## 1 Introduction  
A mass casualty incident (MCI) is the situation where a great number of people have been injured after an accident or sudden disease. Most often MCIs are traffic accidents, construction building accidents, fires, floods, etc. or epidemics of infectious diseases or mass poisoning [1] and chemical incidents [2]. The reason for the MCI can also be certain people's behavior, e.g., a panic during mass events or terrorist attacks [3]. The main feature of MCIs is the randomness of their location and time. Initially, consideration was given to how to prevent mass casualty incidents, but due to the randomness of the time and place of their occurrence, attention was focused on the response phase, i.e., on improving rescue operations. In mass casualty incidents, the organization and management of medical assistance are of paramount importance, and rescue procedures differ from those applicable to ordinary or multiple incidents. The Provincial Emergency System (PES), in whose area of responsibility the incident occurred due to limited resources, is usually unable to meet the service needs of injured persons. They cannot be provided with medical care to the desired extent as in the case of single or multiple incidents. Once the MCI has occurred, forces and resources are separated from the PES to immediately deal with the consequences, forming a Directed EmergencySystem (DES). If the number and/or quality of resources of the PES specific to the incident prove insufficient, then it is necessary to support with forces and resources from another, usually neighboring province. Survival and avoiding extensive disability of the injured in the MCI depend on the efficiency and quality of the DES. In emergency medicine, many approaches have been developed over the years to organize rescue operations to deal with the consequences of MCIs [4]. One of the most widely used is the Anglo-American model, which is also used in Poland. Its characteristic feature is the approach to medical handling of persons injured in the MCI and minimizing the time needed to initiate emergency treatment of victims in Hospital Emergency Departments (EDs). At the scene of an incident, the initial segregation of victims (triage) is carried out upon arrival of the emergency services. Many triage systems for rescue operations have been developed [5]. In Poland, the START (simple triage and rapid treatment--meaning \"simple segregation and rapid treatment\") segregation system is used. All pre-segregation systems have a common denominator--as a result of their implementation, victims of the MCI are assigned to one of the available clinical-transport priority groups, marked with a specific color. Prehospital emergency [6] measures are based on the principle of the so-called survival chain. According to this standard, emergency medical activities should be introduced after approximately 8-10 min. The injured should be transported to the Emergency Department (ED) no later than 30 min after the incident is reported. In emergency medicine, the golden hour rule applies, after which the probability of survival of the injured persons is usually negligible. When selecting an ED for a given casualty, consideration should be given to those that the selected ED has the necessary medical resources at the time of delivery. The assessment of the health status of victims should be repeated periodically as a part of the so-called secondary medical segregation. It is performed by the most competent personnel in emergency medicine (paramedics and medics). The examination is then carried out in more detail based on a selected injury severity scale. In Poland, the Triage Revised Trauma Score (TRTS) system is used in medical segregation, whereby the severity of Trauma of the victim is determined by assessing the state of consciousness, systolic blood pressure and respiratory rate. In current practice, the recording of the injured person's condition at the scene is done using paper segregation sheets [7].