OHCA stands for out-of-hospital cardiac arrest, the emergency where fast bystander action can matter enormously.
Source check: 8 August 2026 · How this page is checked · Report a correction
Quick answer
OHCA: O means Out-of; H means Hospital; C means Cardiac; A means Arrest. OHCA stands for out-of-hospital cardiac arrest, the emergency where fast bystander action can matter enormously.
When OHCA helps
Use OHCA when reading about cardiac arrest statistics, AED programs, community response and why early CPR matters. In the moment, the action language is simpler: DRSABCD, call 000, start CPR and use an AED.
Safety boundary: A remembered sequence must never delay CPR, defibrillation or a Triple Zero (000) call. If a real incident is unfolding, act on the person’s condition, call Triple Zero (000) when it is an emergency and follow the operator’s instructions.
Where it sits: OHCA is commonly read alongside SCA, AED, PAD, CPR, but each term has a different job. The comparisons later on this page explain those boundaries.
What Does OHCA Stand For?
| O | Out-of The arrest has happened away from a hospital setting. |
| H | Hospital Hospital-level care is not yet at the person’s side. |
| C | Cardiac The emergency involves the heart’s ability to pump effectively. |
| A | Arrest The person is unresponsive and not breathing normally. |
Common Mistakes
- Do not wait for someone else to decide it is cardiac arrest if the person is unresponsive and not breathing normally.
- Do not assume gasping means normal breathing.
- Do not leave an AED on the wall because nobody feels like the expert.
OHCA Step-By-Step For Beginners
Use this detailed sequence when learning how OHCA applies to cardiac arrest outside hospital, bystander CPR and public AED response. It connects the letters to observable checks, clear words and a useful handover rather than treating the acronym as a bare list.
- Know what OHCA means. OHCA means out‑of‑hospital cardiac arrest: the person’s heart has stopped (or is not pumping effectively) outside a hospital setting.
- Act on what you can check. You cannot confirm the rhythm as a first aider. If they are unresponsive and not breathing normally, treat it as cardiac arrest.
- Call Triple Zero (000) and send for an AED. Call Triple Zero (000) and ask for an ambulance. Put the phone on speaker. If others are present, send someone for the nearest AED.
- Start CPR immediately. Begin chest compressions hard and fast in the centre of the chest. Keep pauses short.
- Use the AED early. Turn it on, attach pads as shown, stand clear when prompted, and go straight back to CPR after each analysis/shock message.
- Prepare for handover. Share what happened, when they collapsed (if known), when CPR started, and whether any shocks were delivered.
A Real-World OHCA Scenario
The scene: A person collapses outside a train station, away from hospital equipment and clinical staff.
In this OHCA scene, begin with O for Out-of: The arrest has happened away from a hospital setting. That opening prompt matters here because Use OHCA when reading about cardiac arrest statistics, AED programs, community response and why early CPR matters. In the moment, the action language is simpler: DRSABCD, call 000, start CPR and use an AED. Keep the observation tied to cardiac arrest outside hospital, bystander CPR and public AED response; in practice, watch response, airway and whether breathing is normal while emergency help and an AED are organised rather than reciting the letters without checking the person or setting.
For OHCA, A closes the pattern as Arrest. The person is unresponsive and not breathing normally. Before the sequence is treated as complete, relate it to when the collapse happened, what breathing looked like, when CPR started and whether an AED analysed or shocked. A specific trap to avoid is: Do not leave an AED on the wall because nobody feels like the expert.
Where the scenario could change: Do not wait for someone else to decide it is cardiac arrest if the person is unresponsive and not breathing normally. A remembered sequence must never delay CPR, defibrillation or a Triple Zero (000) call. If the facts no longer fit a stable OHCA example, stop rehearsing the acronym and move to the safer emergency, clinical or workplace pathway.
OHCA and similar terms
Out-of-hospital cardiac arrest. It names where the cardiac arrest happened, rather than a different kind of CPR.
Here is how the related terms differ:
- SCA: Sudden cardiac arrest, when the heart suddenly stops pumping effectively. It is different from a heart attack, although a heart attack can lead to cardiac arrest.
- AED: An automated external defibrillator: a device that checks the heart rhythm and gives spoken instructions. CPR is the hands-on care; the AED is the device used alongside it.
- PAD: Public access defibrillation: making AEDs available in places such as workplaces and sports grounds. It describes access to equipment.
- CPR: Cardiopulmonary resuscitation: chest compressions and rescue breaths used when someone is unresponsive and not breathing normally. It is one part of the wider DRSABCD response.
Frequently asked questions
What does OHCA stand for?
O means Out-of; H means Hospital; C means Cardiac; A means Arrest. OHCA stands for out-of-hospital cardiac arrest, the emergency where fast bystander action can matter enormously.
When is OHCA useful?
Use OHCA when reading about cardiac arrest statistics, AED programs, community response and why early CPR matters. In the moment, the action language is simpler: DRSABCD, call 000, start CPR and use an AED.
Is OHCA always sudden?
Often it is sudden, but your response is the same: call Triple Zero (000), start CPR, and use an AED early.
Should I move them to a bed or couch?
No. Keep them where you can do CPR effectively (usually on the floor). Only move if the scene is unsafe.
Do I give water or food while waiting?
No. Do not give food or drink in a cardiac arrest response.
How is OHCA different from SCA?
OHCA is framed here around cardiac arrest outside hospital, bystander CPR and public AED response. SCA is framed around cardiac arrest recognition, bystander CPR and AED action. They may appear in the same course or incident, but they answer different questions and should not be treated as interchangeable.
When should I call Triple Zero (000)?
Call Triple Zero (000) when the person is seriously ill or injured, is deteriorating, or the urgent warning signs described on this page are present. A remembered sequence must never delay CPR, defibrillation or a Triple Zero (000) call.
Related Acronyms
This guide is educational and does not replace accredited first aid training, professional medical advice, or directions from emergency services.
