation is complete. This should be possible within the first day in most patients. Neither gastrointestinal surgery nor pancreatitis are necessarily contraindications to early enteral nutrition. Early enteral nutrition is recommended in trauma patients but in the case of a fractured base of skull it is recommended that the feeding tube be passed via the mouth rather than the nose, to reduce the risk of misplacing the tube.

References:

Zaloga GP, Roberts PR, Marik P. Feeding the hemodynamically unstable patient: A critical evaluation of the evidence. NCP. 2003;18:285-293.
Lewis SJ, Egger M, Sylvester PA et al. Early enteral feeding versus ‘nil by mouth’ after gastrointestinal surgery: systematic review and meta-analysis of controlled trials. BMJ. 2001;323:773-776.
Windsor A, Kanwar S, Li A. Compared with parenteral nutrition, enteral feeding attenuates the acute phase response and improves disease severity in acute pancreatitis. Gut.1998;42:431-435.
Borovich B, Braun J, Yosefovich T, Guilburd JN, Grushkiewicz J, Peyser E. Intracranial penetration of nasogastric tube. Neurosurgery.1981;8(2):245-247.

Question 46

A patient with acute respiratory distress syndrome may benefit from a feeding formula containing supplemental

1: arginine.
2: glutamine.
3: nucleic acids.
4: omega 3 fatty acids.

Answer 46

4: omega 3 fatty acids

Acute respiratory distress syndrome (ARDS) is associated with an inflammatory response. Inflammatory mediators, including prostaglandins and leukotrienes derived from arachidonic acid metabolism, have been implicated in acute lung injury. Formulas containing omega 3 fatty acids may down regulate the inflammatory response. One study of patients with ARDS receiving an omega 3 fatty acid-supplemented formula found decreased ventilator time (days), decreased intensive care unit stay (days), and decreased incidence of organ failure when compared to a standard high fat formula.

References:

A.S.P.E.N. Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. JPEN. 2002;26(1 suppl):1SA-138SA.

Question 47

The use of tube feeding formulas enriched with branched-chain amino acids is best used for patients with

1: cirrhosis.
2: hepatic failure.
3: liver transplantation.
4: intractable encephalopathy.

Answer 47

4: intractable encephalopathy.

Theoretically, increased levels of aromatic amino acids (AAA) generate false neurotransmitters, promoting encephalopathy. Feeding formulas with higher amounts of branched-chain amino acids (BCAA) and less AAA are available. Most randomized trials have shown no benefit in patients with hepatic failure receiving these specialized formulas. Due to the lack of evidence supporting their use and the increased cost of such products, it has been suggested that the use of these formulas be limited to patients with intractable encephalopathy.

References:

Lefton J, Halasa-Esper D, Kochevar M. Enteral Formulations. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.;2007:209-232.

Question 48

Percutaneous endoscopic gastrostomy (PEG) placement in esophageal cancer patients prior to surgery may place the patient at risk for all of the following, EXCEPT:

1: Constipation
2: Delayed gastric emptying
3: Leakage at PEG site
4: Impaired wound healing

Answer 48

4. constipation

Constipation has not been documented as a potential risk of PEG placement in esophageal cancer, and in fact steatorrhea is often observed post esophagectomy. Decreased gastric motility, anastomotic leakage and delayed wound healing are all potential complications of esophageal resection with PEG placement. Placement of a percutaneous endoscopic jejunostomy (PEJ) feeding tube either prior to or during surgery is often the chosen route of feeding due to the potential use of the stomach for esophageal reconstruction.

References:

Roberts S, Mattox T. Cancer. In: Gottschlich MM, ed. The A.S.P.E.N. Nutrition Support Core Curriculum: A Case-Based Approach - The Adult Patient. Silver Spring, MD: A.S.P.E.N.; 2007:649-675.

Question 49

Which of the following is the best method to place a gastrostomy feeding tube in a patient with head and neck cancer?

1: Radiologically
2: Laparoscopically
3: Surgical laparotomy
4: Percutaneous endoscopically

Question 50

Enteral nutrition may be contraindicated in the early post-transplant period in adult patients with hematopoietic cell transplants because of

1: increased incidence of sinusitis with enteral feedings.
2: lack of benefit from enteral feedings in allogeneic patients.
3: gastrointestinal toxicities related to the conditioning regimen.
4: improved survival seen in autologous patients receiving parenteral nutrition.

Answer 50

3. Gastrointestinal toxicities related to the conditioning regimen

While there is much interest in enteral feedings in the early post-transplant period, in reality this has been very difficult to achieve. Several investigators have attempted to use enteral feedings, with little success, primarily due to gastrointestinal toxicities such as nausea, vomiting, delayed gastric emptying, and diarrhea, seen in the first 2-3 weeks post-transplant. This gastrointestinal toxicity is most often related to chemotherapy and total body irradiation; however, GI toxicity may also result from other medications or early acute graft-versus-host disease in this patient population. Currently, there is insufficient data to establish benefits of enteral nutrition over parenteral nutrition with hematopoeitic cell transplants. In one study, parenteral nutrition was found to increase survival in allogenic patients.

References:

Lipkin AC, Lenssen P, Dickson BJ. Nutrition issues in hematopoietic stem cell transplantation: state of the art. NCP. 2005;20:423-439.

Question 51

In a patient with fat malabsorption, an enteral product containing which of the following can provide a concentrated source of energy?

1: Medium chain triglyceride oil
2: Free amino acids
3: Fructooligosaccharides
4: Long chain triglycerides

Answer 51

1. Medium chain triglycerides

Medium chain triglyceride (MCT) oil does not require pancreatic enzymes, bile, bile transport in the lymphatic system, or carnitine dependent transport into the mitochondria. It can be used to provide a concentrated source of energy to patients with fat malabsorption or damage to lymphatic vessels.

References:

Fussell ST, Enteral formulations. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice: A Clinical Guide. 2nd Ed. Philadelphia, PA: Saunders; 2005:188-200.