CNSC PARENTERAL NUTRITION
EXAM QUESTIONS AND
ANSWERS WELL EXPLAINED
According to the ASPEN PN Safety Consensus Recommendations, which of the
following best describes safe PN compounding?
1: The preparation with automated compounding devices (ACDs) ensures an error-free
process
2: All healthcare providers should have the ability to override soft and hard limit alerts
from ACDs
3: Manual compounding of PN is appropriate when volumes of a PN component to be
mixed are less than the ACD can accurately deliver
4: The preparation of compounded sterile preparations (CSPs) for all patient
populations should be done at the same time - Answer-3: Manual compounding of PN is
appropriate when volumes of a PN component to be mixed are less than the ACD can
accurately deliver
Preparing PN with an ACD is not an error-free process, and error rates are reported to
be 22% when automated and 37% when manually prepared. Compounding with ACDs
should lead to improved compounding accuracy, enforcement of proper compounding
sequence, and reduction in opportunities for human touch contamination. Institute for
Safe Medication Practices (ISMP) recommends to install, test, and maximize automated
dose-limit warnings in the pharmacy and ACD order entry systems with each
organization developing weight based dosing limits applicable to their patient
population. ASHP (American Society of Health-System Pharmacists) guidelines for the
safe use of ACDs for the preparation of PN states that the pharmacy department should
develop a monitoring and surveillance plan that promotes safe and efficacious use of
the ACD at all times. This includes a review of dose limit alerts and overrides. When an
ACD is used, it should deliver all PN ingredients. Manual PN compounding is
appropriate when the volume of a PN component is less than the ACD can accurately
deliver or if there is an interaction between a PN component and ACD component.
Manual compounding is also appropriate when chemical interactions between PN
components cannot be mitigated by sequencing the addition of the ingredients, or as a
part of a conservation effort during drug shortages. Facilities that care for adult,
pediatric, and neonatal populations should separate CSP preparation for each
population and develop separation strategies to minimize error.
,References:
Ayers P, Adams S, Boullata J, etal. A.S.P.E.N. parenteral nutrition safety consensus
recommendations. JPEN J Parenter Enteral Nutr. 2014 Mar-Apr;38(3):296-333.
Creaming of a total nutrient admixture (TNA) appears as
1: a translucent band at the surface of the emulsion separate from the remaining TNA
dispersion.
2: yellow-brown oil droplets at or near the TNA surface.
3: a continuous layer of yellow-brown liquid at the surface of the TNA.
4: marbling or streaking of the oil throughout the TNA. - Answer-1: a translucent band at
the surface of the emulsion separate from the remaining TNA dispersion.
Answers b, c, and d describe potential visual signs of the terminal state of emulsion
destabilization, commonly known as cracking. In this stage, small lipid particles
coalesce to form large droplets ranging in size from 5-50 or more microns. These oil
droplets pose potential clinical danger. In contrast, the initial stage in emulsion
breakdown is creaming which occurs almost immediately upon standing once ILE has
been mixed with other chemical constituents. The presence of a cream layer is visible at
the surface of the emulsion as a translucent band separate from the remaining TNA
dispersion. Although the lipid particles in the cream layer are destabilized, their
individual droplet identities are generally preserved. In general, light creaming is a
common occurrence and not a significant determinant of infusion safety except in
extreme cases.
References:
Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J,
Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6
Suppl):S39-S70.
Which of the following complications is most likely to occur when transitioning a critically
ill adult patient from parenteral to enteral nutrition?
1: Hypokalemia
2: Hyperkalemia
3: Hypoglycemia
4: Hyperglycemia - Answer-4: Hyperglycemia
When transitioning from parenteral to enteral nutrition, patients may receive nutrients in
excess during overlap of therapy leading to hyperglycemia. Appropriate adjustments to
limit total carbohydrate intake to no greater than 4 to 5 mg/kg/min can prevent this
metabolic complication in many critically ill adult patients.
Rapid intravenous infusion of sodium or potassium phosphate may result in
, 1: tetany.
2: hypercalcemia.
3: metabolic alkalosis.
4: vitamin D deficiency. - Answer-1: tetany.
