Enteral Nutrition, Monitoring and Complications

Question 1

Which of the following is true regarding infectious complications associated with enteral feedings?

1: Bacterial contamination may originate from the patient’s throat, lung, and stomach
2: Length of enteral product hang time is not correlated with bacterial contamination
3: Open systems typically have less exogenous bacterial contamination
4: Bacterial counts at the enteral tube site should be cultured routinely

Answer 1

1: Bacterial contamination may originate from the patient’s throat, lung, and stomach

Bacterial contamination may occur both exogenously through the feeding equipment and endogenously through retrograde contamination of the feeding apparatus from the patient’s own infected secretions. There is a correlation between prolonged length of enteral product hang time and bacterial contamination. Open systems provide more opportunity for contamination due to nursing manipulation when adding more formula to the bag. There is no need for routine cultures in the uncomplicated enterally-fed patient unless the site shows signs of cellulitis.

References:

Mathus-Vliegen EM, Bredius MW, Binnekade JM. Analysis of sites of bacterial contamination in an enteral feeding system. JPEN. 2006(6):519-525.

Question 2

Mrs. Jones suffered from a stroke two weeks ago and has significant dysphagia. A PEG was placed and an isotonic enteral formula has been infusing continuously at goal rate for two days. The tube is being flushed with 30mL free water three times daily. Mrs. Jones begins to complain of bloating and is mildly distended (to 4 cm from baseline) upon examination. Which of the following interventions would be the best initial strategy to reduce her unpleasant symptoms?

1: Determine when last bowel movement occurred and consider a cathartic if constipation is evident
2: Hold the tube feedings and initiate a pain reliever
3: Switch to a higher fiber formula
4: Use a more concentrated formula administered through bolus feeding

Answer 2

1: Determine when last bowel movement occurred and consider a cathartic if constipation is evident

Abdominal distention upon enteral tube feeding may result from rapid administration of feeding, i.e. bolus feeding; use of hyperosmolar solution, i.e. concentrated formulas; medications that slow peristalsis, i.e. pain relievers; excess air in the stomach or intestines; tube migration from stomach to small intestine; infection; cold formula; inadequate fluid provision leading to constipation; bacterial contamination; and, fat, fiber or lactose intolerance. Aggressive bowel regimens need to be considered in these patients to reduce distention and prevent impaction. Holding enteral feedings is generally not indicated unless abdominal girth exceeds the baseline measurement by at least 8 to 10 cm. Agents such as narcotics or diphenhydramine have well-documented anticholinergic effects often resulting in constipation. Fiber promotes regular bowel movements but also produces excess gas that can increase distention in many patients. Providing more free water to the GI tract usually helps to decrease distention.

References:

Magnuson BL, Clifford TM, Hoskins LA, Bernard AC. Enteral Nutrition and Drug Administration, Interactions, and Complications. NCP. 2005(6):618-624.

Question 3

Your patient has been discharged home to hospice with end-stage ALS (amyotrophic lateral sclerosis). He is receiving enteral feedings and complains of nausea. A decision is made to discontinue enteral feeding. Which of the following is true regarding the dying patient.

1: Intravenous hydration should be used to reduce symptoms of nausea, vomiting, diarrhea and respiratory distress
2: Dehydration, starvation, and ketosis produces a euphoric state that enhances the perception of hunger
3: The most common symptom when nutrition and hydration are witheld is dry mouth
4: Electrolyte imbalance should be expected and may produce a degree of analgesia

Answer 3

3. the most common symptom of withholding nutrition and hydration is dry mouth

Artificial feeding and hydration do not always ensure comfort. Starvation produces a euphoric state that increases comfort and reduces the perception of hunger. During starvation, the body begins to use fat as the predominant energy source leading to increased ketone production with a resulting euphoria. Feeding even small amounts can prevent ketonemia and prolong the sense of hunger. The most common symptom when feeding or fluids are witheld is dry mouth, which is easily alleviated with good mouth care. Intravenous hydration in the terminal patient can increase secretions and congestion to thereby raise the risk of nausea, vomiting, diarrhea and respiratory distress.

References:

Andrews MR, Geppert CMA. Ethics. 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.; 2007:740-760.

Question 4

One method of minimizing the complications associated with refeeding syndrome is to initiate an electrolyte replacement protocol before nutrition therapy begins. Which of the following is true regarding such a plan?

1: Potassium, magnesium, and calcium should be closely monitored
2: Patients considered not-at-risk should also be included in the protocol
3: The protocol should replete all electrolytes ONLY via the feeding tube
4: Feeding should be delayed until the risk of electrolyte imbalance is eliminated

Answer 4

2: Patients considered not-at-risk should also be included in the protocol

Refeeding syndrome describes the occurrence of electrolyte disturbances when attempting to initially feed the undernourished patient. Potassium, magnesium, and phosphorus need to be closely monitored; whereas calcium does not. Patients considered not-at-risk should also be included since methods for screening “at-risk” are inadequate. The protocol should replete all electrolytes via the intravenous, oral or feeding tube route depending on the condition of the patient. Feeding should not be delayed but instead initiated slowly and then advanced based on electrolyte levels and clinical response.

