What must be done if a patient is unresponsive and not breathing?

When a patient is unresponsive and not breathing, the most critical action is to ensure that they receive immediate emergency care, which is effectively achieved by calling for help and beginning CPR. Time is of the essence in cases where a person is not breathing, as this can lead to irreversible brain damage and death within minutes due to lack of oxygen.

Starting CPR promptly enhances the chances of survival, as it maintains blood circulation to vital organs, particularly the brain and heart. By calling for help, you're also ensuring that more advanced medical personnel are on their way to provide further care. Immediate initiation of CPR is aligned with established emergency protocols in such life-threatening situations.

The other options, while they may seem relevant, do not provide the necessary immediate intervention required for an unresponsive and non-breathing individual. Waiting for the patient to wake up or performing a secondary assessment first would unnecessarily delay critical care and potentially worsen the patient's condition. Performing rescue breaths only would not be sufficient without initiating chest compressions, which are vital for effective CPR. Therefore, starting CPR and calling for help is the appropriate and life-saving response in this scenario.