Rapid infusion of phosphate can result in tetany due to an abrupt decrease in serum
calcium concentration. Since phosphate salts are acidifying in nature, alkalosis would
not be anticipated.
References:
Baumgartner TG. Enteral and parenteral electrolyte therapeutics. NCP. 2001;16:226-
235.
A patient on long-term parenteral nutrition begins to experience Parkinson-like
symptoms. Which trace element toxicity is most likely to present with these symptoms?
1: Manganese
2: Copper
3: Zinc
4: Selenium - Answer-1: Manganese
Manganese is an essential trace element routinely added to long-term parenteral
nutrition (PN) solutions. Though manganese deficiency is exceedingly rare, toxicity is
well documented in these patients. Excess manganese accumulates in the brain leading
to Parkinson disease-like symptoms such as tremor, involuntary movements and
rigidity. Patients with abnormal liver function are at an increased risk for toxicity due to
manganese being primarily excreted via bile. Manganese contamination of PN solutions
can also occur during manufacturing and delivery of PN solutions. Despite this
increased risk, there is limited evidence to support manganese-free PN solutions in
patients without symptoms of toxicity or impaired liver function. Current
recommendations for long-term PN patients are to serially monitor liver function as well
as signs and symptoms of manganese toxicity.
The adverse effects of lipid injectable emulsion (ILE) administration in adult PN
prescription is best prevented by
1: supplementing with L-carnitine.
2: avoiding infusion rates >0.05 grams/kg/hour.
3: using Alternative ILEs.
4: ILE free PN solutions. - Answer-3: using Alternative ILEs.
Liver dysfunction results from a complex set of risk factors present in patients receiving
PN, called PN associated liver disease (PNALD). Recommended dosage for all types of
ILE are 1-2g/kg/day, not to exceed 2.5g/kg/day. L-carnitine deficiency exacerbates lipid
abnormalities but existing evidence has not confirmed that supplementation corrects
hypertriglyceridemia. Alternative ILEs may preserve liver function and prevent
EXAM QUESTIONS AND
ANSWERS WELL EXPLAINED
According to the ASPEN PN Safety Consensus Recommendations, which of the
following best describes safe PN compounding?
1: The preparation with automated compounding devices (ACDs) ensures an error-free
process
2: All healthcare providers should have the ability to override soft and hard limit alerts
from ACDs
3: Manual compounding of PN is appropriate when volumes of a PN component to be
mixed are less than the ACD can accurately deliver
4: The preparation of compounded sterile preparations (CSPs) for all patient
populations should be done at the same time - Answer-3: Manual compounding of PN is
appropriate when volumes of a PN component to be mixed are less than the ACD can
accurately deliver
Preparing PN with an ACD is not an error-free process, and error rates are reported to
be 22% when automated and 37% when manually prepared. Compounding with ACDs
should lead to improved compounding accuracy, enforcement of proper compounding
sequence, and reduction in opportunities for human touch contamination. Institute for
Safe Medication Practices (ISMP) recommends to install, test, and maximize automated
dose-limit warnings in the pharmacy and ACD order entry systems with each
organization developing weight based dosing limits applicable to their patient
population. ASHP (American Society of Health-System Pharmacists) guidelines for the
safe use of ACDs for the preparation of PN states that the pharmacy department should
develop a monitoring and surveillance plan that promotes safe and efficacious use of
the ACD at all times. This includes a review of dose limit alerts and overrides. When an
ACD is used, it should deliver all PN ingredients. Manual PN compounding is
appropriate when the volume of a PN component is less than the ACD can accurately
deliver or if there is an interaction between a PN component and ACD component.
Manual compounding is also appropriate when chemical interactions between PN
components cannot be mitigated by sequencing the addition of the ingredients, or as a
part of a conservation effort during drug shortages. Facilities that care for adult,
pediatric, and neonatal populations should separate CSP preparation for each
population and develop separation strategies to minimize error.
,References:
Ayers P, Adams S, Boullata J, etal. A.S.P.E.N. parenteral nutrition safety consensus
recommendations. JPEN J Parenter Enteral Nutr. 2014 Mar-Apr;38(3):296-333.
