Flashcards in Nutrition Module 12: Nutrition Support Deck (63)
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