References:

Flesher ME, Archer KA, Leslie BD, McCollom RA, Martinka GP. Assessing the metabolic and clinical consequences of early enteral feeding in the malnourished patient. JPEN. 2005;29(2):108-117.

Question 5

Which of the following is true regarding the use of magnet tracking for non-invasive verification of nasogastric tube placement?

1: pH can be monitored
2: Checks the tip position related to the pylorus
3: Provides a 3-dimensional localization
4: Shows a time-delayed perspective of the tube tip location

Answer 5

3. Provides a 3-demensional localization

pH is not monitored in this placement technique. The magnet follows the tip placement relative to the lower esophageal sphincter, not the pylorus. The display shows a real-time perspective of the tube tip location with a 3-dimensional localization.

References:

Bercik P, Schlageter V, Mauro M, Rawlinson J, Kucera P, Armstrong D. Noninvasive verification of nasogastric tube placement using a magnet-tracking system: a pilot study in healthy subjects. JPEN. 2005;29(4):305-310.

Question 6

In the patient with a newly placed gastrostomy or jejunostomy tube, observation of which of the following conditions at the tube exit site would signal concern for infection?

1: Serosanguineous drainage
2: Foul-smelling drainage
3: Coffee-ground drainage
4: Greenish-yellow drainage

Answer 6

2: Foul-smelling drainage

Initially, a small amount of serosanguineous drainage can be expected at the gastrostomy or jejunostomy tube exit site. Coffee-ground drainage generally suggests an upper GI bleed, whereas greenish-yellow drainage may indicate leakage of enteric contents, such as bile. Foul-smelling drainage around the tube exit site is a sign of infection.

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 7

Which of the following feeding schedules would be most appropriate for a critically ill patient with labile and poorly controlled blood glucose concentrations?

1: Bolus
2: Continuous
3: Gravity drip
4: Nocturnal infusion

Answer 7

2: Continuous

A continuous infusion may facilitate more steady and predictable blood glucose concentrations in critically ill patients. Intermittent feeding schedules, such as bolus, gravity drip, or nocturnal infusion may cause fluctuations in blood glucose concentrations, making them more difficult to control.

References:

Charney P, Hertzler R. Management of blood glucose and diabetes in the critically ill patient receiving enteral feeding. NCP. 2004;19:129-136.

Question 8

Which of the following is a major risk factor for aspiration in critically ill patients?

1: Gastric residual volume <150 mL
2: Decreased level of consciousness
3: Age
4: Small diameter feeding tube

Answer 8

2: Decreased level of consciousness

Decreased level of consciousness is a major risk factor for risk of aspiration. Other major risk factors include documented previous aspiration, vomiting, tracheal intubation, neuromuscular disease, persistent high gastric residual volumes, and prolonged supine positioning. An association between gastric residual volume amounts and aspiration risk has not been validated. Small bowel feeding should be considered when residual volumes are 250 mL or more on 2 or more consecutive assessments. Age is an additional factor that can increase risk but it is not a major factor in identifying the risk of aspiration. A large diameter feeding tube is also a factor that may increase the risk of aspiration.

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 9

Which would NOT be appropriate management of hypergranulation around the PEG site?

1: Keep the area dry
2: Tube stabilizing device
3: Occlusive dressing
4: Silver nitrate cauterization

Answer 9

3: Occlusive dressing

Granulation tissue may form within feeding tube tracts and may grow out onto the skin surface. Hypergranulation typically develops when the exit site remains moist or the tube is not stabilized and moves more than ¼ inch in the stoma. The main concern when granulation occurs is that it can cause even more moisture accumulation under the external bolster, increasing the risk for skin breakdown. If the tissue is excessive (>0.25 inch for adults or >2 mm in pediatric patients), it may be cauterized with silver nitrate sticks or other cauterizing device. The area may be treated topically with triamcinolone cream. Preventative education should stress the need for keeping the area dry and the tube stabilized. An occlusive dressing may promote the retention of moisture at the exit site and therefore should not be used to manage hypergranulation.

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 10

Which of the following tube feeding orders best reflects the use of an intermittent schedule?

1: Polymeric formula, 240 mL administered over one hour, five times per day
2: Pre-digested formula administered at 50 mL per hour over 24 hours
3: Fiber-containing formula administered at 100 mL per hour over 12 hours
4: 2 kcal/mL concentrated formula, 120 mL administered over 30 minutes one time per day

Answer 10

Intermittent feedings are generally an amount of 200-300 mL administered over 30-60 minutes every 4-6 hours, whereas continuous feedings are delivered at a prescribed rate without interruption. Cyclic feedings are generally administered over 8-20 hours per day, depending on the patient’s volume tolerance.

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 11

Which of the following is an appropriate situation for nutrition support nurses to insert a nasogastric feeding tube without physician supervision?

1: Pre-operatively just prior to transfer to the operating room (OR)
2: Under fluoroscopy in an endoscopy suite
3: In a patient with head and neck trauma admitted to the ICU
4: Post CVA on the inpatient medical unit

Answer 11

4. Post CVA on the inpatient medical unit

It is within the scope of practice for registered nurses to insert nasogastric feeding tubes in the uncomplicated patient on the inpatient floor. If a patient is being transferred to the OR and requires enteral access, the tube should be placed in the OR either by the anesthesia staff or the surgeon after the patient is under sedation. Fluoroscopy requres a radiologist to be in attendance, so this would not be done un-supervised. A patient with head or neck pathology should have direct visualization by pharyngoscopy or have the tube placed with surgeon assistance.

