The first thing to do is to remain calm.

You must be able to think clearly. Even though it's common to panic, now is not the time. People are counting on you for a quick, rational response.

Step 1: Dial 9-1-1

Step 2: Tell the operator what the medical emergency is. If you are in the city of Los Angeles, you'll be connected to the Los Angeles Fire Department. Every operator is an active firefighter and Emergency Medical Technician. They may be able to provide lifesaving instructions to you.

Step 3: Tell the operator where you are. You'll need to think about this. Don't say, "I'm on Second Street." Instead, tell the operator, "I'm in downtown Los Angeles, on Second Street near Hill. If you don't know how to communicate where you are, the operator will have trouble getting the right resources to you quickly.

Step 4: Listen carefully to the operator. They may tell you to stay on the phone. They may ask you about the medical emergency. Answer these questions carefully. Being calm and responding to each question could save a life, even your own.