Your patient’s call light isn’t going off, but when you walk in the room, they are slumped over and unresponsive. Panic tries to set in, but your training kicks in. You immediately check A.B.C. to decide what happens next. This simple framework is the difference between chaos and a controlled life-saving response.
What is A.B.C.?
A.B.C. stands for Airway, Breathing, and Circulation. It is the standard mnemonic used to assess and treat a patient in life-threatening situations. This framework ensures you address the most critical physiological needs first: is the path for oxygen clear, is oxygen entering the lungs, and is it being pumped to the vital organs?
Why A.B.C. Matters in Nursing Practice
This is the ultimate prioritization tool. In a crisis, seconds matter. Without a patent Airway, Breathing is impossible. Without Breathing, Circulation fails. By systematically following A.B.C., you ensure that life-preserving interventions happen before you worry about broken bones, IV access, or blood glucose. It guides everything from emergency response to the daily assessment of unstable patients, forming the basis of the primary survey.
What You’ll See at the Bedside
You will utilize this sequence whenever a patient is deteriorating or found unresponsive. You are looking for obstructions in the mouth, listening for breath sounds, and feeling for a central pulse.
“Mr. Davis was unresponsive when I entered the room. I opened his Airway with a head-tilt chin-lift, but he wasn’t Breathing on his own, so I started bag-mask ventilation while my partner checked Circulation—no pulse, so we immediately began compressions.”
Common Pitfall & Pro Tip
⚠️ Pitfall: Fixating on the wrong problem first. Don’t check a blood pressure on a patient who isn’t breathing. If the oxygen isn’t getting in, the pressure reading is irrelevant to their immediate survival.
đź’ˇ Pro Tip: In CPR, the sequence changed to C-A-B to minimize delays, but for general assessment of a conscious or semi-conscious patient, A-B-C is still your roadmap. Always ask yourself: “Is the airway open?” before you move on to anything else.
Memory Aid for A.B.C.
Think of it as a chain with three unbreakable links. If the first link (Airway) is broken, the second and third links cannot function. You must fix the link at the very top to support the links below it. If you can’t breathe, nothing else matters.
NCLEX Connection
Expect many prioritization questions where you must choose between patients or actions. The correct answer is almost always the one that secures the patient’s Airway or Breathing first. NCLEX wants to know you understand the hierarchy of physiological needs.
Related Nursing Concepts
This foundational concept links directly to the CAB sequence for starting CPR, basic life support (BLS), and triage protocols in the ER. It also connects to oxygenation and perfusion as the ultimate goals of the intervention. If a patient has a compromised airway, they are also at high risk for hypoxia and cardiac arrest.
Quick Reference
âś“ Priority level: Critical
âś“ A: Airway – Open it (head-tilt, jaw thrust, suction)
âś“ B: Breathing – Confirm it (look, listen, feel; provide O2 or ventilation)
âś“ C: Circulation – Assess it (palpate pulse, check BP, control hemorrhage; start compressions if pulseless)
- Always assess before intervening
- Reassess after every intervention
Bottom line: A.B.C. is the blueprint for saving lives. Master it, and you master the first moments of any emergency.