References:

deAguilar-Nascimento JE, Kudsk KA. Clinical Costs of Feeding Tube Placement. JPEN. 2007;31(4):269-273.

Question 12

A patient with oral cancer, who has gained 10 pounds since starting home bolus enteral feedings via gastrostomy tube complains of pain and pressure on the " inside of his stomach" but no redness or drainage at the exterior gastrostomy site. Which of the following is the most appropriate response for the clinician?

1: Tell the patient to take over the counter pain medication and rotate the G tube 180 degrees each day.
2: Refer the patient to the gastroenterologist or enterostomal nurse.
3: Decrease the infusion volume of the formula to half of the current volume to avoid excessive distention of the stomach.
4: Change to a slower tube feed infusion by using a gravity bag for feedings.

Answer 12

Tube complications can be a serious problem if not managed in a timely manner. Any new occurrence of pain at or near the tube site should be promptly evaluated by the patient’s gastroenterologist or enterostomal nurse. Pain may indicate the presence of infection or pressure necrosis on the inside or outside of the body. It might also indicate intraperitoneal leakage which can be life threatening. Weight gain after tube placement places a patient at greater risk of pressure necrosis and ulceration at the tube site because of increase in abdominal girth. In the usual clinical presentation, buried bumper syndrome is noted as excessive pain at the PEG site. Excessive tightening of the external bolster may lead to ischemic necrosis of the gastric wall and migration of the internal bolster either into the gastric wall, abdominal wall, or even into subcutaneous tissue and skin. Incidence of this complication ranges from 0.3% to 2.4% of patients.

References:

Baskin WN. Acute complications associated with bedside placement of feeding tubes. NCP. 2006;21:40-55.

Question 13

Constipation in the enterally fed patient is most often associated with all EXCEPT

1: rapid or bolus infusion.
2: obstruction.
3: lack of adequate hydration.
4: prolonged bed rest.

Answer 13

1. Rapid or bolus infusion

Constipation is a gastrointestinal complication associated with enteral nutrition and may be caused by lack of adequate hydration, long-term fiber-free feedings, prolonged bedrest, impaction, obstruction and narcotics.

References:

Leung FW. Etiologic factors of chronic constipation: review of the scientific evidence. Dig Dis Sci. 2007;52(2):313-316.

Question 14

In the adult enterally-fed patient, watery diarrhea and bloating are most often the result of

1: lactose content of the enteral formula.
2: sorbitol content of liquid medications
3: sorbitol content of the enteral formula
4: lactose content of liquid medications

Answer 14

2: sorbitol content of liquid medications

Although lactose intolerance is well known to result in watery diarrhea and bloating, the vast majority of adult enteral products are lactose free and the lactose content of most individual dosage forms of medication is too small to result in significant problems. Sorbitol is not an ingredient of enteral products but the cumulative daily dose of sorbitol from liquid medication can easily equal purgative dosages.

References:

Rollins CJ. General Pharmacological Issues. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice A Clinical Guide. 2nd ed. Philadelphia: Saunders; 2005:315-336.

Question 15

Approximately 20% of enterally fed patients report nausea and/or vomiting. If delayed gastric emptying is suspected as the causative factor, which of the following is LEAST likely to improve the patient’s symptoms?

1: Reduce or discontinue narcotic medications
2: Switch to a low fat enteral formula
3: Provide enteral formula as a small bolus of 50 to 100 mL per feeding
4: Use a more concentrated enteral formula

Answer 15

4. use a more concentrated enteral formula

Although the etiology of nausea and vomiting is multifactorial, delayed gastric emptying is a common source of tube feeding intolerance. Reduction or discontinuation of narcotic meds, use of low fat formulas, administering enteral formula at room temperature and reducing the rate and/or volume of tube feeding infusion may all improve gastric emptying and reduce the symptoms of nausea and vomiting. Concentrated enteral solutions generally contain more fat and can further contribute to enteral intolerance by presenting a higher osmotic load to the GI tract.

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 16

The initiation of enteral tube feeding should be delayed when the patient is

1: hemodynamically unstable.
2: at a decreased level of consciousness
3: post-operative day 2.
4: scheduled for discharge.

Answer 16

1: hemodynamically unstable.

Early EN is encouraged to attenuate the rapid depletion of nutrient stores after metabolic stress or to help maintain normal immune function. EN initiation should be delayed until the patient is fully volume rescucitated, hemodynamically stable, and mesenteric perfusion has been restored in order to reduce the risk of intestinal ischemia.

References:

Thompson C. Initiation, Advancement, and Transition of Enteral Feedings. In: Charney P, Malone A., eds. ADA Pocket Guide to Enteral Nutrition. Chicago, IL: American Dietetic Association; 2006:123-154.

Question 17

When initiating and advancing enteral feedings in the hospitalized patient, which of the following is most appropriate?

