Mass casualty natural disaster

Introduction

Mass casualty incidents (MCIs) can result from both natural disasters, such as hurricanes, and human-made disasters, such as terrorist attacks. MCIs tax medical infrastructures and require urgent responses from medical personnel from many different disciplines. Physician assistants (PAs) are being called on to respond to the urgent medical needs more frequently than in the past. Many times, PAs are first on the scene and take a leadership role in chaotic situations. In recent years, large-scale disasters such as 9/11 and Hurricane Katrina have raised concerns about our ability to respond in an effective and coordinated manner to the medical (and other) needs created by these disasters.

The World Health Organization (WHO) defines disaster as “a serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses which exceed the ability of the affected community or society to cope using its resources.” Natural disasters include such events as earthquakes, volcanoes, landslides, tsunamis, flooding (river or coastal), tornadoes, droughts, wildfires, sand or dust storms, blizzards, and infestations. Certain geographic locations are more prone to particular natural disasters. For example, midwestern states are prone to tornadoes, whereas western states experience more earthquakes and wildfires. Situational awareness is important to be prepared for natural disasters.

Vulnerability is the “degree to which a socioeconomic system is either susceptible or resilient to the impact of natural hazards.” Vulnerability is determined by hazard awareness, infrastructure, public policy, and the ability to implement disaster management procedures. Poverty remains one of the main causes of vulnerability. There is no better illustration than the vulnerabilities present in Haiti on January 12, 2010, when a 7.0 earthquake struck the capital of Port-au-Prince, killing hundreds of thousands of people. Haiti remains one of the poorest countries in the Western Hemisphere. The Haitian government gave much attention to other natural disasters, such as hurricanes and mudslides, even though Haiti had a documented history of devastating earthquakes dating back to the 1770s. Haiti is located on the borders of the American and Caribbean tectonic plates, making it particularly vulnerable to earthquakes. In addition, because of the deforestation of trees, lumber for buildings became expensive. Therefore buildings shifted to concrete and stone structures that could not withstand the violent shaking during the earthquake. Building codes were either not enforced or were nonexistent. Buildings collapsed, trapping many beneath the ruble. Furthermore, first aid for emergency situations was not readily available, compounding the suffering and loss of life from this disaster. All of these vulnerabilities drastically increased the death toll from this natural disaster.

The WHO defines mass casualty as “an event which generates more patients at one time than locally available resources can manage using routine procedures. It requires exceptional emergency arrangements and additional or extraordinary assistance.” The phrase mass casualty conjures up images of 150 casualties waiting at several hospitals in a metropolitan area in such cases as the Boston Marathon bombings. By definition, mass casualty would also constitute a multivehicle accident with eight casualties being transported to a critical access hospital in a rural area. MCI events can be the result of a terrorist attack, such as the events of 9/11. Another less publicized event was the train derailment in Graniteville, South Carolina in 2005 that resulted in an immediate release of 46 tons of liquid chlorine near a textile mill where 183 people were working the night shift. Each of these events had vastly different origins, but all resulted in an MCI.

The effects of an MCI or natural disaster can be mitigated with well-rehearsed emergency response teams and a prepared community. The community is deemed “recovered” when the health status of the community is restored to its pre-event state. In some instances, this can be a relatively short period of time, but other instances can take many years. The goals of emergency response are to:

1.
Reverse the adverse health effects caused by the event.
2.
Modify the hazard responsible for the event (reducing the risk of the occurrence of another event).
3.
Decrease the vulnerability of the society to future events.
4.
Improve disaster preparedness to respond to future events.

Most MCIs and natural disasters come with little to no warning; therefore it is essential that PAs have a solid foundation in disaster preparedness and emergency response. Understanding the cyclical pattern known as the disaster cycle is essential to understanding the four reactionary stages that occur after a catastrophic event. The four reactionary stages are:

1.
Preparedness
2.
Response
3.
Recovery
4.
Mitigation and prevention

Each stage varies in duration, depending on the type of MCI or natural disaster experienced.

Principles of triage

Triage comes from the French verb “trier,” which means “to sort.” Triage of patients in a mass casualty or natural disaster situation often requires medical providers to alter their thought process about treating patients. Under normal circumstances, the sickest or worst injured get immediate medical attention, and often medical providers try to save the life of a patient at all costs. When medical personnel and medical supplies are limited, however, the critically injured and ill are passed over to help care for patients with a higher likelihood of surviving. Treatment is aimed at doing the most good for the most patients. By assigning priorities for treatment through triage principles, medical personnel make the most efficient use of available resources.

