How does it work?

First aid is the first and immediate assistance given to any person with either a minor or severe illness or injury, with care provided to preserve life, prevent the condition from worsening, or promote recovery until medical services arrive. Someone with basic medical training generally performs first aid. Mental health first aid is an extension of the concept of first aid to cover mental health, while psychological first aid is used as early treatment for people at risk for developing PTSD. Conflict First Aid focused on preserving and recovering an individual's social or relationship well-being, is being piloted in Canada.

Many situations may require first aid, and many countries have legislation, regulation, or guidance that specifies a minimum level of first aid provision in certain circumstances. This can include specific training or equipment available in the workplace (such as an automated external defibrillator), the provision of specialist first aid cover at public gatherings, or mandatory first aid training within schools. Generally, five steps are associated with first aid:

1. Could you assess the surrounding areas?

2. Move to a safe surroundings (if not already; for example, road accidents are unsafe to be dealt with on roads).

3. Call for help: professional medical help and people nearby who might help in first aid, such as cardiopulmonary resuscitation (CPR) compressions.

4. Please perform the first aid that depends on the injury caused by the casualty.

5. Evaluate the casualty for any fatal signs of danger or the possibility of performing first aid again.

https://en.wikipedia.org/wiki/First_aid

Les premiers secours représentent l'ensemble des techniques d'aide apportée aux personnes victimes d'un accident, d'une catastrophe, d'un problème de santé ou d'un problème social compromettant à court terme leur état de santé. Ces techniques permettent d'apporter des réponses efficaces devant un danger vital et ont comme objectif d'en minimiser les conséquences tout en assurant la survie des personnes en leur prodiguant des premiers soins d'urgence. Les premiers secours sont le maillon initial en amont de la chaîne des secours jusqu'à la prise en charge par des services d'urgence spécialisés. 

First aid is the first and immediate assistance given to any person with either a minor or severe illness or injury, with care provided to preserve life, prevent the condition from worsening, or promote recovery. It includes initial intervention in a serious condition before professional medical help is available, such as performing cardiopulmonary resuscitation (CPR) while waiting for an ambulance, and the complete treatment of minor conditions, such as applying a plaster to a cut. Someone with basic medical training generally performs first aid. Mental health first aid is an extension of the concept of first aid to cover mental health, while psychological first aid is used for the early treatment of people at risk for developing PTSD. Conflict First Aid, which focuses on preserving and recovering an individual's social or relationship well-being, is being piloted in Canada.

Many situations may require first aid, and many countries have legislation, regulation, or guidance which specifies a minimum level of first aid provision in certain circumstances. This can include specific training or equipment available in the workplace (such as an automated external defibrillator), the provision of specialist first aid cover at public gatherings, or mandatory first aid training within schools. First aid, however, does not require any particular equipment or prior knowledge and can involve improvisation with materials available at the time, often by untrained people.

Cardiopulmonary resuscitation

Cardiopulmonary resuscitation (CPR) is an emergency procedure consisting of chest compressions, often combined with artificial ventilation, to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is recommended for those unresponsive with no breathing or abnormal breathing, for example, agonal respirations.

CPR involves chest compressions for adults between 5 cm (2.0 in) and 6 cm (2.4 in) deep at a rate of at least 100 to 120 per minute. Chest compression to breathing ratios is set at 30 to 2 in adults. The rescuer may also provide artificial ventilation by exhaling air into the subject's mouth or nose (mouth-to-mouth resuscitation) or using a device that pushes air into the subject's lungs (mechanical ventilation). Current recommendations emphasize early and high-quality chest compressions over artificial ventilation; a simplified CPR method involving only chest compressions is recommended for untrained rescuers. With children, however, 2015 American Heart Association guidelines indicate that doing only compressions may result in worse outcomes because such problems in children commonly arise from respiratory issues rather than cardiac ones, given their young age.

CPR alone is unlikely to restart the heart. Its primary purpose is to restore the partial flow of oxygenated blood to the brain and heart. The objective is to delay tissue death and to extend the brief window of opportunity for a successful resuscitation without permanent brain damage. Administration of an electric shock to the subject's heart, termed defibrillation, is usually needed to restore a viable, or "perfusing," heart rhythm. Defibrillation is effective only for certain heart rhythms, namely ventricular fibrillation or pulseless ventricular tachycardia, rather than asystole or pulseless electrical activity, which usually requires the treatment of underlying conditions to restore cardiac function. Early shock, when appropriate, is recommended. CPR may succeed in inducing a heart rhythm that may be shockable. In general, CPR is continued until the person has a return of spontaneous circulation (ROSC) or is declared dead.

Automated external defibrillator

Defibrillation treats life-threatening cardiac dysrhythmias, specifically ventricular fibrillation (VF) and non-perfusing ventricular tachycardia (VT). A defibrillator delivers a dose of electric current (often called a counter-shock) to the heart. Although not fully understood, this process depolarizes a large amount of the heart muscle, ending dysrhythmia. Subsequently, the body's natural pacemaker in the heart's sinoatrial node can re-establish normal sinus rhythm. A defibrillator cannot restart a heart in asystole (flatline) but would be treated by cardiopulmonary resuscitation (CPR).

In contrast to defibrillation, synchronized electrical cardioversion is an electrical shock delivered synchrony with the cardiac cycle. Although the person may still be critically ill, cardioversion typically aims to end poorly perfusing cardiac dysrhythmias, such as supraventricular tachycardia.

Defibrillators can be external, transvenous, or implanted (implantable cardioverter-defibrillator), depending on the type of device used or needed. Some external units, known as automated external defibrillators (AEDs), automate the diagnosis of treatable rhythms, meaning that lay responders or bystanders can use them successfully with little or no training.

Source: https://en.wikipedia.org/wiki/First_aid