Parenteral Nutrition

Question 1

A pregnant patient is admitted with hyperemesis gravidarium (HG). Which of the following is a clinical indication for PN use?

1: Vomiting NOT controlled with supportive care within 48 hours
2: Intolerance to EN trial and supportive care measures
3: Patient refusal of EN tube placement
4: Fluid and electrolyte imbalances

Answer 1

2: Intolerance to EN trial and supportive care measures

Hyperemesis gravidarum (HG) is a severe form of pregnancy-induced nausea and vomiting. 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 for HG, fluid and electrolyte imbalances, ketonuria, and dehydration would be treated via IV fluid. Multivitamins with additional B vitamins are typically added to address suboptimal vitamin intake and prevent complications such as neuropathies (B6 and B12), Wernicke’s encephalopathy (thiamine), and neural tube defects (folic acid). Antiemetic treatment would begin and oral intake would temporarily be avoided. Initiation of an EN trial for HG would be appropriate if the patient is still unable to take oral feedings after 24-48 hours of supportive therapy as listed above. If the EN trial fails due to exacerbated nausea, vomiting, diarrhea, significant gastric residuals, or tube displacement and is associated with clinically significant weight loss (greater than 5% of body weight), it is appropriate to begin PN.

Question 2

Rapid intravenous infusion of potassium phosphate may result in

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

Answer 2

1: thrombophlebitis.

Infusion rates of phosphate should not exceed 7 mmol/h because faster infusion rates can often cause thrombophlebitis (ie, potassium phosphate) and metastatic calcium-phosphate deposition with potential resultant organ dysfunction.

Question 3

What is the most common complication associated with PN administration?

1: Hypophosphatemia
2: Hyperkalemia
3: Hyponatremia
4: Hyperglycemia

Answer 3

4: Hyperglycemia

Hyperglycemia is the most common complication associated with PN administration and can be caused by various factors. Stress-associated hyperglycemia in acutely ill and septic patients often develops as a result of insulin resistance, increased gluconeogenesis and glycogenolysis, and suppressed insulin secretion.

Question 4

What is the glycemic target for the majority of critically ill adult patients?

1: 80 to 110 mg/dL
2: 220 to 240 mg/dL
3: 140 to 180 mg/dL
4: 180 to 220 mg/dL

Answer 4

3: 140 to 180 mg/dL
The current recommendation for glycemic target by the American Association of Clinical Endocrinologists (AACE) and the American Diabetes Association (ADA) is to maintain the glucose level between 140-180 mg/dL for the majority of critically ill adult patients. Lower glucose targets (110 mg/dl to 140 mg/dL) may be appropriate for some patients, but this is only appropriate when this can be safely achieved. Targets less than 110 mg/dl are not recommended due to the adverse effects of hypoglycemia.

Question 5

What is the preferred approach recommended by the American Association of Clinical Endocrinologists (AACE) and the American Diabetes Association (ADA) for subcutaneous insulin administration in the hospitalized adult patient with diabetes mellitus?

1: Sliding-scale insulin therapy
2: Basal insulin therapy
3: Bolus insulin therapy
4: Basal-bolus insulin therapy

Answer 5

4: Basal-bolus insulin therapy

The preferred approach for subcutaneous insulin administration is basal-bolus insulin therapy. This approach allows for basal insulin administered for hepatic glucose output combined with scheduled bolus insulin administered for meal times. There are three components to basal-bolus insulin therapy: basal insulin, nutritional component prior to meals and a correctional insulin.

Question 6

Which form of glutamine supplementation improves physical compatibility and stability for admixture in PN solutions?

1: Glutamine dipeptide
2: Free glutamine
3: L-glutamine powder
4: Protein bound glutamine.

Answer 6

1: Glutamine dipeptide

Glutamine supplementation is available in parenteral solutions, some predigested enteral formulas, and oral nutrition supplements. However, IV glutamine supplements are not commercially available in the United States. Glutamine dipeptide products such as L-alanyl-L-glutamine and Glycyl-L-glutamine improve water solubility, stability during heat sterilization, and the capability for prolonged shelf life when compounding in parenteral solutions. Free glutamine is unstable in parenteral solutions

Question 7

In the critically ill obese patient, specific guidelines for the provision of calories and protein have been recommended by both the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition. For a patient with a BMI 33.4 kg/m2, which of the following choices best reflects the calorie recommendations for parenteral and enteral nutrition?

