Ch 15: Parenteral Nutrition Formulations

Question 1

What is the desirable pH of ILE?

Answer 1

A pH in the range of 6-9 is most favorable for ILE stability, whereas additives lowering the pH below 5 or increasing the pH above 10 may irreversibly destabilize the emulsion

Question 2

What is the most substantial compatibility concern in PN?

Answer 2

Calcium Phosphate solubility

Question 3

Besides deficiency, what are some other reasons for low serum calcium concentrations?

Answer 3

hypoalbuminemia, fluid retention, or acid base disturbances

Question 4

What is the difference between stability and compatibility in PN?

Answer 4

Stability of PN refers to the degradation of nutrition components that changes their original characteristics

Compatibility in PN formulations generally involves the formation of precipitates

Question 5

What is the only iron supplement approved for addition to PN?

Answer 5

Iron dextran, but this supplement should only be considered for dextrose and AA formulations because ILE formulations are disrupted by iron

Question 6

What sized PN filter should be used for TNA?

What sized PN filter should be used for dextrose-AA mixture?

Answer 6

1.2 um; 0.22 um

Question 7

What is the drawback of SMOF lipids?

Answer 7

Essential acid concentration is lower than the concentration in traditionally available soybean oil-based ILE.

Question 8

What is the most critical factor influencing the pH of a PN formulation?

Answer 8

The crystalline AA solution used for compounding

Question 9

What is the hang time for piggy backed ILE?

Answer 9

12 hours

Question 10

What is ASPENs stance on parenteral glutamine?

Answer 10

Parenteral glutamine is not recommended in adult critically ill patients b/c literature indicates lack of infectious and mortality benefit or even higher mortality rates when IV glutamine is compared to placebo

Question 11

What is a SMOF lipid?

Answer 11

Soybean oil, MCTs, olive oil and fish oil)

Question 12

When should a MVI be added to SCAPN?

Answer 12

Shortly before administration b/c vitamins and essential components of PN that are not stable when added more then 24 hours ahead of use

Question 13

What is ASPENs stance of commercially available multi trace elements?

Answer 13

They are inappropriate, and single element products should be used to meet individual patient needs

Question 14

In which cases may SMOF lipid be useful?

Answer 14

in patients who do not tolerate soybean oil-based ILE during critical illness or metabolic stress and in patients with carnitine deficiency b/c the transport of MCTs into mitochondria is carnitine independent. SMOF has been associated with reduced liver changes and preservation of antioxidant capacity in pedi home PN patients, adult intestinal failure long term PN patients and critically ill patients

Question 15

What are the preferred forms of calcium and magnesium in PN, and why?

Answer 15

Calcium gluconate and Magnesium sulfate are preferred forms of these cations for use in PN formulations b/c they are less likely to produce incompatibilities compared to calcium chloride, calcium gluceptate, and magnesium chloride.

Question 16

Which patients are at greatest risk for aluminum toxicity?

Answer 16

Patients with significant renal dysfunction, high intake of PN, or iron deficiency

Question 17

What are the benefits of structured lipids (such as clinolipid)

Answer 17

1. Decreased peroxidation and lack of in vitro lymphocyte function inhibition
2. Associated w/ faster termination of ventilation and time to ICU d/c compared with soybean oil-based ILE
3. Because olive oil contains approximately 20% of omega 6 FA, the supply of linoleic acid is enough to avoid risk of EFAD

Question 18

What is defined as a possible safe upper limit for parenteral aluminum intake?

Answer 18

Less than 4-5 mcg/kg/day.

Question 19

In a long term PN patient, what factor is thought to contribute to gallbladder sludge/stones?

Answer 19

Lack of enteral stimulation in the GI tract

Question 20

Which form of glutamine supplementation improves physical compatibility and stability for admixture in PN solutions?

Answer 20

Glutamine dipeptide

Question 21

Which is the best method to express the dextrose content on the label of a PN formulation in order to avoid misinterpretation?

Answer 21

Grams per 24-hour nutrient infusion (e.g., 225 g/day)

Question 22

How should electrolytes be ordered in a PN solution?

Answer 22

Electrolytes are to be ordered as complete salt forms as opposed to individual ions.

Question 23

A patient receiving digoxin and parenteral nutrition who is experiencing signs of digoxin toxicity should be assessed for which electrolyte abnormalities?

Answer 23

hypokalemia or hypomagnesemia