There are three major reasons why triage is beneficial when responding to a natural disaster or MCIs. Triage categorizes patients who need rapid medical care to save life or limb. By separating out the minor injuries, triage reduces the urgent burden on medical facilities and organizations. On average, only 10% to 15% of disaster casualties are serious enough to require overnight hospitalization. By providing for the equitable and rational distribution of casualties among the available hospitals, triage reduces the burden on each to a manageable level, often even to “nondisaster” levels. The disaster triage system in the United States is color coded and uses red, yellow, green, and black as follows:

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Red: First priority, most urgent. Life-threatening shock or airway compromise present, but the patient is likely to survive if stabilized.
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Yellow: Second priority, urgent. Injuries have systemic implications but are not yet life threatening. If given appropriate care, the patients should survive without immediate risk.
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Green: Third priority, nonurgent. Injuries localized, unlikely to deteriorate.
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Black: Dead. Any patient with no spontaneous circulation or ventilation is classified dead in a mass casualty situation. No cardiopulmonary resuscitation (CPR) is given. You may consider the placement of catastrophically injured patients in this category (dependent) on resources. These patients are classified as “expectant.” Goals should be adequate pain management. Overzealous efforts toward these patients are likely to have a deleterious effect on other casualties.

Understanding principles of triage is essential for medical providers attending to casualties to save the most lives during an MCI or natural disaster.

Chemical, biological, radiologic, nuclear, explosives, and environmental incidents

Mass casualty incidents and natural disaster events have been the scourge of humankind since antiquity. As we have moved into the 21st century, the causes of disasters have expanded from the natural disasters and infectious disease pandemics of previous centuries to potential human-made events, such as chemical, biological, radiologic, nuclear, and explosives (CBRNE) incidents that have the ability to produce widespread carnage very quickly. As the industrial age flourished, modern manufacturing processes began to use toxic chemicals in their daily operations. These chemicals are transported near urban areas via highways and railroads, which places the general public at great risk when accidental spills occur. Furthermore, these same modern manufacturing processes have allowed people to produce chemical, biological, and nuclear weapons capable of inflicting multitudes of casualties. Combined with the rise of rogue terrorist groups, the potential for one of these weapons of mass destruction to be used against a civilian population is of grave concern. PAs, no matter their practice specialty, need to have a basic understanding in the recognition and treatment of CBRNE injuries, as well as injuries that result from natural disasters.

Chemical disasters

Ancient Greek myths spoke of the effectiveness of chemical warfare, and various agents have been used throughout the ages, culminating with the widespread use in World War I. Many of the chemical agent–related disasters in modern times are related to industrial accidents. One of the most famous chemical disasters was the December 3, 1984 Bhopal disaster in India that killed between 4000 and 20,000 people from exposure to methyl isocyanate.

Disasters from chemical exposures create numerous casualties very quickly and place first responders in danger of also being contaminated. Proper decontamination of patients at the scene by trained civilian or military personnel takes priority before rendering medical care. Contamination of medical personnel and facilities not only risks the provider’s health but also can jeopardize the ability of the hospital to receive casualties. First responders will usually be able to communicate the type of chemical agent involved to the receiving hospital, where treatment of patients should be focused on that contaminant. The injuries associated with chemical disasters depend on the class of agents involved. Some more common agents that may be encountered include:

