Final answer:
Summon EMS personnel for an unresponsive person with a pulse but no breathing, provide rescue breathing, and be prepared to administer CPR and use an AED if needed.
Step-by-step explanation:
When you encounter an unresponsive adult with a pulse but no breathing, you should summon EMS personnel and begin rescue breathing. It is important to focus on providing high-quality breaths at the appropriate rate and depth to effectively oxygenate the victim's organs, especially the brain. As you continue to monitor the victim's condition, if at any point they lose their pulse, you would need to start CPR and use an automated external defibrillator (AED) if one is available. Remember, CPR and rescue breathing are critical life-saving skills that can dramatically improve the chances of survival and recovery for an individual who is not breathing but has a pulse.