What Are the Adult BLS Steps?
When an adult suddenly collapses, the first few moments can feel chaotic. A clear Basic Life Support sequence helps responders focus on what matters most – recognising cardiac arrest quickly, starting CPR without delay, and using an AED as soon as possible.
Adult BLS, or Basic Life Support, is the immediate response given to someone who is unresponsive and not breathing normally. The aim is to maintain circulation and oxygen delivery until emergency services or a resuscitation team can take over.
Step 1 Check the area is safe
Before approaching the casualty, make sure there is no immediate danger to you, the patient or other people nearby. Hazards may include traffic, electrical equipment, sharp instruments, fluids or confined working spaces.
Once the area is safe, approach the person and assess their condition.
Step 2 Check for a response
Speak clearly and ask the person if they can hear you. Gently shake their shoulders if appropriate.
If there is no response:
- shout for help
- ask someone to call 999
- ask for an AED if one is available
In healthcare or dental settings, this may involve activating the emergency response system and bringing emergency equipment to the scene.
Step 3 Open the airway
Use the head tilt and chin lift technique to open the airway unless there is a clear reason not to.
This helps move the tongue away from the back of the throat and allows you to assess breathing more effectively.
Step 4 Check for normal breathing
Look, listen and feel for normal breathing for up to 10 seconds.
Occasional gasping or irregular breaths should not be treated as normal breathing. Agonal breathing can happen during cardiac arrest and should not delay CPR.
If the person is not breathing normally, move quickly to the next step.
Step 5 Call for emergency help and get an AED
If you are alone, call 999 immediately and put the phone on speaker where possible.
If other people are present:
- one person should call emergency services
- another should bring the AED
- another can prepare to assist with CPR
Early defibrillation can significantly improve survival in some cardiac arrest rhythms, so the AED should be brought to the patient as quickly as possible.
Step 6 Start CPR
Begin chest compressions in the centre of the chest.
Current adult BLS guidance uses:
- 30 chest compressions
- followed by 2 rescue breaths
Compressions should be delivered at the correct depth and rate, allowing full chest recoil between each compression.
If rescue breaths cannot be given, chest compressions alone are still far better than doing nothing.
Step 7 Use the AED as soon as it arrives
Switch the AED on immediately and follow the voice prompts.
Attach the pads as shown on the diagrams and continue CPR with as little interruption as possible. The AED will analyse the heart rhythm and advise whether a shock is needed.
Modern AEDs are designed to guide the responder step by step, which is why familiarity and hands-on practice can make such a difference during a real emergency.
Common mistakes during adult BLS
Most problems during BLS come from hesitation or interruptions rather than dramatic errors.
Common issues include:
- taking too long to check breathing
- stopping compressions too often
- shallow chest compressions
- delaying AED use
- uncertainty over team roles
Regular practical training helps reduce these delays and improves confidence under pressure.
Why practical BLS training matters
Reading the adult BLS sequence is useful, but performing it in a real emergency feels very different. Stress, noise and uncertainty can all affect how people respond.
Hands-on training allows learners to:
- practise CPR technique properly
- use an AED safely
- rehearse emergency communication
- work through realistic scenarios
- become more confident with the sequence
For workplaces, healthcare teams and dental practices, practising together can also improve coordination during an emergency response.
Adult BLS in real settings
The core BLS steps remain consistent, but the environment can change the practical response.
In a dental setting, staff may need to manage a patient in a treatment chair before starting CPR. In workplaces, responders may need to direct bystanders while waiting for emergency services. In healthcare and care environments, responders may have access to oxygen, airway equipment or additional clinical support.
That is why role-specific BLS training is often more valuable than purely theoretical teaching.
Understanding the Adult BLS Sequence
The adult BLS sequence is designed to make emergency response more structured and more manageable under pressure. Check safety, assess response, open the airway, check breathing, call for help, begin CPR and use the AED as soon as possible.
The steps themselves are straightforward. The challenge is carrying them out calmly and quickly when somebody urgently needs help. Practical training helps turn those steps into a response people can rely on in a real emergency.