1: 11- 14 Kcal/kg ideal body weight/day
2: 11 - 14 Kcal/kg actual body weight/day
3: 22 - 25 Kcal/kg actual body weight/day
4: 22 - 25 Kcal/kg ideal body weight/day

Answer 7

2: 11 - 14 Kcal/kg actual body weight/day

For all classes of obesity where BMI is >30 kg/m2, the goal of the parenteral and enteral regimen should not exceed 65% to 70% of target energy requirements as measured by indirect calorimetry. If indirect calorimetry is not available, using the weight based equation 11–14 kcal/kg actual body weight/day for patients with BMI 30-50 kg/m2 and 22–25 kcal/kg ideal body weight/day for patients with BMI > 50 kg/m2 is recommended. Protein should be provided in a range greater than or equal to 2.0 g/kg ideal body weight/day for patients with BMI 30–40 kg/m2, and up to 2.5 g/kg ideal body weight/day for patients with BMI ≥40 kg/m2.

Question 8

Which of the following additives has the greatest risk of destabilizing the lipid injectable emulsion (ILE) in a total nutrient admixture (TNA)?

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

Answer 8

3: Iron dextran

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.

Question 9

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 9

2: Calculation of PN dosages

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.

Question 10

According to the ASPEN PN Safety Consensus Recommendations, 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 original concentration added (e.g., 500 mL of 50% dextrose)
2: Grams per liter (e.g., 250g/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 10

4: Grams per 24-hour nutrient infusion (e.g., 225 g/day)

PN ingredients shall be ordered in amounts per day for adults and amounts per kilogram per day for pediatric and neonatal patients. This limits the confusion of conversion from amounts per liter, percent concentration, or volume. Amount per day refers to macronutrients in grams per day and micronutrients in mEq, mmol, mcg, or mg per day.

Question 11

According to the ASPEN PN Safety Consensus Recommendations all of the following are considered to be mandatory for the PN order form EXCEPT

1: Full generic name for each ingredient (unless brand name can identify unique properties of specific dosage form)
2: Recommended laboratory monitoring
3: Infusion schedule (continuous or cyclic)
4: Electrolytes ordered as complete salt form rather than individual ion

Answer 11

2: Recommended laboratory monitoring

The addition of recommended laboratory monitoring to PN order forms is strongly recommended, but it is not required. A complete PN order shall contain the following: complete patient identifiers, birth date or age, allergies, height and dosing weight in metric units, diagnosis/diagnoses, indication(s) for PN, administration route/vascular access device (peripheral versus central), contact information for prescriber, date and time order submitted, administration date and time, volume and infusion rate, infusion schedule (continuous or cyclic), and type of formulation (TNA versus dextrose/amino acids with separate ILE). PN ingredients shall be ordered as follows: amounts per day (for adult patients) or amounts per kilogram per day (for pediatric and neonatal patients), electrolytes as complete salt form, full generic name for each ingredient, using The Joint Commission approved abbreviations and avoiding ISMP error prone abbreviations, symbols, and dose designations, dose for each macronutrient and electrolyte, dose for vitamins (including MVI and individual entities), dose for trace elements (including multi-components and/or individual entities), dose for each non-nutrient medication.

Question 12

According to the ASPEN PN Safety Consensus Recommendations all of the following are considered to be mandatory for the inpatient PN label EXCEPT

1: infusion rate expressed in mL/h.
2: beyond-use date and time.
3: size of in-line filter (1.2 or 0.22 micron).
4: electrolyte content expressed in individual ions.

Answer 12

4: electrolyte content expressed in individual ions.

Ingredients are to be expressed on the PN label in the same sequence and units of measure as the PN order. Electrolytes are to be ordered as complete salt forms as opposed to individual ions.The PN label should include the following: two patient identifiers, patient location or address, dosing weight in metric units, administration date and time, beyond use date and time, route of administration (central versus peripheral), prescribed volume and overfill volume, infusion rate in mL/h, duration of infusion (continuous versus cyclic), size of in-line filter (1.2 or 0.22 micron), completer name of all ingredients, barcode, all ingredients shall be listed in the same sequence and same units of measure as PN order, name of institution or pharmacy, and institution or pharmacy contact information (including telephone number).If ILE is to be infused separately, the ILE label should include: two patient identifiers, patient location or address, dosing weight, administration date and time, route of administration (central versus peripheral), prescribed about of ILE and volume required to deliver that amount, infusion rate in mL/h, duration of infusion (not longer than 12 hours), complete name of ILE, beyond use date and time, name of institution or pharmacy, and institution or pharmacy telephone number.

