Transcript Lecture 5b powerpoint

Parenteral Nutrition
Chapter 15
General Comments on Parenteral
Nutrition
• Infusion of a nutritionally complete, isotonic or hypertonic
formula
• Peripheral (partial) parenteral nutrition (PPN)(isotonic by
peripheral vein) (short-term-7-10 days) and Total Parenteral
Nutrition (TPN)(hypertonic by central line catheter)(longer
term-longer than 10 days)
• Life-saving therapy in patients who have a non-functional GI
tract
– Also used for other clinical conditions such as critical
illness, acute pancreatitis, liver transplantation, AIDS, and
in patients with cancer receiving bone marrow transplants
General Comments on Parenteral Nutrition—
(cont.)
Parenteral Feeding (going around i.e. circumventing the gastrointestinal
tract)
Nutrients go directly into blood stream bypassing gastrointestinal tractthis is done by intravenous needle to peripheral vein (PPN) or catheter to
central vein (TPN)
Used when a patient cannot, due to physical or psychological
impairment, consume sufficient nutrients enterally
Used when patients gi system will not adequately process food for body
Actual infusion depends on site of infusion and patient’s fluid and
nutrient requirements
General Comments on Parenteral
Nutrition—(cont.)
• Overfeeding can cause a life-threatening complication known as
the refeeding syndrome.
• PN is expensive, requires constant monitoring, and has potential
infectious, metabolic, and mechanical complications.
• Used only when an enteral intake is inadequate or contraindicated
and when prolonged nutritional support is needed
• Should be initiated when oral intake has been or is expected to be
inadequate over a 7- to 14-day period
General Comments on Parenteral Nutrition
Usual fluid volume is 1.5-2.5 L over a 24 hour period
for most people
General Comments on Parenteral Nutrition—
(cont.)
Composition of ingredients for intravenous
delivery
Dextrose
Amino acids
Lipid emulsion
Sterile water
Electrolytes
Vitamins
General Comments on Parenteral Nutrition—
(cont.)
Carbohydrate
Dextrose
Concentration is 10.0 % (max for peripheral
introduction) to 70 % (max for total parenteral
nutrition)
Restricted in ventilator patients because
oxidation of glucose produces more carbon
dioxide than does oxidation of fat
General Comments on Parenteral Nutrition—
(cont.)
Protein
Mixture of essential and non-essential amino
acids
Concentration 3.5-15 %
Quantity of amino acids depends on patients
estimated requirements and hepatic and renal
function-why?
General Comments on Parenteral Nutrition—
(cont.)
Lipid emulsions
Safflower and soybean oil with egg lecithin
used as an emulsifier (why the emulsifier and
how does it work?)
Significant source of calories
General Comments on Parenteral Nutrition—(cont.)
Lipid emulsions
Available in 10, 20, 30 % concentrations
Usual dose is 0.5 to 1 g/kg/day to supply 20-30 % of
total kcal requirement
IV fat contradicted for severe hepatic pathology,
hyperlipidemia or severe egg allergies
Used cautiously with atherosclerosis, blood
coagulation disorders
General Comments on Parenteral Nutrition—
(cont.)
Electrolytes
Dictated by patients blood chemistry values and
physical assessment findings
General Comments on Parenteral Nutrition—
(cont.)
Standard multivitamin and trace mineral preparations
added to parenteral solutions to meet micronutrient
needs
General Comments on Parenteral
Nutrition—(cont.)
• Medications
– Patients receiving PN may have insulin ordered if glucose
levels are above 150 to 200 mg/dL.
– Heparin may be added to reduce fibrin buildup on the
catheter tip.
– Medications should not be added to PN solutions
because of the potential incompatibilities of the
medication and nutrients in the solution.
PPN
-must be isotonic and therefore low in dextrose
and amino acids to prevent phlebitis and
increased risk of thrombus formation
-need to maintain isotonic solutions of
dextrose and amino acids while avoiding fluid
overload limits the caloric and nutritional
value of PPN
PPN
delivers complete but limited nutrition
the final concentration cannot exceed 10 %
dextrose-also uses lower concentrations of amino
acids
vitamins and minerals are added
lipid emulsion may be added to supplement calories
depending on the patients tolerance
PPN
-provides temporary nutritional support
-short term- 7-10 days and do not require more than
2000 to 2500 kcal per day
PPN
-may be used for a post surgical ileus or anastomotic
leak or for patients who require nutritional support but
are unable to use TPN because of limited accessibility
to a central vein
-sometimes used to supplement an oral diet or tube
feeding or transition from TPN to enteral intake
Total Parenteral Nutrition
• Catheter placement
– Patient’s anticipated length of need influences
placement of the catheter.
– For short-term central PN in the hospital, a
temporary central venous catheter is placed
percutaneously into the subclavian vein.
– If PN is expected to be more than a few weeks, these
are the catheters of choice:
o A Hickman catheter or Port-a-Cath
o Peripherally inserted central catheter (PICC)
Figure 21-2 p642
Total Parenteral Nutrition—(cont.)
• Composition of PN
– Provide protein, carbohydrate, fat, electrolytes,
vitamins, and trace elements in sterile water
– “Compounded” or mixed in the hospital pharmacy
– Two-in-one formula (dextrose and amino acids)
o Used by most hospitals
o Lipids given separately
– Three-in-one formula (dextrose, amino acids, and
lipids)
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Figure 21-3 p644
Total Parenteral Nutrition—(cont.)
• Administration
– Administered according to facility protocol
– Generally initiated slowly (i.e., 1 L in the first 24
hours)
– Continuous drip by pump infusion is needed to
maintain a slow, constant flow rate.
– Rapid changes in the infusion rate can cause
o Severe hyperglycemia or hypoglycemia
o Potential for coma, convulsions, or death
Total Parenteral Nutrition—(cont.)
• Administration—(cont.)
– After the patient is stable, PN may be infused cyclically.
– Cyclic PN allows serum glucose and insulin levels to drop
during the periods when PN is not infused.
– To give the pancreas time to adjust to the decreasing
glucose load, the infusion rate is tapered near the end of
each cycle.
Total Parenteral Nutrition—(cont.)
• Administration—(cont.)
– During the last hour of infusion, the rate may be reduced by
one-half to prevent rebound hypoglycemia.
– When the patient is able to begin consuming food orally, the
amount of PN is gradually reduced to prevent
o Metabolic complications
o Nutritional inadequacies
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