Parenteral Nutrition

what is parenteral nutrition

form of nutritional support that is provided through intravenous administration

is parenteral nutrition specific to a disease state?

no - it is rather a method of provision of calories/energy used to prevent malnutrition

why is it important to recognize when and when not to use PN?

it is expensive and has risk of serious adverse events (appropriate use is essential)

appropriate use of PN includes:

recognizing when and when not to utilize based on clinical indications, develop a prescription that meets individual needs, monitor and adjust therapy as necessary, transition to enteral nutrition (EN) as soon as possible

what is the purpose of PN therapy

support physiologic energy needs when enteral nutrition cannot be provided safely/effectively, and provides macronutrients and micronutrients through intravenous route

complications of PN therapy:

hyperglycemia/hypoglycemia, electrolyte imbalances, hypertriglyceridemia, liver function abnormalities, pneumothorax, catheter occlusion, thrombus, phlebitis, and infections

what are the common electrolyte imbalances of PN?

hypokalemia, hypophosphatemia, hypomagnesemia (refeeding syndrome)

which labs indicated acute liver function abnormalities?

AST/ALT elevations

which labs indicated chronic liver function abnormalities?

alkaline phos/bilirubin > 2 weeks

T/F: central line associated infections and bacteremia are associated with EN

false

Advantages of Peripheral IV access (PIV) for PN administration:

bedside insertion into the veins of forearm/hand, and use for short-term duration

Disadvantages of Peripheral IV access (PIV) for PN administration:

increased risk of phlebitis, limited use based on osmolarity of the solution (max = 900 mOsm/L), and is not suitable for home PN/long-term use

Advantages of peripherally inserted central catheters (PICC) for PN administration:

bedside insertion into basilic, cephalic, or brachial veins with the tip in the superior vena cava, and is suitable for short-medium duration of PN

Disadvantages of peripherally inserted central catheters (PICC) for PN administration:

may require a radiologist guided placement, increased risk of DVT, and the site limits patient activity, easily removed, and easily infected

Advantages of Tunneled catheters (Ex: Broviac, Hickman) for PN administration:

suitable for long term PN, cuffed to minimize contamination/dislodgement, minimal restrictions to activity, and easier for self-care/hidden

Disadvantages of Tunneled catheters (Ex: Broviac, Hickman) for PN administration:

surgical/radiology guided insertion

what is a 3-in-1 product?

contains all three macronutrients within 1 bag

what is 3-in-1 synonymous with?

total nutritional admixture (TNA) or “all-in-one”

what are the concerns about 3-in-1 products?

compatibility and risk of cracking/”oiling” out

what patient population uses 3-in-1 products more commonly

adults - rarely used in peds

how do 3-in-1 products come prepared?

in premade bags with multiple chambers

what are 2-in-1 products?

contains only two of the macronutrients - dextrose and amino acids

T/F: if a patient is receiving a 2-in-1 product they will not receive any lipids during treatment

false

how are lipids given to patients receiving 2-in-1 products

they are infused as a separate product (co-infused)

which patient population primarily receives 2-in-1 products?

pediatric patients

what is a standard approach?

commercially available - premade PN bags with standardized concentrations

are standard approach premade PN bags used in pediatric patients?

NO

what is individualized approach?

compounded local/outsourced, prescription prepared based on individual patient needs

who typically receives individualized approach PN

NICU/Pediatric patients

what is “cycled” PN?

PN provided over a rate that is not the usual 24-hour period

when is cycled PN used?

used in long-term PN patients to allow for time “off” PN to minimize risk of IFALD

T/F: you should ramp-up and ramp-down the rate in cycled PN to avoid drastic shifts in glucose provided

true

what are the macronutrients in PN

protein (amino acids), carbohydrates (dextrose), and fats (lipids)

what are the micronutrients used in PN

electrolytes, vitamins, and trace elements

what is the kcal/gram of amino acids (protein)?

4

what is the usual osmolarity of amino acids in PN

10 mOsm per g/L or 100 mOsm/%

what types of amino acids are found in PN ?

essential and non-essential amino acids

T/F: amino acids products and concentrations utilized are age dependent

true

what is the kcal/gram of dextrose (carbohydrates)

3.4

what is the osmolarity of dextrose in PN

5 mOsm per g/L or 50 mOsm/%

what is the peripheral limit of dextrose

D10-12.5%

what product is used for PN dextrose?

D70W = 70% for compounding

what is the kcal/gram of fats

~9

what is the maximum rate of infusion for lipid emulsion (fat)

0.15g/kg/hour in pediatrics and 0.11g/kg/hour in adults

which lipid emulsion products are soybean oil based ILE?

Intralipid 20% and Nutrilipid 20% (20% = 2kcal/mL)

what is the goal dosing of Intralipid and Nutrilipid?

