Registered Dietitian Nutritionist Enteral & Parenteral Nutrition Support 2 — Questions and Answers
Question 1: What is the primary indication for parenteral nutrition (PN)?
- Patient refuses oral feeding despite counseling
- Patient has elevated metabolic demands in the ICU
- GI tract is non-functional, inaccessible, or cannot be safely used (Correct answer)
- Patient has a functioning GI tract with marginal oral intake
Correct answer: GI tract is non-functional, inaccessible, or cannot be safely used
Parenteral nutrition is reserved for situations where the GI tract cannot be used safely or at all, distinguishing it from enteral nutrition.
Question 2: Central parenteral nutrition (CPN) is delivered via a catheter whose tip is positioned in the:
- Subclavian vein
- Superior vena cava (Correct answer)
- Femoral vein
- Basilic vein
Correct answer: Superior vena cava
CPN catheter tips are positioned in the superior vena cava to allow the high-osmolarity solution to be diluted rapidly by high blood flow.
Question 3: What is the maximum recommended osmolarity for peripheral parenteral nutrition (PPN) to minimize vein damage?
- 600 mOsm/L
- 900 mOsm/L (Correct answer)
- 1200 mOsm/L
- 1800 mOsm/L
Correct answer: 900 mOsm/L
PPN solutions should not exceed approximately 900 mOsm/L to reduce the risk of phlebitis and thrombosis in peripheral veins.
Question 4: Dextrose (D-glucose monohydrate) used in parenteral nutrition provides how many kilocalories per gram?
- 3.4 kcal/g (Correct answer)
- 4.0 kcal/g
- 5.0 kcal/g
- 7.0 kcal/g
Correct answer: 3.4 kcal/g
Dextrose in IV solutions provides 3.4 kcal/g (not 4.0 kcal/g) because glucose monohydrate contains water of crystallization that reduces caloric density.
Question 5: What is the primary nitrogen source used in parenteral nutrition formulations?
- Whole intact proteins
- Dipeptides and tripeptides
- Crystalline amino acids (Correct answer)
- Protein hydrolysates
Correct answer: Crystalline amino acids
Crystalline amino acids are used in PN because they are stable in solution and directly utilizable without digestion.
Question 6: Which laboratory test should be monitored most frequently when initiating parenteral nutrition to assess metabolic tolerance?
- Serum albumin
- Blood glucose (Correct answer)
- Total bilirubin
- Serum calcium
Correct answer: Blood glucose
Blood glucose requires frequent monitoring at PN initiation because the concentrated dextrose load can cause significant hyperglycemia.
Question 7: In an ICU patient receiving both propofol and lipid-containing PN, which complication should the dietitian monitor for?
- Essential fatty acid deficiency
- Linoleic acid toxicity
- Hypertriglyceridemia (Correct answer)
- Chylomicronemia syndrome from omega-3 overload
Correct answer: Hypertriglyceridemia
Propofol is formulated in a 10% lipid emulsion (1.1 kcal/mL), and when combined with lipid-containing PN, the cumulative fat load can cause hypertriglyceridemia.
Registered Dietitian Nutritionist Enteral & Parenteral Nutrition Support 2
What is the primary indication for parenteral nutrition (PN)?