CNSC EXAM PRACTICE QUESTIONS WITH
VERIFIED ANSWERS
Half life of albumin and pre-albumin
Albumin: 14-20 days
Prealbumin: 2-3 days
List negative acute phase proteins
Prealbumin
Albumin
Transferrin
Retinol-binding protein
(decreased in inflammation)
List positive acute-phase proteins
Cytokines
CRP (c-reactive protein)
Define sarcopenia
Age-related muscle loss
Cachexia
Loss of muscle mass, irrespective of adipose tissue changes (not responsive to nutrition
interventions/support)
+1 edema
2 mm depression or less
Rebound immediate
+2 edema
2-4 mm deppression
Rebound after a few seconds
+3 edema
4-6 mm depression
Rebound after 10-12 seconds
+4 edema
6-8 mm depression
Rebound in >20 seconds
Electrolyte abnormalities with refeeding risk
,-Hypophosphatemia (in most cases)
-Low K
-Low mag
-Low ca
-Hyponatremia
-Hyperglycemia
Other symptoms of refeeding
-Cardiac arrest/arrythmias
-Thiamin deficiency
-Hypotension
-Fluid retention
-Shortness of breath/resp failure
Advancement of EN if at risk of refeeding
Advancing to goal rate over 3-5 days
What is volume-based feeding?
When EN is prescribed in goal volume per day instead of per hour in critically ill patients.
Protocols involve starting at goal rate or rapid advancement.
When should EN be delayed in critically ill patients?
If they are hemodynamically unstable --> MAPs <50, starting high dose/increasing rate of
vasopressors (may result in gut ischemia due to low blood pressure to the gut)
Definition of hypocaloric feeding
65-70% of energy needs based on indirect calorimetry for obese critically ill patients
Benefit of hypocaloric feeding in obese patients
Minimizes metabolic complications of feeding, mobilize adipose store and increases insulin
sensitivity
What factors can impact the accuracy of a nitrogen balance study?
-Impaired renal function
-Incomplete collection of GI losses through fistulas, stool or ostomies
What are the essential fatty acids?
1. Linoleic acid 2. Linolenic acid
What is osmolality?
the concentration of a solution expressed as the total number of solute particles per kilogram.
What is considered a hyperosmolar solution?
,>320 mOsm/kg
-Can contribute to diarrhea (though this is only likely with formulas containing sucrose delivered
into small intestine directly since formula gets diluted by saliva/gastric juices in stomach)
Hang time for open system ready-to-feed formula
8-12 hours
Hang time for reconstituted formula
4 hours
Time allowed in refrigerator for reconstituted formula
24 hours
Hang time for closed system formula
24-48 hours
Target glucose levels in hospitalized patients
140-180
Composition of diabetic formulas and their use
1. High in fat/fiber to reduce gastric emptying and help glycemic control
2. Lower in carbohydrates
*ADA does not recommend a specific macronutrient distribution for diabetes, instead should
individualize based on the patient
*Not studied for ICU patients --> this population can control BGs with insulin gtt
Evidence to support elemental formulas in malabsorptive disorders
ESPEN advises against elemental formula for Crohn's, short bowel or UC
Recommendations for use of specialty/elemental formulas in ICU patient
ASPEN does not recommend due to lack of clear benefit demonstrated in the literature
Theory behind specialty formulas for hepatic encephalopathy
-Higher BCAAs clear ammonia in the skeletal muscle, lower amounts of aromatic amino acids
-Research does not show benefit of BCAA supplementation in improving patient outcomes
When to use immune-modulating formulas
-Potential benefit in surgical patients and SICU post-op to reduce infection
-Contraindicated in severe sepsis/illness
Composition of pulmonary formula
Low carb, high fat, concentrated formulas (lower respiratory quotient of lipid vs. carb)
, Evidence to support pulmonary formulas
Conflicting evidence/recommendations, use clinical judgement
Benefit of HMB in wasting conditions and which specific conditions does evidence support
-Help preserve/increase muscle mass in AIDS, cancer cachexia and sarcopenia
Components of immune-modulating formulas
-Arginine
-Omega 3's
-Antioxidants
-Sometimes glutatmine
Estimated calorie needs for hypocaloric feeding based on BMI if IC not available
BMI 30-50: 11-14 kcal/kg actual
BMI>50: 22-25 kcal/kg Ideal BW
Deciding between nasoenteric tube and permanent feeding tube (expected length of need(
Naso-enteric tube: 4-6 weeks
Permanent tube: >6 weeks expected
Indications for J-tube feedings
-Gastric outlet obstructions
-Gastroparesis
-Pancreatitis
-Increased aspiration risk
Indications for a G-J tube
-Gastric outlet obstruction
-Severe gastric reflux
-Gastroparesis
-Early post-operative feeding
Polyurethane vs. silicone tube differences (comfort, stiffness, wall width, fungal
degradation, common use)
Polyurethane: Less comfort, more stiff, thinner wall width, more resistant to fungal degradation,
used for nasal feeding tubes
Silicone: More comfortable, less stiff, thicker wall width, less resistant to fungal degradation,
used for percutaneous tubes
What does french size indicate?
