Medical issues in disasters

Introduction

Health emergency and disaster risk management, encompassing related terms such as emergency management and disaster management, involves a complex, multidisciplinary system of which emergency medicine comprises one component. Domestically, fire fighters, law enforcement, ambulance services, civil defence, State Emergency Services, Red Cross national society, defence forces and other aid organizations commonly play major roles. Internationally, governmental and nongovernmental organizations, International Federation of the Red Cross and Red Crescent Societies and United Nations agencies are frequently involved. The health and medical management of hazardous events, which includes mass casualty incidents, community emergencies and disasters, can also cut across healthcare disciplines, requiring contributions from emergency medicine, public health, primary care, surgery, anaesthetics and intensive care.

From the health perspective, certain types of events are usually associated with well-described patterns of morbidity and mortality. The clinical and public health needs of an affected community therefore also vary according to the type and extent of the event. Emergency physicians should understand the public health and medical consequences of the various types of events in order to determine their own roles in preparedness and response. In practice, emergency physicians are most actively involved in the response to acute-onset events that involves multiple casualties, such as transportation incidents. Other types of events, including floods, are generally associated with few casualties. The health and medical needs in these settings usually involve augmenting public health and primary care services. Emergency physicians should be familiar with disaster epidemiology and local emergency management arrangements and understand the medical response to events involving multiple casualties.

The differential effects of events on communities in all countries are associated with risk factors which make some communities and subpopulations more vulnerable and less capable of dealing with the risks than others. A defining feature of disasters is the level of impact and disruption to the functioning of society which is often widespread and long term. Apart from health and medical issues, disasters can cause significant social, economic and environmental losses that may have devastating effects on the general well-being of the affected community. They may set back years of development progress in poorer countries, including the disruption of health systems, such as in the Haiti earthquake of 2010, Pakistan floods of 2010 and Hurricane Irma in the Caribbean of 2017. Their effects may be felt well beyond the borders of the first affected country. Epidemics may be prone to widespread international spread, with broad range economic and sociopolitical consequences, for example, the Ebola outbreak in Sierra Leone, Liberia and Guinea of 2014 to 2016, the Zika virus epidemic in Latin America of 2015 to 2016 and the H1N1 pandemic of 2009. It is estimated that a global influenza pandemic could result in tens of millions of deaths and cost the global economy up to $US4 trillion.

Definitions and classification

In February 2017, the United Nations General Assembly endorsed a set of terms to support the implementation of the Sendai Framework for Disaster Risk Reduction 2015 to 2030 which included a definition of a disaster as ‘a serious disruption of the functioning of a community or a society at any scale due to hazardous events interacting with conditions of exposure, vulnerability and capacity, leading to one or more of the following: human, material, economic and environmental losses and impacts’. The annotation provides further clarification: ‘the effect of the disaster can be immediate and localized, but is often widespread and could last for a long period of time. The effect may test or exceed the capacity of a community or society to cope using its own resources, and therefore may require assistance from external sources, which could include neighbouring jurisdictions, or those at the national or international levels.’ The term ‘emergency’, while sometimes used interchangeably with the term ‘disaster’, does not usually have the connotation of a serious disruption nor that the local capacity is overwhelmed by the event.

The Australian Emergency Management Glossary defines disaster as: ‘a serious disruption to community life which threatens or causes death or injury in that community and/or damage to property which is beyond the day-to-day capacity of the prescribed statutory authorities and which requires special mobilization and organization of resources other than those normally available to those authorities’.

The Center for Research on the Epidemiology of Disasters (CRED), which compiles the data behind the annual World Disasters Report of the International Federation of Red Cross and Red Crescent Societies, stipulates a quantitative surveillance definition involving one of the following: 10 or more people killed; 100 or more people affected; declaration of state of emergency; or an appeal for international assistance. Thus international data tend to be focused on large-scale events.

Disaster risk management is ‘the application of disaster risk reduction policies and strategies to prevent new disaster risk, reduce existing disaster risk and manage residual risk, contributing to the strengthening of resilience and reduction of disaster losses’. Disaster risk management activities are designed to establish and maintain control over disaster and emergency situations and to provide a framework for helping at-risk populations avoid or recover from the impact of an event. It addresses a much broader array of issues than health alone, including a multisectoral approach to hazard identification, vulnerability analysis, risk assessment, risk evaluation and risk treatments.

Disaster medicine can be defined as the study and application of clinical care, public health, mental health and disaster management to the prevention, preparedness, response and recovery from the health problems arising from disasters. This must be achieved in cooperation with other agencies and disciplines involved in comprehensive health emergency and disaster risk management. In practice, emergency medicine and public health are the two specialties most intimately involved in disaster medicine.

A mass casualty incident is an event causing illness or injury among multiple patients simultaneously through a similar mechanism, such as a major vehicular crash, structural collapse, explosion or exposure to a hazardous material. A complex emergency (CE) is an event complicated by civil conflict, government instability, macroeconomic collapse, population migration and an elusive political solution. Events are commonly classified as natural versus human induced ( Box 29.3.1 ).

