Case Study: Sudden Unresponsiveness in a Child

A 9 year-old female is carried into your acute care center by her parents who state that the patient “suddenly fell out.” You observe an unresponsive, 36 kg female, breathing easily at a rate of 28 per minute. There is no sign of increased work of breathing. The peripheral pulses are weak and are palpated at a rate greater than 250 per minute. Capillary refill is greater than 5 seconds. The parents deny any past trauma or medical history, and have no idea what is happening.

The patient is placed on oxygen and her airway maintained. Initiation of ECG monitoring shows a widened QRS, regular tachycardia at a rate of 270 per minute. Lungs auscultate clear, and there are no signs of increased work of breathing or trauma.

QUESTION 1:

What is your differential diagnosis?

INTERVENTION

Based on the size of the patient (36 kg), synchronized cardioversion using 30 joules was administered. No sedation was given prior to delivery of the countershock. The ECG showed a small isoelectric segment immediately following the shock, followed by resumption of a narrow-QRS, regular rhythm at a rate of 122 per minute. The patient began taking deep breaths and regained an acceptable level of consciousness within several minutes.

CLINICAL CONSIDERATIONS

QUESTION 2:

Why was unstable tachyarrhythmia chosen over other causes?

QUESTION 3:

On what criteria should you base the decision to use electrical cardioversion?

QUESTION 4:

What type of pediatric specialist should immediately evaluate the patient?

QUESTION 5:

Why was adenosine not chosen as a first-line intervention?