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Choking agents that target the pulmonary system, such as chlorine and phosgene. These agents are lung irritants that cause injury to the lung–blood barrier, resulting in asphyxia.
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Blood agents, such as hydrogen cyanide, that are rapidly lethal via halting cellular respiration. Treatment is the rapid removal of the victim from the environment, application of oxygen, and administration of sodium nitrite.
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Blister agents or vesicants, such as mustard gas, which are some of the most common chemical warfare agents. These oily substances act via inhalation and contact with skin. Blister agents affect the eyes, respiratory tract, and skin, first as an irritant and then by affecting cell metabolism. Blister agents cause large and often life-threatening skin blisters that resemble severe burns. The effects of mustard agents are typically delayed. Exposure to vapors becomes evident in 4 to 6 hours, and skin exposure is seen in 2 to 48 hours. Treatment is decontamination and supportive care targeted to address life-threatening respiratory compromise.
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Nerve agents, which are perhaps the most rapidly lethal chemical agents and result in respiratory paralysis and death in a matter of minutes. Nerve agents, such as sarin and VX, enter the body through inhalation or through the skin. Symptom severity depends on the level of exposure. Classic symptoms of moderate to high doses of nerve agent result in pronounced secretion of mucus, bronchoconstriction, abdominal cramping, vomiting, involuntary urination and defecation, muscle weakness, convulsions, and death by suffocation. Treatment must be rapid to prevent death and should include decontamination and administration of high doses of atropine and 2-PAM (2-pyridine aldoxime methyl) chloride. Supportive care must be aggressive because the physiologic effects can continue long after the nerve agent is reversed.
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Riot control agents , such as tear gas, which are chemical compounds that temporarily make people unable to function by causing irritation to the eyes, mouth, throat, lungs, and skin. The effects of exposure to a riot control agent last about 15 to 30 minutes after the patient has been decontaminated. Immediate signs and symptoms of exposure to a riot control agent include excessive tearing, eye burning, blurred vision, a runny nose, difficulty swallowing, chest tightness, coughing, and nausea and vomiting. Long-lasting exposure or exposure to a large dose of a riot control agent can result in blindness, glaucoma, and sometimes death from respiratory compromise. Treatment includes the removal of the patient from the environment, copious irrigation, and symptomatic treatment.
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Toxins, which are poisons produced by living organisms. One of the most well-known toxins is botulinum toxin. Botulinum toxin is produced by the bacteria Clostridium botulinum and is extremely lethal. The lethal dose has been estimated to be about 1 microgram if ingested and even less if inhaled. The incubation period is between 1 and 3 days, at which time the patient presents with abdominal pain, diarrhea, visual changes, and muscular weakness. Paralysis ensues, compromising respiratory function, and asphyxia ensues. No specific treatment is available for botulinum toxin. Treatment is directed at supporting the cardiopulmonary system.

Biological disasters

Biological disasters are diseases conveyed by biological vectors, including exposure to pathogenic microorganisms, toxins, and bioactive substances that can cause injury, illness, social and economic disruption, and death. Biological disasters can be naturally occurring or can be human-made in the form of accidental release or bioterrorism. Naturally occurring biological disasters can be divided into epidemics and pandemics. An epidemic is a disease process affecting a disproportionately large number of individuals within a population, community, or region at the same time. A pandemic is an epidemic that spreads across a continent or worldwide, such as the 2020 COVID-19 pandemic. Epidemics are common after tropical storms, floods, earthquakes, and wars, when normal hygiene and sanitation services are disrupted. Examples of natural epidemics include the avian flu common in southeast Asia; the cholera outbreak in Haiti after the earthquake in 2010 as the result of improper sanitation protocols by Nepalese soldiers who were part of the United Nations forces; dengue fever and malaria outbreaks from mosquito-borne vectors; the Ebola outbreak in West Africa in 2015; and measles, which has once again become common in the United States as the result of low vaccination rates in certain segments of the population. Measles has a high mortality rate in developing countries.

Epidemics can also be the result of bioterrorism. Bioterrorism is a method that disseminates widespread panic in a population and produces a slow onset of mass casualties. Bioterrorism can be targeted to both a human population and an animal population, and it can produce large-scale economic losses. Many of the common bioterror weapons such as smallpox, anthrax, and plague were weaponized by the United States and the Soviet Union after World War II. Although many of these bioweapon stocks were destroyed as the result of arms agreements, some stockpiles remain in the former Soviet Union. These stockpiles, as well as the scientific ability to produce these weapons, are sought after by terrorist groups. Recognizing bioterrorism is a critical first step in decreasing the number of casualties. Incidentally, frontline medical professionals may be the first to recognize health trends that indicate a bioterrorism attack.

Biological disasters present differently from chemical disasters. The vectors are different and can include agents dispersed into the air that may drift for miles; animals, including fleas, mice, mosquitoes, and livestock; food and water supplies; and from person to person, such as smallpox. Unlike chemical agents, there is a lag time between exposure and the appearance of symptoms. This lag time gives the vector more time to expose a greater number of victims. Furthermore, it increases the time it takes before the disease is recognized, isolated, and treated. Three categories of biological agents can cause mass casualties:

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Category A (which pose the most risk to public health): These agents are easily disseminated from person to person and have a high mortality rate. These agents include smallpox, Ebola, Lassa fever, anthrax, plague, tularemia, and botulism. Special isolation precautions of contaminated patients are required. Consequently, multiple casualties can be devastating to the medical system as patients require an inordinate amount of resources.
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Category B: These agents are moderately easy to disseminate; have moderate morbidity and low mortality rates; and include alphaviruses, Brucella (brucellosis), Burkholderia mallei (glanders), Coxiella burnetii (Q fever), ricin, staphylococcus enterotoxin B, Salmonella, Vibrio cholera, and Escherichia coli O157:H7. Children, older adults, and immunocompromised individuals are more at risk for complications from these diseases. Early, aggressive treatment is critical in reducing the long-term morbidity of the diseases.
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Category C: These agents include many that have insect vectors, including Nipah, yellow fever, tick-borne hemorrhagic fever viruses, tick-borne encephalitis, and bacteria such as Mycobacterium tuberculosis. Although these diseases have the potential for morbidity and mortality, they are less likely to be widespread public health threats.

