Scientific Framework for Research on Disaster and Mass Casualty Incident in Korea: Building Consensus Using Delphi Method

Disaster is generally defined as an event that demands more resources than the community can provide in natural or man-made incidents (1). In Korea, according to the Act No. 7188 (March 11, 2004) the framework act on the management of disaster and safety, disaster is defined as a natural event (e.g. a typhoon, a flood, etc.), a technical event (e.g. a fire, a collapse, an explosion, etc.), and any events which can damage the life, the health, and the property of the people (2). In medical concerns, disaster can be defined as an event that requires excess medical resources than the local health system can afford such as Mass Casualty Incident (MCI) (3, 4).

Disasters and MCIs occur more frequently in various types, such as pandemic diseases, traffic accidents, industrial accidents, terrors, mass gatherings, and natural catastrophes due to outbreaks of new infectious diseases, the evolution of mass transportations and the global climate changes (5). According to the report by the Centre for Research on the Epidemiology of Disasters (CRED), the number of natural disasters multiplied at least 10 times from 1900 to 2000. When disasters and MCIs are not properly prepared, these can cause high mortality and failure rate, although we are spending the whole medical resources of the local community in short or long term period. In addition, disaster and the MCI impact on such a broad population in the community so that they cannot be managed without supports from outside (6-8). Thus the epidemiologic approach for the public health concerns is mandatory by recognition of the impact on the population, verification of the risk factor of the population, and allocation of the medical resources for the response to disasters and MCI.

Despite of the necessity of the epidemiologic research, little research has been conducted since there is no international standardized definition of the disaster and MCI (9). Moreover, the reality is that the epidemiologic approach has been very difficult because of the lack of a standardized epidemiologic index for the national or international data collection. Although there are some research for disaster and MCI, those were dealt with just each single case.

Therefore, we aimed to determine the Korean terminology, definition and classification, and useful indicators of disasters and MCIs for measuring the epidemiologic outcomes using the Delphi method.

Characteristics of respondents of the first-stage survey and the second-stage survey were summarized in Table 1. Most of them were physicians. Among them three or four respondents had an experience of research on disaster or MCI and 6 had period an experience of disaster or MCI education for 1-6 yr.

Table 1
Characteristics of respondents for Delphi survey for building scientific framework for research on disaster and MCI in Korea

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There was a consensus among respondents about the terminology in Korean for disaster and MCI in the first-stage Delphi survey. Respondents agreed that "jaenan" (90% agreement) and "dajung sonsang sago" (80%, 80%, and 90% agreement, respectively) is proper the Korean terminology for disaster and MCI (Table 2).

For the definition of disaster, respondents made a consensus for the size of affected area (Table 3) upon more than one municipal area (city, county and district) (100% agreement) but did not make an agreement for the number of involved victims (Table 4) in the first-stage survey. For the definition of MCI, respondents did not make an agreement for both the size of affected area (Table 3) and the number of involved victims (Table 4) except 'no matter with minimum number of hospital patients visited' (70% agreement) and 'no matter with the minimum number of patients transported by the ambulance and/or helicopter' (70% agreement) in the first-stage survey. In the second-stage survey, there was a consensus about the definition of disaster and MCI based on the number of victims. They made a consensus that to define a disaster an event should have a death (85.7% agreement) or injured (97.1% agreement) and the minimum number of victims is 10 in death or 50 in injured. Moreover, they made a consensus that to define an MCI an event should have any injured (100% agreement) and the minimum number of victims is 6 in injured (Table 5).

Table 3
Items and results of the first-stage survey for definition of disaster and MCI by the size of affected area^*

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Table 4
Items and results of the first-stage survey for definition of disaster & MCI by number of involved victims

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Table 5
Items and results of the second-stage survey for definition of disaster and MCI by number of involved victims

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In the first-stage survey, for epidemiologic indices respondents showed over 60% agreement on necessary for 17 among 24 health effects indices, 4 among 4 incidences of event indices and 4 among 11 resource usage indices in the second round survey (Table 6). Any indices were not agreed as an unessential item.

