After analyzing the rhythm of a 6-year-old in cardiac arrest and the AED advises no shock, you should:

When a 6-year-old is in cardiac arrest and the AED indicates "no shock advised," the appropriate action is to resume chest compressions immediately. This is crucial because high-quality chest compressions are essential for maintaining blood flow to vital organs during cardiac arrest, which is pivotal in improving outcomes.

The AED’s indication that a shock is not advised typically means that the rhythm is not shockable, such as in cases of asystole or pulseless electrical activity (PEA). Therefore, prioritizing chest compressions helps to support circulation and oxygenation until advanced medical assistance is available or a shockable rhythm is identified.

Continuing with CPR for a duration of time is also critical, but the best immediate action following an AED's no-shock advisement is to begin or resume chest compressions without delay. This ensures that the child is receiving immediate care, maximizing the chances of survival as care proceeds.