Cardiac arrest can happen anywhere: on the ward, in the car park, at church, at home. For every minute without CPR and defibrillation, the chance of survival falls. Every nurse is expected to start basic life support (BLS) immediately and well. This guide summarises the adult sequence based on international resuscitation guidelines. It is not a substitute for a hands-on course, which every nurse should complete and renew regularly.
The chain of survival
- Early recognition and call for help.
- Early CPR.
- Early defibrillation.
- Advanced life support and post-resuscitation care.
The adult BLS sequence
1. Make sure it is safe
Check for danger to yourself and others: traffic, electricity, fire, sharps. In hospital, put on gloves if immediately available, but do not delay.
2. Check for a response
Gently shake the shoulders and ask loudly, “Are you all right?”
3. Open the airway and check breathing
Use the head tilt, chin lift. Look, listen and feel for normal breathing for no more than 10 seconds. Trained healthcare staff may check for a carotid pulse at the same time. Agonal breathing (occasional, slow, noisy gasps) is common in the first minutes of cardiac arrest and is not normal breathing. If in doubt, act as if it is cardiac arrest.
4. Call for help
In hospital, shout for help, press the emergency buzzer and call the resuscitation team using your emergency number. Ask someone to bring the defibrillator (AED) and resuscitation trolley. Outside hospital, call the emergency services (use speakerphone so you can keep going).
5. Start chest compressions
- Place the heel of one hand on the centre of the chest (lower half of the breastbone), the other hand on top, fingers interlocked.
- Arms straight, shoulders above your hands.
- Compress to a depth of 5–6 cm.
- At a rate of 100–120 compressions per minute.
- Allow full recoil after each compression; don’t lean on the chest.
- Minimise interruptions.
- In hospital, lower the bed, use the CPR function on the mattress if it has one, and use a backboard according to policy.
6. Give rescue breaths: 30 compressions to 2 breaths
In hospital, use a pocket mask or bag-valve-mask with oxygen as soon as it is available. Each breath should take about one second and make the chest rise visibly. If you are unable or unwilling to give breaths, continue compression-only CPR.
7. Use the AED as soon as it arrives
- Switch it on and follow the voice prompts.
- Attach the pads to the bare chest: one below the right collarbone, one on the left side below the armpit. Dry the chest or shave excessive hair if needed.
- Continue compressions while the pads are applied.
- When the AED analyses, stand clear. If a shock is advised, make sure no one is touching the patient and deliver it.
- Restart compressions immediately after the shock, without checking for a pulse, and follow prompts.
8. Keep going
Continue until the resuscitation team takes over, the patient shows signs of life (waking, moving, opening eyes, breathing normally), or you are too exhausted to continue. Swap compressors every 2 minutes to maintain quality.
When the team arrives
Give a brief handover: what happened, when the arrest was recognised, how long CPR has been going, any shocks given, and relevant history. The team will continue with advanced life support (rhythm analysis, adrenaline, airway management, finding reversible causes). Nurses often continue to do compressions, record timings, prepare drugs and support relatives.
Common mistakes
- Delaying CPR to look for a pulse for too long, or mistaking gasping for breathing.
- Compressions too shallow or too fast; leaning on the chest.
- Long pauses to give breaths, check pulse or move the patient.
- Not swapping compressors, so quality fades.
- Waiting for the doctor before attaching the AED.
Special situations (brief)
- Pregnancy (from about 20 weeks): manually displace the uterus to the left to relieve pressure on the major blood vessels.
- Choking: encourage coughing; if ineffective, give up to 5 back blows then up to 5 abdominal thrusts, repeating. If the person becomes unresponsive, start CPR.
- Children and infants follow paediatric BLS, which starts with 5 rescue breaths because arrests are usually caused by breathing problems.
- Do Not Attempt CPR (DNACPR) decisions: check for a valid decision in hospital, but if unsure, start CPR.
After the event
Document clearly (time of collapse, time CPR started, shocks, drugs, outcome). Take part in a debrief. Cardiac arrests are stressful even when the outcome is good. Check the resuscitation trolley is restocked.
Related: NEWS2 and recognising deterioration · Newborn resuscitation · Anaphylaxis
Based on European Resuscitation Council, Resuscitation Council UK and American Heart Association guidelines. Not a substitute for certified hands-on training.