Parenteral Nutrition

Question 1

Question: 1

Which of the following additives has the greatest risk over time of destabilizing the intravenous fat emulsion (IVFE) in a total nutrient admixture (TNA)?

1: Sodium chloride
2: Calcium acetate
3: Iron dextran
4: Potassium phosphate

Answer 1

Phase separation and the liberation of free oil from the destabilization of TNAs can result over time when an excess of cations is added to a given formulation. The higher the cation valence, the greater the destabilizing power; thus, trivalent cations such as Fe +3 (from iron dextran) are more disruptive than divalent cations such as calcium and magnesium. Monovalent cations such as sodium and potassium are least disruptive to the emulsifier, yet when given in sufficiently high concentrations, they may also produce instability. There is no safe concentration of iron dextran in any TNA. Answer - 3

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 2

Question: 2

Which of the following factors has been associated with an increase in prescribing errors related to PN formulations?

1: Standardized PN order form
2: Calculation of PN dosages
3: PN components ordered as amount per day
4: PN components listed in same sequence on order form as PN label

Answer 2

Common factors associated with the majority of PN prescribing errors include: inadequate knowledge regarding PN therapy, certain patient characteristics related to PN therapy (e.g., age, impaired renal function), miscalculation of PN dosages, specialized PN dosage formulation characteristics, and prescribing nomenclature. Answer 2

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 3

Question: 3

According to the A.S.P.E.N. Safe Practices Guidelines, which of the following is the best method to express the dextrose content on the label of a PN formulation in order to avoid misinterpretation?

1: Volume of the percent of original concentration added (e.g., 500 mL of 50% dextrose)
2: Grams per liter (e.g., 250 g/L)
3: Percent of final concentration after admixture (e.g., 35% dextrose)
4: Grams per 24-hour nutrient infusion (e.g., 225 g/day)

Answer 3

Grams per total volume, with use of a 24-hour nutrient infusion system, is most consistent with that of a nutrient label, requiring the least number of calculations to determine the calorie or gram dose per day. Answer - 4

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 4

Question: 4

All of the following are considered to be mandatory for the PN order form EXCEPT

1: general statement warning of the potential for PN formulation incompatibilities.
2: contact number for the person writing the order.
3: hangtime guidelines.
4: recommended PN laboratory tests.

Answer 4

The following are mandatory for the PN order form: clarity of the form, contact number for the person writing the order, contact number for assistance with PN ordering, time by which orders need to be received, location of venous access device, height, weight/dosing weight, PN indication, hangtime guidelines, institutional policy for infusion rates, and information regarding potential incompatibilities. Recommended PN laboratory tests are strongly recommended for inclusion on the PN order form but are not mandatory.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 5

Question: 5

According to the A.S.P.E.N. Safe Practices Guidelines, the following are strongly recommended for inclusion on the PN label EXCEPT

1: route of administration.
2: dose of macronutrients for 24 hours.
3: dosing weight.
4: location of venous access device.

Answer 5

The labels for PN formulations shall be standardized to include: the amount of macronutrients per day, the dosing weight, and the route of administration. Although the location of venous access device is mandatory for inclusion on the PN order form, it is not necessary for inclusion on the PN label. Answer - 4

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 6

Question: 6

What is the nutritional value of the following PN formula? 1000mL 30% dextrose, 800mL 15% amino acids, 200mL 20% IVFE.

1: 1352 kcal, 200 grams carbohydrate, 68 grams protein, 40 grams fat
2: 1692 kcal, 300 grams carbohydrate, 68 grams protein, 40 grams fat
3: 1900 kcal, 300 grams carbohydrate, 120 grams protein, 40 grams fat
4: 2000 kcal, 300 grams carbohydrate, 120 grams protein, 50 grams fat

Answer 6

Dextrose 30% provides 30 g/100 mL; thus, 1000 mL provides 300 grams of dextrose. Amino acids 15% provides 15 grams/100mL; thus, 800 mL provides 120 grams protein. IVFE 20% provides 20 g/100mL; thus 200 mL provides 40 grams. 1 gram of carbohydrate is equal to 3.4 calories. 1 gram of protein is equal to 4 calories. 1 mL of 20% IVFE is equal to 2 calories. Answer - 3

References:

Wall-Alonso E, Sullivan MM, Byrne TA. Gastrointestinal and pancreatic disease. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice A Clinical Guide. 2nd ed. Philadelphia: Saunders; 2003:412-444.

Question 7

Question: 7

A patient is receiving 65 mL/hr of 7.5% amino acids and 17.5% dextrose of a 2-in-1 PN solution in addition to 250 mL of 20% IVFE. What is the daily caloric content of this regimen?

1: 1345 kcal/day
2: 1395 kcal/day
3: 1846 kcal/day
4: 1896 kcal/day

Answer 7

In a 24-hour period, the patient will receive 1560 mL of PN solution. The formula expresses percents as weight-per-volume (g/100 mL). The amino acid content calculates to 7.5 g/100 mL or 117 g in 1560 mL. The dextrose content calculates to 17.5 g/100 mL or 273 g in 1560 mL. A 20% IVFE provides 2 kcal/mL. With 4 kcal/g protein and 3.4 kcal/g carbohydrate, the total daily caloric intake equals 468 kcal (protein) + 928 kcal (carbohydrate) + 500 kcal (lipids) or 1896 kcal/day. Answer - 4

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 8

Question: 8

What significant benefit has hypocaloric PN support shown in ICU patients with obesity?

