Introduction

Catastrophic events can range from natural disasters such as Hurricane Maria, which devastated Puerto Rico on September 20, 2017, to mass casualty terrorist attacks such as when the World Trade Center was destroyed on September 11, 2001.[1] Hydrometeorological catastrophes such as hurricanes, tornadoes, and floods are predictable. On the other hand, geologic disasters such as earthquakes are not. Many natural disasters affect the entire infrastructure, including buildings, roads, electricity, and communications. While natural disasters can affect all, they disproportionately affect the poor and vulnerable. Terrorist attacks usually affect urban areas as they have an intentional goal to cause as many victims as possible. Complex humanitarian emergencies result in deaths from violence as well as disease.

A multicasualty incident (MCI) is an event in which resources (rescue personnel, healthcare providers, facilities, and equipment) are insufficient to deal with the incident. In a disaster, not only are there not enough resources but a complete breakdown in communication and the ability to deliver these resources. The local rescue workers and health care personnel may become the victims or be unable to arrive at work. The local healthcare facilities may be damaged or destroyed.

Issues of Concern

Earthquakes

Earthquakes can appear suddenly without warning. The event's timing may be significant regarding the number of casualties. An earthquake that suddenly strikes in the evening when people are asleep at home is more devastating than one during the day when people are awake and can flee. Aftershocks may also lead to casualties. Initial injuries include fractures, lacerations, and crush injuries. Many of those who suffer from crush injury develop crush syndrome, which may consist of rhabdomyolysis and renal failure. A significant proportion of these patients require dialysis. Some victims with crush injuries need to undergo a fasciotomy. There are subsequent risks of infectious disease epidemics.[2]

Hurricanes and Floods

Theoretically, there is a certain amount of time to plan, including the ability to evacuate. However, one still has to deal with the issue of damage to the medical infrastructure itself. Victims suffer from similar injuries to those from an earthquake. Bacterial infections by Vibrio vulnificus or leptospirosis can be caused by contaminated flood water.[3]

Radiation Emergencies

Radiation emergencies can be from an accident in a healthcare facility or nuclear site, a terrorist attack, or an act of war. Terrorist attacks could theoretically include the detonation of a radiological dispersal device (RDD), also known as a dirty bomb. The initial blast and subsequent fires will kill many. The immediate health effects of radiation include bone marrow failure and damage to the gastrointestinal tract. Higher doses of radiation will lead to death.[1]

Infectious Disease

Infectious disease disasters can be primary, such as the Ebola epidemic between 2013 and 2016[2], or secondary, such as the cholera outbreak after the devastating earthquake in Haiti in 2010.[3] For infectious diseases that can spread by contact, proper infection control techniques, including hand washing, personal protective equipment for the health care provider, and appropriate patient isolation, are required.

Terrorist Attacks

Although terrorist attacks can often result in an MCI, they rarely result in a catastrophic event such as occurred on 9/11. In a terrorist bombing, deaths are caused by the four stages of blast injury: the blast wave, shrapnel, propelling of the victim, and secondary causes such as fires or building collapse. This was magnified on 9/11 by the massive explosion caused by airplanes crashing into the Twin Towers, as well as the collapse of two of the tallest buildings in the world.[4][5]

Complex Humanitarian Emergencies

Complex humanitarian emergencies (CHE) are political instability or armed conflict crises. They can lead to violent death, malnutrition, and disease. This includes recent conflicts in Syria, Afghanistan, Bosnia, Rwanda, Kosovo, the Democratic Republic of Congo, and East Timor. Over many years, these have caused more deaths than all disasters combined. Violent deaths can be due to shootings, shrapnel, or landmines. Infectious diseases have often been the primary cause of morbidity and mortality in CHE in Asia and Africa. These include diarrheal diseases, acute respiratory tract infections, measles, meningitis, and malaria. Malnutrition, mental health disorders, and sexual violence are also prevalent.[6]

Clinical Significance

Role of Emergency Medical Services 

The emergency medical system has a unique role in disaster response. They already have an in-place infrastructure, many personnel, and integrated communication systems; however, much of this may be affected. The dispatch center may be destroyed, the call system may not work, and communication with other agencies may be affected. In addition, ambulances or the station may be damaged, and personnel themselves may be injured or killed. Those that survive may be unable to respond due to damage to their vehicles or destruction of roads. Their family members may be disabled or property damaged, and they may need to prioritize these needs over responding to the catastrophe. Emergency medical services (EMS) must set up casualty collection points and perform mass casualty triage.

EMS Issues

Fundamental changes in the conventional EMS structure will need to take place. Dispatch will be only for life-threatening emergencies; basic life support ambulances may need to respond to advanced calls, and patients may need to be transported in vehicles other than ambulances. In an actual disaster, resuscitation should not even be started.

