PALS Tachycardia 3 — Questions and Answers
Question 1: A 10-year-old presents with a wide-complex tachycardia at 180 bpm with hemodynamic stability. Which drug is preferred when the rhythm is uncertain?
- Adenosine 0.1 mg/kg rapid IV (Correct answer)
- Verapamil 0.1 mg/kg IV
- Digoxin 10 mcg/kg IV
- Lidocaine 1 mg/kg IV
Correct answer: Adenosine 0.1 mg/kg rapid IV
Adenosine is preferred for stable wide-complex tachycardia of uncertain origin because it is safe if the rhythm is SVT with aberrancy and has a short half-life.
Question 2: Which medication is CONTRAINDICATED in pediatric SVT management?
- Adenosine
- Amiodarone
- Verapamil in infants <1 year (Correct answer)
- Synchronized cardioversion
Correct answer: Verapamil in infants <1 year
Verapamil is contraindicated in infants under 1 year because it can cause severe hypotension, bradycardia, and cardiac arrest in this age group.
Question 3: A 3-year-old with a history of congenital heart disease develops a wide-complex tachycardia at 190 bpm with signs of shock. What is the first action?
- Administer adenosine 0.1 mg/kg IV
- Prepare for synchronized cardioversion (Correct answer)
- Start amiodarone infusion
- Obtain 12-lead ECG
Correct answer: Prepare for synchronized cardioversion
Unstable wide-complex tachycardia with shock requires immediate synchronized cardioversion regardless of rhythm identification.
Question 4: What is the recommended adenosine dose for the SECOND administration in a child with SVT?
- 0.05 mg/kg
- 0.1 mg/kg
- 0.2 mg/kg (Correct answer)
- 0.3 mg/kg
Correct answer: 0.2 mg/kg
If the first dose of adenosine (0.1 mg/kg) is ineffective, the second dose is doubled to 0.2 mg/kg (maximum 12 mg).
Question 5: During SVT cardioversion in an awake child, which consideration is most important?
- Use unsynchronized mode for faster delivery
- Ensure sedation and analgesia before delivery (Correct answer)
- Use 4 J/kg as the starting dose
- Avoid pads and use paddles only
Correct answer: Ensure sedation and analgesia before delivery
If the clinical situation allows time, sedation and analgesia should be provided before elective synchronized cardioversion in a conscious child.
Question 6: A child with SVT is given adenosine via a peripheral IV in the antecubital fossa. What technique should be used to maximize drug effectiveness?
- Slow push over 1 minute to reduce side effects
- Rapid IV push followed immediately by a normal saline flush (Correct answer)
- Mix adenosine in 50 mL NS before infusing
- Give half the dose IM for faster absorption
Correct answer: Rapid IV push followed immediately by a normal saline flush
Adenosine must be given as a rapid IV bolus followed immediately by a large-volume saline flush to ensure the drug reaches central circulation before it is metabolized.
Question 7: Which of the following is the MOST common cause of tachycardia in a febrile 6-month-old infant?
- SVT
- Ventricular tachycardia
- Sinus tachycardia secondary to fever (Correct answer)
- Atrial flutter
Correct answer: Sinus tachycardia secondary to fever
Sinus tachycardia secondary to fever and physiologic stress is by far the most common tachyarrhythmia in febrile infants.
PALS Tachycardia 3
A 10-year-old presents with a wide-complex tachycardia at 180 bpm with hemodynamic stability.
Which drug is preferred when the rhythm is uncertain?