For adults and adolescents, when should you call/activate EMS?
Immediately — before starting CPR. For an unresponsive adult or adolescent, activate EMS (call 911) and get an AED as soon as you find them, then begin CPR. This is the opposite of the infant/child rule, where you give 2 minutes of CPR first if you're alone and no one saw them collapse.
The rule in one line
Adult or adolescent, unresponsive → call 911 and get an AED first, then start CPR.
This is called "call first." It exists because most adult cardiac arrests are caused by a sudden electrical problem in the heart (like ventricular fibrillation). The single most effective treatment is a shock from an AED, and that only happens if you summon help and a defibrillator immediately.
The contrast that trips people up
For infants and children, a lone rescuer who did not witness the collapse does the opposite — "CPR first" — giving about 2 minutes (5 cycles) of CPR before leaving to call. Kids more commonly arrest from a respiratory cause (choking, drowning, breathing failure), so restoring oxygen with quick CPR takes priority over the phone.
Walk the decision above to see which branch you're on.
Why this shows up on every CPR exam
The American Heart Association and Red Cross both test this because getting it backwards costs minutes that matter. The mnemonic:
- Adults collapse → heart problem → phone/AED first.
- Kids collapse → oxygen problem → compressions first (if alone & unwitnessed).
- Anyone else present? They call and fetch the AED while you compress — no delay either way.
This is general first-aid education, not medical advice or a substitute for a certified CPR course. Always follow your certifying organization's current guidelines.
- 1
Is the person unresponsive and not breathing normally?
Tap and shout. If no normal response and no normal breathing, this is a cardiac emergency.
- 2
Is the victim an adult or adolescent (past puberty)?
- 3
Activate EMS and get an AED NOW
- 4
Then begin CPR
Frequently asked
Why do you call EMS before CPR for adults but after for children?
Adults usually collapse from a sudden cardiac arrhythmia that a defibrillator can correct, so getting an AED and paramedics en route immediately matters most. Children more often arrest from a breathing/oxygen problem, so a lone rescuer gives about 2 minutes of CPR first to restore oxygen before leaving to call.
What if someone else is with you?
Send them to call 911 and get the AED while you start CPR right away — regardless of the victim's age. The 'call first vs. CPR first' rule only matters when you are alone.
What number do you call to activate EMS?
911 in the United States and Canada. Put your phone on speaker so you can keep your hands free for compressions.
Should you get an AED before or after calling EMS?
Do both as fast as possible. If alone with an adult, call 911 first (or simultaneously on speaker), then grab the nearest AED before starting compressions.