Clinicians should be aware of the diseases that lend themselves to becoming bioweapons. Anthrax, smallpox, plague, tularemia, and brucellosis are diseases that are relatively easy to produce, inexpensive, readily spread from person to person, and can be “weaponized” for distribution over a wide area. Bioweapons are considered to be a “poor man’s nuclear bomb” and can produce widespread casualties. For example, smallpox causes a one in five mortality rate. Furthermore, these bioweapons can cause associated widespread panic and economic chaos. Unlike chemical weapons, where casualties would occur quickly after an attack, victims of bioterrorism would present days after the exposure with initial “flulike” symptoms. Be aware that with modern air travel, a bioterrorism victim on another continent may present to an emergency department (ED) or medical office in the United States with the early stages of the disease. It cannot be emphasized enough that a thorough travel history must be obtained on every ill patient. Clinicians should inquire about friends and family members with similar symptoms and maintain a high index of suspicion if multiple patients present with similar symptoms. Clinicians should also become suspicious of an epidemic curve that rises and falls during a short period of time, an endemic disease rapidly emerging at an uncharacteristic time of the year, lower attack rates of people who have been indoors, clusters of patients arriving from a single location, and large numbers of rapidly fatal cases. Isolation of the patient and those exposed to the patient should take first priority, including providing personal protective equipment (PPE) for all staff. Decontamination should only be considered in cases of gross contamination, and this determination needs to be made in conjunction with local and state health departments. Basic decontamination includes the removal of clothing and bathing in soap and water. Clinicians should notify the hospital’s infection control personnel, public health officials, law enforcement, emergency medical services (EMS), and the Centers for Disease Control and Prevention (CDC) promptly. Postexposure immunization and prophylaxis measures depend on the biologic agent involved. Furthermore, the determination on proceeding with an intervention should be made in conjunction with the local and state health departments. Treatment of patients should be directed at addressing presenting symptoms because exposure to many of the bioterror agents presents with respiratory or gastrointestinal complaints. Additionally, clinicians should be ready to address the potential for respiratory failure, hemorrhagic shock, or septic shock.

Nuclear and radiologic disasters

Nuclear and radiation disasters are, fortunately, uncommon in the United States. Although the prospect for a large-scale nuclear power disaster on the scale of the Fukushima, Japan accident is remote, incidents involving radiologic dispersal devices (i.e., dirty bombs), occupational accidents, or even an explosion from an improvised nuclear device are possible events. Clinicians should be prepared for these events and be familiar with the types of nuclear and radiologic devices, methods for decontamination, and ways of recognizing radiation sickness; they should also have a basic knowledge of treatment for radiation injuries.

Improvised nuclear devices

Improvised nuclear devices are a type of nuclear weapon that generates four types of energy: a blast wave, intense light, heat, and radiation. Depending on the size of the device, victims in the initial blast zone have an extremely high mortality rate from the blast wave. Furthermore, any survivors would sustain severe burns, blindness, and rapid onset of acute radiation syndrome (ARS). ARS is caused by irradiation of the entire body by a high dose of radiation over a few minutes. The major cause of ARS is the depletion of immature parenchymal stem cells in certain tissues. The radiation dose must be greater than 70 rads, from an external source of gamma rays. Symptoms include anorexia, fever, malaise, severe diarrhea, dehydration, and electrolyte imbalances. Death usually occurs in 3 days and is the result of infection, dehydration, and electrolyte imbalances. Mortality rates depend on the radiation dose received. As a general rule, nausea and vomiting that start within 4 hours of exposure are a poor prognosticator. Victims farther from the blast zone can expect radiation sickness and may have to contend with contaminated food and water. Rapid decontamination and supportive care are critical to decreasing mortality and morbidity.

Radiologic dispersal devices (dirty bombs)

A “dirty bomb” is a device that is a more likely scenario in a radiologic terrorist attack. A dirty bomb or radiologic dispersal device (RDD) is a mix of radioactive material and a high explosive that does not create a nuclear blast but disperses the radioactive material over an area. Easy to produce, the potential radioactive material can include industrial waste or even the byproducts of common medical procedures. The danger from an RDD is from blast trauma. The radiation exposure is only a concern for people near the blast, and the potential for radiation exposure serves as a “fear weapon,” possibly slowing first responders. Basic decontamination procedures need to be followed but should not impede the rapid evaluation and treatment of trauma injuries.