Question 13

Your patient is receiving the following PN order. 2400 mL with 300 grams dextrose, 90 grams protein in addition to 225 mL 20% ILE. How many total calories and grams of fat is your patient receiving?

1: 1830 kcal, 40 grams fat
2: 2010 kcal, 40 grams fat
3: 1830 kcal, 45 grams fat
4: 1470 kcal, 45 grams fat

Answer 13

3: 1830 kcal, 45 grams fat
One (1) gram of dextrose is equal to 3.4 calories. One (1) gram of protein is equal to 4 calories. One (1) mL of 20% ILE is equal to 2 calories. The total daily caloric intake equals 468 kcal (protein) + 928 kcal (dextrose) + 500 kcal (ILE) or 1896 kcal/day. When divided by the patient’s weight of 75 kg the total daily caloric intake per kg is 25.3 kcal/kg/day.

Question 14

In the critically ill obese patient, specific guidelines for the provision of calories and protein have been recommended by both the Society of Critical Care Medicine and the American Society for Parenteral and Enteral Nutrition. For a patient with a BMI > 33.4 kg/m2, which of the following choices best reflects those recommendations for the provision of protein in parenteral and enteral nutrition?

1: Less than 2.0 g/kg ideal body weight/day
2: Greater than or equal to 2.0 g/kg ideal body weight/day
3: Less than 2.0 g/kg actual body weight/day
4: Greater than or equal to 2.0 g/kg actual body weight/day

Answer 14

2: Greater than or equal to 2.0 g/kg ideal body weight/day

For all classes of obesity where BMI is >30 kg/m2, the goal of the parenteral and enteral regimen should not exceed 65% to 70% of target energy requirements as measured by indirect calorimetry. If indirect calorimetry is not available, using the weight based equation 11–14 kcal/kg actual body weight/day for patients with BMI 30-50 kg/m2 and 22–25 kcal/kg ideal body weight/day for patients with BMI > 50 kg/m2 is recommended. Protein should be provided in a range greater than or equal to 2.0 g/kg ideal body weight/day for patients with BMI 30–40 kg/m2, and up to 2.5 g/kg ideal body weight/day for patients with BMI ≥ 40 kg/m2.

Question 15

Which of the following is an indication for the use of parenteral nutrition (PN)?

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

Answer 15

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. 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.

Question 16

When is parenteral nutrition (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: Enteral nutrition is contraindicated or unlikely to meet nutrition needs
4: Within 7-10 days after hospital admission

Answer 16

3: Enteral nutrition 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.

Question 17

The routine use of preoperative parenteral nutrition (PN) is indicated for patients with a non-functioning GI tract who are

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

Answer 17

4: severely malnourished.

Many studies have identified the severely malnourished patient 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.

Question 18

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

1: Abdominal tumor resulting in an unresolved small bowel obstruction for greater than seven days
2: Metastatic cancer, receiving palliative care
3: Receiving concurrent chemotherapy and radiation therapy
4: Mild malnutrition, scheduled for tumor resection surgery in three days

Answer 18

1: Abdominal tumor resulting in an unresolved small bowel obstruction for greater than seven days

Any adult patient with a gastrointestinal obstruction that precludes oral intake for at least one week may benefit from nutrition support. Mildly malnourished patients do not require PN 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. Most side effects of chemotherapy and radiation can be managed without the use of PN. Adult cancer patients scheduled for surgery who are severely malnourished may benefit from PN if the therapy can continue for 7-10 days preoperatively.

Question 19

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 19

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.

Question 20

Current recommendations regarding safe administration of lipid injectable emulsion (ILE) include

1: ILE hang time up to 24 hours when included as part of a total nutrient admixture (TNA).
2: ILE hang time up to 24 hours when administered as an infusion separate from PN (2 in 1 PN).
3: ILE when a part of a TNA is stable for 1 week at room temperature.
4: ILE should be filtered with a 0.22 micron filter when administered for nutrition.