0.15g/kg/hour in pediatrics and 0.11g/kg/hour in adults

when is Intralipid and Nutrilipid used?

patients requiring PN as a source of EFA to prevent EFAD

which lipid products are combo products of soybean, MCT, olive, and fish oil-based

SMOF-lipid 20% (20% = 2kcal/mL)

goal dosing of SMOF-lipid 20%

neonates/infants - 3g/kg/day

children/adolescents - 2.5-3g/kg/day

when is SMOF-lipid 20% used?

patients requiring PN as a source of EFA to prevent EFAD

which lipid emulsion product is fish oil-based

Omegaven 10% (10% = 1.1 kcal/mL)

goal dosing of Omegaven 10%

neonates, infants, children, and adolescents - 1g/kg/day

when is Omegaven 10% used

in pediatric patients with PN-associated cholestasis

what must lipid emulsions be administered with?

must administer 1.2 micrometer (micron) filter

what is the maximum hang time for a single container of lipids?

12 hours (24-hour infusion = 2 “bags'“)

what is CI with lipid emulsions?

egg/soybean/fish allergies (dependent on product)

what things need to be monitored related to lipid emulsions

Intestinal failure associated liver disease (IFALD), hypertriglyceridemia, and essential fatty acid deficiency (EFAD)

what is hypertriglyceridemia in neonatal/pediatrics

> 200 mg/dL

what is hypertriglyceridemia in adults?

>400 mg/dL

what tests should be done to check for IFALD

liver function tests and bilirubin

who should be monitored for EFAD?

malnourished neonatal/pediatric patients or any patients utilizing lipid minimization strategies

how is potassium supplied in PN?

-chloride, -acetate, -phosphate

how is sodium supplied in PN

-chloride, -acetate, -phosphate

how is phosphate supplied in PN

potassium phosphate and sodium phosphate

what is calcium-phosphate precipitation

a concentration dependent reaction leading to in-solution precipitates to form

what are the factors that affect solubility of calcium-phosphate

dose of Ca/Phos in PN, pH of the final solution, temperature, time, and salt form (preference calcium gluconate)

T/F: when compounding, separate order of additives to minimize risk

true

should calcium or phosphate be added first to minimize calcium-phosphate precipitation?

phosphate

purpose of multivitamins:

essential for various organ system and physiological function (pediatrics need for neurodevelopment and growth)

which patients may require additional supplementation (multivitamins)

long-term PN and individualized

what are trace elements

included at standard dosing and commercial product utilized (zinc, copper, manganese, chromium, selenium)

what is anion balance

all positive cations provided must associate with negative anion (chloride, acetate)

T/F: chloride and acetate are intrinsic negative anions

true

how are orders usually prescribed for chloride and acetate

prescribed as ratios or min/maximum

what should be increased/decreased in metabolic acidosis

increase acetate, decreased chloride

what should be increased/decreased in metabolic alkalosis

decrease acetate, increase chloride

what is “creaming”?

compatibility of 3-in-1 solutions that is safe to use and is reversible with gentle agitation

what is “cracking”?

compatibility of 3-in-1 solutions that is unsafe to use and separation is irreversible

what is the minimum for stability in 3-in-1 solutions

AA 4%, Dextrose 10%, and ILE 2%

med examples that can be added to PN?

insulin, levocarnitine, heparin, famotidine (check compatibility, determine risk or clinical utility provided over 24-hours)

what safety checks should be performed when giving PNs

max lipid rate (0.15 g/kg/hour), glucose infusion rate (mg/kg/min), estimate osmolarity (AA + Dextrose), and check line/access (central vs. peripheral)

what monitoring should be done to determine efficacy of intervention?

weight, fluid balance, electrolytes + BUN/Cr, glucose, nitrogen balance, and long term (trace elements, vitamins, and EFA)

what monitoring should be done to determine toxicity of intervention?

refeeding syndrome, liver function tests/bilirubin, triglycerides, and infection (sign/symptoms)

what is the goal of nitrogen balance

achieve positive nitrogen balance which means the patient is in anabolic state (energy in > energy out)

how to determine how much nitrogen in?

Grams of protein / 6.25

how to determine how much nitrogen out?

UUN (g) - urine urea nitrogen (determined from a 12 to 24 hour urine collection)

what factor is used for insensible losses not captured within UUN?

+4

what is refeeding syndrome?

occurrence of electrolyte abnormalities in severely malnourished patients during rapid initiation of nutrition (enteral or parenteral)

what can refeeding syndrome lead to besides electrolyte depletion

fluid overload - monitor fluid status closely

which electrolytes needs to be monitored and aggressively supplemented in refeeding syndrome

potassium, phosphate, and magnesium