Parenteral Nutrition Designing the Solution Mark H. DeLegge, MD, FACG, AGAF, FASGE Digestive Disease Center Medical University of South Carolina

Avoid That Which is Unknown

Lipids Carbohydrates Protein

Parenteral Nutrition  Infusion of nutrients through a vein  Indications: dysfuntional GI system –Malabsorption –Obstruction –Fistula –Inability to obtain enteral access –Bowel rest ?

Parenteral Nutrition  Central: Infused into a major vein (CPN) –Generally with catheter tip in the last 1/3 of Superior Vena Cava  Peripheral: Infused into a peripheral vein (PPN) –Limited by mixture osmolality (< 900 mOsmo) –May limit ability to deliver total caloric needs

PPN CPN Superior Vena Cava

Osmolality Gradient and Carbohydrates Glucose Concentration % CaloriesKcal/LOsmolalitymOsmo/L

Knowing the Solution  % Solution  10% AA = 10 gm AA/100 H0  10% AA = 10 gm AA/100 H 2 0  20% Lipids = 20 gm lipids/100 cc H 2 O  30% Jack Daniels = 30 gm Jack Daniels/100 cc H 2 0

What You Need to Know To Write A PN Prescription  Calorie Requirements  Protein Requirements  Electrolyte Requirements  Mineral Requirements  Vitamin Requirements  Water Requirements  Other Additives

Calorie Needs  Harris Benedict:  Male (wt in kg) + 5 (height in cm) – 6.8 (age in years)  Female (weight in kg) (ht in cm) – 4.7 (age in years) Stress Factor Mild Moderate Severe 1.5

Simple Calorie Calculation  Maintenance/mild stress: kcal/kg/day  Moderate stress: kcal/kg/day  Severe Stress : kcal/kg/day

Protein Needs  Maintenance – mild stress: g/kg/day  Moderate stress: gm/kg/day  Severe stress: 1.5 – 2.0 gm/kg/day  Very high stress: > 2 gm/kg/day

Make Note of Common Lab Values Na mEq/L K+ Serum mEq/L Chloride mmol/L CO mmol/L BUN 8-20 mg/dL Creatinine mg/dL Calcium mg/dL Phosphorus mg/dL Magnesium mg/dL

Example of a Standard PN Electrolyte Matrix  NACl 75 mEq/L  Na Acetate 25 m Eq/L (CO)  Na Acetate 25 m Eq/L (CO 2 )  K Phosphate15 mmol  (3 mmol of P = 4.4 mEq/K)  Na Phosphate 15 mmol  (3 mmol of P = 4 mEq Na)  Ca Gluconate 2 gm  Mg sulfate 1 gram

Standard Trace Minerals  Added to Daily PN Prescription  Chromium10 mcg  Copper1 mg  Manganese0.5 mg  Selenium60 mcg  Zinc5 mg

Standard Multivitamins Provided Daily  Vitamin A3300 IU  Vitamin D200 IU  Vitamin E 10 IU  Vitamin B1 6 mg  Vitamin B2 3.6 mg  Vitamin B340 mg  Vitamin B515 mg  Vitamin B6 6 mg  Vitamin C200 mg  Biotin 60 mcg  Folic Acid600 mcg  Vitamin K150 mcg

Daily Fluid Needs  30 cc/kg/day  Reduce if volume overloaded  Increase for excessive stool, urine, vomiting, sweating.  You do not have to correct major electrolyte, mineral, fluid abnormalities in the PN solution. Use a supplemental infusion.

Additives  H2 Blocker  Heparin  Insulin –Need at least 10 units/L to see clinical effect –Add ½ to ¾ of previous day’s insulin requirements to TPN bag

Additional Potential Additives Vitamin C: mg/day for wound healing. Zinc: 3-5 mg/day for wound healing Folic Acid: 1 mg/day with alcohol abuse or pregnancy Thiamine: 100 mg/day with alcohol abuse

Important Facts  Lipids: no more than 2.5 gm/kg/day  Carbohydrates: Maximal glucose infusion rate 3-5 g/kg/day  Protein: as described  1 gram lipids = 9 kcal  1 gram protein = 4 kcal  1 gram carbohydrates = 3.4 kcal

The Situation  A 40 year old male s/p recurrent fistula formation in the distal jejunum. He has lost 6 kg in 2 weeks. A central PN catheter is placed and you are asked to write a PN order. The patient weighs 70 kg.

Estimated Needs  Calories30 kcal/g x 70 kg = 2100 kcal  Protein1.2 g/kg x 70 kg = 84 kg  Fluids30 ml/kg = 2100 cc  His electrolytes are normal except for a Kof 3.3.  His electrolytes are normal except for a K + of 3.3.

1 st Add Protein  84 g of protein  4 kcal/g (326 kcal)  2100 kcal – 326 kcal = 1774 kcal more required

2 nd Add Lipids  g/kg  70 kg x 1 g/kg = 70 gm  70 gm = 700 kcal  1774 calories – 700 kcal = 1074 kcal remaining

3 rd Add Carbohydrates  1074 kcal remaining  1074/3.4 kcal/g carbohydrate = 295 g  Double check for maximal carbohydrate infusion  295 g carbohydrate/70 kg = 4.21 g/kg/day

Determine a Volume  70 kg x 30 cc/kg = 2100 cc  Add multivitamins  Add trace minerals  Add drugs if necessary

What if the TPN Form Asks Me to Add Components as Solutions?  15% amino acids (15 gm/100 cc) –We need 84 grams = 560 cc  20 Lipids (20 gm/100 cc) –We need 70 gm = 350 cc  70% dextrose (70 gm/100 cc) –We need 295 gm = 421 cc –2100 cc volume – 1361 cc = 739 cc H0 –2100 cc volume – 1361 cc = 739 cc H 2 0 –Add trace minerals, multivitamins and other drugs

How do you Determine a Rate  Continuous  Total volume/24 hr = cc/hr  2100/24 = 87 cc/hr  Intermittent  Total volume over 12 hours  2100/12 = 175 cc/hr

Conclusion  1. Be able to determine calorie, protein, fluid needs  2. Be familiar with a standard electrolyte formulation  3. Make your PN formula sequentially  4. Be familiar with solutions and what they mean  5. Add this to your knowledge base

Don’t leave Nutrition Support up to Someone Else