CDR Enteral and Parenteral Nutrition 1 — Questions and Answers
Question 1: Which formula type is most appropriate for a patient with severe malabsorption and short bowel syndrome?
- Standard polymeric formula
- Elemental (monomeric) formula (Correct answer)
- Semi-elemental formula
- High-fiber formula
Correct answer: Elemental (monomeric) formula
Elemental formulas contain nutrients in their simplest absorbable forms (amino acids, monosaccharides, fatty acids), making them ideal for patients with severely compromised digestive and absorptive capacity.
Question 2: What is the primary indication for using a nasojejunal (NJ) tube instead of a nasogastric (NG) tube?
- Patient preference for comfort
- High risk of aspiration due to gastroparesis or delayed gastric emptying (Correct answer)
- Need for long-term enteral access
- Inability to tolerate lipid-containing formulas
Correct answer: High risk of aspiration due to gastroparesis or delayed gastric emptying
NJ tubes bypass the stomach and deliver formula directly into the jejunum, significantly reducing aspiration risk in patients with gastroparesis, gastroesophageal reflux, or impaired gastric motility.
Question 3: A patient on total parenteral nutrition (TPN) develops refeeding syndrome. Which electrolyte abnormality is the hallmark of this condition?
- Hyperkalemia
- Hypernatremia
- Hypophosphatemia (Correct answer)
- Hypercalcemia
Correct answer: Hypophosphatemia
Hypophosphatemia is the hallmark of refeeding syndrome; rapid carbohydrate administration shifts phosphorus intracellularly for ATP synthesis, causing dangerous drops in serum phosphorus.
Question 4: What osmolality range is generally considered safe for peripheral parenteral nutrition (PPN) to avoid thrombophlebitis?
- Less than 600 mOsm/L
- Less than 900 mOsm/L (Correct answer)
- Less than 1200 mOsm/L
- Less than 1500 mOsm/L
Correct answer: Less than 900 mOsm/L
PPN solutions should not exceed approximately 900 mOsm/L to minimize the risk of thrombophlebitis and vein irritation when infusing through a peripheral vein.
Question 5: Which complication is most commonly associated with long-term parenteral nutrition use?
- Metabolic alkalosis
- Parenteral nutrition-associated liver disease (PNALD) (Correct answer)
- Iron deficiency anemia
- Respiratory alkalosis
Correct answer: Parenteral nutrition-associated liver disease (PNALD)
Parenteral nutrition-associated liver disease (PNALD) is the most common serious long-term complication of PN, characterized by cholestasis, steatosis, and potentially progressing to cirrhosis.
Question 6: When initiating enteral nutrition in a critically ill patient, what is the preferred delivery site?
- Gastric feeding whenever feasible (Correct answer)
- Esophageal feeding
- Colonic feeding
- Duodenal feeding only
Correct answer: Gastric feeding whenever feasible
Gastric feeding is the preferred initial route in most critically ill patients as it is physiologically normal, stimulates gut hormones, and is easier to initiate; post-pyloric feeding is reserved for those with high aspiration risk.
Question 7: What is the caloric density of a standard 20% lipid emulsion used in parenteral nutrition?
- 1.0 kcal/mL
- 2.0 kcal/mL (Correct answer)
- 3.0 kcal/mL
- 4.5 kcal/mL
Correct answer: 2.0 kcal/mL
A 20% lipid emulsion provides 2.0 kcal/mL; the 10% emulsion provides 1.1 kcal/mL and the 30% emulsion provides 3.0 kcal/mL.
CDR Enteral and Parenteral Nutrition 1
Which formula type is most appropriate for a patient with severe malabsorption and short bowel syndrome?