TPN: Total Parenteral Nutrition

1. TPN: Total Parenteral Nutrition Chad Bradford. Touro University College of Pharmacy

2. What is TPN? A compounded formulation which includes the necessary macronutrients and micronutrients required to sustain life The formulation is used for patients who are malnourished or at high risk of becoming malnourished because alternative routes of feeding have failed or have become unavailable Chad Bradford. Touro University College of Pharmacy

3. TPN Indications NPO = Nothing by Mouth, where patients essentially can not tolerate feedings through the GI tract for a prolonged period Anatomical Abnormalities Infants with immature bowels, patients with surgical resections Motility Problems Obstructive complications of the GI tract Critically Ill Patients with conditions favoring catabolism, Cancer A typical period is > 5-7 days that is expected to persist > 7-10 days. TPN is NOT INDICATED for 1 day TPN is NOT INDICATED for perioperative use Complications of the line placement and of the formulation itself Chad Bradford. Touro University College of Pharmacy

4. Requirements Step 1: Make sure TPN is indicated Step 2: Obtain baseline labs: Chem 10, LFT, ABG, etc Step 3: Make sure a central line is in place TPN is a hyperosmolar formulation 2000-2500 mosmol/L If TPN is infused peripherally blood cells will undergo implosive lysis and destroy the vein Central vein infusion dilutes the slow infusion and preserves blood cells and veins The standard central line placement is in the SVC � Superior Vena Cava Subclavian approach Jugular approach PICC � Peripherally Inserted Central Catheter Implant � to SVC or SV, with or without a port Femoral lines are not appropriate Step 4: If infused at home ensure patient has access to the appropriate pump and supplies as well as caregiving if needed Step 5: Follow up regarding the patient�s nutritional status and review labs for adjustments to the formulation Chad Bradford. Touro University College of Pharmacy

5. Complications Complication rates increase with duration the catheter is in place and the number of catheter lumens Catheter related complications are the most common Long Term Infection: CRBSI and exit site Thrombotic Placement and Catheter Hemothorax, Pneumothorax Air embolisms and infections Metabolic Acute: E-lyte, Acid-Base, glycemic abnormalities Chronic: Bone mineral disease, liver disease Chad Bradford. Touro University College of Pharmacy

6. TPN Formula Dependent on the individual patient�s needs and based off of a reference weight. Use Cockcroft-Gault rules to determine the weight to use: AW, ADJ, IBW Monitor weight to make adjustments to the formulation Take into account non-metabolically active weight: fluid from edema, ascites Total Calories: RDA = 28-29 kcal/kg The typical range is 20-35 kcal/kg Not all patients require the same caloric intake therfore you must take into account Weight: Comparison to ideal weight Body Content: Fat vs. Muscle vs. Water Functionality: Normal function vs. Abnormal Obese Patients: BMI > 30 May require less calories Inactive Patients May require less calories Malnourished Patients: < 80% UBW, < 75% IBW, >10% Involuntary Loss May require more calories Critically Ill Patients: Cancer patient in catabolic protein state May require more calories Chad Bradford. Touro University College of Pharmacy

7. Formula: Macronutrients Chad Bradford. Touro University College of Pharmacy

8. Formula: Micronutrients Na: 60-130mEq/d Available as: NaCl, Na Acetate, Na Phosphate K: 70-150mEq/d Available as: KCl, K Actate, K Phosphate Mg: 8-24mEq/d Usually Mg Sulfate Ca: 5-22mEq/d Usually Ca Gluconate Phosphate: 15-40mmol/d Available as Na and K Phosphate Cl, Acetate Available as Na and K. Used to balance Acid Base Multivitamin Most people receive Trace: Zn, Se, Cu, Cr, Mn Most people receive Electrolytes are adjusted based on patients labs and patients normal reference range. Ca and Phosphate should be added at two separate times to avoid precipitation and instability of the lipid formulations Chad Bradford. Touro University College of Pharmacy

9. Formula: Misc/Other Drugs may also be added to the formulation H2RA, Insulin, Fe Dextran etc. Total Fluid requirements vary by patient age and condition Stability varies among formulations and facilities Hospitals make TPN daily: May be stable for less time Home Infusion makes a weekly batch: Longer stability Most TPN lasts about 1 month Most TPN facilities mark them as stable for 7-14 days TPN is usually started with nutrients at less than goal Once labs on day 2 suggest the formulation is okay the TPN is advanced toward goal Starting the TPN at CHO goal can lead to high gycemic indices and low electrolyte values Chad Bradford. Touro University College of Pharmacy

10. Calculating Macronutrients Step 1: Determine the reference weight Step 2: Determine the Total Calories Step 3: Determine Protein Calories Step 4: Determine Non-Protein Calories Step 5: Determine the Lipid volume Step 6: Determine the CHO Calories Chad Bradford. Touro University College of Pharmacy

