A 6-year-old girl who has been running a fever for the past…
A 6-year-old girl who has been running a fever for the past 2 days presents with lethargy and tachycardia. Her heart rate is 170 beats/min and varies with activity. Her skin is cool and clammy, and her capillary refill time is 4 seconds. The cardiac monitor reveals a narrow complex tachycardia with a rate that varies between 150 and 170 beats/min. You should: