CRNI Infusion-Related Pharmacology 4 — Questions and Answers
Question 1: A patient receiving vancomycin develops flushing, erythema, and pruritus on the face and upper torso during the infusion. What is the most likely cause?
- Anaphylactic reaction requiring epinephrine
- Red man syndrome due to rapid infusion rate (Correct answer)
- Vancomycin allergy requiring drug discontinuation
- Histamine release from a contaminated vial
Correct answer: Red man syndrome due to rapid infusion rate
Red man syndrome is a non-immune-mediated reaction caused by rapid vancomycin infusion that triggers histamine release, and slowing the infusion rate typically resolves symptoms.
Question 2: Which electrolyte imbalance is most commonly associated with amphotericin B infusion therapy?
- Hyperkalemia
- Hypernatremia
- Hypokalemia (Correct answer)
- Hypercalcemia
Correct answer: Hypokalemia
Amphotericin B causes renal tubular dysfunction leading to potassium wasting and hypokalemia, requiring routine electrolyte monitoring and replacement.
Question 3: A nurse is preparing to administer IV phenytoin. Which solution is compatible for dilution?
- Dextrose 5% in water (D5W)
- Normal saline (0.9% NaCl) (Correct answer)
- Lactated Ringer's solution
- Dextrose 10% in water
Correct answer: Normal saline (0.9% NaCl)
Phenytoin is only compatible with normal saline; dextrose solutions cause precipitation due to the drug's alkaline pH and poor aqueous solubility.
Question 4: When administering a continuous heparin infusion, the patient's aPTT is 3.5 times the control value. What is the priority nursing action?
- Continue the infusion and recheck aPTT in 6 hours
- Hold the infusion and notify the prescriber per protocol (Correct answer)
- Administer protamine sulfate immediately
- Increase the infusion rate to achieve therapeutic levels
Correct answer: Hold the infusion and notify the prescriber per protocol
An aPTT greater than 3 times the control indicates supratherapeutic anticoagulation; the infusion should be held and the prescriber notified per institutional protocol.
Question 5: A patient is receiving a dopamine infusion at 15 mcg/kg/min. The nurse notes the patient's urine output has decreased significantly. What pharmacological effect is most likely occurring?
- Dopaminergic renal vasodilation at low doses
- Alpha-adrenergic renal vasoconstriction at high doses (Correct answer)
- Beta-1 adrenergic decreased cardiac output
- Direct nephrotoxicity from the dopamine infusion
Correct answer: Alpha-adrenergic renal vasoconstriction at high doses
At doses above 10 mcg/kg/min, dopamine stimulates alpha-adrenergic receptors causing renal vasoconstriction, which can decrease renal perfusion and urine output.
Question 6: Which monitoring parameter is MOST critical when administering IV magnesium sulfate for eclampsia prevention?
- Blood glucose levels every 2 hours
- Serum potassium before each dose
- Patellar deep tendon reflexes (Correct answer)
- Liver function tests every 4 hours
Correct answer: Patellar deep tendon reflexes
Loss of patellar deep tendon reflexes is an early sign of magnesium toxicity and occurs before respiratory depression, making it the most critical monitoring parameter.
Question 7: A patient receiving IV insulin is ordered to have blood glucose checks every hour. At what blood glucose level should the infusion be stopped and dextrose administered per standard protocol?
- Below 180 mg/dL
- Below 140 mg/dL
- Below 100 mg/dL
- Below 70 mg/dL (Correct answer)
Correct answer: Below 70 mg/dL
A blood glucose below 70 mg/dL indicates hypoglycemia; the insulin infusion should be stopped and dextrose administered to prevent serious neurological complications.
CRNI Infusion-Related Pharmacology 4
A patient receiving vancomycin develops flushing, erythema, and pruritus on the face and upper torso during the infusion.
What is the most likely cause?