Answer 20

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

TNA are more likely to be stable for 30 hours at room temperature (25 degrees Celsius) or for 9 days refrigerated (5 degrees Celsius) followed by 24 hours at room temperature. Prolonged storage and/or light exposure can result in degradation of some components of TNA. ILE is most stable at their manufactured pH (~6-9), and the addition of acidic dextrose can contribute to TNA instability. Electrolytes, especially positively charged cations calcium and magnesium neutralize the negative charge on the surface of the lipid particle. Commercially available ILE in the US are stabilized with egg yolk phosphatides providing a mechanical and electrical barrier to particle coalescence. Amino acids offer a protective effect by enhancing the admixtures buffering effect. ILE administered via piggyback separate from amino acid and dextrose should have a hang time of 12 hours and have tubing and filter changes with each new infusion. Recently package inserts for ILE have been updated to state that 1.2 micron filters should be used during ILE administration. This 1.2 micron filter could stop fat emboli, air emboli, microorganisms, and particulate matter from reaching the patient.

Question 21

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 21

2: Superior vena cava

A peripherally inserted central catheter (PICC) is defined as a catheter inserted via peripheral vein whose distal tip lies in the vena cava. The cephalic or basilic vein is often used as the insertion site for PICCs. Central or peripheral access is not defined by the initial point of entry into the vascular system but rather by the position of the distal catheter tip. Central lines are defined as catheters with the distal tip in either the superior or inferior vena cava. Therefore, by definition, a PICC is used as central venous access.

Question 22

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

1: Limited self-care ability
2: High risk of pneumothorax
3: Requires repeated skin puncture
4: Only available with single lumen

Answer 22

1: Limited self-care ability

PICC line disadvantages include: high rate of malposition or coiling; limited patient arm mobility associated with limited ability to perform daily self-care due to the availability of only one hand; and longer catheter that may be more prone to occlusion. Advantages of PICC lines include: no risk of pneumothorax or puncture or internal carotid or subclavian arteries; available in single, double, and triple lumens; and repeated skin puncture is not required.

Question 23

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 23

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 to its correct location in the superior vena cava. PN solutions can be started immediately if the catheter was inserted with the use of fluoroscopy. However, central catheters placed at bedside without fluoroscopy should be radiographically confirmed and documented in the medical record before initial use. Once it has been determined the catheter is in the correct position, PN may be initiated. Auscultation is not a method to determine central venous catheter tip placement.

Question 24

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

1: Scheduled replacement is recommended to prevent catheter-related blood stream infections (CRBSIs)
2: Remove the PICC line immediately if fever develops
3: Guidewire exchange should be used when the PICC is a suspected source of infection
4: Remove the PICC line only if it is suspected or known to be the source of infection

Answer 24

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

Current CDC recommendations: Do not routinely replace central venous catheters, peripherally inserted central catheters, hemodialysis catheters, or pulmonary artery catheters to prevent catheter-related infections. Catheter replacement at scheduled time intervals has not shown a decrease in CRBSI. Do not remove CVCs or PICCs based on fever alone. Clinical judgment should be used to determine appropriateness of catheter removal if infection is evidenced from another site or a noninfectious cause is suspected. Catheter insertion over a guidewire is associated with less discomfort and a lower rate of mechanical complication when compared to percutaneous insertion at a new site, but replacement of temporary catheters during bacteremia should not be done over a guidewire due to source of infection (colonization of skin to insertion site).

Question 25

Which of the following central venous catheters is the LEAST favorable for PN infusion?

1: Peripherally Inserted Central Catheter (PICC)
2: Femoral Catheter
3: Subclavian Catheter
4: Internal Jugular Catheter

Answer 25

2: Femoral Catheter

The Institute for Healthcare Improvement (IHI) Central Line Bundle should be used for central vascular access devices. This bundle is a group of evidenced-based interventions for patients with intravascular central catheters that, when implemented together, result in better outcomes than when implemented individually. One of the key components is optimal catheter site selection, with avoidance of central venous access devices with high risk for infection, such as femoral catheters, when alternate access is available.

Question 26

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 6% amino acid
4: 20% dextrose and 6% amino acid

Answer 26

1: 10% dextrose and 3% amino acid

ASPEN Clinical Guidelines suggest that PN with an osmolarity of up to 900 mOsm/L can be safely infused peripherally. Infusion of hypertonic parenteral solutions exceeding 900 mOsm/L through a peripheral catheter may result in phlebitis. Solutions with an osmolarity> 900 mOsm/L require central access. The lower concentrated dextrose solutions (5, 10%) and amino acid solutions (3%) are most often used for peripheral administration. The osmolarity of 10% dextrose= 500 mOsm/L. The osmolarity of 3% amino acid= 300 mOsm/L. 5 mOsm per gram of dextrose and 10 mOsm per gram of AA

Question 27

Which of the following reduces the risk of calcium phosphate precipitation in PN?

