Final answer:
During a pediatric cardiac arrest, high-quality CPR and use of an AED are critical interventions. Medication use such as epinephrine may be administered, guided by healthcare professionals and current resuscitation protocols.
Step-by-step explanation:
The most important drug to administer to a child in cardiac arrest while CPR (cardiopulmonary resuscitation) is being performed is not specified in general. In a cardiac emergency, the initial focus is on providing high-quality chest compressions and using an Automated External Defibrillator (AED), if one is available. The AED is a lifesaving device designed for use by both professionals and laypersons, which automatically diagnoses the patient's heart rhythm and delivers a shock if necessary to restore normal heart rhythm. In most pediatric cases, epinephrine is the first medication given during a cardiac arrest, but decisions on drug administration should be at the discretion of the healthcare provider based on the individual situation and prevailing resuscitation guidelines.