Flashcards in Nutrition Module 12: Nutrition Support Deck (63)
What 4 events are bypassed during IV feeding?
1. Stimulation of mucosal cells
2. Stimulation of GI hormonal response
3. Direct transport to the liver (first pass)
4. Packaging of lipids in chylomicrons
What are some of the long term complications of IV feeding associated with?
Lack of stimulation of GI tract and CKK
What happens to the lumen of the GI tract when it does not receive nutrients for a while?
1. Decreased overall weight of tissue
2. Shortened microvilli
3. Decreased absorptive area
4. Openings on surface
5. Impaired barrier function
What ion causes CKK secretion?
What GI tract hormone stimulates pancreatic secretions?
What AA is an important oxidative fuel for the intestinal mucosa?
What is glutamine a precursor for?
Why is glutamine conditionally essential?
Because needed in diet in severe illness
What causes large amounts of glutamine to be released for gluconeogenesis? From where?
From lungs and skeletal muscle
What would a lack of glutamine in the intestine cause?
Deterioration of mucosal barrier
What foods contain glutamine?
All natural proteins
Is glutamine used in enteral formulas?
Is glutamine used in parenteral formulas? Why?
NOPE because short-lived in solution (but can be added individually)
What are the 3 functions of short-chain FAs?
1. Energy source for intestinal enterocytes and liver
2. Maintain integrity of large intestine by stimulating proliferation and increasing blood flow
3. Stimulate intestinal water and sodium absorption
What are short FAs produced by in the intestine?
Bacteria from dietary fiber
What 10 conditions require specialized nutrition support?
3. Unable to swallow
4. Vomiting (eg: pregnant)
6. GI obstruction
8. Very high energy demands: trauma, major surgery, burns, sepsis
9. Failure to thrive
10. Eating disorder
What organ gets first access to most nutrients?
Why can parenteral feedback affect lipid clearance and metabolism?
Because lipids enter the circulation directly as droplets instead of having the liver control distribution and having normal packaging and apoproteins to regulate absorption
Where is food received in enteral feeding?
Stomach or small intestine
When should supplemental nutrition be initiated?
When inadequate oral intake is expected over a 7 to 14 day period
What are the 3 compartments the body can be divided in? How do these differ between men and women? Include % and acronyms for each.
1. Bone mass (3% lower in women): 12-15%
2. FM = Fat mass (10% higher in women): 15-25%
3. LBM = Metabolic tissues and water (7% lower in women): 63-70%
What does FFM stand for?
Fat Free Mass = body mass - FM
What is a good predictor of basal metabolic rate?
What is one way of estimating LBM? Why?
Creatinine index because it's produced by muscle at a rate proportional to muscle mass and is only excreted in urine
How to calculate the creatinine height index?
CHI (%) = measured 24h urine creatinine / ideal 24h creatinine for height/gender based on healthy young adults *100
For what patients does the creatinine height index grossly overestimates LBM?
Stressed patients where muscle metabolism is high
For what patients does the creatinine height index grossly underestimates LBM?
Vegetarians because of low creatinine intake
What does the amount of increased energy needs depend on in stressed patients?
Degree of illness
What is one way of measuring total energy expenditure?
How does indirect calorimetry estimate TEE?
Measured CO2 production or O2 uptake
When is indirect calorimetry used?
To prevent over or under feeding of critically ill, malnourished, or extremely obese patients
How can the precise TEE be calculated with indirect calorimetry?
By estimating the actual nutrient mix from the respiratory quotient = CO2/O2
What is the RQ of carb oxidation?
What is the RQ of fat oxidation?
What is the RQ of protein oxidation?
What fuel source produces the least amount of CO2 per O2 consumed?
What is the normal total RQ?
How will starvation affect the RQ?
How high is variability of RQ in stressed patients?
Up to 50%
3 steps to calculate TEE with indirect calorimetry?
1. Measure urine nitrogen to determine amount of protein oxidized
2. Measure RQ
3. Use 3 linear equations to calculate TEE, carb oxidation, and fat oxidation
Why can carb and fat oxidation be predicted only with RQ?
Because they are completely oxidized
Are DRI equations appropriate for the critically ill?
What 2 equations to use to calculate BEE?
1. Harris-Benedict equation
2. Penn State 2003
What are 2 reasons for why stressed patients have increased TEE?
What 3 conditions cause hypometabolism?
2. Spinal cord injuries
3. Some cancers
By how much does fever increase the metabolic rate?
By 10% for each degree above 37
Explain the pathophysiology of refeeding syndrome.
Aggressive oral, enteral, or parenteral carb feedback following a period of nutritional deprivation => sudden glucose influx in cells => sequestration of magnesium, potassium, and phosphorus => dangerously low blood concentrations => cardiac arrest, neuromuscular complications, and respiratory dysfunction
What is cachexia?
Accelerated breakdown of muscle and adipose tissue often observed in patients with advanced cancer
What are the 8 patients at risk for refeeding syndrome?
1. Old pts with depression or dementia
4. Malnutrition due to hunger, stress, or fasting
5. Marasmus or Kwashiorkor
6. Chronic alcoholism
7. NPO status for over 7 days
What are the 5 ways of preventing refeeding syndrome?
1. Start low and go slow with calories
2. Avoid excess glucose
3. Measure and provide P, Mg, and K
4. Restrict fluid intake and initiate Na-containing fluids slowly
5. Thiamin supplement
What are the 3 veins through which parenteral feeding can be administered? Which one delivers nutrients at a lower concentration?
1. Subclavian vein
2. Internal jugular vein
3. Peripheral vein (lower concentration)
What is short-bowel syndrome? When does it occur? Treatment?
Occurs following removal of a large portion of the bowel and results in reduced absorption => malabsorption requiring parenteral support until adaptation happens over months and sometimes years
What % loss of our bowel can we tolerate?
Up to 50%
Where does adaptation of short-bowel syndrome occur? What will never adapt fully though?
Adaptation and improved nutrition in ileum and jejunum but jejunum will not develop active absorption of bile acids and VB12
What are 4 complications of long-term parenteral feeding?
1. Catheter-related infection leading to sepsis
2. Liver disease
3. Metabolic bone disease
4. Micronutrient deficiencies
What parts of the GI tract need to be preserved to avoid indefinite parenteral feeding?
1. Terminal ileum
2. Ileocecal valve
What are 2 ways of administering the enteral feeding? When do we use each?
1. Nasoenteric tube: less than 1 month duration
2. Gastrostomy tube: more than 1 month duration
What are the 4 complications of enteral feeding?
1. Reflux of stomach contents into the lungs => aspiration pneumonia
3. Refeeding syndrome
4. Altered glucose, lipid, acid-base balances
How do we know when to start feeding a patient normally again?
We hear bowel movements
What can underfeeding cause?
1. Protein used as energy
2. Poor wound healing and decubitus ulcers
3. Low energy levels and weakness
4. Protein calorie malnutrition
What can overfeeding cause?
2. CO2 retention: acidosis
3. Hepatis steatosis = fatty liver
What can overfeeding cause in patients on mechanical ventilators?
Difficulties with ventilator support and weaning off it