Creaming of a total nutrient admixture (TNA) appears as
1: a translucent band at the surface of the emulsion separate from the remaining TNA
dispersion.
2: yellow-brown oil droplets at or near the TNA surface.
3: a continuous layer of yellow-brown liquid at the surface of the TNA.
4: marbling or streaking of the oil throughout the TNA. - Answer-1: a translucent band at
the surface of the emulsion separate from the remaining TNA dispersion.
Answers b, c, and d describe potential visual signs of the terminal state of emulsion
destabilization, commonly known as cracking. In this stage, small lipid particles
coalesce to form large droplets ranging in size from 5-50 or more microns. These oil
droplets pose potential clinical danger. In contrast, the initial stage in emulsion
breakdown is creaming which occurs almost immediately upon standing once ILE has
been mixed with other chemical constituents. The presence of a cream layer is visible at
the surface of the emulsion as a translucent band separate from the remaining TNA
dispersion. Although the lipid particles in the cream layer are destabilized, their
individual droplet identities are generally preserved. In general, light creaming is a
common occurrence and not a significant determinant of infusion safety except in
extreme cases.
References:
Task Force for the Revision of Safe Practices for Parenteral Nutrition: Mirtallo J,
Canada T, Johnson D, et al. Safe practices for parenteral nutrition. JPEN. 2004;28(6
Suppl):S39-S70.
Which of the following complications is most likely to occur when transitioning a critically
ill adult patient from parenteral to enteral nutrition?
1: Hypokalemia
2: Hyperkalemia
3: Hypoglycemia
4: Hyperglycemia - Answer-4: Hyperglycemia
When transitioning from parenteral to enteral nutrition, patients may receive nutrients in
excess during overlap of therapy leading to hyperglycemia. Appropriate adjustments to
limit total carbohydrate intake to no greater than 4 to 5 mg/kg/min can prevent this
metabolic complication in many critically ill adult patients.
Rapid intravenous infusion of sodium or potassium phosphate may result in
, 1: tetany.
2: hypercalcemia.
3: metabolic alkalosis.
4: vitamin D deficiency. - Answer-1: tetany.
Rapid infusion of phosphate can result in tetany due to an abrupt decrease in serum
calcium concentration. Since phosphate salts are acidifying in nature, alkalosis would
not be anticipated.
References:
Baumgartner TG. Enteral and parenteral electrolyte therapeutics. NCP. 2001;16:226-
235.
A patient on long-term parenteral nutrition begins to experience Parkinson-like
symptoms. Which trace element toxicity is most likely to present with these symptoms?
1: Manganese
2: Copper
3: Zinc
4: Selenium - Answer-1: Manganese
Manganese is an essential trace element routinely added to long-term parenteral
nutrition (PN) solutions. Though manganese deficiency is exceedingly rare, toxicity is
well documented in these patients. Excess manganese accumulates in the brain leading
to Parkinson disease-like symptoms such as tremor, involuntary movements and
rigidity. Patients with abnormal liver function are at an increased risk for toxicity due to
manganese being primarily excreted via bile. Manganese contamination of PN solutions
can also occur during manufacturing and delivery of PN solutions. Despite this
increased risk, there is limited evidence to support manganese-free PN solutions in
patients without symptoms of toxicity or impaired liver function. Current
recommendations for long-term PN patients are to serially monitor liver function as well
as signs and symptoms of manganese toxicity.
The adverse effects of lipid injectable emulsion (ILE) administration in adult PN
prescription is best prevented by
1: supplementing with L-carnitine.
2: avoiding infusion rates >0.05 grams/kg/hour.
3: using Alternative ILEs.
4: ILE free PN solutions. - Answer-3: using Alternative ILEs.
Liver dysfunction results from a complex set of risk factors present in patients receiving
PN, called PN associated liver disease (PNALD). Recommended dosage for all types of
ILE are 1-2g/kg/day, not to exceed 2.5g/kg/day. L-carnitine deficiency exacerbates lipid
abnormalities but existing evidence has not confirmed that supplementation corrects
hypertriglyceridemia. Alternative ILEs may preserve liver function and prevent
