Heba Elkholy, Pharm. DA. Senior Clinical Pharmacist, SKMC

Goals

To provide a brief explanation about TPN. To illustrate one common problem which

could occur when writing TPN prescription and how it could be avoided.

To discuses the current Canadian guidelines recommendation supported by evidence based.

To briefly go through some calculations related to PPO TPN at SKMC

Total Parenteral Nutrition Normal Diet

Protein Carbohydrates Fat Vitamins Minerals Water

Total Parenteral Nutrition

Normal Diet TPN Protein………………...Amino Acids Carbohydrates…….Dextrose Fat……………………….Lipid Emulsion Vitamins………………Multivitamin

Infusion Minerals……………….Electrolytes and

Trace Elements

Carbohydrate-CHO

The most commonly used carbohydrate energy substrate is dextrose.

1gm dextrose= 3.4 kcal/g. According to the United States

Pharmacopoeia (USP), dextrose are acidic, with a pH ranging from 3.5 to 6.5, and vary in osmolarity depending upon their concentration.

Carbohydrate-CHO

Higher dextrose concentrations (greater than 10%) are generally reserved for central venous administration

the propensity to cause thrombophlebitis in peripheral veins.

Use your brain

True or false?

Dextrose 10% can be given as peripheral?

Protein

Crystalline amino acids . 4 kcal/g. essential and nonessential amino

acids.

Electrolytes Daily Electrolyte Requirements Sodium 1–2 mEq/kg Chloride As needed to maintain acid–

base balance Acetate As needed to maintain acid–

base balance Calcium 10–15 mEq Magnesium 8–20 mEq Phosphate 20–40 mmol

How to Measure the Energy requirement?

Harris–Benedict Equation Men: Energy expenditure= 66 +

13.75 (wt in kg)+ 5 (ht) in cm -68 (age)

Women: Energy expenditure= 655 + 9.6 (wt in kg)+ 1.8 (ht in cm) -4.78 (age)

Energy for critically ill patient Swinmer: RMR (Kcal/day)= BSA

(941)-age(6.3)+T (104)+RR(24)+Vt (804)-4243.

Penn State: RMR (Kcal/day)= HBE (0.85)+Ve(33)+Tm (175)-6433

Special population

Spontaneously Breathing Patients

IJEE (s) = 629 − 11(A) + 25(W) − 609(O)

Ventilator-Dependent Patients IJEE (v)=1784−11(A) + 5(W) +

244(S) + 239T+804(B).

TPN complication Underfeeding: Decreased respiratory muscle strength Decreased ventilatory drive Failure to wean from mechanical

ventilation Impaired organ function Immunosuppression Poor wound healing Increased risk of nosocomial infection

TPN complication

Overfeeding: Hyperglycemia Azotemia Hypertriglyceridemia Electrolyte imbalance Immunosuppression Alterations in hydration status Hepatic steatosis

osmolarity

Osmolarity is dependent on the dextrose, amino acid, and electrolyte Content.

PN is a hypertonic to body fluid. Inappropriate administration can lead

to venous thrombosis , thrombophlebitis, and extravasation.

For Peripheral TPN, maximum allowed osmolarity is 900 mosm/L.

Use your brain

Which of the following may increase the risk of phlebitis with peripherally administered parenteral nutrition (PPN)?

A. Osmolarity ≤900 mOsm/L B. Potassium 100 mEq/L C. Intravenous fat emulsion (IVFE)

piggybacked with PPN. D. Addition of heparin to the PPN

When is TPN recommended?

Criteria for 2007 A.S.P.E.N Guidelines Patient has failed EN trial with appropriate

tube placement (postpyloric). When EN is contraindicated or the intestinal

tract has severely diminished function due to the following:

• Paralytic ileus• Mesenteric ischemia• Small bowel obstruction• GI fistula except when enteral access may be

placed posterior to the fistula.

Critically ill patients Gut failure in critically ill patients is

common.

In critically ill patients, PN is indicated if EN is not possible, and hypermetabolism is expected to last more than 4 to 5 days.

Critically ill patients requiring PN are those who are: hemodynamically stable and have:

a paralytic ileus. acute GI bleeding. Complete bowel obstruction

Problem

What problem could occur when mixing TPN?

Calcium – Phosphorus compound

Calcium and phosphorus are common essential electrolytes in PN solutions . If mixing in high conc.…… insoluble

precipitate of ca-phosphate compound could occur.

PE secondary to ca-phosphate ppt. has been reported.

Calcium-Phosphate compatibility

Factors which affect stability Additive concentration Choice of calcium salt Order of mixing Amino acid product (brand) Amino acid concentration Dextrose Concentration Temperature (not what you think) Storage time Addition of l-cysteine (neonatal)

Case report Microvascular Pulmonary Emboli Secondary

to Precipitated Crystals in a Patient Receiving Total Parenteral Nutrition,

21-year-old man receiving immunosuppressive therapy and TPN developed fever, shortness of breath, and chest tightness.

