Indications

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  Functional GI tract

  
  
• 
  

  Moderate-severe nutrient deficiency

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  Nutritional support required >2 weeks or when attempts at enteral feeding have failed

  
  
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  Moderate to severe nutrient deficiency

  
  
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  Complete intestinal obstruction

  
  
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  Short bowel syndrome

  
  
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  High-output intestinal fistulas

  
  
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  Severe intractable diarrhea or emesis

  
  
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  Severe malabsorption

  
  
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  Edematous or friable bowel

  
  
• 
  

  After extensive GI surgery or bleed

  
  
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  Severely malnourished or catabolic patient (required to be NPO for 5 days)

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  For short-term use (3-5 days) in patients who have limited oral intake because of frequent tests requiring NPO status or during an evaluation of possible obstruction

  
  
• 
  

  Short-term bowel dysfunction

  
  
• 
  

  Mild-moderate nutrient deficiency

Total caloric

1,800-2,800 calories daily

2,000-4,000 calories daily

1,400-2,000 calories daily

Polymeric formula:

Dextrose 20% to 50% (provides 3.4 calorie/g): Use to meet 50% to 60% of calorie requirements. Maximum recommended infusion rate in adults is 5 mg/kg/min.
Lipids (10% solution provides 1.1 calorie/mL; 20% solution provides 2 calorie/mL): Use to meet 30% of calorie requirements. Provides essential fatty acids to prevent deficiency. Use of lipids has been shown to decrease elevated hepatic function tests and hepatic steatosis compared to dextrose-only based regimens.
Protein (provides 4 calorie/g): Use standard 4.5% or 8% concentration to meet 10% to 20% calorie requirements. Standard formulas contain essential and nonessential amino acids. Restriction is indicated occasionally (eg, in hepatic encephalopathy or in renal failure if dialysis is not being used).
Vitamins: Use standard parenteral multivitamin preparation; add vitamin K (1 mg/day) separately.
Trace elements: Use standard parenteral preparation, which includes zinc, copper, manganese, chromium, and selenium.
Electrolytes: Average daily recommendations for TPN electrolytes for adults:

Dextrose 5% to 10% solution is maximum concentration that can be administered peripherally (3-4 L/day).
Lipids: Use of lipids is required to reduce overall osmolarity. The maximum concentration that may be administered peripherally is 10% to 20% (500 mL/day)
Protein: Protein solutions suitable for peripheral administration are 3% to 4.5% (1-2 L/day)
Vitamins: Use standard parenteral multivitamin preparation; vitamin K (1 mg/day) is usually administered separately or as an intramuscular injection.
Trace minerals: Use standard parenteral preparation, which includes zinc, copper, manganese, chromium, and selenium.
Electrolytes: Concentrations for peripheral administration are different than parenteral. Maximum peripheral infusion rate for potassium—20 mEq/h.

Standard: 1 calorie/mL; 80% to 85% water.

Concentrated: 1.5-2.0 calorie/mL; 70% to 75% water. (Use for fluid-restricted patients.)

Partially hydrolyzed: One or more micronutrients are partially or completely broken down into smaller components. Use is limited; may be required in some cases of malabsorption

Disease specific: These products are expensive and their efficacy is controversial (ie, hepatic, renal, pulmonary).

Considerations in choosing a formula:

1. Calorie and protein requirements

2. Fluid requirements and restrictions

3. Known patient intolerances (eg, fat)

Sodium—100 mEq

Potassium—60-120 mEq

Phosphorus—10-22 mmol

Magnesium—8-20 mEq

Calcium—10-15 mEq

Chloride—100 mEq

Site of delivery

Enteral via gastric tube, gastrostomy tube, or jejunal tube

Intravenous via central venous catheter

Intravenous by way of peripheral venous access. At least 20-gauge needle, although 18-gauge or higher is preferred.

Method of delivery

Continuous: Used for any patient and any site of delivery, especially those who have been NPO for more than 1 week. With gastric feedings, once tolerance to continuous infusion has been established, conversion to cyclic or bolus infusion can be attempted if desired.

Continuous: Parenteral nutrition is generally initiated at a continuous 24-hour infusion rate.
Cyclic: Once tolerance to goal rate is established, conversion to a nocturnal, cyclic schedule may be possible. This permits unrestricted ambulation during the day.

Continuous: This method does not provide for nutritional repletion or, in most patients, even nutritional maintenance. Rapid progression to centrally administered PN or oral/tube feeding is recommended.

Cyclic: Used for a 12-hour nocturnal infusion, allowing mobility during the day. If administered via gastric or duodenal sites, implement aspiration precautions.

Bolus: For patients who wish to take feedings that mimic meals. This is an acceptable method for gastric feedings. The feeding may be administered via a syringe or gravity drip. Prevent potential complications.

Special assessment

1. 
   

   Assess for nausea and vomiting, bloating, and increased abdominal girth, indicating delayed motility and may require decreasing infusion rate or discontinuation of feeding.

   
   
2. 
   

   Assess volume status for dehydration. The estimated daily fluid requirement is 30 mL/kg. Include water used for tube flushing. Overhydration can be monitored via input/output records and rapid weight gain.

   
   
3. 
   

   Assess for diarrhea.

   
   
4. 
   

   Assess for constipation. Adequate fluid intake is essential to aid in prevention. A fiber-containing formula may be beneficial as well.

1. 
   

   Assess line access site for signs or symptoms of infection at least daily.

   
   
2. 
   

