Lec 2&3: Parenteral Nutrition Part 1 & 2 Flashcards
LEC 2
Total Parenteral Nutrition
Difference between EN and TPN:
EN
-
-
TPN
-
-
-
-
Indications:
->
-
-
-
-
-
-
-
-
EN
- Nutrition are provided via GI
- EN formula can contain food
TPN
- Nutrients are provided via veins
- TPN formula only contain nutrient compounds
- More invasive [defense mechanism that is your Gut is not there thru TPN - going instantly to blood - therefore invasive as it is risky putting items direct into blood]
- by passess liver and gut / contamination more likely
-> Unable to meet nutritional needs by mouth AND who are not candidates for EN
- Massive bowel restriction; SBS, radiation enteritis, ischemic bowel; mulitsystem organ failure
- Intractable vomiting
- GI tract obstruction; impaired GI motility; extreme SBS, chronic severe malabsorption, GI ischemia
- Abdominal trauma, injury or infection
- Enterocutaneous fistula (abnormal connection between GI and skin)
- Vascular event with diminished perfusion to gut (a blood clot reducing blood flow to the gut)
- Functional GI system
- Only NPO (nothing by mouth) for short time (5-7 days)
- Ethical Issues complex (terminal illness or poor prognosis)
Ethical Issues
RDs responsibilities for TPN:
:varies by institution
- delivery route usually decided by physician
Delivery Route
1
-
-
2
-
-
-
1 Central Line
- Central Venous Catheter [CVC] : inserted at clavical - enters right subclavian vein/ right superior vena cava - goes directly into heart & is rapidly diluted therefore no concern mOsm
- Peripherally inserted central catheter [PICC] : inserted right at vein in arm (elbow region) -> left subclavian vein
(enters as IV would)
2 Peripheral Route (Line)
- Access is via peripheral vein in the extremities, usually hand or forearm
- Catheter tip stays there
- Peripheral veins can only tolerate <900 mOsm/L may develop phlebitis (inflammation of the vein) after 1-2 weeks [if doing longer than 1-2wks do Central route]
- does not pump to/thru heart - stays in arm
- usually uses more fat solution than central as lipid has lower mOsm than dextrose, therefore less irritation
[Need normal renal, cardiac, lipid metabolism]
Equipment for Parenteral Nutrition
> Same basic equipment and sterile techniques as for other IV lines
> Pump to control rate of delivery
Parenteral Feeding Solutions:
1
2
3
1 Compounded in hospital pharmacy
- is equipment pumping exactly what you ordered
2 3-in-1
- has Lipid, CHO and Amino Acid compartment + air tight + blind port/ additive port and infusion port
3 2-in-1
- Dextrose/AA/Electrolytes (bag 1) has lipids separate (bag 2)
Parenteral Nutrition Order
-> Dextrose
=
-
- energy density
-
-
- energy density
-
-
- energy density
-
->
= Dextrose monohydrate = glucose + water
- acts as energy source
- 3.4 kcal/g
- Concentrations 5% to 70% (w/v)
(most pharmacies use 50% w/v)
- Min infusion 1mg/kg/min; max infusion 4-5 mg/kg/min
->
- Individual AA
- Maintain N balance, inhibit skeletal muscle break down
- 3.8 kcal/g
- Concentrations 3% - 15% (w/v)
(most pharm use 10% w/v) (Max infusion is 2.0 g/kg/d)
->
- LCT w/ phospholipids
- Provides energy, essential fatty acids
- 10 kcal/g
- Concentrations 10%, 20% & 30% (w/v)
(most pharm use 20% w/v) (Max infusion rate is 2.0-2.5 g/kg/d)
Exceeding max infusion rates: pg 85-86 course pack
OVERFEEDING
is not the same as ____
=
Visual — Slide 31 - explain
____ Refeeding syndrome (although TPN patients are prone to refeeding syndrome too)
= giving the body more Macronutrients than can be metabolized - going via the blood can give nutr quicker than body can handle
Slide 31:
Overfeeding
CHO = LUNGS - respiratory failure // hyperinsulinemia - damage veins/arteries tissues
FAT + CHO = going over total energy expenditure - affects liver: increase in liver enzymes (increased fatty deposition)
PRO = KIDNEYS - N excretion impaired / Blood Urea Nitrogen / Albumin
Acid-Base balance
- is determined by…
- adjust …
Vitamins and Minerals
->
Electrolytes
->
-
Fluids
-
-
-
Osmolarity VS osmolality
whats the difference? -
-
- … by the concentration of hydrogen ion (H+) present in body fluids as a result of the production, neutralization and elimination of various acids
- adjust… acetate/chloride ratio
-> Standard multivitamin is commonly used
-> Daily monitoring and adjustment
- takes time to figure out balance per person but v important for lung and heart function etc.
- Fluid requirement
- Room for all compounds
- Ins and Outs
Osmolarity: term used for TPN
- Important for peripheral infusion
? - units measured is really the only difference
- not v important when using Central line b/c of lg blood vessels BUT peripheral line is sm vein - doesn’t get watered down as quick — can be fluid shift - water into vein = damage - caused by osmotic pressure
IF giving peripheral route - try to keep close mOsm close to physiological mOsm conc
** TPN Calculations **
Protocols for starting and maintaining TPN
DAY ONE:
-
-
-
DAY TWO and beyond:
-
-
-
TPN needs a pump
1:
- RDs usually start at a certain % of their goal rate on the first day
- 50% is pretty typical
- start lower if refeeding syndrome could be a problem
- in uncomplicated pt can get to target in 3-4 days
2:
- Advance to target rate over 72-96 hours
- Infusion usually over 24 h/d
- Monitoring blood values daily until stable
[fluid status/ electrolytes (spec if refeeding is likely) / blood glucose levels (spec in those with DM) / check triglycerides (spec in those with history of hypertriglyceridemia)]
Complications
Short term:
-
-
-
-
-
-
-
- Pneumothorax = air in the thorax
- Hemothorax = blood in the thorax
- Hyperglycemia - most common complication: can impair wound healing and increase risk of infection
- Catheter-related infections
- Refeeding syndrome
- Fluid/electrolyte imbalances
- Azotema - high N in blood sometimes
-
-
(longest term patients usually when lg part of intestine is removed)
-> Transitional Feeding (FYI only)
- Gallstones - why?: bile sits = perfect environment to generate stones as GI isn’t used
- Osteoporosis - multi-factorial: Ca def/ steriods, underlying disease, NOT Vit D problem
- Sepsis = infection in the blood
