1.7 Levels of EMS care providers 

The basis of emergency medical assistance is the "chain of rescue" which is based on the collaboration of different actors. The most advanced cares can only be performed by Physicians and surgeons but the acute event often happens outside the hospitals (prehospital cares): at home, in the street, at work, in a public building… 

Actors involved are: 

• The first witness of the event/first responder, who will call for help and possibly provide first Aid 
• The Dispatch center service/call center that will receive the call and provide advice, and decide the action required ;( dispatch ambulance from the nearest ambulance station, consider dissemination of the incident information to other stakeholders such as: fire, rescue, police, security …) 
• Ambulance crew who will start the ABC life saving care and the person is in a safe environment; 
• Ambulance that will take the casualty from its location to health institution 

The EMS care at scene can be basic life support care which didn‘t involve invasive care or Advanced life support care which involves invasive cares depending on qualification of teams