1: Increased amino acid concentration
2: Use of calcium chloride as the calcium salt
3: Increased temperature
4: Adding calcium salt immediately after adding phosphate salt

Answer 27

1: Increased amino acid concentration

Increased concentration of amino acids reduce the risk of calcium phosphate precipitation by forming soluble complexes with calcium, thereby reducing the free calcium ions available to form insoluble dibasic calcium phosphate precipitates. Additionally, higher concentrations of amino acids may lower the pH of the PN formulation, which also improves calcium phosphate solubility. Calcium chloride dissociates more readily than calcium gluconate, increasing the free calcium ions available to bind with phosphate ions when using calcium chloride. Increasing temperature increases the dissociation of calcium salts. Storage under refrigeration reduces risk of calcium phosphate precipitation. When compounding PN, it is recommended to add the phosphate first and then add the calcium near the end of compounding to utilize the maximum volume of the PN formulation to dilute the salts. Adding the calcium and phosphate salts back-to-back causes locally high concentrations of these salts prior to adequate mixing.

Question 28

Which parenteral amino acid (AA) formulation should be used in a hospitalized adult patient with acute kidney injury (AKI) requiring parenteral nutrition support?

1: Standard AA formulation
2: Branched-chain AA formulation
3: Essential AA formulation
4: Renal specialty AA formulation

Answer 28

1: Standard AA formulation

The ability to synthesize nonessential amino acids is reduced in patients with acute renal insufficiency. Enrichment of parenteral nutrition with branched chain amino acids has been studied, but there is insufficient evidence to recommend this approach. Renal amino acid formulations are composed primarily of essential amino acids and are relatively dilute. Studies have found no difference in mortality with a renal acid formulation. Therefore it is recommended to provide standard AA formulation for AKI patients.

Question 29

Branched-chain amino acid (BCAA) 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 despite optimal pharmacotherapy.

Answer 29

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

Use of branched-chain amino acid-enriched diets nutrition support formulas is only indicated in chronic encephalopathy for those who cannot tolerate at least 1gm/kg/day of standard protein despite optimal pharmacotherapy. The use of BCAA solutions is not fully supported by the literature in hepatic encephalopathy. Encephalopathy is usually not caused by altered protein in the diet. Protein consumption with the recommended range does not worsen hepatic encephalopathy and in fact leads to improved body composition. ASPEN recommends the use of standard formulations for critically ill patients with acute or chronic liver disease.

Question 30

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 30

4: essential fatty acid deficiency (EFAD).

Although rare in recent years, EFAD may still occur in the contemporary practice of nutrition support therapy. 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. For infants, it is recommended to provide 0.5 to 1 g/kg/day of lipid in order to prevent EFAD.

Question 31

The adverse effects of lipid injectable emulsion (ILE) administration in adults is best prevented by

1: supplementing with L-carnitine.
2: avoiding infusion rates >0.05 grams/kg/hour.
3: using 10% ILE preparations.
4: avoiding serum triglyceride levels >400 mg/dL.

Answer 31

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

Several investigators have determined that the infusion rate of ILE not exceed 0.11 grams/kg/hour in adults, 0.15 grams/kg/hour in children, and 0.17 grams/kg/hour in neonates in order to avoid serious metabolic effects. The excess phospholipid content of 10% versus 20% ILE is associated with plasma lipid alterations. Use of 20% ILE allows more efficient triglyceride clearance and metabolism. ILE should be infused at dosages to avoid serum triglyceride levels >400 mg/dL in adults and >200 mg/dL in pediatric populations. A deficiency of L-carnitine may be common in specific patient populations (e.g., those with end-stage renal disease undergoing hemodialysis). L-carnitine deficiency can be treated with supplementation; however, while it is thought that deficiency exacerbates lipid abnormalities, the existing evidence has not confirmed that supplementation will correct hypertriglyceridemia.

Question 32

Which of the following best describes a lipid injectable emulsion (ILE) 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 32

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

Question 33

In a patient with hepatobiliary disease, which of the following trace elements should be withheld or requires a dosage reduction when prescribing parenteral nutrition?