1: Reduction in mortality
2: Reduction in length of stay in ICU
3: Reduction of days on insulin therapy
4: Reduction in ventilator days

Answer 8

There is evidence establishing that obese, non-insulin dependent diabetic patients in the ICU experienced a statistically-significant reduction in the number of days that they required insulin therapy when given a hypocaloric PN formula. Although improvements in glucose control and positive nitrogen balance were noted in the hypocaloric group of critically ill obese patients, the study results were not significant. More recently (2002), in critically ill patients with obesity, hypocaloric enteral nutrition showed improved outcomes, i.e., reducing length of stay in the ICU and reducing the number of days on a ventilator. Answer - 3

References:

Choban PS, Burge JC, Scales D, Flancbaum L. Hypoenergetic nutrition support in hospitalized obese patients: a simplified method for clinical application. Am J Clin Nutr. 1997; 66:546-550.
Breen HB, Ireton-Jones CS. Predicting energy needs in obese patients. NCP.2004; 19:284-289.
Choban PS, Dickerson RN. Morbid obesity and nutrition support: is bigger different? NCP.2005; 20(4):480-487.
Dickerson RN, Boschert KJ, Kudsk KA, Brown RO. Hypocaloric enteral tube feeding in critically ill obese patients. Nutrition.2002;18:241 –246.[Medline]
Shikora SA, Jensen G. Editorial an Hypoenergetic nutrition support. Am J Clin Nutr. 1997; 66:679-680.

Question 9

Question: 9

Which of the following is an absolute indication for the use of PN?

1: High output fistula
2: Crohn’s disease
3: Pancreatitis
4: Hyperemesis gravidarum

Answer 9

1: High output fistula

PN is indicated for a non-functioning or inaccessible gastrointestinal tract. PN is indicated in patients with a high output fistula (>500 mL/day). PN is not routinely needed as nutrition support for Crohn’s disease unless the patient has a high output fistula. The preferred route of administration for nutrition intervention in patients with acute pancreatitis is EN. Only patients with severe hyperemesis gravidarum refractory to EN and pharmacotherapy would require PN.

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 10

Question: 10

In patients with ulcerative colitis, the use of PN as a primary treatment has been shown to be

1: of no benefit in influencing the disease response.
2: effective in reducing the inflammatory response.
3: effective in reducing both operative and mortality rates.
4: more effective than intravenous methylprednisolone in reducing the disease response.

Answer 10

1: of no benefit in influencing the disease response.

EN is the preferred route of feeding for patients with inflammatory bowel disease. The use of PN in patients with ulcerative colitis as a primary treatment modality has not been demonstrated to offer benefit. There is no support for the concept that improved nutrition status coupled with bowel rest would achieve clinical remission and avoid colectomy.

References:

Wall-Alonso E, Sullivan MM, Byrne TA. Gastrointestinal and pancreatic disease. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice A Clinical Guide. 2nd ed. Philadelphia: Saunders; 2003:412-444.

Question 11

Question: 11

When is PN indicated in severe burn patients?

1: Total body surface area burn exceeds 20%
2: As soon as possible after admission due to extremely high caloric needs
3: EN is contraindicated or unlikely to meet nutrition needs
4: Within 7-10 days after hospital admission

Answer 11

3: EN is contraindicated or unlikely to meet nutrition needs

Several studies have found that the use of PN in patients with burns has been associated with increased mortality. The use of PN in patients with burns is, therefore, reserved for patients who are unable to be fed enterally.

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

Question: 12

The routine use of perioperative PN is indicated for patients who are

1: normally nourished.
2: mildly to moderately malnourished.
3: mildly malnourished with secondary co-morbidities.
4: severely malnourished.

Answer 12

4: severely malnourished.

Many studies have identified the severely malnourished as benefiting from preoperative nutrition support with PN. Results from multiple preoperative PN studies of surgical patients have shown no overall reduction in perioperative mortality. However, significant reductions in perioperative complications are achieved in the severely malnourished patient receiving more than 7 days of preoperative PN.

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 13

Question: 13

PN has traditionally been used in patients with hyperemesis gravidarum, but current research is establishing EN as a viable treatment option. Which of the following is NOT an indication for the use of PN in patients with hyperemesis gravidarium?

1: Vomiting cannot be controlled with hydration, bowel rest, and/or antiemetics within 48 hours
2: EN tube displacement due to repeated episodes of vomiting
3: Severe fluid and electrolyte imbalances
4: PPN (peripheral parenteral nutrition) cannot meet nutritional requirements

Answer 13

4: PPN (peripheral parenteral nutrition) cannot meet nutritional requirements

Hyperemesis gravidarum, a severe form of pregnancy-induced nausea and vomiting, occurs in about 0.5% of all pregnancies resulting in live births. Due to the likelihood that the patient’s nutritional intake has been poor for several weeks due to vomiting, EN or PN may be required. Prior to implementation of nutritional therapy, fluid and electrolyte imbalances, ketonuria, and dehydration would be treated via IV fluid. Multivitamins would most likely be added to address suboptimal vitamin intake. Antiemetic treatment would begin. Additionally, oral intake would temporarily be avoided. Initiation of an EN trial would be appropriate if the patient is still unable to take oral feedings after 24-48 hours. If the trial fails due to exacerbated nausea, diarrhea, significant gastric residuals, or tube displacement, it is appropriate to begin PN. PPN may be attempted as a temporary measure of intravenous support, but may not be adequate to meet the caloric requirements to support fetal growth.