1: 1/2 strength formula at 25cc per hour, advance to goal rate and strength over 5-7 days
2: 240 cc bolus feeds of full strength hypertonic formulas every 4 hours
3: full strength formula at 10-40 mL/hour and advance by 10-20 mL/hr every 8-12 hours until goal rate is achieved
4: 1/4 strength formula at goal rate. Advance to full strength over 3-5 days

Answer 17

3. Full strength formula at 10-40 ml/hr and advance by 10-20 ml/hr every 8 to 12 hours until goal rate achieved

Currently, it is recommended that feedings in adults and children be initiated with full strength formulas at a slow rate and steadily advanced. This approach allows goal rates to be achieved earlier and reduces the risk for microbial contamination by minimizing the number of times the formulas is manipulated. This regimen has been noted to be well tolerated.

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 18

While a patient is receiving speech therapy, oral foods have been introduced during the daytime hours. Polymeric tube feeding is required during the night at a rate of 75 mL per hour over 8 hours. The night feeding is an example of

1: bolus feeding.
2: intermittent feeding.
3: cyclic feeding.
4: continuous feeding.

Answer 18

3. Cyclic feeding

Cyclic feedings are generally administered over 8-20 hours per day, depending on the patient’s tolerance. This cycle allows freedom from the feeding equipment for a few hours each day and insures that nutrient requirements are met. During the day, the patient is likely to experience hunger and gradually increase the oral intake during the transition from enteral to oral feeding. Intermittent feedings are usually given in rates of about 200-300 mL over 30-60 minutes every 4-6 hours. Continuous feedings are uninterrupted, and bolus feedings are the infusion of a predetermined volume of formula over a short period of time via gravity or syringe at specified time intervals.

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 19

Which of the following individuals would best benefit from cyclic tube feeding?

1: Status post CVA who has initiated oral foods during the day
2: Critically ill motorcycle accident victim in the ICU
3: Critically ill diabetic with hyperglycemia
4: Post-operative bowel surgery patient who has an ileus

Answer 19

1: Status post CVA who has initiated oral foods during the day

Cyclic feedings are generally administered over 8-20 hours nocturnally in order to supplement oral intake and promote unobstructed activity during the day. A patient status post CVA, who is transitioning from tube feeding to an oral diet and will likely begin a rigorous therapy program can benefit from the use of cyclic nocturnal feeding. Critically ill patients are more likely to require continuous feeding, and the post-op individual with an ileus may require parenteral nutrition depending upon the length of time without enteral support.

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 20

Which type of insulin should be used when initiating enteral nutrition in a hospitalized diabetic patient?

1: 70/30 (70% insulin protamine suspension / 30% insulin aspart injection)
2: regular insulin
3: insulin suspension, isophane or insulin-zinc suspension
4: insulin glargine

Answer 20

2: regular insulin

When initiating tube feeding, use of short-acting insulin (regular insulin) is recommended to minimize the risk of hypoglycemia which could result from continued absorption of insulin from an intermediate insulin (insulin suspension, isophane, insulin-zinc suspension, or 70/30) or long-acting insulin (insulin glargine).

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 21

Which of the following metabolic alterations is NOT associated with the development of tube feeding syndrome?

1: Ketonemia
2: Dehydration
3: Azotemia
4: Hypernatremia

Answer 21

1. Ketonemia

Tube feeding syndrome is the development of azotemia, hypernatremia, and dehydration related to the use of high-protein tube feedings with a high renal solute load and inadequate fluid provision. Prevention and treatment requires the provision of adequate fluid (at least 1 mL/kcal plus replacement of any respiratory, renal, or GI losses). A reduction in protein loads may be necessary if the ability to excrete byproducts of protein metabolism during adequate fluid provision is compromised. Ketonemia is an elevated circulating ketone level secondary to increased fatty acid oxidation occurring with starvation, catabolic illness, or inadequate dietary carbohydrate intake during pregnancy.

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 22

Question: 22

Most enteral formulas designed for oral consumption are composed primarily of

1: carbohydrates.
2: protein.
3: fat.
4: vitamins.

Answer 22

1. carbohydrates

Generally, enteral products designed for oral use contain more sucrose to improve palatability. This translates into a higher carbohydrate to protein and fat ratio. Most enteral products for oral use provide approximately 40% to 60% of total calories from carbohydrate, 15% to 25% from protein, and 15% to 35% from fat. Vitamins, although an important part of enteral products, are generally a very small percentage of the total formula.

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 23

Which of the following best describes the addition of blue dye to enteral feedings?

1: It prevents aspiration of enteral formula
2: Its use in detection of aspiration is highly sensitive
3: It should be added only in small amounts
4: It is no longer recommended for the detection of aspiration of enteral formula

Answer 23

4: It is no longer recommended for the detection of aspiration of enteral formula

The addition of blue dye to enteral feedings was common practice in the past to help detect aspiration of formula. The use of blue dye in detecting aspiration of formula has a low sensitivity. Several reports of systemic toxicity, some resulting in death, have been published in recent years. As a result the U.S. Food and Drug Administration removed FD and C Blue #1 from the market in 2003.

References:

Baskin WN. Acute complications associated with bedside placement of feeding tubes. NCP. 2006;21:40-55.

Question 24

What is the enteral nutrition feeding method in which 240-480 mL of formula flows into the stomach over 10-15 minutes through the barrel of a 50 mL syringe attached to the end of the feeding tube?