1: Selenium and manganese
2: Copper and selenium
3: Zinc and chromium
4: Copper and manganese

Answer 33

4: Copper and manganese

Reductions in manganese and copper dosing should be considered in patients with hepatobiliary disease due to impaired excretion. Manganese is a contaminant found within the PN solution components, thus patients will likely receive small doses of manganese even if eliminated from the PN trace element prescription. If removed, ongoing monitoring for deficiency should occur. Excretion of copper and manganese is impaired in patients with hepatobiliary disease. Supplementation in parenteral nutrition can lead to excessive accumulation in the body and eventually toxicity. Reduction or removal of copper and manganese from the PN solution is recommended for patient with decreased liver function. Patients should receive periodic monitoring for signs and symptoms of deficiency.

Question 34

Which of the following components is NOT a major source of aluminum contamination in parenteral nutrition solutions?

1: Potassium phosphate
2: Sodium phosphate
3: Calcium Gluconate
4: Lipid injectable emulsion (ILE)

Answer 34

4: Lipid injectable emulsion (ILE)

Parenteral nutrition is a major source of aluminum exposure due to contamination of its various components. Contamination usually occurs during manufacturing through raw materials and byproducts of the manufacturing process. Nearly all parenteral components contain some aluminum though content varies from manufacturer-to-manufacturer. Calcium and phosphate salts, particularly calcium gluconate and potassium phosphate, are a major contributor to aluminum contamination of solutions. Due to the evidence linking parenteral nutrition to aluminum toxicity, the FDA mandates all manufacturers to measure and report the maximum content of aluminum in their products. Large volume components such as amino acids, dextrose, lipids and water, must contain less than 25 mcg/L. Small volume additives require labeling of aluminum content at the time of expiry on the container label.

Question 35

A long term parenteral nutrition patient begins to experience Parkinson-like symptoms. Which trace element toxicity is most likely to present with these symptoms?

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

Answer 35

1: Manganese

Manganese is an essential trace element routinely added to long-term parenteral nutrition solutions. Though manganese deficiency is exceedingly rare, toxicity is well documented in these patients. Excess manganese accumulates in the brain leading to Parkinson disease-like symptoms such as tremor, involuntary movements and rigidity. Patients with abnormal liver function are at an increased risk for toxicity due to manganese being primarily excreted via bile. Manganese contamination of PN solutions can also occur during manufacturing and delivery of PN solutions. Despite this increased risk there is limited evidence to support manganese-free PN solutions in patients without symptoms of toxicity or impaired liver function. Current recommendations for long-term PN patients are to monitor manganese associated liver enzymes as well as signs and symptoms of manganese toxicity. Patients with chronic liver disease should receive manganese-free solutions due to impaired elimination.

Question 36

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

1: lower.
2: equal.
3: two times higher.
4: four times higher.

Answer 36

2: equal.

The current recommended daily dose for parenteral fat-soluble vitamins is approximately the same as the oral Recommended Dietary Allowance (RDA) or Adequate Intake (AI). Though bioavailability of intravenous vitamins is much greater than those received orally, patients requiring parenteral nutrition are frequently found to have higher vitamin requirements. This is often due to these patients presenting with malnutrition, baseline vitamin deficiencies and metabolic changes secondary to acute and chronic illness. The provision of high parenteral vitamin doses has been in practice for over 30 years and no cases of toxicity have been reported.

Question 37

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: higher.

Answer 37

4. higher

Current water-soluble vitamin daily parenteral doses are 2 to 2.5 times greater than the Recommended Dietary Allowance (RDA) or Adequate Intake (AI) because of increased requirements due to malnutrition, baseline vitamin deficiencies, and increased urinary excretion of water-soluble vitamins when used intravenously.

Question 38

According to United States Pharmacopeia (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 38

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. Low-risk compounding involves only transfer, measuring, and mixing manipulations with closed or sealed packaging systems that are performed promptly and attentively (i.e. reconstitution of a single-dose vial of lyophilized powder with sterile diluents for transfer into another container). 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 (i.e. as in the question above). High-risk compounding differs from low- and medium risk compounding in that it involves using nonsterile ingredients or nonsterile devices prior to terminal sterilization (i.e. extemporaneously compounded L-glutamine for supplementation in a PN formulation).

Question 39

According to the ASPEN PN Safety Consensus Recommendations, which of the following best describes safe PN compounding?

