TPN

Question 1

Advantages of nutrition support therapy

Answer 1

*Reduce disease severity
*Diminish complications
*Decrease length of hospital stay
*Increase patient’s qualify of life
*Decrease costs of medical care
*Severe chronic intestinal failure
*Neonates who cannot be fed by mouth

Goal is to provide adequate calories to prevent malnutrition and associated complications

Question 2

Classification of Malnutrition

Answer 2

• Weight and recent weight loss
• Actual body weight vs. ideal body weight vs.
  adjusted body weight
• Weight dynamics
• Body mass index (BMI)
• Albumin (half-life 18-21 days)
• Transferrin (half-life 8-10 days)
• Prealbumin (half-life 2-3 days)
• Retinol-binding protein (half-life 0.5 day)

Question 3

Enteral Nutrition (EN) vs. PN

Answer 3

• If the gut works, use it
• Enteral feeding:
  -EN maintains gut integrity
  -Fewer infections
  -Lower costs & shorter hospital stays
• Parenteral feeding:
  -Useful if enteral access is not feasible, inadequate,
  or not tolerated
  -PN has less risk of gastric retention, emesis, and
  aspiration

Question 4

Options for tube feeding

Answer 4

*Nasal vs. ostomy
*Sites for formula delivery
-Gastric (preferred)
-Duodenal
-Jejunal

Question 5

Indications for PN:

Answer 5

• Short bowel
• Radiation enteritis
• Distal high output fistulas
• Persistent ileus
• Pseudo obstruction
• Mechanical obstruction

Question 6

IV Access for PN therapy

Answer 6

• Peripheral IV (PIV aka PPN)
  -Limited use (<7days)
• Central Line (TPN) - PICC: Peripherally inserted central catheter
• CVC triple lumen
• Port a Cath

Question 7

Maximum Dextrose Concentrations and Osmolarity Limits

Answer 7

• Peripheral line (PPN):
  -Max Concentration: Dextrose 10%
  -Osm: 900 mOsm/L
• Central line (TPN):
  -Max Concentration: Dextrose 25%
  -Osm: 1500 mOsm/L

Question 8

Estimated Energy Requirement Examples

Answer 8

• Healthy, maintenance: 20-25 kcal/kg/day
• Malnourished or stressed: 25-30 kcal/kg/day
• Severe stress: 30-35 kcal/kg/day

Question 9

Protein requirements

Answer 9

• Based on body weight, degree of stress and disease state
• Estimated protein needs:
  -Maintenance: 0.8-1.2 g/kg/day
  -Mild catabolism: 1.2-1.5
  -Moderate cat: 1.5-2.0
  -Severe cat: 2.0-2.5
• Note: Protein and amino acids are restricted in patients with renal and hepatic dysfunction
  -Require only 0.6-0.8 g/kg daily

Question 10

Protein

Answer 10

• Protein in PN is supplied as an amino acid mixture
• Protein provides 4 kcal/g
• Notated as “AA” and various percentages
• Ex: AA 10% = 10g/100mL
• Max AA% in PN = 8%

Question 11

Carbohydrates

Answer 11

• Dextrose is the most common carbohydrate for IV use
• Dextrose provides 3.4 kcal/g
• Carbohydrates to meet 70-85% of nonprotein calories

Question 12

Fat

Answer 12

• Lipid or fat provides 9 kcal/g
• IV formulas supplied as 10% and 20% lipid
  emulsion
• 10% lipids provide 1.1 kcal/mL
• 20% lipids provide 2 kcal/mL
• Fat to provide 15-30% of nonprotein calories

Question 13

Why include lipids in PN?

Answer 13

• Required for cell membrane synthesis and production of immune response mediators
• Used to prevent EFAD
• Essential fatty acid deficiency (EFAD) occurs
  after 1 week-1 month of no fat intake
• Monitor triglycerides weekly
• Note: Lipids are held if the patient is on Propofol or if TG ≥ 400 mg/dLq

Question 14

Daily fluid requirements

Answer 14

*1500 mL + 20 mL/kg in excess of 20 kg
* Range 20-40 mL/kg/day
* Can also estimate 1 mL/kcal
* Replacing fluid losses in patient on PN

Question 14

Other ingredients in PN

Answer 14

• Electrolytes :
  -Na, K, Mg, Phos, Ca
• Multivitamin :
  -ADEK + B1/B2/B6/B12/C + Folic Acid
• Trace elements: Zinc, Chromium, Selenium, Copper, & Manganese
  -Renal trace elements contain all trace elements at a reduced amount
  -Hepatic trace elements only contain zinc, chromium, and selenium

Question 14

Nutritional Requirements

Answer 14

• Total calories: 20-35 kcal/kg/d
• Protein: 0.8-2.5 g/kg/d
• Carbohydrates to meet 70-85% of non-protein calories
• Fat to provide 15-30% of non-protein calories
• Fluids: 20-40 mL/kg/d
• Vitamins, trace elements, electrolytes

Question 14

Calcium and Phosphate

Answer 14

• Avoid mixing in close sequence
• Add phosphate before calcium
• Avoid excess Calcium/Phosphate
• Utilize the Calcium/Phosphate Curve

Question 14

Monitoring patients on PN

Answer 14

• Body weight
• Intake (PO, IVF, IV medications, PN)
• Output (Drainage, fistula, diarrhea)
• Blood glucose & metabolic panel
• Hepatic panel & triglycerides
• Signs and symptoms of line infection

Question 15

Tips for Adjusting Electrolytes

Answer 15

• Sodium: 136-145 mmol/L
  -Avoid too rapid a correction of serum [Na+] to
  avoid serious neurological complications
• Calcium: 8.6 -10.2 mg/dL
  -Calculate corrected calcium first
• Potassium*: 3.5-5.1 mmol/L
• Magnesium*: 1.7-2.6 mg/dL
• Phosphorous*: 2.7-4.5 mg/dL
• Use with caution if adding to PN in AKI/IHD/CRRT patients and discuss with nephrology

Question 16

Renal Impairment

Answer 16

• AKI/IHD/CRRT
• Very conservative if barely any electrolytes in PN
• Watch K, Mg, & Phos
• Discuss with Nephrology
• Renal adjustments for amino acid (protein requirement reduced to 0.6-0.8 g/kg daily) and trace elements

Question 17

Hepatic Impairment

Answer 17

• Monitor liver function tests (LFTs)
• Adjust trace elements if total bilirubin >1.2 mg/dL
• Adjustments for amino acids

Question 18

Potential Complications of PN

Answer 18

• Mechanical (catheter occlusion = use heparin or sodium citrate)
• Infectious (maintain access)
• Metabolic:
  -Hyperglycemia (limit dextrose rate <4, insulin)
  -Electrolyte disturbances (monitor daily BMP/Mg/Phos, weekly TG/Liver)
  -Refeeding syndrome (start slow, advance slow)
  -Liver (steatosis, cholestasis)
  -Bone (ca deficiency, osteos, Al/Vit D tox)

Question 19

Insulin in PN

Answer 19

• Only regular insulin can be used in PN
• Discuss with Endocrinology
• Monitor closely and use with caution
• Reasonable starting point is 0.05-0.1 units/g of dextrose if warranted
• If patient becomes hypoglycemic, all sources of insulin would stop (including PN)