Occupational accidents and radiologic exposure devices

Occupational accidents and the use of radiologic exposure devices (REDs) are both situations in which a person has been exposed to radioactive material. Occupational accidents are seen mostly in research facilities, hospitals, and some manufacturing operations. Exposure to an RED is a criminal attempt to expose victims to a radiation source, usually in a public place, such as a food court or bus. In both situations, the physiologic response of the victim depends on the type and amount of exposure, the length of exposure, and what body part was exposed. High levels of exposure can result in ARS; however, the effects of low-dose exposure could take weeks to appear. Treatment is directed toward symptoms; however, the patient will require long-term monitoring specifically evaluating for leukopenia and bone marrow suppression, with resultant infection.

Natural disasters

By far, the most common type of mass casualty event seen worldwide is a natural disaster. Depending on location, PAs should be prepared for natural disasters that are common to that location. The gulf coast and the eastern coast of the United States are prone to hurricanes, which can produce widespread devastation, resulting in not only mass casualties as the result of trauma (i.e., penetrating and crush injuries) but also infectious disease issues as the result of a loss of infrastructure and sanitation. The Midwest and the southern United States are prone to tornadoes. Tornadoes give very little warning and tend to cause injuries similar to those from hurricanes, except in a smaller geographic area. The West Coast and Alaska are prone to earthquakes and tsunamis, which give little or no warning and generate widespread destruction. In the case of earthquakes, many of the injuries are crush injuries from collapsed structures or injuries related to resulting fires or explosions. Similar to hurricanes, earthquakes involve a wide area and can result in severe impairment of local fire departments and EMS to render care. Tsunamis result in widespread inland flooding and structural damage. Many of the deaths are the result of drowning; however, exposure to sewage, industrial chemicals, and waterborne pathogens can result in a widespread public health emergency. By knowing what types of environmental events are common to an area, proper preparation can ensure a better outcome in the event of one of these disasters.

Hurricanes

Hurricanes have plagued the southeastern and eastern United States, resulting in catastrophic loss of property and life. Hurricanes have become a bigger problem over the past 50 years because more people are living in coastal regions and sea levels are rising. Hurricanes inflict damage by both wind and water. Wind damage, as the result of 150 plus–mph winds, results in the structural collapse of buildings, homes, and utilities and can expose people to wind-blown shrapnel, causing penetrating injuries. Water damage occurs as the wind pushes wave action inland, resulting in flooding and potential drowning deaths. Subsequent exposure to waterborne illnesses is a very real risk. People in poor health and older adults are susceptible to aggravation of preexisting health problems caused by a lack of medications, prolonged exposure to heat, and lack of a clean water supply. The widespread devastation to health care facilities and transportation infrastructure makes treating and evacuating large numbers of patients problematic and usually requires a state or federal response. Hurricane Katrina highlighted the problematic nature of providing medical care in an environment where electricity, water, and transportation are absent. Clinicians should be ready to treat patients in poor conditions with limited supplies. Emphasis should be on the triage of patients, with prompt evacuation to intact facilities. Many times, such disasters require the assistance of ground and air military assets. Clinicians should be mindful to take care of themselves in this type of environment, with proper hydration, nutrition, and rest–work cycles to avoid fatigue and injuries.

Tornadoes

Tornadoes strike with little or no warning, usually in the spring and summer in the midwestern and southeastern United States. Although the destruction is usually confined to a narrow area, mortality and morbidity can be high. Winds exceeding 200 mph result in structural collapse and flying debris that produce crush injuries, penetrating injuries, and lacerations. Health care facilities should be prepared to receive ambulatory patients quickly after an event. Disaster protocols should be routinely rehearsed in tornado-prone areas and recall rosters updated to allow for a quick surge of staff to the ED. In some cases, the local hospital can be at “ground zero” from a tornado strike, as happened in Joplin, Missouri. In these situations, the hospital is rendered inoperable, and the staff must deal with transferring inpatients to another facility, as well as setting up a treatment area in whatever structure is available. Mutual aid compacts established beforehand between hospitals and states are critical to mitigating suffering and death. Routine disaster drills in conjunction with local emergency medicine services, hospitals, Air National Guard CRBNE Enhanced Response Force Package (CERFP) Medical Teams, and Federal Disaster Medical Assistance Teams (DMAT) can reduce confusion and provide for a quicker response in the event of a catastrophic tornado.

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