Field triage such as START (Simple Triage and Rapid Treatment- ability to obey commands, respiratory rate, and radial pulse or capillary refill), SALT (Sort, Assess, Life-Saving Interventions, Treatment, and Transport), Triage Sieve and Sort (using respiratory rate and either capillary refill or heart rate), or CareFlight Triage (ability to obey commands, the presence of respirations, and being able to palpate a radial pulse) will need to be implemented.[7][8]

Fundamental Treatment Issues

In an actual disaster, patients who are unable to breathe spontaneously are declared expectant and placed in a separate area with the dead. At the other extreme are the lightly injured and the walking wounded. Although they usually would be transported to a medical facility, in a disaster, they are treated at the scene and discharged. Simple fractures may be splinted, and wounds should be thoroughly rinsed. Patients who are moderately or severely injured should be stabilized. Those who can breathe spontaneously with minimal assistance, such as a jaw thrust, are transported to the hospital. If a tension pneumothorax can be clinically identified, needle application should be performed, or a chest tube should be inserted. Active external bleeding should be stopped with bandages and tourniquets. Besides trauma victims, it should be noted that there may be acute exacerbations of chronic diseases such as asthma, congestive heart failure, or diabetes.

Transport of Victims

Different theories exist on transferring patients from the disaster site to local hospitals. In the conventional method of transportation, all ambulances take patients directly from the disaster site to area hospitals. Rescue, triage, and primary emergency care occur at the catastrophe site.

In the sequential or conveyance method, rescue and emergency care occur at the disaster site. Patients are then taken to a mobile emergency medical center (MEMC). At the MEMC site, patients with minor injuries can be rapidly treated and discharged. In addition, more severely injured patients can be stabilized before a long journey to the hospital. The first line of ambulances transports patients from the disaster zone to the MEMC; the second line of ambulances transports patients from the MEMC to the hospital. Theoretically, this is a more regulated system for ambulance transportation similar to the concept in rural areas of stabilizing a patient in a level 3 emergency department before transfer to a level 1 trauma center.

The location of the MEMC can be derived from Google Maps, which uses artificial intelligence to help derive the best possible routes. The limitation to this is that in a true catastrophe, many routes may be unpassable. Another limitation is that the MEMC is ideally designated in advance; however, in real life, the disaster may affect the location itself. An advantage of the conventional method is that the suggested hospital destination comes from physicians, which may decrease hospital overcrowding.[6]

At the same time, the hospital emergency departments will become organized and activate their disaster response system to prepare for an incoming wave of patients. The incident command system will be started, and all disaster response team members will be called in. To expand surge capacity, the emergency department will begin to discharge all possible patients and immediately admit any patients who need continued treatment or further workup. Other areas, such as lounges and waiting areas, may be transformed into treatment zones to increase surge capacity.

Field Hospitals

Field hospitals may need to be set up for the definitive treatment of many casualties. The World Health Organization (WHO) recently took the lead in certifying emergency medical teams (EMTs) to respond to disasters. These may be from the same country, National Team (N-EMT), or a foreign country, International Team (I-EMT). All must maintain general hygiene standards, official registration of workers, malpractice insurance, and proper medical records. There are three levels of EMTs, which vary based on the numbers and increasing complexity of patients they will be treated: the EMT-1 may operate similarly to a medical clinic, the EMT-2 enables inpatient surgical care, and the EMT-3 adds inpatient referral care. The EMT-3 field hospital can house two operating suites, up to 6 intensive care unit beds, and 40 inpatient beds. The emergency department of the EMT-3 can handle up to 200 patients a day. Laboratory and X-ray services are available. In a disaster, the EMS provider may transport a patient to any one of these or may be involved in transferring the patient from a lower level to a higher-level field hospital.[9]

Mortality and Morbidity of Rescuers

In catastrophes, rescuers may also become victims. Besides the firefighters and emergency medical technicians who died responding to the World Trade Center disaster in 2001, thousands more suffered from long-term medical and psychological effects. This included pulmonary illness from toxic dust. Periodic health assessments include chest x-rays, pulmonary function tests, blood work, and urinalysis testing. In addition, mental health screening is performed. More than 20% of the general responder cohort suffer from physical and mental health problems directly due to 9/11. After the Chornobyl nuclear power plant disaster in 1986, up to 600,000 "liquidators' (civil and military personnel who were involved in cleaning the fallout) suffered increased rates of leukemia, thyroid cancer, and other malignancies. Japan has started a program for those exposed to the Fukushima disaster, which includes annual eye examinations for cataracts, cancer screening, and thyroid tests.

Ethical Issues

In a catastrophe, most ethicists believe the goal is to save as many lives as possible. This means that the needs of the majority take priority over the individual. Daily, priority is given to the sickest patient; however, in a catastrophe, it may be decided that those with little chance of survival who require large amounts of resources will not be attended to as this will take away from the care for many more patients.[10]