This patient’s calcium-phosphate product was at times as high as 47.5 mmol/L

CHEST 1999; 115:892–895).

In response to this, the Food and Drug Administration (FDA) issued a safety alert warning of the hazards of TPN and offered guidelines that may help prevent future morbidity.

Different image of lung

poorly marginated micronodules throughout all lung zones

Calcium-Phosphate compatibilityHow to minimize calcium phosphate precipitation Additive concentration……..……....use lower the conc. Choice of Ca ……..…..…...use Ca Gluconate, not CaCl2 Order of mixing…....add phosphate first, calcium last Amino acid product …Aminosyn best, FreAmine worst Amino acid concentration……….…use higher AA conc. Dextrose concentration………use higher Dextrose conc. Temperature………………………………………….…Refrigerate Storage time……………………....Minimized storage time l-cysteine (neonatal) ……..greatly increases solubility

How can the physician help?

Please, Keep the total amount of calcium and phosphorus less than 45meq/L.

Calcium-Phosphate compatibility

Ca-Po4 chart

What are we doing regarding Pediatric patients?Compatibility of calcium and phosphate in four parenteral

nutrition solutions for preterm neonates, LUIS PEREIRA-DA-SILVA, M.D., NURMAMODO, et al , Am J Health-Syst Pharm. 2003; 60:1041-4 .

An inorganic source of phosphorus (monobasic sodium phosphate,NaH2PO4 27.5%) was used in mixtures A and C, while an organic source (sodium glycerophosphate [Glycophos] was used in mixtures B and D.

Organic phosphates have been recommended as sources of phosphorus in PN solutions for premature infants because of their higher compatibility with calcium than inorganic phosphates.

What is new?

Glutamine amino acid that is reported to become

“conditionally essential” during critical illness.

It is vital fuel for rapidly dividing cells such as fibroblasts, reticuloendothelial cells, malignant cell, and gut epithelial cells.

Glutamine

clinical conditions, such as exercise, trauma, and sepsis, the body’s glutamine requirement exceeds its ability to synthesize glutamine; this leads to a fall in plasma and intracellular glutamine which increased mortality.

Glutamine evidence-base

Efficacy of glutamine dipeptide-supplemented total parenteral nutrition in critically ill patients: a prospective, double-blind randomized trial.

Method: 53 assigned to Glu-TPN and 64 to S-

TPN.

Critical Care 2008, 12(Suppl 2):P146.

Glutamine evidence-base

Result: Less new infections occurred in Glu-

TPN patients: nosocomial pneumonia 8.04 versus 29.25 episodes-urinary tract infections 2.5 versus 16.7 episodes.

no differences in the incidence of catheter-related sepsis, primary bacteremia and intra-abdominal infections.

Glutamine evidence-base

Conclusion:

Glu-TPN used in critically ill patients for longer than 3 days significantly reduces the incidence of nosocomial pneu-monias and urinary tract infections, and decreases the severity of organ failures.

Glutamine in different studies glutamine supplementation reduces length of

stay, particularly among surgical patients. parenteral glutamine supplementation

nutrition led to a statistically significant decrease in infectious complications and insulin resistance in critically ill patients.

The use of intravenous glutamine supplementation in critically ill patients on total

parenteral nutrition is currently the standard of care.

Canadian Clinical Practice Guidelines,January 8th 2007 Based on 4 level 1 studies and 5 level 2

studies, when parenteral nutrition is prescribed to critically ill patients, parenteral supplementation with glutamine, where available, is recommended.

There are insufficient data to generate recommendations for intravenous glutamine in critically ill patients who are receiving enteral nutrition.

TPN at SKMC

TPN at SKMC Calculation of Peripheral TPN: 2.75%=2.75gm /100ml= 27.5gm/1L. Each 1gm AA give 4gm Kcal, 1L of 2.75%AA has 110 kcal 10% dextrose= 10gm/100ml=

100gm/1L Each 1gm dextrose give 3.4Kcal 1L of 10% dextrose= 340 Kcal Total calories PPN = 110+ 340=450Kcal

TPN at SKMC Calculation of central TPN: 5%=5gm /100ml= 50gm/1L. Each 1gm AA give 4gm Kcal, 1L of 2.75%AA has 200 kcal 25% dextrose= 25gm/100ml= 250gm/1L Each 1gm dextrose give 3.4Kcal 1L of 10% dextrose= 850 Kcal Total calories central = 850+

200=1050Kcal

Finally

Potential complications can be minimized if special attention is paid to each step of the preparation and administration of total parenteral nutrition solutions.

Cooperation between physician, pharmacist , dietitian and nurse results in the best outcome for those patients who are candidates for TPN administration.

The End

Thanks for your attention