References:

Cimbalik C, Paauw J, Davis A. Pregnancy and Lactation. 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.; 2007:383-404.

Question 14

Question: 14

Which of the following is an absolute indication for PN support in a cancer patient?

1: Small bowel obstruction for seven days
2: Metastatic cancer, receiving palliative care
3: Receiving concurrent chemotherapy and radiation therapy
4: Mild malnutrition, scheduled for surgery in three days

Answer 14

1: Small bowel obstruction for seven days

A patient with a gastrointestinal obstruction that limits oral intake for at least one week may benefit from nutrition support. Mildly malnourished patients do not require specialized nutrition support unless oral intake is anticipated to be inadequate for more than one week. The palliative use of nutrition support in terminally ill cancer patients is rarely indicated.

References:

Trujillo EB, Bergerson SL, Graf JC, Michael M. Cancer. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:150-170.

Question 15

Question: 15

When should PN be used in Crohn’s disease?

1: As a primary therapy to rest the bowel
2: Only after failure to tolerate EN
3: To prevent associated malnutrition
4: Preoperatively regardless of nutrition status

Answer 15

2: Only after failure to tolerate EN

Studies comparing PN to EN in patients with Crohn’s disease found no advantage of parenteral over enteral nutrition. Remission rates were similar and there was no evidence that bowel rest with PN had any advantage. Therefore, EN should be used in patients with Crohn’s disease requiring nutrition support therapy. PN should be reserved for Crohn’s patients who do not tolerate EN. Peri-operative specialized nutrition support is indicated in patients with inflammatory bowel disease who are severely malnourished and in whom surgery may be safely postponed.

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 16

Question: 16

Current recommendations regarding safe administration of intravenous fat emulsion (IVFE) include

1: IVFE hang time up to 24 hours when included as part of a total nutrient admixture (TNA).
2: IVFE hang time up to 24 hours when administered as an infusion separate from PN.
3: Use of a 0.22 micron filter when administering a TNA to remove microorganisms from a contaminated PN.
4: Use of a 1.2 micron filter when administering a TNA to remove microorganisms from a contaminated PN.

Answer 16

1: IVFE hang time up to 24 hours when included as part of a total nutrient admixture (TNA).

The recommended maximum hang time for a TNA is 24 hours, whereas the recommended maximum hang time for IVFE administered as an infusion separate from PN is 12 hours. The higher osmolarity and lower pH (~ 6.0) of the TNA compared to IVFE alone make the TNA less conducive to growth of most microorganisms. A 0.22 micron filter should not be used to filter an admixture containing IVFE as this will compromise the integrity of the fat emulsion globules. Although a 1.2 micron filter is recommended for use with TNA, such a filter removes larger particulates but not most microorganisms.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 17

Question: 17

Which of the following is the most appropriate distal catheter tip placement of a peripherally inserted central catheter (PICC)?

1: Cephalic vein
2: Superior vena cava
3: Internal jugular vein
4: Supraclavicular vein

Answer 17

2: Superior vena cava

Central lines are defined as catheters with the distal tip in either the superior or inferior vena cava. Although the cephalic or basilic vein is often used as the insertion site for PICCs, central catheters, including PICCs, are defined by the placement of the distal tip into a central vein.

References:

Vanek VW. The ins and outs of venous access: Part II. NCP. 2002;17(3):142-155.

Question 18

Question: 18

Which of the following is a disadvantage of a peripherally-inserted central catheter (PICC)?

1: High rate of catheter malposition
2: High risk of pneumothorax
3: Requires repeated skin puncture
4: Only available with single lumen

Answer 18

1: High rate of catheter malposition

PICC line disadvantages include: high rate of malposition; limited arm mobility; and limited ability to perform daily self-care due to the availability of only one hand. Advantages of PICC lines include: no risk of pneumothorax; available in single, double, and triple lumens; and repeated skin puncture not required.

References:

Vanek VW. The ins and outs of venous access: Part II. NCP. 2002;17(3):142-155.

Question 19

Question: 19

When is it most appropriate to start PN infusion in a patient with a new central venous catheter inserted at the bedside without fluoroscopy?

1: Immediately
2: After auscultating for catheter tip placement
3: After chest X-ray confirms correct placement of catheter tip
4: After ensuring there were no complications with insertion

Answer 19

3: After chest X-ray confirms correct placement of catheter tip

A common complication of central venous catheters inserted at the bedside is catheter misplacement, including pneumothorax. The use of fluoroscopy during catheter insertion allows immediate repositioning of the catheter tip into its correct location in the superior vena cava. PN infusions can be started immediately if the catheter was inserted with the use of fluoroscopy. However, central venous catheters placed at the bedside without fluoroscopy, require a chest X-ray be obtained after insertion to document catheter placement and rule out a pneumothorax. Once it has been determined the catheter is in the correct position, PN can be started at the ordered rate. Auscultation is not a method to determine central venous catheter tip 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 20

Question: 20

According to the Centers for Disease Control and Prevention (CDC), which of the following is true regarding PICC line care?