1: The preparation with automated compounding devices (ACDs) ensures an error free process
2: All healthcare providers should have the ability to override soft and hard limit alerts from ACDs
3: Manual compounding of PN is appropriate when volumes of a PN component to be mixed are less than the ACD can accurately deliver
4: The preparation of compounded sterile preparations (CSPs) for all patient populations should be done at the same time

Answer 39

3: Manual compounding of PN is appropriate when volumes of a PN component to be mixed are less than the ACD can accurately deliver

Preparing PN with an ACD is not an error free process, and error rates are reported to be 22% when automated and 37% when manually prepared. Compounding with ACDs should lead to improved compounding accuracy, enforcement of proper compounding sequence, and reduction in opportunities for human touch contamination. Institute for Safe Medication Practices (ISMP) recommends to install, test, and maximize automated dose-limit warnings in the pharmacy and ACD order entry systems with each organization developing weight based dosing limits applicable to their patient population. ASHP (American Society of Health-System Pharmacists) guidelines for the safe use of ACDs for the preparation of PN states that the pharmacy department should develop a monitoring and surveillance plan that promotes safe and efficacious use of the ACD at all times. This includes a review of dose limit alerts and overrides. When an ACD is used, it should deliver all PN ingredients. Manual PN compounding is appropriate when the volume of a PN component is less than the ACD can accurately deliver or if there is an interaction between a PN component and ACD component. Manual compounding is also appropriate when chemical interactions between PN components cannot be mitigated by sequencing the addition of the ingredients, or as a part of a conservation effort during drug shortages. Facilities that care for adult, pediatric, and neonatal populations should separate CSP preparation for each population and develop separation strategies to minimize error.

Question 40

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 40

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

Answers b, c, and d describe potential visual signs of the terminal state of emulsion destabilization, commonly known as cracking. In this stage, small lipid particles coalesce to form large droplets ranging in size from 5-50 or more microns. These oil droplets pose potential clinical danger. In contrast, the initial stage in emulsion breakdown is creaming which occurs almost immediately upon standing once ILE has been mixed with 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.

Question 41

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

1: Hypokalemia
2: Hyperkalemia
3: Hypoglycemia
4: Hyperglycemia

Answer 41

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 total carbohydrate intake to no greater than 4 mg/kg/min can prevent this metabolic complication in many critically ill adult patients.

Question 42

Rapid intravenous infusion of sodium or potassium phosphate may result in

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

Answer 42

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.

Question 43

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

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

Answer 43

3: Potassium

Metabolic acidosis, tissue catabolism, and pseudohyperkalemia results in an extracellular shift of potassium. Metabolic acidosis results in an extracellular shift to maintain electroneutrality. For every 0.1 decrease in pH, potassium will increase by 0.6mEq per liter generally. Correction of the underlying metabolic acidosis redistributes potassium into the intracellular space and corrects the hyperkalemia. Clinical manifestations of hyperkalemia are related to changes in neuromuscular and cardiac function. The potassium content in the PN formula and exogenous potassium may need to be adjusted based on serum potassium level.

Question 44

What is considered to be the most serious complication of significant hyperphosphatemia?

1: Osteoporosis and fractures
2: Soft tissue and vascular complications
3: Hypoventilation
4: Hypercalcemia

Answer 44

2: Soft tissue and vascular complications

The most serious complication of hyperphosphatemia is soft tissue and vascular calcifications. Calcification occurs when the serum calcium level multiplied by the serum phosphorus level exceeds 55 mg per deciliter. Additional consequences of hyperphosphatemia are secondary hyperparathyroidism and renal osteodystrophy, and hypocalcemia.

Question 45

What biochemical evidence indicates essential fatty acid deficiency (EFAD)?

1: A serum triglyceride level < 50 mg/dL
2: A lymphocyte absolute count < 1000/microliter
3: A serum cholesterol level < 100 mg/dL
4: A triene to tetraene ratio > 0.2

Answer 45

4: A triene to tetraene ratio > 0.2

Biochemical evidence of EFAD is determined by a triene: tetraene ratio greater than 0.2 (Holman Index) and can occur within 1 to 3 weeks in adults receiving PN without intravenous fat emulsion (ILE). Two polyunsaturated fatty acids (linoleic, alpha-linolenic) cannot be synthesized by the body and are considered essential. Thus, an exogenous source of fat must be provided. To prevent EFAD, 2% to 4% of daily energy requirements should be derived from linoleic acid and about 0.25-0.5% of energy from alpha-linolenic acid. 500 mL of 10% ILE, 250 mL of 20% ILE administered twice weekly, or 500 mL of a 20% ILE can be given once a week to prevent EFAD. A trial of topical skin application or oral ingestion of oils to alleviate biochemical deficiency of EFAD may be given to patients who are intolerant to ILE.

