Do Not Give Anything By Mouth:
Never give the person anything to drink or eat, not even water or aspirin, unless specifically instructed to do so by the emergency operator. They could choke.
Stay Calm and Don't Abandon: Your presence and actions, even if it's just chest compressions, maintain a minimum vital circulation to the brain and heart until professional help arrives.
You are the most critical link in the chain of survival.
Remembering and mentally practicing these steps can mean the difference between life and death.
Formal CPR and AED training is invaluable, but even without it, knowing how to call emergency services and begin chest compressions is the most powerful intervention you can offer.