1: Routine placement is recommended to prevent catheter-related blood stream infections (CRBSIs)
2: Remove the PICC line immediately if fever develops
3: Use routine guidewire exchange of PICC line to prevent catheter-related blood stream infections
4: Remove the PICC line only if it is suspected or known to be the source of infection

Answer 20

4: Remove the PICC line only if it is suspected or known to be the source of infection

Current CDC Guidelines: A.) Do not routinely replace CVCs, PICCs, hemodialysis catheters, or pulmonary artery catheters to prevent catheter-related infections. B.) Do not remove CVCs or PICC lines based on fever alone. Use clinical judgement regarding the appropriateness of removing the catheter if infection is evident elsewhere or if non-infectious fever is suspected. C.) Do not use guidewire exchanges routinely for non-tunneled catheters (PICCs) to prevent infection. D.) Use clinical judgement to determine when to replace a catheter that could be a source of infection, e.g., do not routinely replace catheters in patients whose only indication of infection is fever. Do not routinely replace venous catheters in patients who are bacteremic or fungemic if the source of infection is unlikely to be the catheter. Replace any short-term CVC if purulence is observed at the insertion site, which indicates infectio. Replace all CVCs if the patient is hemodynamically unstable and CRBSI is suspected. Do not use guidewire techniques to replace catheters in patients suspected of having catheter-related infection.

References:

O’Grady NP, Alexander M, Dellinger EP, et al. Guidelines for the Prevention of Intravascular Catheter-Related Infections. Clinical Infectious Diseases. 2002;35:1281-1307.

Question 21

Question: 21

PN solutions containing a final dextrose concentration exceeding 20% should NOT be infused via a catheter inserted in which vein?

1: Basilic
2: Femoral
3: Subclavian
4: Internal jugular

Answer 21

1: Basilic

Hypertonic PN solutions containing a final dextrose concentration exceeding 10% or more can only be administered via a central vein, such as the subclavian, femoral, or internal jugular veins. The basilic vein is a peripheral vein.

References:

Vanek VW. The ins and outs of venous access: Part I. NCP. 2002;17(2):85-98.

Question 22

Question: 22

Which of the following PN formulas can be safely administered through a peripheral catheter?

1: 10% dextrose and 3% amino acid
2: 20% dextrose and 3% amino acid
3: 10% dextrose and 10% amino acid
4: 20% dextrose and 10% amino acid

Answer 22

1: 10% dextrose and 3% amino acid

Generally, PN formulas exceeding 900 mOsm/L are inappropriate for administration by peripheral catheter due to the high risk of phlebitis. In PN formulas of unknown osmolarity, concentrations of 10% dextrose and 3% amino acid should not be exceeded when a peripheral IV catheter is used.

References:

Vanek VW. The ins and outs of venous access: Part I. NCP. 2002;17(2):85-98.

Question 23

Question: 23

A total nutrient admixture (TNA) contains which macronutrients?

1: Water and amino acids
2: Carbohydrates and amino acids
3: Water, amino acids, and IV fat emulsion (IVFE)
4: Carbohydrates, amino acids, and IVFE

Answer 23

4: Carbohydrates, amino acids, and IVFE

A total nutrient admixture (TNA), also referred to as 3-in-1, is a PN formulation containing IVFE as well as the other components of PN (carbohydrate, amino acids, vitamins, minerals, trace elements, water, and other additives) in a single container.

References:

Teitelbaum D, Guenter P, Howell WH, et al. Definitions of terms, style, and conventions used in A.S.P.E.N. Guidelines and Standards. NCP. 2005;20:281-285.

Question 24

Question: 24

Glutamine supplementation in PN is limited by

1: the presence of intravenous fat emulsion (IVFE) in a total nutrient admixture (TNA) formula.
2: expense of the commercially available product.
3: physical stability after compounding.
4: the presence of calcium in the PN.

Answer 24

3: physical stability after compounding.

Glutamine is a non essential amino acid that is a primary fuel for the small bowel. In critical illness, glutamine deficiency can develop; therefore, the amino acid becomes a conditionally essential amino acid. Glutamine is not added to commercial intravenous amino acid formulations because of physical incompatibility over time. Glutamine may be added to PN formulations, including 3-in-1 admixtures as long as it is administered within 48 hours after compounding.

References:

Kearns LR, Phillips MC, Ness-Abramof R, et al. Update on parenteral amino acids. NCP. 2001;16(4):219-225

Question 25

Question: 25

The primary difference between renal and standard intravenous amino acid formulas is that renal formulas contain a higher proportion of which type of amino acids?

1: Non-essential
2: Conditionally essential
3: Essential
4: Branched-chain

Answer 25

3: Essential

Intravenous renal formulations contain a higher proportion of essential amino acids than standard formulations. Most recent studies have shown no difference in mortality, nitrogen balance, or blood urea nitrogen (BUN) when compared to balanced amino acid formulations. Data suggest an increased incidence of hyperammonemia and metabolic encephalopathy when only essential amino acids are used for longer than 2 to 3 weeks. In patients with renal failure, it is suggested that the nonessential amino acids arginine, ornithine, and citrulline should be given to enable detoxification of ammonia via the krebs cycle. There appears to be no indication for the use of “essential amino acid only” formulations.