   Use a dedicated line, not breaking integrity. Fluids and tubing should be changed daily due to infection.

   
   
3. 
   

   If the new bag of solution is unavailable, hang dextrose 10%.

   
   
4. 
   

   Monitor for electrolyte imbalances and notify responsible health care professionals (physicians, pharmacists, nutritionists) to alter TPN formulation as needed.

   
   
5. 
   

   Ensure vitamin and mineral replacement.

   
   
6. 
   

   In prolonged therapy, assess for acalculous cholecystitis (elevated bilirubin, RUQ discomfort, jaundice).

1. 
   

   Assess line access for signs and symptoms of phlebitis or infection.

   
   
2. 
   

   Monitor glucose and electrolytes periodically.

   
   
3. 
   

   After 3-5 days of therapy, consider whether extended support will necessitate another method of nutritional supplementation.

Unique nursing management

1. 
   

   Minimize risk of aspiration by checking residuals.

   
   

   With continuous feedings, check q4h until tolerance to goal infusion rate is established. New literature suggests that assessing residual volumes may not be reflective of the aspiration risk or intolerance, and the need to hold feeding based residual volume alone is not appropriate (McClave & Snider, 2002). This remains a controversial stance, and many still consider the following guidelines as standard of care (McClave et al, 2002).

   
   

   Residuals of 100 mL or less are acceptable and should be reinfused so the patient is not missing needed nutrients. If residuals are high, the infusion rate may be lowered.

   
   

   With bolus feedings, check before each feeding and hold for 150 mL or greater. In patients taking oral feeding in addition to tube feeding, evaluation of residuals is not possible.

   
   
2. 
   

   Minimize the risk of aspiration for gastric or duodenal feedings by elevating the head of the bed by at least a 45-degree angle. Stop feedings for 2 hours prior to and during any procedure requiring prolonged supine positioning.

   
   
3. 
   

   Avoid tube clogging by flushing with 30-60 mL water after any medication administration and before and after each bolus or cyclic feeding.

   
   
4. 
   

   Medications should be in liquid form, or pills finely crushed. Time-released pills cannot be crushed and should not be administered via a tube. Check with the pharmacist regarding medication administration via a jejunostomy, because some medications may have special mixing instructions to ensure bioavailability, and the osmolality may be too high for jejunal administration.

   
   
5. 
   

   Minimize risk of infection and diarrhea by careful handling of formula. For continuous feedings: hang no more than 4 hours worth of formula; do not add new formula to that already hanging; insert feeding administration container with water before adding new formula; refrigerate unused portion of canned formula in a covered container. Discard formula after 24 hours and change feeding administration container and tubing daily.

1. 
   

   Prevention of metabolic complications:

   
   

   Hyperglycemia: Most common with infection or on corticosteroids. Dextrose content of PN should be decreased.

   
   

   Maximal use of lipids can replace the dextrose calories.

   
   

   Addition of insulin therapy is commonly needed.

   
   

   Electrolyte abnormalities: May be afupon fected by other medications or clinical. conditions, and alleviated or exacerbated by parenteral nutrition.

   
   

   Hypertriglyceridemia: Reduce lipid calories if level is 400 mg/dL.

   
   
2. 
   

   Avoid overfeeding total calories.

   
   
3. 
   

   Hepatic abnormalities:

   
   

   Avoid overfeeding. Mild, transient elevations can occur in any hepatic function, which peaks within 10-15 days of PN initiation.

   
   
4. 
   

   Cholestasis/cholecystitis:

   
   

   Lack of GI stimulation during the prolonged fasting frequently associated with PN can contribute to gall bladder abnormalities. Some form of oral or tube feeding is encouraged as soon as the patient can tolerate

   
   
5. 
   

   Hypercapnia: Can result from excess dextrose calories.

   
   

   Avoid overfeeding, and replace a portion of the dextrose calories with lipid calories to help decrease carbon dioxide production.

1. 
   

   Use a 20-gauge or larger IV catheter.

   
   
2. 
   

   Maintain a dedicated line for peripheral nutrition.

   
   
3. 
   

   Change IV tubing and fluid daily.

Laboratory monitoring

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  Daily, progressing to weekly in chronic use:

  
  

  Serum/plasma glucose

  
  

  Metabolic panel: sodium, potassium, chloride, carbon dioxide, urea nitrogen, creatinine, phosphate, calcium, magnesium

  
  
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  Several times a week, progressing to every 2-4 weeks in chronic use:

  
  

  Serum nutritional tests—albumin, prealbumin, transferrin

  
  

  Liver function tests

  
  

  Triglycerides

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  Twice daily, progressing to weekly in chronic use:

  
  

  Serum/plasma glucose

  
  

  Metabolic panel: sodium, potassium, chloride, carbon dioxide, blood urea nitrogen, creatinine, phosphate, calcium, magnesium

  
  
• 
  

  Several times a week, progressing to every 2-4 weeks in chronic use:

  
  

  Serum nutritional tests—albumin, prealbumin, transferrin

  
  

  Liver function tests

  
  

  Triglycerides

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  Once to twice daily:

  
  

  Serum/plasma glucose

  
  

  Electrolytes

  
  
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  Baseline only or weekly if continued that long: Metabolic panel: Sodium, potasblood sium, chloride, carbon dioxide, blood urea nitrogen, creatinine, phosphate, calcium, magnesium

  
  

  Serum nutritional tests—albumin, prealbumin, transferrin

  
  

  Liver function tests

  
  

  Triglycerides