Events may also be classified according to other characteristics, including sudden versus slow onset, short versus long duration, unifocal versus multifocal distribution and primary versus secondary. Classifications of event magnitude exist for selected natural hazards, such as earthquakes and cyclones; however, there is currently no standard classification of severity of disaster impact.

Epidemiology

Globally, the types of events associated with the greatest numbers of deaths are CEs. These are crises characterized by political instability, armed conflict, large population displacements, food shortages and collapse of public health infrastructure. Because of insecurity and poor access to the affected population, aggregate epidemiological data for CEs are somewhat limited. However, between 1998 and 2007 in the Democratic Republic of Congo, it is estimated that 5.4 million people lost their lives due to the consequences of the major humanitarian crisis afflicting that country. This was four times the United Nations Office for Disaster Risk Reduction (UNISDR) estimate of deaths globally due to natural and technological disasters during the 20 years between 1992 and 2012. During the Syrian conflict that started in 2011, some sources indicate that up to 350,000 people may have been killed. This does not include excess deaths due to other causes linked to the deterioration in the health system.

According to information reported by the International Federation of the Red Cross, there has been a significant increase in the total number of natural and technological disasters worldwide during the past 50 years. From 1960 to 2010, the annual number of disasters rose from 50 per year to approximately 700/year peaking at 810 in 2005. The annual average number of disasters was 609/year for the decade 2006 to 2015. While the total number of people killed by natural and technological disasters was approximately 77000/year (for the decade 2006 to 2015), there was a wide annual range (14,389 in 2014 to 314,503 in 2010 due to the Haiti earthquake and the Russian heatwave). Moreover, the total number affected has almost quadrupled over the past three decades. It is estimated that approximately 190 million people are directly affected on an annual basis. Selected data are presented in Figs. 29.3.1 and 29.3.2 .

The commonest types of disasters across the globe are: transportation incidents, floods, windstorms, industrial incidents, building collapses, droughts, and earthquakes/tsunamis (see Fig. 29.3.1 ). Asia is the region of the world most prone to natural and technological disasters, recording 40% of such incidents between 2006 and 2015. It is followed by Africa (24%), the Americas (20%), Europe (13%) and Oceania (3%). Compared with other regions of the world, Australasia and Oceania have a relatively low incidence of disasters. Nonetheless, the World Risk Index (WRI) Report of 2016 included Vanuatu, Tonga and the Solomon Islands among the 10 countries most at risk for natural hazards.

Over the past 10 years, the commonest causes of disasters in Australia have been severe storms, transportation events and bushfires. Historically, the leading cause of death from disasters due to natural hazards in Australia have been heatwaves (438 killed in 1939, 404 killed in 2009), followed by cyclone and bushfire. Human-induced disasters resulting in multiple casualties have occurred more frequently in Australia in recent years. The commonest causes of mass casualty incidents have been bus crashes, structural fires, mining incidents, aviation incidents and train crashes. The impact of disasters in New Zealand over the period 2001 to 2010 was dominated by the Christchurch earthquake that caused 185 deaths. The incidence of disasters also differs from Australia, with the commonest major events being transportation disasters, industrial disasters and earthquakes.

Data reporting on the incidence of armed conflict is complicated by varying and changing definitions and political motivations of the reporting agencies. The Uppsala Conflict Database Program identified 49 ongoing conflicts on five continents in 2016. As of December 2017, it was estimated that 135.6 million people require humanitarian assistance—the highest on record. This need is largely driven by conflict. The number includes 65.6 million people who have been forcibly displaced from their homes—also the highest on record. In spite of the overwhelming needs, the humanitarian community will target 105.1 million people (67%) for assistance in 2018, due to pervasive operational constraints including insecurity, limited local capacities, lack of funding and bureaucratic constraints.

The countries recording the highest number of terrorist attacks in 2016 were Iraq, Afghanistan, India, Pakistan and the Philippines, although data on terrorist attacks in Syria has been difficult to capture. Iraq, Afghanistan, Syria, Nigeria and Pakistan accounted for 75% of all deaths due to acts of terrorism. Slightly more than half of the attacks in 2016 did not cause any deaths while 5 percent of attacks caused more than 10 deaths. Overall, the number of deaths due to terrorism is just a very small fraction of the total number deaths attributed to natural and technological disasters and CEs.

Disaster epidemiology globally, including the Australasian region, is being affected by climate change. Global warming has already been associated with an increase in the frequency, severity, and unpredictability of weather-related disasters, such as heatwaves, wild fires, floods and droughts. Rising temperatures have been implicated in the spread of infectious disease, such as malaria and dengue, through increases in vector populations, such as mosquitoes. Other important diseases are also sensitive to changing temperatures and rainfall, including malnutrition and diarrhoea. The health-related and other impacts of climate change will not be evenly distributed. Disasters associated with global warming are particularly likely to threaten the lives and livelihoods of coastal communities, those living on low-lying islands (e.g. due to rising sea levels) including in the Pacific Ocean and in arid and high mountain zones.