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ABCs and
Emergency Priorities

Learn how nurses decide who to treat first using Airway, Breathing, and Circulation to save lives in an emergency.

NCLEX-RN

What Are the ABCs?

When more than one patient needs help, a nurse cannot treat everyone at once. The ABCs give a fast, reliable order for deciding what to fix first. They follow the order in which problems will kill a patient soonest.

The Three Letters

A — Airway
Is the passage to the lungs open? Look for choking, gurgling, or no air movement.
B — Breathing
Is the patient actually breathing? Check rate, effort, and oxygen level.
C — Circulation
Is blood moving? Check pulse, blood pressure, and bleeding.

Why Order Matters

Priority order A Airway Death in minutes if blocked B Breathing Death soon without oxygen C Circulation Death from blood loss / no pulse

The Core Rule

We can write the urgency ranking as a simple ordering. If \( U \) is "urgency to treat," then for any emergency:

$$ U(\text{Airway}) > U(\text{Breathing}) > U(\text{Circulation}) $$

One Big Exception

For a patient in cardiac arrest (no pulse), modern CPR uses CAB instead of ABC. Chest compressions (Circulation) start first because the heart has stopped pumping blood.

Urgent vs. Important

Life-Threatening
Will harm or kill quickly. Examples: blocked airway, no breathing, heavy bleeding. Do first.
Important but Stable
Needs care, but the patient is safe for now. Examples: pain, a small wound, anxiety. Do after ABCs.

How to Apply It

1
Check Airway. Is it open and clear? Listen and look for air movement.
2
Check Breathing. Is the patient breathing well, with good oxygen?
3
Check Circulation. Is there a pulse? Any major bleeding?
4
Act on the first problem found. Fix it before moving down the list.

Example 1: Two Patients

You have two patients. Who do you see first?

Patient A
Making a high-pitched gurgling sound and turning blue. Airway problem.
Patient B
Complaining loudly of leg pain after a fall. Breathing normally.

Example 2: Pick the Priority

Four patients arrive at once. Rank them using the ABCs:

1
Choking, cannot speak. Airway blocked — top priority.
2
Severe asthma attack, gasping. Breathing failing — second.
3
Bleeding heavily from arm. Circulation threatened — third.
4
Sprained ankle, walking. Stable — last.

Example 3: No Pulse

A patient collapses and you find no pulse and no breathing. What comes first?

The urgency rule flips because the heart has stopped. We need to move blood right away:

$$ U(\text{Circulation}) > U(\text{Airway}) > U(\text{Breathing}) $$

Common Mistakes

✕ Treating Noise First
A loud, complaining patient is not always the sickest. Quiet can mean a failing airway.
✕ Skipping Steps
Don't jump to circulation before confirming airway and breathing are okay.
✕ Forgetting CAB
In cardiac arrest, compressions come first — not the airway.

Quick Summary

Check If It Fails
A — Airway Is the airway open? Death in minutes
B — Breathing Is air moving in/out? Death from low oxygen
C — Circulation Pulse and bleeding? Death from blood loss

Question 1 of 5

In the ABCs, which problem must a nurse address first?

Question 2 of 5

Which patient should the nurse see first?

Question 3 of 5

For a patient in cardiac arrest with no pulse, what does CPR address first?

Question 4 of 5

A patient is breathing normally but bleeding heavily from a cut. Which letter of the ABCs is the problem?

Question 5 of 5

Why is a quiet patient sometimes a higher priority than a loud one?

Putting It Together

1
Always work top to bottom: Airway, then Breathing, then Circulation.
2
Fix the most life-threatening problem first, not the loudest one.
3
Switch to CAB when there is no pulse (cardiac arrest).

You've Got the Priorities

Remember A → B → C — and C → A → B for cardiac arrest. Treat the threat that kills soonest, first.