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Disaster Management 

Disaster Management
Chapter:
Disaster Management
Author(s):

Michael J. Murray

DOI:
10.1093/med/9780199377275.003.0016
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date: 29 October 2020

Oklahoma City; 9/11; the tornado that struck Joplin, Missouri; hurricanes Sandy, Ike, and Katrina; and the Boston Marathon bombing have left indelible marks on our national consciousness. All of us have either been directly affected by or witnesses to the tragedies that occurred. We can’t predict when or where the next major disaster such as an earthquake in California or Haiti will occur (It is far more likely to be from a natural cause than an act of terrorism), but it is possible to prepare and plan. Anesthesiologists should know their departments’ and facilities’ disaster response plan and what their role will be should a disaster that generates mass casualties occur.

Disaster management in the traditional sense includes disaster prevention, preparedness, relief, and recovery phases. Disasters cannot be prevented, but the scope of the disaster can be mitigated through disaster prevention strategies that decrease mortality and morbidity rates by creating effective evacuation plans and by environmental planning (e.g., construction of earthquake-resistant buildings, flood control projects). Disaster preparedness is the primary means of minimizing the loss of life and damage, for example, by relocating people and property from an at-risk location, and by providing rescue, treatment, and rehabilitation in a timely and effective fashion. Disaster relief activities include relocation and rescue of affected individuals, along with the provision of water, food, and shelter, prevention of communicable disease, restoration of vital services such as electricity and telecommunications, and the provision of emergency health care. Disaster recovery includes the reconstruction of infrastructure that might have been damaged or destroyed and re-establishment of routine health care delivery and rehabilitation services. For anesthesiologists’ purposes this chapter’s emphasis is on pre-disaster preparedness, care of patients who have been injured by the catastrophic event, and mitigation of the effects of disasters on ourselves and on our facilities.

The term mass casualty refers to a large number of injuries or deaths that have the potential to overwhelm a hospital or a city’s hospital system. The same event that created the increased number of patients might also affect the functionality of the hospital itself. For example, there might be structural damage to a hospital after an earthquake or tornado or interruption of the hospital’s electrical power by flood waters. A mass casualty event is a unique process, one that many of us will not personally experience in our lifetimes, but one for which we must be prepared. When these events occur, the best outcomes are achieved with a multidisciplinary team approach.

The terms mass casualty incident refers to a situation in which the health care facility has the resources to manage the number of casualties that arrive at the facility. In contrast, a mass casualty event occurs when the number of patients overwhelms the hospital, which does not have the requisite resources to cope with, or manage, the number of patients arriving at the facility. Although a mass casualty event could occur in a rural setting most often they occur in urban centers that have protocols that direct emergency medical technicians (EMTs) and paramedics to transport patients to specific locations based on their severity of illness. After the Boston Marathon bombing, patients arrived at 29 different hospitals, with the most severely injured distributed equally to the several Level I trauma centers in the city. Patients do not, however, always wait for the EMTs or paramedics for evaluation and transportation; this was the case in Tokyo after the subway Sarin nerve gas attacks in 1995 and in Israel during the 1990s after multiple suicide bombings. Patients either transport themselves, or are transported by passersby, to the nearest hospital. Several thousand patients overwhelmed St. Luke’s hospital in Tokyo after sarin gas was released by the Aum Shinrikyo terrorist group in 1995. There was no decontamination or triage of the victims. In fact, 20 physicians were exposed to sufficient agent to become casualties themselves, consuming resources and decreasing the number of personnel on the health care team. The distinction between a mass casualty incident and an event is therefore arbitrary and is of not much significance to an anesthesiologist who is called to the hospital because of a disaster.

Pre-Disaster Planning

One limitation that a hospital could have in responding to a disaster is a lack of adequate staffing to manage the number of casualties arriving at the institution. Physicians are notoriously ill-prepared for responding to disasters and must therefore make arrangements for their family, pets, and valuable belongings before attending to professional responsibilities. During Hurricane Katrina, for example, one-third of the hospital’s work force would not or could not report to the hospital.

Family Disaster Plan

The four components of a family plan (Box 16.1) are: 1) identification of most likely disaster to occur in geographic area, 2) family disaster plan, 3) checklists, and 4) periodic drills to test the efficacy of the plan.

Each family should create two pre-arranged meeting points. One should be outside the home in case of a fire in the home and the other outside the neighborhood in case of a flood or other widespread disaster. Copies of important documents should be stored in a safe place off-site (e.g., in a bank safety deposit box). All members of the family should know how to turn off water and power to the house in case evacuation is required. Provisions for pets or family members who are disabled are critical components of an emergency plan but are often overlooked.

