Parenteral Nutrition

Definition

• TPN = Total Parenteral Nutrition

• Provision of nutrients intravenously– Central– Peripheral

• For patients who are already malnourished or have the potential for developing malnutrition and who are not candidates for enteral nutrition

Advantage:

      Potentially life-saving when GI tract cannot be used or when oral/parenteral nutrition cannot meet nutrient requirements of patient.

Disadvantages:

• Costly

• Long term risk of liver dysfunction, kidney and bone disease, and nutrient deficiencies

Routes for Parenteral NutritionCentral Venous Access

Central Parenteral Nutrition (CPN): Central Venous Access– Utilization of large central veins for the

administration of a patient’s complete nutrient needs

– Can deliver daily requirement for kcals, protein, micronutrients in concentrated volumes

Routes for Parenteral NutritionCentral Venous Access

• PICC Line– Peripherally inserted central catheter

– Benefits• Access to central vein• Can accommodate hypertonic fluids• Lower risk of phlebitis than PPN• Easier to insert than central line

Indications for TPN

– NPO for extended period

– Enteral nutrition support projected to be inadequate for

– Severe acute pancreatitis

– High output enterocutaneous fistulas

C. TPN Solution1. Carbohydrate: Dextrose

a. Most common concentrations: 50% and 70%

2. Protein: AAs a. Most common concentrations: 8.5% and 15%.

3. Lipid: IV emulsiona. 10% solution =

b. 20% solution =

c. Concentrated source of kcals

Lipid, cont.e. Helps minimize hyperglycemiaf. Helps prevent respiratory acidosis (in

respiratory failure)g. Need at least 10% of kcals from lipid to

prevent EFA deficiencyh. Excessive lipid administration may

suppress immune fx.i. Often hung separatelyj. Admixtures (3:1) becoming more

commonk. Potential source of vit. K: potential

problem if anticoagulants used

4. Vitamins

Daily MV in formula is standard

5. Electrolytes– Start with standard amounts– Adjust as needed

6. Common Medications – Insulin

– H2 antagonists

– heparin

Peripheral Parenteral Nutrition (PPN)

Utilization of peripheral veins for the administration of nutrients

A. Indications for use: 1. PN necessary but no access to central vein

2. Malnourished patients with frequent NPO for procedures/tests

B. Contraindications:

1. Patient can be fed enterally

2. Pt. has weak peripheral veins

C. Limitations

1. Peripheral site more prone to inflammation/infection

2. Catheter may need to be repeatedly inserted Poor choice for long-term nutrition

D. PPN Solution

1. Typically delivers 1400-2500 kcals/day

2. Carbohydrate: Dextrose (glucose)

3. Protein: AAs

4. Lipid: IV lipid emulsion

a. Concentrated source of kcals

b. Isotonic

c. Administered every day to protect vein

Intravenous SolutionsAbbreviations:D: dextroseW: waterNS: normal saline (0.9% sodium chloride

solution)

TPN Administration A. Rate

1. Start slowly, especially w/dextrose. Allows blood to adapt to increased glucose/osmolality

2. Infusion pump is used to ensure proper rate.

a. If rate is increased too quickly, hyperglycemia may result

b. Monitor tolerance: electrolytes, blood glucose, triglycerides, ammonia, etc.

4. Introduce lipids gradually to avoid adverse reactions (fever, chills, backache, chest pain, allergic reactions, palpitations, rapid breathing, wheezing, cyanosis, nausea, and unpleasant taste in the mouth)

5. When pt. is taken off TPN, rate must be tapered off gradually to prevent hypoglycemia.

6. ( TPN by ½ X 2 hrs, then DC – usually sufficient to prevent hypoglycemia)

7. PPN doesn’t need to be tapered off (uses more dilute solution w/less dextrose)

B. Cyclic Infusion1. TPN infused at a constant rate for only <24

hours/day  (e.g. 12-14hr overnight)

2. Allows more freedom/normal daytime activity

3. Can be used to reverse fatty liver resulting from continuous infusion

(Chronically high insulin levels may inhibit fat mobilization fatty liver)

4. Fewer kcals may be necessary to maintain N balance (body fat better mobilized for energy)

5. Requires higher infusion rate: not all patients can tolerate it.

Potential TPN Complications

A. Catheter or Care-Related Complications:• Fluid in the chest (hydrothorax)• Air or gas in the chest (pneumothorax)• Blood in the chest (hemothorax)• Sepsis• Blood clot (thrombosis)• Infusion pump malfunctions• Myocardial or arterial puncture

B. Metabolic or Nutrition-related Complications – Hyperglycemia/Hypoglycemia– Dehydration/Fluid overload– Electrolyte imbalances– Hyperammonemia– Acid-base imbalance– Fatty liver– Bone demineralization