1: Gravity feeding
2: Cyclic feeding
3: Bolus feeding
4: Continuous feeding

Answer 24

1. Bolus Feeding

Bolus feeding is the simplest way to deliver gastric feeding and is popular with home care patients. Gravity drip is a variation of bolus feeding in which an administration set or bag delivers the enteral formula over a period of 30-60 minutes. Continuous infusion feeding formula is delivered from an administration set into the feeding tube via an enteral pump to allow a continuous rate. Cyclic feeding is similar to the continuous infusion method, except that the rate of formula delivery increases allowing patients to meet nutrient goals with a shorter infusion period of 8-16 hours. This method is also popular in home enteral nutrition.

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 25

Infusion of a predetermined volume of formula over 12 hours is an example of this method.

1: Bolus
2: Cyclic
3: Continuous
4: Needle Catheter

Answer 25

2. Cyclic

Cyclic feedings are generally administered over 8 -20 hours per day depending on tolerance. Continuous feedings are given at a prescribed rate without interruption over a 24 hour period. Bolus feedings are best tolerated when provided at less than 60 mL per minute. When a syringe is used, the infusion rate can be gravity-controlled by raising or lowering the syringe.

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 26

Which of the following types of feeding delivery methods is most commonly used for patients with a jejunal feeding tube?

1: Bolus feeding
2: Gravity feeding
3: Intermittent feeding
4: Continuous pump feeding

Answer 26

4. Continuous Pump Feeding

Jejunal feeding is usually delivered by a continuous pump to minimize the chance of diarrhea and abdominal bloating. Gastric feeding can be given by the bolus or intermittent gravity methods. The stomach serves as a reservoir thus delaying the rapid emptying of formula into the small bowel. It has been reported that some patients do tolerate bolus or gravity feeding into the jejunum.

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 an appropriate enteral tube feeding administration technique that will not pose an increased risk of contamination of enteral formulas?

1: Mix or reconstitute enteral formulations at bedside just prior to administration
2: Change the feeding administration set every 48 hours
3: Limit hang time of canned, ready-to-use formulas to no more than 24 hours
4: Use tap water to reconstitute enteral formulations in most adult patient populations

Answer 27

4: Use tap water to reconstitute enteral formulations in most adult patient populations

Potential points of contamination for enteral formulas include the preparation and dispensing of enteral formulas, setting up tube feeding, and administration techniques. When possible, enteral formulas should be mixed, reconstituted, or diluted in a centralized location, such as an enteral formulary room or pharmacy, to minimize risk of contamination. The feeding administration set should be changed every 24 hours and disposable feeding administration sets should not be reused. Only an 8 to 12-hour supply of formula should be poured into an open administration set. Hang time of canned, ready-to-use formulas should be no longer than 12 hours. Prefilled, closed containers can be safely used for 24-36 hours after opening, depending on manufacturer’s guidelines. Tap water may be used in most instances to reconstitute enteral formulations; however in areas with poor water supply or in severely immunocompromised patients, distilled or sterile water should be used. Adding fresh formula to formula already hanging in the administration set should be avoided. To avoid contamination, hands should be washed thoroughly before touching any component of the tube feeding system and formula should be transferred without touching the component of the feeding set that comes in contact with the formula.

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 28

Which of the following is most likely to be a benefit of a closed system enteral formulation?

1: Less costly
2: Shorter hang time
3: Ability to develop modular feedings
4: Less nursing time required for administration

Answer 28

4. Less nursing time required for administration

Closed enteral feeding systems are purchased as bags or rigid containers pre-filled with the formula. No changes may be made to the formula. It is less susceptible to microbial contamination, has a longer hang time (24 to 48 hours), and requires less nursing time.

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 29

Which of the following is a potential advantage of using an open system for delivery of tube feedings?

1: Less nursing time
2: Longer hang time
3: Less contamination
4: Less formula wastage

Answer 29

4. Less formula wastage

Open systems may not waste as much formula as compared to closed systems that are packaged in 1 liter volumes or greater. In open system feedings, bags must be filled with enteral formula. Due to the higher risk of microbial contamination, hang time should be limited to 8-12 hours. The shorter hang time requires additional nursing intervention in preparing enteral formulas to be administered to the patient.

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 30

Which of the following is a potential advantage of using an open system for delivery of tube feedings?

1: Less nursing time
2: Longer hang time
3: Less contamination
4: Less formula wastage

Answer 30

4. Less formula wastage

Open systems may not waste as much formula as compared to closed systems that are packaged in 1 liter volumes or greater. In open system feedings, bags must be filled with enteral formula. Due to the higher risk of microbial contamination, hang time should be limited to 8-12 hours. The shorter hang time requires additional nursing intervention in preparing enteral formulas to be administered to the patient.

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 31

In transitioning from enteral tube to oral feeding, tube feeding may be discontinued when adequacy of oral intake meets at least

1: 30% of nutrient needs.
2: 40% of nutrient needs.
3: 50% of nutrient needs.
4: 60% of nutrient needs.

Answer 31

4: 60% of nutrient needs.

While there are no clinically proven points at which tube feeding should be discontinued with adequacy of oral intake, a general guideline established by A.S.P.E.N. is that oral intake should meet at least 60% of nutrient intake or the determination could be based on clinical judgment.

References:

Crary MA, Groher ME. Reinstituting oral feeding in tube-fed adult patients with dysphagia. NCP. 2006;21(6):576-586.