Measure of external diameter
VERIFIED ANSWERS
Half life of albumin and pre-albumin
Albumin: 14-20 days
Prealbumin: 2-3 days
List negative acute phase proteins
Prealbumin
Albumin
Transferrin
Retinol-binding protein
(decreased in inflammation)
List positive acute-phase proteins
Cytokines
CRP (c-reactive protein)
Define sarcopenia
Age-related muscle loss
Cachexia
Loss of muscle mass, irrespective of adipose tissue changes (not responsive to nutrition
interventions/support)
+1 edema
2 mm depression or less
Rebound immediate
+2 edema
2-4 mm deppression
Rebound after a few seconds
+3 edema
4-6 mm depression
Rebound after 10-12 seconds
+4 edema
6-8 mm depression
Rebound in >20 seconds
Electrolyte abnormalities with refeeding risk
,-Hypophosphatemia (in most cases)
-Low K
-Low mag
-Low ca
-Hyponatremia
-Hyperglycemia
Other symptoms of refeeding
-Cardiac arrest/arrythmias
-Thiamin deficiency
-Hypotension
-Fluid retention
-Shortness of breath/resp failure
Advancement of EN if at risk of refeeding
Advancing to goal rate over 3-5 days
What is volume-based feeding?
When EN is prescribed in goal volume per day instead of per hour in critically ill patients.
Protocols involve starting at goal rate or rapid advancement.
When should EN be delayed in critically ill patients?
If they are hemodynamically unstable --> MAPs <50, starting high dose/increasing rate of
vasopressors (may result in gut ischemia due to low blood pressure to the gut)
Definition of hypocaloric feeding
65-70% of energy needs based on indirect calorimetry for obese critically ill patients
Benefit of hypocaloric feeding in obese patients
Minimizes metabolic complications of feeding, mobilize adipose store and increases insulin
sensitivity
What factors can impact the accuracy of a nitrogen balance study?
-Impaired renal function
-Incomplete collection of GI losses through fistulas, stool or ostomies
What are the essential fatty acids?
1. Linoleic acid 2. Linolenic acid
What is osmolality?
the concentration of a solution expressed as the total number of solute particles per kilogram.
What is considered a hyperosmolar solution?
,>320 mOsm/kg
-Can contribute to diarrhea (though this is only likely with formulas containing sucrose delivered
into small intestine directly since formula gets diluted by saliva/gastric juices in stomach)
Hang time for open system ready-to-feed formula
8-12 hours
Hang time for reconstituted formula
4 hours
Time allowed in refrigerator for reconstituted formula
24 hours
Hang time for closed system formula
24-48 hours
Target glucose levels in hospitalized patients
140-180
Composition of diabetic formulas and their use
1. High in fat/fiber to reduce gastric emptying and help glycemic control
2. Lower in carbohydrates
*ADA does not recommend a specific macronutrient distribution for diabetes, instead should
individualize based on the patient
*Not studied for ICU patients --> this population can control BGs with insulin gtt
Evidence to support elemental formulas in malabsorptive disorders
ESPEN advises against elemental formula for Crohn's, short bowel or UC
Recommendations for use of specialty/elemental formulas in ICU patient
ASPEN does not recommend due to lack of clear benefit demonstrated in the literature
Theory behind specialty formulas for hepatic encephalopathy
-Higher BCAAs clear ammonia in the skeletal muscle, lower amounts of aromatic amino acids
-Research does not show benefit of BCAA supplementation in improving patient outcomes
When to use immune-modulating formulas
-Potential benefit in surgical patients and SICU post-op to reduce infection
-Contraindicated in severe sepsis/illness
Composition of pulmonary formula
Low carb, high fat, concentrated formulas (lower respiratory quotient of lipid vs. carb)
, Evidence to support pulmonary formulas
Conflicting evidence/recommendations, use clinical judgement
Benefit of HMB in wasting conditions and which specific conditions does evidence support
-Help preserve/increase muscle mass in AIDS, cancer cachexia and sarcopenia
Components of immune-modulating formulas
-Arginine
-Omega 3's
-Antioxidants
-Sometimes glutatmine
Estimated calorie needs for hypocaloric feeding based on BMI if IC not available
BMI 30-50: 11-14 kcal/kg actual
BMI>50: 22-25 kcal/kg Ideal BW
Deciding between nasoenteric tube and permanent feeding tube (expected length of need(
Naso-enteric tube: 4-6 weeks
Permanent tube: >6 weeks expected
Indications for J-tube feedings
-Gastric outlet obstructions
-Gastroparesis
-Pancreatitis
-Increased aspiration risk
Indications for a G-J tube
-Gastric outlet obstruction
-Severe gastric reflux
-Gastroparesis
-Early post-operative feeding
Polyurethane vs. silicone tube differences (comfort, stiffness, wall width, fungal
degradation, common use)
Polyurethane: Less comfort, more stiff, thinner wall width, more resistant to fungal degradation,
used for nasal feeding tubes
Silicone: More comfortable, less stiff, thicker wall width, less resistant to fungal degradation,
used for percutaneous tubes
What does french size indicate?
Measure of external diameter