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

Question: 26

Branched-chain amino acid formulas would be most appropriate for

1: a patient with a recent diagnosis of hepatocellular cancer.
2: prevention of a first episode of hepatic encephalopathy in a patient who has undergone a transjugular intrahepatic portosystemic shunt (TIPS) procedure.
3: initial management of acute hepatic encephalopathy.
4: a cirrhotic patient with chronic encephalopathy who is intolerant of standard protein sources.

Answer 26

4: a cirrhotic patient with chronic encephalopathy who is intolerant of standard protein sources.

Use of branched-chain amino acid-enriched diets and specialized nutrition support (SNS) formulas is only indicated in chronic encephalopathy for those who cannot tolerate at least 1 gm/kg/day of standard protein despite optimal pharmacotherapy.

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

Question: 27

Failure to provide linoleic and alpha linolenic acids with PN will most likely result in

1: metabolic acidosis.
2: hyperglycemia.
3: metabolic bone disease.
4: essential fatty acid deficiency (EFAD).

Answer 27

4: essential fatty acid deficiency (EFAD).

Although rare in recent years, EFAD may still occur in the contemporary practice of specialized nutrition support. Failure to provide at least 2% to 4% of the total caloric intake as linoleic acid and 0.25% to 0.5% of total caloric intake as alpha linolenic acid may lead to a deficiency of these two fatty acids.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 28

Question: 28

The adverse effects of intravenous fat emulsion (IVFE) administration in adults is best prevented by

1: supplementing with L-carnitine.
2: avoiding infusion rates >0.1 grams/kg/hour.
3: using 10% IVFE preparations.
4: avoiding serum triglyceride levels >400 mg/dL.

Answer 28

4: avoiding serum triglyceride levels >400 mg/dL.

Confusion surrounds the safe administration of IVFE in patients with hypertriglyceridemia. Several investigators have determined that the infusion rate of IVFE not exceed 0.125 grams/kg/hour in order to avoid serious metabolic effects. The excess phospholipid content of 10% versus 20% IVFE is associated with plasma lipid alterations. The excess phospholipids produce lipoprotein X-like substances that can compete with chylomicron remnants for hepatocyte binding sites. This may interfere with lipid clearance by delaying peripheral hydrolysis of triglycerides by lipoprotein lipase. Use of 20% IVFE allows more efficient triglyceride clearance and metabolism. IVFE should be infused at rates to avoid serum triglyceride levels >400 mg/dL in adults and >200 mg/dL in neonates. The clinical consequences associated with hypertriglyceridemia in both adults and neonates include an increased risk of pancreatitis, immunosuppression, and altered pulmonary hemodynamics, whereas, hypertriglyceridemia in the preterm infant with physiologic jaundice and hyperbilirubinemia (>18 mg/dL) is associated with kernicterus.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 29

Question: 29

Which of the following best describes an intravenous fat emulsion (IVFE) produced by the transesterification of fatty acids to form a composite triglyceride molecule?

1: Single oil
2: Multi-oil
3: Structured
4: Physical mixture

Answer 29

3: Structured

When two or more oils are mixed together, the emulsion product is called a physical mixture. Medium-chain fatty acid (MCFA)/Long-chain fatty acid (LCFA) structured lipids are similar to MCFA/LCFA physical mixtures in that they combine the properties of the two types of fatty acids. However, the structured lipid is created through hydrolysis of triglycerides and transesterification of fatty acids to form a composite triglyceride molecule that has various proportions of both MCFA and LCFA. The structured lipids are thought to have an advantage over the physical mixture of MCFA and LCFA because of a slower rate of release and utilization of the MCFA. These products are currently investigational only.

References:

Kumpf VJ, Mirtallo JM, Peterson C. Parenteral nutrition formulations: preparation and ordering. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:97-107.

Question 30

Question: 30

Which of the following trace elements should NOT be added to the PN for a patient with hepatobiliary disease?

1: Zinc and manganese
2: Zinc and magnesium
3: Copper and manganese
4: Copper and magnesium

Answer 30

3: Copper and manganese

Reductions in manganese and copper dosing should be considered in patients with hepatobiliary disease due to impaired excretion.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 31

Question: 31

Which of the following PN components is NOT a source of aluminum contamination?

1: Heparin
2: L-cysteine
3: Potassium phosphate
4: Regular insulin

Answer 31

4: Regular insulin

Many drug products used routinely in parenteral therapy may contain levels of aluminum sufficiently high to cause clinical manifestations of aluminum toxicity (CNS and bone toxicity.) Aluminum contamination occurs primarily from the introduction of raw materials during the manufacturing process. Product sources of primary concern include calcium and phosphate salts, heparin, and albumin. L-cysteine is also reported to be a source of aluminum contamination. In response to the evidence linking the use of parenteral drug products containing aluminum to morbidity and mortality, the FDA now mandates manufacturers to measure and report the maximal amount of aluminum content at product expiration.

References:

Charney PJ, Chair. A.S.P.E.N. Statement on aluminum in parenteral nutrition solutions. NCP. 2004;19:416-417.