Question 32

Which of the following should appear on the label of an enteral feeding product given to a patient in the hospital?

1: Product name, rate, volume, additives, caloric density, expiration date, and time
2: Patient’s name, product name, strength, additives, volume, expiration date, and time
3: Patient’s name, product name, rate, strength, osmolality, expiration date, and volume
4: Patient’s name, room number, strength, additives, volume, time, and expiration date

Answer 32

2: Patient’s name, product name, strength, additives, volume, expiration date, and time

An enteral product given to a patient should be labeled with the patient’s name, product name, strength, additives, volume, expiration date, and time. The importance of providing this information ensures the patient is receiving what was ordered. Labeling the bottle with specific information is important because illness could occur due to an expired product or extended hang time.

References:

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

Question 33

In addition to a physical exam, which of the following is an appropriate clinical measurement that can be performed at the bedside to assess gastric emptying?

1: Radionuclide scintigraphy
2: Paracetamol absorption test
3: Measurement of gastric reflux
4: Measurement of gastric residual volume

Answer 33

4: Measurement of gastric residual volume

Although other methods to assess gastric emptying exist including the paracetamol absorption test and radionuclide scintigraphy, a practical method in conjunction with physical exam at the bedside is the measurement of gastric residual volume (GRV). GRV is the measurement most frequently done by nursing personnel for the assessment of gastric emptying. GRV is generally measured every 4-6 hours. When patients are receiving intermittent enteral feeds, GRV is measured prior to the scheduled feeding. The significance of GRV is controversial. GRV can be affected by the variability in pooling of gastric secretions in relationship to the patient’s position and will not be measured appropriately if the ports of the feeding tube are positioned above the pool of gastric fluid.

References:

Methany NA, Schallom ME, Edwards SJ. Effect of gastrointestinal motility and feeding tube site on aspiration risk in critically ill patients: A review. Heart Lung. 2004;33:131-145.

Question 34

When administering multiple medications via enteral feeding tubes, medications should be

1: crushed, dissolved, and administered separately, followed by a 15-30 mL water flush.
2: mixed together in a 30 mL slurry and flushed together.
3: delivered in liquid form without extra water flushes.
4: mixed directly into the feeding formulations, delivered by syringe, gravity bag or feeding pump.

Answer 34

1: crushed, dissolved, and administered separately, followed by a 15-30 mL water flush.

Medications should only be administered via feeding tube as a last option. The site of delivery, feeding tube size, and medication absorption and actions should be considered when developing pharmacotherapy plans. Liquid medications are preferred and should be flushed with water individually to avoid adherence to the feeding tube, causing protein denaturation and tube clogging. Standard tablets can be crushed to form a fine powder and then dissolved or suspended in 30-60 mL water. Enteric-coated, controlled-release, and sustained-release medications should not be crushed. Feeding tubes should be flushed with 15-30 mL of water before and after drug adminstration, delivered separately. Medications should not be mixed directly into the enteral formulation. Mixing acidic medications into formula may result in protein denaturation.

References:

Magnuson BL, Clifford TM, Hoskins LA, Bernard AC. Enteral nutrition and drug administration, interactions, and complications. NCP. 2005;20:618-624.

Question 35

Which of the following tubes requires immediate replacement if it becomes dislodged?

1: Jejunostomy tube
2: Nasogastric tube
3: Gastrostomy tube
4: Nasoduodenal tube

Answer 35

1: Jejunostomy tube

It should be a priority to replace any feeding tube that becomes dislodged so that the patient can continue to receive nutrition support. However, the jejunostomy tube requires immediate replacement since the tract for the jejunostomy tube can close quickly. Replacement of a jejunostomy tube requires radiographic verification with contrast medium. The first replacement gastrostomy and percutaneous endoscopic gastrostomy tube should be typically performed by the physician who inserted the tube. After that, it is appropriate for trained nurses to replace these tubes. A nasogastric or nasoduodenal tube can be replaced by a physician, physician assistant, or appropriately trained nurse.

References:

Worthington PH, Reyen L. Initiating and managing enteral nutrition. In: Worthington PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders, 2004;311-341.

Question 36

An occluded feeding tube is most likely caused by a

1: low fat formula.
2: low fiber formula.
3: peptide based formula.
4: high viscosity formula.

Answer 36

4. High viscosity formula

The viscosity of a formula depends on the concentration and characteristics of the macronutrients and fiber. Higher viscosity products may affect the rate of delivery of feeding pumps and are more likely to occlude small-bore feeding tubes .

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 37

Which of the following is most appropriate for maintaining patency of a feeding tube?

1: Administer medications through feeding tube with 5mL of water
2: Use a 20 mL or smaller syringe to flush small-bore feeding tubes
3: Flush feeding tube with 10-30 mL of water every 4-6 hours during continuous feeding
4: Change feeding tube every 72 hours

Answer 37

3. Flush feeding tube with 10-30 ml of water everey 4-6 hrs during continuous tube feeds

Several interventions should be implemented to ensure patency of feeding tubes including flushing the tube with water every 4-6 hours during continuous feeding and after each intermittent feeding. The feeding tube should also be flushed with 15-30 mL of water before and after medication administration to prevent interaction of formula with medication and the tube should also be flushed between medications. A 50-60 mL syringe is most appropriate for flushing feeding tubes. Smaller syringes (20 mL or less) may generate sufficient pressure in small-bore feeding tubes to cause a rupture and should not be used. When appropriate, the feeding tube should be changed to a larger size (10-12 French) when administering concentrated or fiber-enriched formulas. Medications should be administered through feeding tubes with 30mL of water.

