Parenteral Nutrition (TPN) Flashcards
Indications for TPN
GI tract dysfunction from malabsorption, obstruction, or dysmotility Adjunctive treatment for cancer Pancreatitis Critically ill Perioperative Hyperemesis Eating disorders
Features of central TPN
Provides “complete” TPN, osmolality of components generally exceeds 900 mOsm/L
Who to choose peripheral TPN in
No significant malnutrition
Have good peripheral vascular access
Can tolerate large volumes of fluid (2.5-3L/day)
Need 5-14 days of parental nutritional support
Steps to initiating TPN regimen
Establish vascular access Calculate macronutrient requirements Evaluate electrolyte needs Evaluate trace element and vitamin needs Evaluate fluid requirements Determine insulin need Review compatibility
Daily requirement of sodium and potassium
1-2 mEq/kg
Daily requirement of chloride and acetate
PRN to balance acid/base status
Daily requirement of calcium
10-15mEq
Daily requirement of magnesium
8-20 mEq
Daily requirement of phosphate
20-40 mMol
What happens if there’s a vitamin shortage?
Don’t use pediatric product in adults and vice versa; if vitamins are completely out, attempt to give individual vitamins
Trace element needs
Deficiency syndromes generally occur with un-supplemented, long-term parenteral nutrition; requirements vary on the basis of the patient’s clinical condition
Increased fluid requirements: environment
Radiant warmer
Increased ambient temperature
Excessive sweating
Increased fluid requirements: GI losses
Diarrhea, vomiting
Ostomy or fistula drainage
NG tube suction
Increased fluid requirements: urinary losses
Glycosuria, diuretics, diabetes insipidus
Increased fluid requirements: miscellaneous
Hyperthyroid, hyperventilation, phototherapy
Decreased fluid requirements: environment
Heat shields, high humidity
Decreased fluid requirements: diseases/conditions
HF, ESRD/CKD, SIADH, hypoalbuminemia with starvation, humidified air via mechanical ventilation
Usual fluid requirements
30-40ml/kg/day or 1ml/kcal/day
Calcium phosphate compatibility: amino acid concentration
Increases pH, decreases solubility
Calcium phosphate compatibility: amino acid product composition (pH or PO4 content)
Important to evaluate a change in amino acid product to determine if solubility will be impacted
Calcium phosphate compatibility: calcium and PO4 concentrations
Increasing the concentration of calcium and/or PO4 decreases solubility
Calcium phosphate compatibility: calcium salt
Gluconate less dissociated than chloride
NEVER ADD CACL TO A TPN BAG
Calcium phosphate compatibility: dextrose concentration
Lowers pH, increases solubility
Calcium phosphate compatibility: pH of formulation
Low pH favors the presence of monobasic calcium phosphate (aka more soluble)
Calcium phosphate compatibility: temperature
Inverse solubility (increase temp, decrease solubility)
Calcium phosphate compatibility: order of mixing
ADD PHOSPHATE BEFORE CALCIUM
Medication administration in TPN criteria
Compatibility and stability have been established
Clinically effective as a continuous solution
Drug dosage is stable (can’t titrate up!)
TPN infusion rate is stable
TPN components
Protein, carbs, lipids
Protein conversion
4 kcal/g
6.25g protein=1g nitrogen
Most common carb source
Dextrose
Dextrose conversion
3.4 kcal/g
Glycerol conversion
4.3 kcal/g
Lipids (IVFE) are available as what product?
Oil suspensions in an aqueous medium (so basically an emulsion)
Emulsifying agent in IVFE
Egg phospholipid –> avoid in patients with an egg allergy
Lipid emulsions are also a source of what vitamin?
Vitamin K, which can interfere with warfarin!
Oil in a lipid emulsion
Soybean oil (IVLE)–> avoid in patients with a soybean allergy
Lipid conversion
9 kcal/g
Lipid emulsions: monitoring
Monitor for infusion reactions, especially on the first dose
Hypertriglyceridemia
Hepatic toxicity (PNALD) with chronic TPN
Refeeding syndrome
Rapid, severe depletion of potassium, magnesium, and phosphate in starved patients
Refeeding syndrome treatment
Aggressive supplementation of lytes plus thiamine 50-100mg/day
The more nutritionally depleted a patient is, what does that do to the rate of administration?
The rate decreases
TPN complications: economic
It’s very expensive; labor intensity, frequency of monitoring and management of complications contribute to cost
TPN complications: mechanical
Pneumothorax, thrombosis, thrombophlebitis (PPN)
TPN complications: infectious
Line sepsis/fungemia, increased bacterial translocation
TPN complications: metabolic
Electrolyte abnormalities, hyper/hypoglycemia, hypertriglyceridemia, fluid overload, osteoporosis/osteomalacia
TPN complications: GI tract
Hepatobiliary (PNALD)
How often to monitor fluid and weights during TPN
Daily
How often to monitor glucose during TPN
q1-6h
How often to monitor electrolytes during TPN
daily-three times a week
How often to monitor LFTs during TPN
1-2x/week
How often to monitor visceral proteins during TPN
1-2x/week
How often to monitor CBC, PT/PTT during TPN
1-2x/week
How often to monitor protein turnover during TPN
weekly
How often to monitor lipids during TPN
weekly