Question 32

Question: 32

A long term PN patient experiences extrapyramidal symptoms. Which trace element toxicity is most likely to present with these symptoms?

1: Manganese
2: Copper
3: Zinc
4: Selenium

Answer 32

1: Manganese

Extrapyramidal symptoms may include involuntary movements, tremor, and rigidity. Manganese undergoes biliary excretion. Toxicity may occur in long-term PN patients with cholestasis who receive supplemental manganese. The early phase of manganese toxicity is characterized by weakness, anorexia, headache, and apathy followed by Parkinson-like features including muscle rigidity, mask-like face, staggered gait, and fine tremor.

References:

Clark SF. Vitamins and Trace Elements. 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.; 2007:129-159.

Question 33

Question: 33

When compared to the Dietary Reference Intakes (DRIs) for fat-soluble vitamins given orally, the DRIs for parenterally administered fat-soluble vitamins are

1: less.
2: equal.
3: two times greater.
4: four times greater.

Answer 33

1: less.

The DRI for parenteral administration of the fat-soluble vitamins are less than the DRIs for the orally given fat-soluble vitamins. Requirements are lower because there is no loss from the gastrointestinal tract when the doses are given intravenously.

References:

Sacks GS. Alternate dosing of multivitamins in parenteral nutrition: Economically savvy or clinically unsafe? NCP. 2001;16:S1-S4.

Question 34

Question: 34

When compared to the Dietary Reference Intakes (DRIs) for water-soluble vitamins given orally, the DRIs for parenterally administered water-soluble vitamins are

1: one-third.
2: one-half.
3: equal.
4: greater.

Answer 34

4: greater.

The DRIs for parenterally administered water-soluble vitamins are greater than the DRIs for orally given water-soluble vitamins. Patients receiving PN are considered more stressed and may require a greater intake of the water-soluble vitamins.

References:

Sacks GS. Alternate dosing of multivitamins in parenteral nutrition: Economically savvy or clinically unsafe? NCP. 2001;16:S1-S4.

Question 35

Question: 35

According to USP Chapter 797, a PN solution prepared from 8.5% amino acid solution with electrolytes and 70% dextrose, with multivitamins, trace elements, and famotidine added would be classified as

1: no risk.
2: low risk.
3: medium risk.
4: high risk.

Answer 35

3: medium risk.

The appropriate risk level, low, medium, or high, is assigned according to the corresponding probability of contaminating a compounded sterile preparation with(1) microbial contamination and (2) chemical and physical contamination.

• Compounding of PN using manual or automated devices during which there are multiple injections, detachments, and attachments of nutrient source products to the device or machine to deliver all nutritional components to a final sterile container is classified as medium-risk.
• Low-risk compounding involves only transfer, measuring, and mixing manipulations with closed or sealed packaging systems that are performed promptly and attentively.
• High-risk compounding differs from low- and medium-risk compounding in that it involves using nonsterile ingredients or nonsterile devices prior to terminal sterilization.

References:

United States Pharmacopeia, Inc. Chapter <797>: Pharmaceutical Compounding – Sterile Preparations. USP Pharmacist’s Pharmacopeia. 1st edition. Rockville, MD: United States Pharmacopeial Convention; 2005:413-431.

Question 36

Question: 36

Which one of the following best describes a safe compounding practice for PN?

1: The physical appearance of a final PN formulation containing amino acids, dextrose, and additives should be visually assessed to detect the presence of particulate matter.
2: Visual assessment of the final formulation of a total nutrient admixture is not recommended as it is not anticipated that problems can be visually detected in an opaque dispersion.
3: Manual methods for compounding PN formulations are no longer recommended; automated methods have been shown to be safer and more cost effective.
4: Using brands of PN components (e.g., amino acids, dextrose, intravenous fat emulsion) from different manufacturers to compound PN formulations is a safe practice that should not raise concerns.

Answer 36

1: The physical appearance of a final PN formulation containing amino acids, dextrose, and additives should be visually assessed to detect the presence of particulate matter.

Visual inspection of the final PN formulation may lead to detection of particulates such as “cores” from vials and cotton fibers. Such inspection may also detect other signs of physical incompatibility such as gas formation, turbidity, or crystallization. It should be kept in mind that the visual absence of physical signs of incompatibility does not insure safety, as the naked eye cannot detect all small particulates that could still be harmful to the patient. Even with total nutrient admixtures, final visual inspection should be performed to check for phase separation. Both manual and automated PN compounding techniques are still widely utilized. Although automated techniques are labor saving when a large number of PN formulations are being made daily, cost-effectiveness may be difficult to demonstrate in small institutions where a limited number of PN formulations are utilized. Mixing brands of PN components from different manufacturers should be undertaken only when there are data to support stability, compatibility, and safety of the final combinations.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 37

Question: 37

Creaming of a total nutrient admixture (TNA) appears as

1: a translucent band at the surface of the emulsion separate from the remaining TNA dispersion.
2: yellow-brown oil droplets at or near the TNA surface.
3: a continuous layer of yellow-brown liquid at the surface of the TNA.
4: marbling or streaking of the oil throughout the TNA.

Answer 37

1: a translucent band at the surface of the emulsion separate from the remaining TNA dispersion.