11. Calculating Macronutrients Step 1: Assume the proper reference weight is 70 kg Step 2: Recall that the Total Cal = 20-35 kcal/kg Therefore: 70 kg x 25 kcal/kg = 1750 kcal Step 3: Recall that the Protein/AA = 1-2 g/kg/d Therefore: 70 kg x 1g/kg/d = 70 g/d This value is in grams, but we need to convert it to kcal to determine the amount of the total calories that will come from a non-protein source. Recall that Protein has 4kcal/g Therefore: 70 g/d x 4 kcal/g = 280 kcal/d Step 4: Determine the non-protein calories Since we have the Total Calories and the Protein Calories the Non-Protein Calories are just the difference Therefore: 1750 kcal - 280 kcal = 1470 kcal The Non-Protein Calories come from the Lipids and Dextrose Step 5: Recall that the Lipid = 10-25% with max of 2.5 g/kg/d Therefore: 1470 kcal x 20% = 300 Kcal (approximately) This value is in kcal, but we need to convert it to volume. Recall that 20% Lipid has 2 kcal/mL Therefore: 300 kcal x mL/2Kcal = 150 mL Step 6: Recall that the CHO = Remaining portion of the Calories Since we have the Non-Protein and Lipid Calories the CHO Calories are just the difference Therefore: 1470 kcal � 300 kcal = 1170 Kcal This value is in kcal but we need to convert it to grams Recall that CHO has 3.4 kcal/g Therefore 1170 kcal x g/3.4 kcal = 344 g Chad Bradford. Touro University College of Pharmacy

12. Calculating Volume New TPN Order 111g AA, 70g Lipid, 279g Dextrose Final Volume: 2520mL Infused over 24 hours Stock Supply: 10% AA, 20% Lipid, 50% Dextrose Recall that 10% AA = 10g/100mL Therefore 111g AA x 100mL/10g = 1110mL AA Recall that 20% Lipid = 20g/100mL Therefore 70g Lipid x 100ml/20g = 350mL Lipid Recall that 50% Dextrose = 50g/100mL Therefore 279g Dextrose x 100ml/50g = 558mL Dextrose Total Volume = AA + Lipid + Dextrose Therefore 1100mL + 350mL + 558mL = 2018mL However this volume is less than the desired Therefore we make up the remainder by adding sterile water Total Volume � Current Volume = The volume of sterile water to add Therefore 2520mL - 2018mL = 502mL Sterile Water Typically you add some overfill so the volume of sterile water with 100mL overfill would be 602mL bringing the total volume to 2620mL Recall this TPN should be infused over 24 hours Therefore 2520mL/24h = 105mL/h Chad Bradford. Touro University College of Pharmacy

13. Calculating Cycle Changes New TPN Order Currently 2520mL over 24 hours, change to 20 hour cycle Step 1: Subtract the desired # of hours � � hour Therefore 20 hours � � hour = 19.5 hours This accounts for the � hour taper up and down at the beginning and end of the TPN Step 2: Divide total volume by the hours Therefore 2520mL/19.5 h = 129mL/h This is the infusion rate Step 3: Multiply the infusion rate by the total hours � 1 129mL/h x 19 = 2451mL This is the amount infused over 19 hours Step 4: Subtract the 19 hour volume from the total volume 2520mL - 2451mL = 69mL This is the amount to infusion during the taper The Order: Infuse 129mL/h for 19h with a 69mL/h taper at the beginning and end for 30 minutes Check: 129ml/h x 19h = 2451, + 69mL = 2520mL Chad Bradford. Touro University College of Pharmacy

14. Calculating a TPN Order Total Volume: 1068mL/d including excess Step 1: Calculate Macronutrients The order is for 5% AA 5g/100mL = x/1068mL ? 53.4g AA The stock is Aminosyn 10% Therefore 10g/100mL = 53.4g/x ? 534mL Aminosyn 10% The order is for 25% Dextrose 25g/100ml = x/1068mL ? 267g Dextrose The Stock is Dextrose 70% Therefore 70g/100mL = 267g/x ? 381mL Dextrose 70% The total volume of macronutrients 534mL + 381mL = 915mL Chad Bradford. Touro University College of Pharmacy

15. Calculating a TPN Order Step 2: Calculate Micronutrients The order is for 15mmol/L Phosphate 15mmol/L x 1.068L = 16.02mmol is needed The stock is K Phos: 3 mmol phos/mL Therefore 3mmol/ml = 16.02 mmol/x ? 5.34mL K Phos The order if for 30mEq/L Potassium 30mEq/L x 1.068 L = 32.04mEq is needed The stock is KCl: 2.0mEq/ml However some potassium was added with the phosphate 5.34 ml K Phos x 4.4 mEq/mL = 23.50mEq K The difference that needs to be added 32.04mEq � 23.50mEq = 8.54mEq Therefore 2.0mEq/ml = 8.54mEq/x ? 4.27mL KCL This process is completed for all micronutrients, drugs, etc and any remaining volume at the end is met with the addition of sterile water Chad Bradford. Touro University College of Pharmacy

16. Pharmacist Role Often TPN is ordered per pharmacy just like antibiotics and other drugs. Pharmacists will then handle all aspects of TPN Compounding, Dispensing, Monitoring, Adjusting, and Follow Up. The majority of TPN calculations and compounding are done via automated systems However in the event these systems become unavailable and a stat order is needed, it is important to know how to perform the calculations and compounding Chad Bradford. Touro University College of Pharmacy

17. Questions ??? Chad Bradford. Touro University College of Pharmacy