When the heart stops, every minute without help reduces the chances of survival. Basic life support (BLS) is the set of simple actions that keeps blood circulating until specialist help arrives. This lesson explains the sequence in theory. Learning the actions needs practice with an instructor and a manikin.
The chain of survival
Cardiac arrest has a chain of actions that reinforce one another:
- recognise the situation and call for help (112);
- start chest compressions early;
- use the defibrillator (AED) as soon as possible;
- continue with the specialist care of the INEM and the hospital.
The people on the scene carry out the first three actions. That is why the action of bystanders is decisive.
The sequence
1. Safety. Check that the place is safe for the rescuer and the casualty.
2. Check whether the person responds. Gently shake the shoulders and ask loudly: "Are you all right? Can you hear me?".
3. If they do not respond, check whether they are breathing normally. Look, listen and feel (LLF, in Portuguese VOS) for chest movement and air at the mouth. Rare, noisy breathing, like snoring or gasping, is not normal breathing: it can be a sign of cardiac arrest. This step should not take long.
4. If they are not breathing normally, call 112 or send someone to call. Use the speaker. Also ask for the AED, if there is one on site.
5. Lay the person on their back on a firm surface and start chest compressions.
How to do compressions
- Place the heel of one hand on the centre of the chest, with the other hand on top and the fingers interlocked.
- Keep your arms straight, vertical above the chest.
- Press down about 5 cm, without going beyond 6 cm in adults, and let the chest return fully to its starting position.
- Keep a rate of 100 to 120 compressions per minute.
- Interrupt as little as possible.
It is tiring effort. When more people are present, it helps to swap every two minutes, or sooner if needed, with the shortest possible pause.
Rescue breaths
Anyone who knows how and is willing alternates 30 compressions with 2 rescue breaths. To give a breath, open the airway, pinch the nose, seal your mouth over the casualty's mouth and blow until the chest rises, for about one second. Pocket masks exist to protect the rescuer.
Anyone who does not know how, is unwilling or is unable to give breaths should do compressions only, without stopping. Compressions without breaths are much better than doing nothing.
For how long
Continue until:
- help arrives and takes over;
- the person reacts: opens their eyes, moves, breathes normally;
- the rescuer is exhausted and cannot continue;
- an AED is ready to use (covered next, in a lesson of its own).
Special situations
- Children and babies. The sequence differs: you normally begin with five rescue breaths, and compressions use a technique and depth adapted to the size of the child or baby. So anyone who works with children needs training of their own.
- Fear of causing harm. The fear of breaking a rib or being sued stops many people from acting. Ribs can break, and that is less serious than not giving compressions to someone in cardiac arrest.
- Infection. The risk of catching an illness from this action is very low. If you are worried, do compressions only.
What this is not
This lesson does not teach you to do BLS. To know how, you need a practical course. BLS courses have a limited validity and should be repeated.