The initial stage in emulsion breakdown is creaming which occurs almost immediately upon standing once IVFE has been mixed with the other chemical constituents. The presence of a cream layer is visible at the surface of the emulsion as a translucent band separate from the remaining TNA dispersion, although the lipid particles in the cream layer are destabilized; their individual droplet identities are generally preserved. In general, light creaming is a common occurrence and not a significant determinant of infusion safety except in extreme cases.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 38

Question: 38

Which of the following complications is most likely to occur when transitioning a critically ill patient from parenteral to enteral nutrition?

1: Hypocalcemia
2: Hypercalcemia
3: Hypoglycemia
4: Hyperglycemia

Answer 38

4: Hyperglycemia

When transitioning from parenteral to enteral nutrition, patients may receive nutrients in excess during overlap of therapy leading to hyperglycemia. Appropriate adjustments to limit carbohydrate intake to 4 mg/kg/min can prevent this metabolic complication.

References:

Piazza-Barnett R. Combined and transitional feeding modalities. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice: A Clinical Guide. 2nd Ed. Philadelphia: Saunders; 2003:290-299.

Question 39

Question: 39

Rapid intravenous infusion of sodium or potassium phosphate may result in

1: tetany.
2: hypercalcemia.
3: metabolic alkalosis.
4: vitamin D deficiency.

Answer 39

1: tetany.

Rapid infusion of phosphate can result in tetany due to an abrupt decrease in serum calcium concentration. Since phosphate salts are acidifying in nature, alkalosis would not be anticipated.

References:

Baumgartner TG. Enteral and parenteral electrolyte therapeutics. NCP. 2001;16:226-235.

Question 40

Question: 40

Which of the following should be monitored regularly in an adult patient receiving IVFE?

1: Fecal fat
2: Serum osmolarity
3: Prothrombin time
4: Retinol-binding protein

Answer 40

3: Prothrombin time

IVFE is a significant but inconsistent source of vitamin K. Therefore, patients receiving IVFE with varying amounts of vitamin K should have periodic monitoring of prothrombin time.

References:

Singh H, Duerksen DR. Vitamin K and nutrition support. NCP. 2003;18:359-365.

Question 41

Question: 41

A patient receiving PN develops metabolic acidosis. Which serum electrolyte level needs to be monitored most closely?

1: Sodium
2: Chloride
3: Potassium
4: Magnesium

Answer 41

3: Potassium

Metabolic acidosis results in an extracellular shift of potassium, without changes in total body potassium. Correction of the underlying metabolic acidosis redistributes potassium into the intracellular space and corrects the hyperkalemia. Due to potassium involvement in muscle contraction, cardiac arrest is the most severe manifestation of hyperkalemia. The potassium content in the PN formula may need to be adjusted based on serum potassium level.

References:

Kraft MD, Btaiche IF, Sacks GS, et al. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm. 2005;62:1663-1682.

Question 42

Question: 42

Which of the following is a clinical sign of hyperphosphatemia?

1: Tachycardia
2: Tetany
3: Hyperventilation
4: Altered mental status

Answer 42

2: Tetany

The most common clinical manifestation of hyperphosphatemia is hypocalcemia due to calcium-phosphate precipitation, which can lead to tetany and other clinical manifestations of hypocalcemia. The risk of calcium-phosphate precipitation appears to increase when the serum calcium level multiplied by the serum phosphorus concentration exceeds 55-60 mg2/dL2. Calcium-phosphate crystals can also deposit into soft tissues and cause further organ damage.

References:

Kraft MD, Btaiche IF, Sacks GS, et al. Treatment of electrolyte disorders in adult patients in the intensive care unit. Am J Health Syst Pharm. 2005;62:1663-1682.

Question 43

Question: 43

What laboratory findings are diagnostic for essential fatty acid deficiency?

1: A serum triglyceride level < 100 mg/dL
2: A lymphocyte absolute count < 1000/microliter
3: A serum cholesterol level < 100 mg/dL
4: A triene to tetraene ratio greater than 0.4

Answer 43

4: A triene to tetraene ratio greater than 0.4

The essential fatty acids, linoleic and linolenic, are long chain triglycerides (LCT). The LCTs rely on chylomicron formation and the lymphatic system for transport. Medium chain triglycerides (MCTs) are transported directly into portal circulation and can be used to provide additional calories on a very low fat diet; however, MCTs do not meet a patient’s requirement for essential fatty acids. Essential fatty acid deficiency is diagnosed with the triene-to-tetraene ratio. IVFE will bypass the gastrointestinal digestion of LCT into chyle while providing essential fatty acids.

References:

Gura KN, Parsons SK, Bechard LJ, et al. Use of a fish oil-based lipid emulsion to treat essential fatty acid deficiency in a soy allergic patient receiving parenteral nutrition. Clin Nutrition. 2005;24:839-847.

Question 44

Question: 44

Concurrent infusion of IVFE and propofol would most likely cause

1: hyperglycemia.
2: hypertriglyceridemia.
3: azotemia.
4: hypernatremia.

Answer 44

2: hypertriglyceridemia.

Propofol, an anesthetic agent, is used for intensive care unit sedation. The vehicle for administering this drug is 10% IVFE. The concurrent administration of propofol and IVFE in PN can result in higher than recommended doses of IVFE and hypertriglyceridemia if appropriate adjustments are not made.

