PALS Pharmacology 3 — Questions and Answers
Question 1: A 3-year-old (15 kg) in septic shock needs a norepinephrine infusion. What hemodynamic effect makes norepinephrine preferred over dopamine in fluid-refractory cold shock?
- Increases heart rate predominantly
- Primarily increases SVR via alpha-1 effects (Correct answer)
- Primarily increases cardiac contractility
- Causes bronchodilation
Correct answer: Primarily increases SVR via alpha-1 effects
Norepinephrine's strong alpha-1 agonism raises systemic vascular resistance, making it preferred for vasodilatory (warm) shock, while its use in cold shock targets refractory cases.
Question 2: Which of the following best describes the mechanism of adenosine in terminating SVT?
- Blocks sodium channels in ventricular myocardium
- Transiently blocks AV nodal conduction (Correct answer)
- Increases automaticity of SA node
- Prolongs the QT interval
Correct answer: Transiently blocks AV nodal conduction
Adenosine transiently blocks AV nodal conduction, interrupting re-entrant SVT circuits that depend on the AV node.
Question 3: What is the correct IO epinephrine dose during pediatric cardiac arrest?
- 0.001 mg/kg of 1:10,000 solution
- 0.01 mg/kg of 1:10,000 solution (Correct answer)
- 0.1 mg/kg of 1:1,000 solution
- 1 mg/kg of 1:10,000 solution
Correct answer: 0.01 mg/kg of 1:10,000 solution
Epinephrine for cardiac arrest is 0.01 mg/kg (0.1 mL/kg of 1:10,000 solution) IV/IO, maximum 1 mg per dose.
Question 4: Dopamine at a dose of 10–20 mcg/kg/min primarily exerts which effect?
- Renal vasodilation
- Increased cardiac contractility and heart rate
- Alpha-mediated vasoconstriction (Correct answer)
- Vagolytic bradycardia reversal
Correct answer: Alpha-mediated vasoconstriction
At doses of 10–20 mcg/kg/min, dopamine primarily stimulates alpha-adrenergic receptors, causing vasoconstriction.
Question 5: A child with wide-complex tachycardia and a pulse receives lidocaine. What is the correct IV/IO dose?
- 0.01 mg/kg
- 0.5–1 mg/kg (Correct answer)
- 5 mg/kg
- 10 mg/kg
Correct answer: 0.5–1 mg/kg
Lidocaine for ventricular arrhythmias in children is 1 mg/kg IV/IO (range 0.5–1 mg/kg).
Question 6: Which of the following is a key reason epinephrine is given every 3–5 minutes during CPR?
- It has a half-life of approximately 2–3 minutes in circulation (Correct answer)
- It requires hepatic metabolism before becoming active
- It crosses the blood-brain barrier slowly
- It binds irreversibly to adrenergic receptors
Correct answer: It has a half-life of approximately 2–3 minutes in circulation
Epinephrine has a very short half-life (~2 minutes), so repeat dosing every 3–5 minutes maintains its vasopressor effect during CPR.
Question 7: Calcium chloride is indicated in pediatric resuscitation for which of these conditions?
- Hyperkalemia, hypocalcemia, or calcium-channel blocker overdose (Correct answer)
- Hyponatremia
- Respiratory acidosis
- Opioid toxicity
Correct answer: Hyperkalemia, hypocalcemia, or calcium-channel blocker overdose
Calcium chloride is used in pediatric arrest for documented hypocalcemia, hyperkalemia, hypermagnesemia, or calcium-channel blocker toxicity.
PALS Pharmacology 3
A 3-year-old (15 kg) in septic shock needs a norepinephrine infusion.
What hemodynamic effect makes norepinephrine preferred over dopamine in fluid-refractory cold shock?