Cardiac arrest: life-saving steps and chain of survival

A person in cardiac arrest collapses suddenly, stops responding, and does not react to speech or touch. Breathing stops or is reduced to gasping, noisy and irregular breaths that should not be mistaken for normal breathing. This sign still misleads many bystanders, who hesitate before acting even though every second counts.

Faced with these signs, check for a response by shaking the shoulders and speaking loudly, then watch the chest for a few seconds. If the person does not move and is not breathing normally, the chain of survival must start without delay, without checking for a pulse or waiting for medical confirmation.

In France the emergency numbers 15 or 112 should be dialled as soon as cardiac arrest is confirmed, ideally on speakerphone to keep both hands free. A precise address, a visible landmark and the number of people present help the dispatcher direct rescuers quickly and guide the bystander step by step until they arrive.

If several people are present, one calls for help while another starts compressions and a third fetches the nearest DAE, often marked by a green and white sign at the entrance of buildings. Alone with the situation, compress first and call in parallel, never interrupting compressions for more than a few seconds.

Chest compressions are performed at the centre of the chest, the heel of one hand on the sternum, the other hand on top, arms straight. The rate should be between 100 and 120 compressions per minute, with a depth of 5 to 6 centimetres, letting the chest rise fully between each compression so the heart can refill.

Compressions must continue without interruption until the DAE arrives or professional rescuers take over. Fatigue quickly reduces the quality of compressions: when several bystanders are present, switching every two minutes keeps the pressure steady and effective.

A DAE is designed to be used by anyone, without prior training. Once switched on, the device guides every step out loud: baring the chest, attaching the pads where the diagrams show, then letting the device analyse the heart rhythm.

The device only delivers a shock if the heart rhythm requires it: there is no risk in applying it to someone whose heart is beating normally. During analysis and the shock, no one should touch the victim, and as soon as the device allows it, compressions resume immediately.

These actions follow a precise sequence, summed up by first responders as four inseparable links. A weak or missing link greatly reduces the chances of survival, even if the others are carried out perfectly.

Many people think training is required to touch a DAE, or fear doing something wrong. The device is precisely designed for a non-medical public and refuses to deliver a shock unless it is necessary. Waiting for rescuers without acting, out of fear of getting it wrong, is the real risk.

Another misconception: chest compressions might break ribs, so it is better not to try. Rib fractures are possible, but they heal. The absence of compressions, on the other hand, deprives the brain of oxygen in an irreversible way within minutes. Compressing always remains preferable to doing nothing.

First aid training, such as public awareness sessions or the SST (the French workplace first-aid certificate), turns these steps into reflexes. A few hours are enough to practise on a manikin, compress at the right rate and handle a training DAE, without the pressure of a real situation.

In a company, a school or a sports club, it is better to train several people rather than just one, and to renew the training every two to three years to keep the actions accurate. A place where several bystanders know how to react significantly increases the chances of survival in the event of cardiac arrest.