10: Nutrition Flashcards
What is special about leucine, isoleucine, and valine?
- They are branch-chained amino acids
- Metabolized in muscle
- Possibly important in patients with liver failure
- They are essential amino acids
[The essential amino acids are leucine, isoleucine, valine, arginine, histidine, lysine, methionine, phenylalanine, threonine, and tryptophan.]
Which vitamin deficiency is characterized by all of the following?
- Impaired decarboxylation of factors II, VII, IX, and X
- Prolongation of prothrombin time (INR)
Vitamin K deficiency
What is the difference between the composition of central line parenteral nutrition (TPN) and peripheral line parenteral nutrition (PPN)?
- TPN is glucose based (10% amino acid solution, 50% dextrose solution, electrolytes, minerals, and vitamins. Lipids are given separately from TPN)
- PPN is fat based
[The maximum glucose administration in TPN is 3 g/kg/hr.]
What is the Cori cycle?
- Glucose is utilized and converted to lactate in the muscle
- Lactate then goes to the liver and is converted back to pyruvate and eventually to glucose via gluconeogenesis
- Glucose is then transported back to the muscle
What are the acute indicators of nutritional status?
- Retinal binding protein
- Prealbumin
- Transferrin
What are the 4 precursors to gluconeogenesis?
- Amino acids (especially Alanine)
- Lactate
- Pyruvate
- Glycerol
In which patients should protein intake be limited and why?
Patients with liver or renal failure should have limited protein intake to avoid buildup of ammonia and possible worsening of encephalopathy
When do the following postoperative phases typically occur?
- Diuresis phase
- Catabolic phase
- Anabolic phase
- Diuresis phase: POD# 2-5
- Catabolic phase: POD# 0-3 (negative nitrogen balance)
- Anabolic phase: POD# 3-6 (positive nitrogen balance)
What do the following respiratory quotients indicate?
- RQ < 0.7
- RQ = 0.7
- RQ = 0.8
- RQ = 1.0
- RQ > 1
- RQ < 0.7: Ketosis and fat oxidation (Starvation)
- RQ = 0.7: Pure fat utilization
- RQ = 0.8: Pure protein utilization
- RQ = 1.0: Pure carbohydrate utilization
- RQ > 1: Lipogenesis (Overfeeding)
[Respiratory quotient is the ratio of CO2 produced to O2 consumed. It is a measurement of energy expenditure.]
What is the appropriate calorie breakdown by percentage for an average healthy adult male?
- Protein
- Fat
- Carbohydrates
- Protein: 20% (1 g protein/kg/day)
- Fat: 30%
- Carbohydrates: 50%
[20% protein and 30% fat should be essential amino acids and essential fatty acids respectively.]
How long do glycogen stores last after onset of starvation?
24-36 hours
[2/3 of glycogen is in skeletal muscle, 1/3 of glycogen is in the liver. After glycogen stores are depleted, the body begins to metabolize fat stores.
The Harris-Benedict equation calculates basal energy expenditure based on which 4 factors?
- Weight
- Height
- Age
- Gender
What is the difference between the energy sources utilized in starvation vs in trauma or postoperative patients?
Fat (ketones) are the main source of energy in both, however, in trauma/postop patients the energy source is more mixed (fat and protein)
[Protein-conserving mechanisms do not occur after trauma or surgery secondary to catecholamines and cortisol. Most patients can tolerate a 15% weight loss without major complications.]
What activates trypsinogen?
Enterokinase released from the duodenum
[Trypsin can then autoactivate other trypsinogen molecules.]
What are the two essential fatty acids and what are they needed for?
- Linolenic acid
- Linoleic acid
They are needed for prostaglandin synthesis (long-chain fatty acids) and they are important for immune cells
