Upon encountering a child in cardiac arrest and being alone, what is your first action?

In a scenario where you encounter a child in cardiac arrest and are alone, the most critical first action is to perform about 2 minutes of CPR. This action is vital because high-quality CPR helps maintain blood flow to the heart and brain, which is essential for the child's survival and can significantly increase chances of a successful outcome.

During those first few minutes, the child’s body is deprived of oxygen, so initiating CPR as quickly as possible is crucial. The guidelines recommend performing CPR for about 2 minutes before leaving the child to call for help, which allows for vital oxygenation and can stabilize the child until emergency services can take over.

Checking for responsiveness is important, but in the case of cardiac arrest, immediate intervention is necessary. Using an AED is also important but should typically occur after starting CPR, especially in a solo rescuer situation. Calling for help is essential, but since there's a priority on maintaining circulation, starting CPR first is the best approach in an emergency.