A 4-week-old boy is brought to the emergency department due to irritability and poor feeding that began earlier today. The mother notes he feels warm and is breathing faster than usual. On physical examination, the infant is awake but fussy. Capillary refill is 2 seconds, and peripheral pulses are strong. Vital signs are significant for a heart rate of 280/min, respiratory rate of 50/min, and blood pressure of 84/48 mm Hg. A 12-lead electrocardiogram demonstrates a regular, narrow QRS complex tachycardia with no discernible P waves. Intravenous access is successfully established. Arrange the following management steps in the most appropriate chronological sequence for this patient.
- 1Apply a plastic bag filled with ice water to the infant's upper face for up to 15 seconds
- 2Administer a rapid intravenous push of adenosine followed immediately by a normal saline flush
- 3Perform synchronized electrical cardioversion at 0.5 to 1 J/kg
- 4Initiate maintenance pharmacotherapy with an oral beta-blocker
Answer
The correct sequence of interventions is: 1) Apply an ice water bag to the face, 2) Administer intravenous adenosine, 3) Perform synchronized electrical cardioversion, 4) Initiate maintenance pharmacotherapy.
This patient presents with supraventricular tachycardia (SVT), the most common symptomatic dysrhythmia in infants. Crucially, this patient is hemodynamically stable (normal blood pressure, strong pulses, alert). According to Pediatric Advanced Life Support (PALS) guidelines, the initial treatment for stable SVT is a vagal maneuver. In infants, this is best achieved by applying a bag of ice water to the upper half of the face to elicit the mammalian diving reflex. If vagal maneuvers are unsuccessful, the next appropriate step is rapid intravenous administration of adenosine, which temporarily blocks AV node conduction and terminates re-entrant circuits. If adenosine is ineffective after multiple escalating doses, or if the patient becomes hemodynamically unstable at any point, synchronized electrical cardioversion is indicated. Finally, after successful conversion to sinus rhythm, maintenance therapy (e.g., a beta-blocker like propranolol) is initiated to prevent subsequent episodes.
Step-by-Step Solution
Key Concept
Management of Supraventricular Tachycardia (SVT) in infants