List two components when deciding whether parenteral nutrition is needed
- Timing and duration
2. Indication
What is the timing and duration of administering PN
It is anticipated that the patient will be unable to be fed orally or enterally for at least 7 days
When should PN be initiated as soon as possible?
- High nutritional risk OR
- Severely malnourished AND
cannot tolerate EN
List three inflammatory disorders which are indications for PN
- Severe pancreatitis in patients who cannot tolerate EN
- Peritonitis
- Severe inflammatory bowel disease
List three medication conditions that are not principally inflammatory that are indications for PN
- Extensive bowel resection (e.g. short bowel syndrome) causing malabsorption or maldigestion
- Complete bowel obstruction
- Severe intractable vomiting or diarrhea
A seventh indication for PN is for patients who are unable to meet full nutritional needs by ____ route alone
Enteral
- Can use PN as a supplement to EN
What are two principle types of access routes for PN?
- Peripheral
2. Central
Define peripheral access
Peripheral access is defined as the catheter tip position outside the central vessels or inferior or superior vena cava. This includes midline catheters.
Peripheral administration of PN can be used when three conditions are met (indication, circumstance, duration)
- Used in patients with an appropriate indication for PN
- When central IV acess is unavailable
- The need for PN is expected to be less than 2 weeks.
Special considers for peripheral PN formulations: Dextrose must not exceed
10% or less
Special considers for peripheral PN formulations: AA concentration must not exceed
2.5% to 4%
Special considers for peripheral PN formulations: Ca2+ concentration must not exceed
5 mEq/L or less
Special considers for peripheral PN formulations: K+ concentration must not exceed
40-60 mEq/L or less
Special considers for peripheral PN formulations: Osmolarity must not exceed
900 mOsm/L or less
Estimating the Osmolarity of PN: AA
10 mOsm/g
Estimating the Osmolarity of PN: Dextrose
5 mOsm/g
Estimating the Osmolarity of PN: Lipid emulsion 10-20%
1.3-1.5 mOsm/g
Estimating the Osmolarity of PN: Sodium chloride/acetate
2 mOsm/mEq
Estimating the Osmolarity of PN: Potassium chloride/acetate
2 mOsm/mEq
Estimating the Osmolarity of PN: Calcium gluconate
0.68 mOsm/mL
Estimating the Osmolarity of PN: Magnesium sulfate
4.06 mOsm/mL
What is the preferred type of venous access for PN?
Central
Define central access
- Intravenous catheter (peripherally inserted central catheter, Hickman, Port-A-Cath)
- Where tip is in the superior vena cava or adjacent to the right atrium
What type of central catheter should be avoided for PN and why?
- Femoral catheter
2. High risk of venous thrombosis and catheter-related infection
Over what duration is PN typically infused for hospitalized patients?
Continuous infusion over 24 hours
Over what duration is PN typically infused for ambulatory patients?
Cyclic continuous infusion over 12 hours
Infusions are generally tolerated by patients if they are removed from the _____ and allowed to come to _______ before infusion
- refrigerator
2. room temperature
What is a 2-in-1 PN?
PN in which all nutrients are mixed in the same IV bag, except for lipids, which are administered by a separate infusion
What is a 3-in-1 PN?
Also called a total nutrient admixture, refers to PN in which all nutrients are mixed in the same IV bag.
When lipids are infused separately, no faster than __ g/kg/hour in adults, using a ___ micron filter
- 0.1 g/kg/hour in adults
2. Using a 1.2-micron filter
Rapid administration of lipids is associated with what 3 “temperature” related side effects?
- fever
- sweating
- flushing
Rapid infusion of lipids is associated with what two types of “pain”
- Headache
2. Back or chest pain
Rapid infusion of lipids is associated with what two “respiratory” symptoms?
- dyspnea
2. cyanosis
Rapid infusion of lipids is associated with what laboratory derangement?
Hypertriglyceridemia
Rapid infusion of lipids is associated with what GI-like side effect?
Nausea
Lipid infusion time should be less than ___ hours because of the potential for _____ after this time
- Less than 12 hours
2. Potential for microbial growth after this time
Why do 3-in-1 admixtures have less risk of microbial growth of lipids?
- Dextrose and AAs
2. Reduce pH and increase osmolarity
How often should administration tubing for the dextrose/AA admixture of 2-in-1 tubing and the total nutrient admixture of 3-in-1 tubing be change?
- Administration tubing for a 2-in-1 should be changed every 24 hours
- Administration tubing for a 3-in-1 should be changed every 24 hours
When should lipid tubing be changed?
Lipid tubing should be discarded after use (no longer than 12 hours)
The stability of a 3-in-1 depends on the ___, which is determined primarily by the final ___ concentration. It should be maintained at least __%
- pH
- AA
- At least 4%
Do not add concentrated ___ directly to a _____ emulsion when mixing a total nutrient admixture
Dextrose
Avoid excessive amounts of these two elements when compounding 3-in-1 PN:
- Ca2+
2. Magnesium
Total nutrient admixtures should have a final concentration of AA __%; monohydrated dextrose ____%; injectable lipid emulsion greater than __%
- AA: at least 4%
- Dextrose at least 10%
- Lipid at least 2%.
List four premixed PN products available in the US
- Clinimix
- ProcalAmine
- Kabiven
- Perikabiven
Describe Clinimix (hint: design, product variations, how to use, how to use lipids)
- Two-compartment bag containing AAs in one compartment and dextrose in the other
- Available with and without electrolytes
- Seal between the two-compartment bag must be broken to mix the AAs and dextrose
- Lipids can be added to the container after compartments are mixed or can be administered by Y-site
Describe ProcalAmine (hint: contents, including kcal/g; limitation)
- Solution containing 3% AAs, glycerin (4.3 kcal/g), electrolytes in a single container
- Not sufficient for most patients because of insufficient protein and calories
Describe Kabiven (hint: contents, design)
- Newer solution containing AAs, electrolytes, dextrose and a lipid emulsion
- Available in a 3-compartment bag for central line administration only
Describe perikabiven
- Variation of kabiven
2. Formulated for peripheral administration, can also be administered centrally.
What does the evidence say about the superiority of customized PN to standardized premixed PN?
Evidence is insufficient to show that customized PN is superior to standardized premixed products
What type of patient would be a good candidate for premixed standardized PN? (hint: consider in ___, avoid in ____)
- Consider in stable patients who require PN
2. Avoid in patients with fluid restriction or high protein needs.
Premixed products require fewer ______ and have a lower risk of _____ and ______ (three advantages)
- Fewer manipulations, therefore they have
- Lower risk of contamination
- Compounding errors.
What three additives are sometimes added to premixed PN?
- Electrolytes
- vitamins
- Trace elements