References:

Davis AM, Stanko-Kline R. Pediatrics. In: Matarese LE, Gottschlich MM, eds. Contemporary Nutrition Support Practice: A Clinical Guide. 2nd ed. Philadelphia: Saunders; 2003:357-375.

Question 45

Question: 46

When initiating a PN regimen that contains regular insulin, how often should capillary blood glucose levels be monitored?

1: Every 6 hours
2: Every 8 hours
3: Every 12 hours
4: Every 24 hours

Answer 45

1: Every 6 hours

Capillary blood glucose levels should be monitored every 6 hours and supplemented with an appropriately dosed sliding scale insulin coverage given subcutaneously as needed to maintain glucose in goal range. Once glucose concentrations are stable, the frequency of measuring capillary blood glucose concentrations can often be decreased.

References:

Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 46

Question: 47

A patient is receiving 120 mL/hr of a cyclic PN solution containing 50 units of regular insulin. How should the PN solution be tapered off?

1: Cut the rate in one quarter for the last two hours prior to discontinuation
2: Cut the rate in one quarter for the last four hours prior to discontinuation
3: Cut the rate in half for the last two hours prior to discontinuation
4: Cut the rate in half for the last four hours prior to discontinuation

Answer 46

3: Cut the rate in half for the last two hours prior to discontinuation

Rebound hypoglycemia upon discontinuation of PN has been reported, although this is an extremely uncommon event. Some experts continue to recommend that, particularly for patients receiving large amounts of insulin along with their PN, the infusion rate can be cut in half for the last two hours prior to discontinuation. This approach can avoid the need for excessive blood glucose monitoring during discontinuation of PN.

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

Question: 48

In adult parenteral nutrition patients, intravenous fat emulsion (IVFE) use should be limited to the provision of essential fatty acids only when serum triglyceride levels rise above

1: 400 mg/dL.
2: 300 mg/dL.
3: 200 mg/dL.
4: 100 mg/dL.

Answer 47

1: 400 mg/dL.

Serum triglycerides provide a reasonable estimate of body lipid clearance. Hypertriglyceridemia in adults has resulted in impaired pulmonary function, immune suppression and increased risk of pancreatitis. When serum triglyceride levels exceed 400 mg/dL fat provision should to be limited to provision of essential fatty acids only to prevent deficiency. This can be accomplished by infusing 250 mL of a 20% IVFE once or twice weekly. Alternatively, topical administration of soybean or safflower oil may be useful to prevent EFAD in cases of extreme hypertriglyceridemia. These oils are absorbed transcutaneously into the plasma without exacerbating hypertriglyceridemia.

References:

Sacks G, Mayhew S, Johnson D. Parenteral Nutrition Implementation and Management. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual. 2nd ed. Silver Spring, MD: A.S.P.E.N.; 2005:108-117.

Question 48

Question: 49

Long term use of which parenteral nutrition (PN) product would most likely contribute to aluminum accumulation in a person requiring chronic parenteral nutrition?

1: Vitamin K
2: Potassium phosphate
3: 10% intravenous fat emulsion
4: Parenteral amino acids

Answer 48

2: Potassium phosphate

Many PN products are contaminated with aluminum from the introduction of raw materials during the manufacturing process. Products of primary concern include calcium and phosphate salts, heparin and albumin. Variable levels have also been noted with some trace element, vitamin, and macronutrient products. Those most vulnerable to aluminum toxicity include infants, children, those with renal insufficiency, and those on chronic PN. Alterations in bone formation and mineralization, parathyroid hormone secretion, and urinary calcium excretion have been attributed to aluminum toxicity. The FDA currently recommends that all manufactures list the maximum aluminum concentration at product expiration and that daily intake of parenteral aluminum not exceed 5 mcg/kg/day.

References:

American Society for Parenteral and Enteral Nutrition Aluminum Task Force: Charney P, Chair. A.S.P.E.N. Statement on Aluminum in Parenteral Nutrition Solutions. NCP. 2004;19:416-417.
Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J, Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6 Suppl):S39-S70.

Question 49

Many PN products are contaminated with aluminum from the introduction of raw materials during the manufacturing process. Products of primary concern include…

Answer 49

calcium and phosphate salts, heparin and albumin

Question 50

Question: 50

Commonly reported advantages to cycling parenteral nutrition include all except

1: more rapid restoration of serum albumin levels.
2: prevention of parenteral nutrition-induced fatty infiltration of the liver.
3: prevention of parenteral nutrition-associated hyperglycemia.
4: higher level of social activity and interaction in parenteral nutrition-dependent patients.

Answer 50

3: prevention of parenteral nutrition-associated hyperglycemia.

All have been documented as benefits of cyclic parenteral nutrition in long term parenteral nutrition patients except prevention of hyperglycemia. In fact, hyperglycemia is a common result of cyclic parenteral nutrition and may limit one’s ability to minimize infusion duration.

References:

Longhurst C, Naumovski L, Garcia-Careaga M, Kerner J. A Practical Guideline for Calculating Parenteral Nutrition Cycles. NCP. 2003;18:517-520.
Kovacevich D, Orr M. Considerations in Home Nutrition Care. In: Merritt R, ed. The A.S.P.E.N. Nutrition Support Practice Manual 2nd Ed. Silver Spring, MD: A.S.P.E.N.; 2005:371-377.