PALS Tachycardia With a Pulse 3 — Questions and Answers
Question 1: A 7-year-old with a known history of WPW presents with a wide-complex tachycardia and a pulse. Which drug should be AVOIDED?
- Adenosine (Correct answer)
- Amiodarone
- Procainamide
- Synchronized cardioversion
Correct answer: Adenosine
Adenosine can enhance accessory pathway conduction in WPW during wide-complex tachycardia, potentially causing ventricular fibrillation.
Question 2: What is the maximum single dose of adenosine for treating SVT in a pediatric patient?
- 12 mg (Correct answer)
- 6 mg
- 18 mg
- 0.3 mg/kg
Correct answer: 12 mg
The maximum single dose of adenosine in pediatric PALS is 12 mg, regardless of weight.
Question 3: An infant presents with a heart rate of 280 bpm, pallor, and cool extremities. Which finding would MOST indicate SVT over sinus tachycardia?
- Absent P-waves with retrograde conduction on ECG (Correct answer)
- Recent history of fever and vomiting
- Gradual onset over 30 minutes
- Heart rate that decreases with crying
Correct answer: Absent P-waves with retrograde conduction on ECG
Absent or retrograde P-waves are characteristic of SVT, whereas sinus tachycardia always shows normal P-waves preceding each QRS.
Question 4: Which of the following is TRUE regarding vagal maneuvers in pediatric SVT?
- Ice water facial immersion is preferred over carotid sinus massage in infants (Correct answer)
- Carotid sinus massage is the first choice in all age groups
- Valsalva maneuver is the only recommended technique in PALS
- Vagal maneuvers are contraindicated in children under 2 years
Correct answer: Ice water facial immersion is preferred over carotid sinus massage in infants
Ice water facial immersion activates the diving reflex and is the preferred vagal maneuver in infants; carotid massage is reserved for older children.
Question 5: A 10-year-old with SVT successfully converts with adenosine. Thirty seconds later, the heart rate rises to 230 bpm again. What is the next step?
- Administer a second dose of adenosine at 0.2 mg/kg (Correct answer)
- Proceed to synchronized cardioversion immediately
- Administer amiodarone 5 mg/kg IV over 20 minutes
- Repeat vagal maneuvers and reassess
Correct answer: Administer a second dose of adenosine at 0.2 mg/kg
Recurrent SVT after adenosine conversion warrants a second adenosine dose at the higher dose of 0.2 mg/kg before escalating therapy.
Question 6: Which of the following best describes the typical heart rate range for SVT in infants?
- 220–300 bpm (Correct answer)
- 150–180 bpm
- 180–200 bpm
- 100–150 bpm
Correct answer: 220–300 bpm
SVT in infants typically presents with heart rates of 220–300 bpm, which is substantially higher than sinus tachycardia.
Question 7: Amiodarone is ordered for a stable child with wide-complex tachycardia. Over what time frame should the 5 mg/kg dose be infused?
- 20–60 minutes (Correct answer)
- 1–2 minutes
- 5–10 minutes
- 2–4 hours
Correct answer: 20–60 minutes
Amiodarone 5 mg/kg for stable tachycardia is infused over 20–60 minutes to minimize hypotension and bradycardia.
PALS Tachycardia With a Pulse 3
A 7-year-old with a known history of WPW presents with a wide-complex tachycardia and a pulse.
Which drug should be AVOIDED?