When a 2nd rescuer of equal certification arrives on the scene of CPR in progress, what is the first thing the 2nd rescuer must do?

The first priority when a second rescuer arrives on the scene of CPR in progress is to ensure that emergency medical services (EMS) have been called. This step is crucial because even if CPR is being administered, prompt advanced medical assistance is necessary for the victim's survival, especially if they are in cardiac arrest. The second rescuer should quickly assess the situation, confirm that 911 has been contacted, and provide any necessary information to the dispatcher.

Once it's established that emergency services are on their way, the second rescuer can assist with CPR or get the Automated External Defibrillator (AED) ready, assessing the victim’s condition if needed. However, confirming that help is on the way is the first and most critical action to ensure the victim receives comprehensive care.