References:

Worthington PH, Reyen L. Initiating and managing enteral nutrition. In: Worthington PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders, 2004;311-341.

Question 38

Which of the following is NOT a research-based method used to successfully restore patency to clogged enteral feeding tubes?

1: Water flush
2: Cranberry juice flush
3: Mechanical declogging devices
4: Sodium bicarbonate and pancrelipase

Answer 38

2. Cranberry juice flush

Proper tube feeding administration and handling should minimize the incidence of tube clogging. Feeding tubes should be flushed with 15-30 mL of water before and after medication administration to prevent clogging of tubes. When a feeding tube becomes clogged, several research-based techniques can be used to restore patency including pancrelipase, a digestive enzyme; pancrelipase and sodium bicarbonate; and mechanical declogging devices that physically grind down clogs. The low pH of cranberry juice is known to acidify the protein in enteral formulas and potentially cause clogging.

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 39

In order to prevent clogged feeding tubes, before checking gastric residuals, what should occur?

1: Tube should be flushed with 20-30 mL of water.
2: Patient should be placed in Trendelenburg position.
3: Enteral feedings should be held one hour.
4: A 60 mL syringe of air should be instilled into the tube.

Answer 39

1: Tube should be flushed with 20-30 mL of water.

To prevent tube clogging from an enteral intact protein formula being exposed to gastric acid (pH ~1.5), 20-30 mL of water should be flushed before retrieving gastric contents.

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 40

Which of the following interventions has NOT been proven effective in reducing the risks associated with enteral tube feeding in critically ill patients?

1: Elevating the head of the bed
2: Frequent checking of gastric residual volumes
3: Placing the distal end of the tube into the small bowel
4: Using motility agents for patients with high gastric residual volumes

Answer 40

2: Frequent checking of gastric residual volumes

Evidence-based guidelines for nutrition support in critically ill patients developed by the Canadian Critical Care Practice Guidelines Committee provide recommendations regarding interventions that maximized the benefit and minimized the risk of enteral nutrition in critically ill patients. Recommendations included use of metoclopramide as a motility agent in critically ill patients who experience feeding intolerance (high gastric residuals, emesis), small bowel feeding compared with gastric feeding to reduce pneumonia in critically ill patients, and head of bed elevated to 45 degrees in critically ill patients receiving tube feeding. The committee also noted a paucity of data that demonstrate checking gastric residual volumes influences clinical outcomes in critically ill patients.

References:

Heyland DK, Dhaliwal R, Drover JW, et al. Canadian clinical practice guidelines for nutrition support in mechanically ventilated, critically ill adult patients. JPEN. 2003;27:355-373.

Question 41

Which of the following is a primary cause of oozing stools in a tube fed patient?

1: Bowel impaction
2: Fluid restriction
3: Physical inactivity
4: Narcotic usage

Answer 41

1: Bowel impaction

Impaction can be manifested by symptoms of diarrhea. Passage or secretion of fluid around the impaction may be responsible for the loose stool. The volume of stool usually is not great and the patient may intermittently pass small volumes of liquid stool and experience abdominal distention and cramping. Fluid restriction, physical inactivity and narcotic usage lead to constipation rather than diarrhea.

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 42

If a postoperative trauma patient develops new onset diarrhea in the intensive care unit, the first intervention should be to

1: change to an elemental feeding.
2: obtain an order for a bile-sequestering agent.
3: obtain a Clostridium difficile toxin stool assay.
4: obtain an order for an antidiarrheal medication.

Answer 42

3: obtain a Clostridium difficile toxin stool assay.

There are many causes of diarrhea in the tube-fed patient including the patient’s underlying medical condition, tube-feeding intolerance, medication effects, and infectious causes including bacterial contamination of enteral tube feeding formula or equipment and Clostridium difficile. Clostridium difficile should be ruled out in any patient recently receiving antibiotic therapy. This should be done prior to ordering antidiarrheal medication. If stool cultures are positive for Clostridium difficile, only antidiarrheal products containing kaolin and pectin can be safely administered. Once a patient is treated for Clostridium difficile, the diarrhea quickly resolves. There is no need to change to an elemental formula if there are no other indications for an elemental diet.

References:

Worthington PH, Reyen L. Initiating and managing enteral nutrition. In: Worthington PH, Ed. Practical Aspects of Nutritional Support: An Advanced Practice Guide. Philadelphia: Saunders, 2004;311-341.

Question 43

Which of the following best describes the use of oral rehydration solutions in a patient with short bowel and an end-jejunostomy?

