ic7 nutritional support Flashcards
recommended energy requirement for general patients
25 - 35kcal/kg
ways to measure basal metabolic rate
1) Indirect calorimetry
gold standard but tedious
2) predictive equations
schofield equation, harris benedict equation
Protein requirement for:
healthy adult
surgery, burn
sepsis / critical illness
CKD
not on dialysis
dialysis
CRRT (continuous dialysis in ICU)
normal - 0.8g/kg/day
surgery: 1.5 - 2
Sepsis / critical illness: up to 2.5
CKD
not on dialysis: 0.6 - 0.8 (lower cos kidney cannot clear)
on HD, PD: 1.2
CRRT: up to 2
Who should be on enteral nutrition
Patients who are unable to receive or tolerate adequate nutrition orally
eg. swallowing impairment, mechanical ventilation, altered mental status, motility disorders (complication with uncontrolled diabetes)
benefits of prepyloric
cons of prepyloric
more physiologic (depend on other parts of GI tract to digest food)
higher tolerance to bolus feeding
higher tolerance to enteral products that differ in osmolarity, pH (as food is diluted in gastric acid)
should not be used in patients with delayed gastric emptying
benefits of postpyloric
small bore (tube diameter), less discomfort but more risk of clogging
can be used in delayed gastric emptying
lower risk of aspiration pneumonia
Nasal vs percutaneous endoscopic tubes
PE can last longer, less discomfort but need to do surgery
types of enteral nutrition and their uses
Modular
- contains single nutrient eg. protein or oil
- used as fortifier to enhance a component of the diet
Semi-elemental
- contains partially or completely hydrolysed nutrients
- for patients with impaired GI function
Polymeric
- contains intact macronutrients (for the GI to digest)
- requires sufficiently functional GI tract
Disease specific
- to meet disease needs
- may not meet individual’s full nutritional needs
Complications that may occur with drug administration into EN tube (3 points)
how to mitigate
1) binding of medication to tube eg. phenytoin
2) medication feed interaction eg. fluoroquinolones with polyvalent cations
3) Special coating of medication becomes ineffective when crushed
Flush device before and after drug administration
or
Use other alternatives compatible with tube
Complications with enteral feeding
Refeeding syndrome
Occlusion of feeding tube
Tube displacement (feed travels upwards into stomach for post pyloric feeding)
- may be due to coughing
Aspiration pneumonia risk
Infections due to contaminated enteral feed (dont dilute enteral feeds with water)
nausea, vomiting, diarrhea, constipation
What is gastric residual volume
When doctor aspirate out contents of stomach to monitor if patient is able to tolerate feeds
- done 1hr after enteral feeding
- High GRV = poor gastric emptying, GI dysfunction
- pH higher than usual gastric acid = feeds still remain in stomach, patient not tolerating feeds
How to tolerate enteral feeds better
Use continuous feeding instead of bolus
Use boost isocal (the most isotonic, wont cause osmotic diarrhea(
prokinetic agents eg. domperidone, metoclopramide, IV erythromycin
how long should peripheral access be changed vs central access for TPN
Peripehral: every 72hrs
Central: can use up to years
macronutrients and energy / g
amino acids: 4 kcal/g
dextrose: 3.4 kcal/g
lipid emulsion:10 kcal/g
if PN has lipid, change tube every 24hrs
Complications from drug and parenteral administration
phase separation of lipid emulsion in PN
- drug interaction can cause oil and water to separate
precipitation
loss of drug activity
complications from parenteral nutrition
intestinal failure associated liver disease
- gut will fail if we dont stimulate it
- prevent this by still giving enteral feed to stimulate gut
metabolic bone disease
- aluminum toxicity from long term TPN can cause low bone turnover, osteomalacia, osteoporosis
How does refeeding syndrome occur?
During starvation, body is in catabolic phase. Glucagon released, breaking down protein and glucose.
Blood is low in K, Mg, Phosphate. Body draws from cells.
During feeding, insulin is released to take in glucose. K, Mg, Phosphate, Vitamin B1 (thiamine) is taken up by cells.
Resulting in HypoK, HypoMg, Hypophosphate
Complications: potentially fatal, may result in arrhythmia, cardiac failure, neuromuscular complications
Criteria for high risk patients of refeeding syndrome
1 of the following
- BMI < 16
- Unintentional weight loss > 15% in past 3-6 months
- Little to no nutritional intake > 10 days
- Low K, Mg, Phosphate before feeding
2 of the following
- BMI < 18.5
- Unintentional weight loss > 10% in past 3-6 months
- Little to no nutritional intake > 5 days
- History of alcohol misuse or drugs, including insulin, chemo, antacids, diuretics
How to treat refeeding syndrome
Identify high risk patients
Check serum electrolytes at baseline
Correct deficiency before feeding, dont feed if electrolytes are critically low
Supplement vitamin B1 (thiamine)
- Vitamin B1 is cofactor for energy metabolism
- 100 - 200mg for 7-10 days
Start feeding at 50% of estimated energy requirement