Whenever the new area of research was introduced to Korea, the language or translation into Korean might be a barrier to spread idea widely. Disaster is common in non-medical research area, for example social science or engineering, but is emerging subject in medical research. According to the literature review, the Korean terms for "disaster" and "mass casualty incident" are various and are not formally defined in the Korean medical dictionary or the Korean emergency medical dictionary. Since the enforcement of the provisions of the act on the management of disaster and safety, Korean term "jaenan" is mainly used for "disaster", which the agreement of experts in our study was the same as well, reflecting the statement of the law. In the aspect of MCI, even though respondents agreed to use "dajung sonsang sago", there is still controversy. As a matter fact, "dajung" that authors suggest means "crowds" or "a great number of people". However "dajung" that made by other Chinese means "multiple" so that there could be confused if "dajung sonsang sago" were used without additional Chinese characteristics. In other aspect "sonsang" means "injury" as well as "trauma". Therefore, "dajung sonsang sago" include a meaning of the wide range of event that result in trauma and all kinds of injury. We hope that the "dajung sonsang sago" takes root because language can have a power to survive by itself when many people use.

The agreement on the definition of disaster was the events that have minimum death 10 and/or minimum injured 50, reflecting the influence of the epidemiologic definition of international research institutes. Using this definition, researchers can be fallen a pitfall because if 9 deaths are occurring by a single event, this event is not disaster by this definition. Some experts also pointed this problem in the workshop or survey, however, many of the experts said that they understand the definition is not for a real response or preparedness but for research or surveillance of disaster and MCI. That is the reason why the definition of this study is different from the protocol of NEMA.

As to the definition of MCI, experts agreed in the event that results in 6 injured at least and the number of deaths are no matter to define MCI. That can be interpreted that the experts suggested if the minimum number casualties including death and injured is over 6, the event can be defined as MCI. In another aspect, based on the fact that 1,350 ambulances are operated by NEMA in 285 municipal government, prehospital medical resources in the most of a single municipal are limited to maximum 5 casualties simultaneously, thus more than 6 simultaneous casualties need to be supported prehospital medical resources from nearest local area (11). Therefore the definition of MCI suggested this survey is useful for research or surveillance as well as for an emergency response. If an event related with over 6 casualties is occurred, the local agency for MCI response has to operate an emergency response system till the situation is resolved.

Basically simple and clear indices are needed to express and explain an event and outcome of health properly. In disaster and MCI, it is not easy to show many indices because the data collection is very limited. Therefore important indices should be settled before the development a surveillance system or data collecting system for disaster and MCI. We try to decide the indices that are needed basically to study disaster or MCI based on the expert consensus. Some indices have been used in previous research for disaster or MCI (12, 13) and others have been used to show the general characteristics of trauma, for example severity using the Injury Severity Score. Resource usage indices are special for disaster and MCI because the recruitment and allocation of the resource are the key in emergency response. If prehospital agency can apply these indices retrospectively, they can estimate the amount of the resource by scale of event. That is very useful way to prepare future event because utilization and response of prehospital EMS is an important index for local disaster preparedness and influential to the prognosis of victims. In this way, the cooperation with the fire department is very important to build the data collection system and produced meaningful indices. Also, the hospital medical record survey should be included in the further survey and surveillance system of disasters and MCIs in order to calculate the severity of casualties as well as other medical related indices.

This study has several possible limitations. First, there could be limited to the selection and representation of experts. Recently disaster medicine has emerged in Korea and related not only to the emergency medicine, but also to multidiscipline. In reality, experts in various fields of disaster medicine are few. Therefore, experts in our study, most of whom are board certified emergency physician, are the instructor of NDLS® course, official disaster training course of the AMA. They are involved with the education, training and/or research on the disaster and MCI and their experience period ranges 1 to 6 yr. Further academic interchanges and co-works are mandatory in order to achieve the consensus among the disaster researchers in the various disciplines. Second, because items in this survey were determined based not on strict scientific evidences but on literature reviews and expert opinions, several problematic issues could be occurred in the development and the application of further surveillance system. This should be complemented by comparing the arrangement of database with international and national. In conclusion, experts could determine the scientific terminology in Korean and definition for research on disaster medicine considering the distinct characteristics of Korea and current research trends. The data collection system and research on patients who related to MCI and disaster should be constructed and standardized considering these definitions and indices.