1: A glucose-free oral rehydration solution is preferred
2: Sodium and water should be fairly well absorbed from hypertonic solutions
3: Supplementation of iron will likely be required in addition to the oral rehydration solution
4: Optimal sodium concentration of an oral rehydration solution is higher than commercially available solutions

Answer 43

4: Optimal sodium concentration of an oral rehydration solution is higher than commercially available solutions

Use of oral rehydration solutions may help to prevent dehydration in patients with short bowel syndrome and an end-enterostomy. Sodium and chloride are readily absorbed from the jejunum when delivered in solutions with high concentrations of these electrolytes. The optimal sodium concentration in oral rehydration solutions is about 90 mmol/L, whereas commercially available solutions generally contain 20-50 mmol/L. Glucose is an important component in oral rehydration solutions as it promotes salt and water absorption. Hyper- or hypotonic solutions are not well absorbed and may increase osmotic diarrhea in patients with short bowel syndrome. Iron is principally absorbed in the duodenum and is therefore not routinely required as a supplement in short bowel syndrome patients.

References:

Buchman AL, Scolapio J, Fryer J. AGA technical review on short bowel syndrome and intestinal transplantation. Gastroenterology. 2003;124:111-1134.

Question 44

What is the optimal sodium concentration of an oral rehydration solution for patients with short bowel syndrome?

• *1: 40 mmol/liter
  2: 60 mmol/liter
  3: 70 mmol/liter
  4: 90 mmol/liter**

Answer 44

4. 90 mmol/liter

The optimal sodium concentration of oral rehydration solutions is 90 mmol or 90 mEq per liter. Oral rehydration solutions work by the solvent drag mechanism in the jejunum in which nutrients such as glucose promote the passive absorption of electrolytes (sodium) and water. To avoid passive secretion of salt and water, solutions should be isotonic with plasma, i.e. 90 mmol per liter, 250-300 mosm/kg. Mmol is equivalent to mEq for sodium.

References:

Scolapio JS. Short bowel syndrome. JPEN. 2002;26(5 Suppl):S11-S16.

Question 45

A 55-year-old female afebrile patient is receiving a 1 kcal/mL enteral formula at 70 ml/hr continuous feed. Based on the formula of providing 1 mL per calorie, the patient needs approximately 1680 mL of fluid per day. How much additional water from flushes is needed to meet the approximate fluid needs?

1: about 350mL
2: about 700 mL
3: about 1200 mL
4: no added flushes are needed

Answer 45

1: about 350mL

1 kcal/mL enteral formulas supply between 75-85% free water. At a feeding rate of 70 mL/hr, the total daily fluid volume provided by the enteral formula would be 1680 mL. Using the mid-point free water range of a 1 kcal/mL formula, 80% of 1680 mL is 1344 mL. To meet total estimated water needs of this patient, an additional (approximate) 336 mL would need to be given. To obtain a more precise figure, the actual free water content of the enteral formula would need to be obtained.

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 46

The osmolality of an isotonic enteral formula is approximately

1: 200 mOsm/kg of water.
2: 300 mOsm/kg of water.
3: 400 mOsm/kg of water.
4: 500 mOsm/kg of water.

Answer 46

2: 300 mOsm/kg of water.

Osmolality of human body fluids is about 280-300 mOsm/L. In an Isotonic formula, the osmolality is approximately 300 mOsm. Review definitions: Osmolality: the concentration of a solution in terms of osmoles of solutes per kilogram of solvent. In a solution, the fewer the particles of solute in proportion to the number of units of water (solvent), the less concentrated the solution. A low serum osmolality would be indicative of a higher than usual amount of water in relation to the amount of particles dissolved in it. It would be expected, then, that a low serum osmolality would accompany overhydration or edema, and an increased serum osmolality would be present in a state of fluid volume deficit. Measurement of the serum osmolality gives information about the hydration status within the cells because of the osmotic equilibrium that is constantly being maintained on either side of the cell membrane (homeostasis). Water moves freely back and forth across the membrane in response to the osmotic pressure being exerted by the molecules of solute in the intracellular and extracellular fluids. Serum osmolality reflects the status of hydration of the intracellular as well as the extracellular compartments and thus describes total body hydration. Isotonic: denotes a solution in which body cells can be bathed without a net flow of water across the semipermeable cell membrane. Isotonic also denotes a solution having the same tonicity as some other solution with which it is compared, such as physiologic salt solution and the blood serum. Definitions were taken from: http://medical-dictionary.thefreedictionary.com/osmolality and http://www.biology-online.org/dictionary/Isotonic

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 47

When implementing early enteral feeds (EN) in critically ill patients, which of the following factors is most likely to increase success in moving patients toward target feeding rate?

1: Degree of adherence to physician’s orders
2: Combined use of EN and parenteral nutrition
3: Use of gastric feeding
4: Implementation of an interdisciplinary infusion protocol

Answer 47

4: Implementation of an interdisciplinary infusion protocol

Early delivery of EN in the critical ill patient is extremely challenging, in many cases due to a lack of standardized procedures. Performance improvements in meeting EN targets have been accomplished, and are related to several factors, including the reduction of inappropriate PN usage, medical director endorsement of an evidence-based multi-disciplinary protocol, efforts of local opinion leaders, and compliance with the guidelines. Effective use of a nutrition support protocol requires support from all medical disciplines involved.

References:

Mackenzie S. Implementation of a Nutrition Support Protocol Increases the Proportion of Mechanically Ventilated Patients Reaching Enteral Nutrition Targets in the Adult Intensive Care Unit. JPEN. 2005;29:74-80.