Question 46

A patient in the ICU receiving concurrent infusions of lipid injectable emulsion (ILE) and propofol. These concurrent infusions could potentially cause

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

Answer 46

2: hypertriglyceridemia.

Propofol, an anesthetic agent, is used in the intensive care area for sedation. The vehicle for administering this drug is 10% IV lipid emulsion. The concurrent administration of propofol and ILE in PN can result in higher than recommended doses of IV lipid emulsion andhypertriglyceridemia if appropriate adjustments are not made

Question 47

Which component of parenteral nutrition (PN) is most likely to impact anticoagulation in a patient receiving warfarin?

1: Standard amino acids and electrolytes
2: Dextrose and trace elements
3: lipid injectable emulsion (ILE) and vitamins
4: Branched-chain amino acids and electrolytes

Answer 47

3: lipid injectable emulsion (ILE) and vitamins

Parenteral multivitamin products are available with or without vitamin K. ILE are also a source of vitamin K, though the amount is variable. Patients receiving PN who are also on warfarin may require dosing adjustments to account for the additional vitamin K. The INR level should be closely monitored to ensure it is within therapeutic range.

Question 48

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 48

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.

Question 49

What risk is associated with the abrupt cessation of a parenteral nutrition solution?

1: Hypokalemia
2: Hypoglycemia
3: Hypervolemia
4: Hypomagnesemia

Answer 49

2: Hypoglycemia

Abrupt discontinuation of PN solutions has been associated with rebound hypoglycemia. Patients requiring large doses of insulin have a greater propensity for rebound hypoglycemia, but predetermining which patients will experience rebound hypoglycemia is difficult. Therefore, to reduce the risk of rebound hypoglycemia in susceptible patients, a 1- to 2-hour taper down of the infusion may be necessary.

Question 50

In adult parenteral nutrition patients, intravenous lipid emulsion (ILE) use should be limited when serum triglyceride levels rise above

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

Answer 50

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 ILE infusion should be decreased to levels that prevent fatty acid deficiency.

Question 51

The FDA currently recommends that daily intake of parenteral aluminum not exceed what amount?

1: 2 mcg/kg/day
2: 5 mcg/kg/day
3: 7 mcg/kg/day
4: 10 mcg/kg/day

Answer 51

2: 5 mcg/kg/day

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. Alterations in bone formation and mineralization, parathyroid hormone secretion, and urinary calcium excretion have been attributed to aluminum toxicity. Those most vulnerable to aluminum toxicity include infants, children, those with renal insufficiency, and those on chronic PN. The FDA currently recommends that all manufacturers list the maximum aluminum concentration at product expiration and that daily intake of parenteral aluminum not exceed 5 mcg/kg/day. Inclusion of potential aluminum load on the label of compounded PN is not mandated in the FDA ruling.

Question 52

Cycling parenteral nutrition is recommended in

1: patients receiving short term parenteral nutrition.
2: patients at risk for liver dysfunction.
3: patients at risk for parenteral nutrition-associated hyperglycemia.
4: patients who are bed bound.

Answer 52

2: patients at risk for liver dysfunction.

Cycling of PN formulations should be considered for patients with or at risk for liver dysfunction, on long-term TPN or those who are stable and active and may benefit from infusion free periods. Continuous PN infusion can result in hyperinsulinemia and hepatic fat deposition, thereby increasing risk for liver complications. Cyclic PN infusion has been shown to reduce serum liver enzyme and conjugated bilirubin concentrations when compared to continuous PN infusion and may reduce the risk of parenteral nutrition-associated liver disease, especially in long-term PN-dependent patients.

Question 53

A patient who weighs 75 kg is receiving 65 mL/hour of a 2-in-1 PN solution that contains 117 grams protein and 273 grams dextrose in addition to 250 mL of 20% ILE. What is the daily caloric content of this regimen per kg body weight?

1: 27.5 kcal/kg/day
2: 21.9 kcal/kg/day
3: 26.5 kcal/kg/day
4: 25.3 kcal/kg/day

Answer 53

4: 25.3 kcal/kg/day

One (1) gram of dextrose is equal to 3.4 calories. One (1) gram of protein is equal to 4 calories. One (1) mL of 20% ILE is equal to 2 calories. The total daily caloric intake equals 468 kcal (protein) + 928 kcal (dextrose) + 500 kcal (ILE) or 1896 kcal/day. When divided by the patient’s weight of 75 kg the total daily caloric intake per kg is 25.3 kcal/kg/day.