Discussion

A standardized concept of MCI is still lacking 7 years after the publication of the last study which analyzed the MCI of a specific region of Spain. Efforts have been made in order to centralize the data collected for every MCI, as a result it was possible to gather the MCI’s information of 5 different autonomous communities in Spain, looking forward to scale-up the system to the entire country.

During this period de incidence rate of MCI was 0.36 per 100000 inhabitants per year. Compared with other studies, Helsinki (Finland) reported 1.8/100000, Western Cape Province (South Africa) registered 13.1/100000, ^{Reference Kuisma, Hiltunen and Määttä15,Reference van Hoving, Lategan and Wallis16} but these numbers are influenced by the definition criteria used for MCI by each research author. In addition, we could expect an existing relation between the emergency infrastructure and the specific conditions (social, environmental, structural) of each region studied.

The most common type of MCIs were those related to motor vehicles on roads (79.8%); they lead the list in USA (62.7%), South Korea (75.7%) and Western Cape (94.0%). In contrast, the second most frequent type of MCI was different; in USA it was catalogued as ‘Other’ which included water transport crashes, smoke inhalation, etc., (10.3%), South Korea registered industrial incident as a second cause of MCI (10.4%), residential fire occupied the second place in Helsinki (Finland) (15.2%), and chemical incidents in Western Cape (South Africa) (1.5%). ^{Reference Kuisma, Hiltunen and Määttä15–Reference Schenk, Wijetunge and Mann18} It is important to note that traffic accidents are by far the most frequent type MCI, more than any other. This is an issue of special concern of public health, as we will see when we discuss the mortality rate of each type of MCI. This is an important aspect to bear in mind when stablishing specific training programs, which should focus on the epidemiology of MCI in each region, and to decide the appropriate material and their allocation, to improve preparation and response to MCI. Also, results coming from analyzing MCI can help to validate previous risk assessment studies, most of them based on hypothesis which need to be confirmed thanks to MCI and disasters databases.

Most MCI were concentrated in the afternoon, between 14:00 and 20:00 hours. Given that traffic accidents are the leading cause of MCIs, it is expected to find more accidents when the roads are busy. In comparison to other studies, it was found that the same pattern occurred in USA which recorded 38.1% of the MCIs between 15:00 and 21:00. ^{Reference Kim, Kim and Shin17} Meanwhile, in Western Cape (South Africa) there were 2 hourly peaks of MCIs observed from 04:00 to 08:00 and 16:00 to 20:00, both periods accumulated 39.3% of the MCIs. ^{Reference Kuisma, Hiltunen and Määttä15}

The distribution of patients according to their triage categorization varied. Traffic accidents caused 64% minor injured victims (green) and had a lethality of 2% (black). Residential fires had mostly minor injured outcomes (80%) and only 1 death (which represents 0.3%). In comparison, nautical incidents were related to a high lethality of 40%, probably related to the difficult of emergency response, which will be discussed below. In Western Cape (South Africa) most patients were also catalogued as minor injured (54.6%) and the percentage of deaths was 4.4%. ^{Reference Kuisma, Hiltunen and Määttä15} Analyzing severity of patients according to each type of MCI may help us to decide resources activation, as many mild patients may have an impact on transport logistics, but more severe patients have an impact on prehospital medical care and evacuation. Establishing the MCI profile of specific regions is an important aspect to be part of the risk analysis stages.

The average response for road traffic incidents was 31.32 minutes, the response in residential fires was 26.36 minutes and sea-related accidents had the higher time of response of 37.75 (P < 0,05), probably related to the difficult accessibility of emergency units to the event. In Helsinki (Finland), the average response to traffic incidents was 7.6 minutes, and residential fires were reached in 9.7 minutes. ¹⁴ It is important to note that the territory evaluated in this study covers a large area with low population density, therefore the emergency system must cover a bigger area, compared to an urban area, with high population density like Helsinki. ^{Reference Park, Shin and Song11}

It is important to note that the different definitions used for MCI could limit the approach to a standardized MCI data collection. The actual concept proposed by WHO is more likely to reflect the lack of a well-established emergency response systems, but it doesn’t assess the severity of the MCI. ¹ A motor vehicle accident in a rural area will be catalogued as MCI if there are not enough emergency units, but in an urban area with the same amount of victims and enough emergency units it won’t be catalogued as an MCI. If we analyze the consequences of this concept, low-income countries will tend to have more MCIs than high income countries, just because of the emergency infrastructure. These discrepancies could give a bias even though the same number of incidences happen in different regions.

As a conclusion, road traffic accidents are the most frequent MCI, followed by fires or explosions. Minor injuries predominate, with high rescue medicalization needs in traffic accidents. More than half of MCI have 5 or less patients. Fires had significantly more minor-injured patients but had a significantly greater number of units deployed, and sea-related incidents had significantly more fatal victims. MCI are more frequent in January, July, on Sundays, and during afternoon and night periods. Sea-related incidences had a minor significant incident duration, and intoxications, fires and others had a significant longer duration. Analyzing MCI allows us to improve our knowledge and have more data to plan according to MCI profiles.