Personal Emergency Preparedness Plan

In addition to a family plan, preparations should be made for responding to a disaster. During an evacuation (e.g., before a hurricane), roads may be so jammed with traffic that they may be impassable, or bridges may be closed by wind or destroyed by an earthquake. It is therefore important to have contingency plans for timely arrival at the hospital during a mass casualty event. As important as having a 3-day supply of food at home, one should have a bag prepared in advance with cash, personal hygiene items and clothes, and a vehicle filled with fuel (ATMs and fuel pumps do not work without electricity). Communication networks are frequently inoperative following a disaster because the circuits are overloaded or because transmission sites and lines were destroyed. In such circumstances a battery-powered radio and/or a satellite telephone might be helpful.

Professional Emergency Preparedness

Maintaining competency in the management of patients injured by a weapon of mass destruction or infected with a biologic agent during an outbreak is difficult if not impossible, so several health care organizations have developed “just-in-time” training tools. A professional emergency preparedness plan should include familiarization with how to access these tools, which offer concise information specific to the patient population being managed at the point of care. The “training” can be downloaded from the Internet, which in the majority of events would be functioning and accessible, but the truly prepared physician would have previously downloaded and stored the information for use on her or his personal digital assistant when needed.

Although hospitals are required to test their facilities’ emergency response plan biannually, <15% of anesthesiologists in the United States have ever participated in such drills. Physicians who have participated in mass casualty situations state afterward that being better educated and trained would have helped them to provide better care for patients. If it is not possible to participate in a hospital-wide disaster response drill, an anesthesiologist should at a minimum familiarize himself or herself with the anesthesiology department’s plan.

Perhaps of more concern to anesthesiologists responding to a mass casualty incident or event caused by terrorism is that many hospitals do not have the resources to store and maintain equipment that will only be used in the event of a disaster. In a survey conducted by the Centers for Disease Control and Prevention, only 9% of the 789 hospitals that responded were fully prepared for a disaster, and each had on average only 14 personal protective suits. Personnel may also have to arrange for access to an N-95 (face mask) respirator that is capable of capturing 95% of airborne particles between 1 µm to over 100 µm in size over a range of airflows of between 10 L/min to 100 L/min. A retrospective analysis of 47 nurses managing patients with SARS (severe acute respiratory syndrome) in the intensive care unit (ICU) found that wearing an N-95 respirator while the patients were being intubated prevented the nurses from acquiring SARS. It would seem prudent then to have been fitted in advance for an N-95 mask, and to know where that mask was stored.

Disasters not only disrupt the physical environment (e.g., houses, buildings, roads), but, as observed during Hurricane Katrina, they also change social behavior. Hospital emergency response plans should therefore include locking the facility down to control access. One should know how to access the hospital in advance and how to find the command and control center, which is typically in the emergency department.

Anesthesiologists are able to rapidly assess patients with traumatic injury, manage airways, and obtain vascular access. They can also provide sedation, pain control, and comfort care and also have an in-depth knowledge of the drugs used in the treatment of injuries. Therefore, they could be assigned by the control center to assist with triage outside the hospital, to the emergency department, to the operating suite, or to the ICU.

Response to a Disaster

Most people are concerned about a mass casualty event that is caused by the use of a weapon of mass destruction, but >90% of the disasters in the world are natural events (Table 16.1). These events, which affect >200 million people annually, are broadly classified as meteorologic, geophysical, and biologic. They are in the national conscience because they occur so frequently, and they are events with which most people are familiar. Physicians likewise, have experience treating the types of injuries and illnesses caused by natural events; patients receive blunt or penetrating injuries, for example, or they develop pneumonitis from an infectious agent. Everyone has heard about the threats posed by weapons of mass destruction (WMD)—chemical, biologic, radiologic, nuclear, and (high-energy) explosive (CBRNE) devices—but few physicians have ever seen or managed a patient injured by WMD. Although these weapons are rarely used, all physicians should understand some of the basic tenets of managing patients injured by WMD.

Table 16.1 Disasters That May Result in Mass Casualties

Natural

Unintentional

Intentional

  • Weather

  • Hurricane

  • Airplane, train, or bus crash

  • Boat sinking

  • Chemical

  • Biologic

Tornado

Fire

Radiologic

Flood

Nuclear power plant accident

Nuclear

  • Earthquake

  • Infectious

  • Building collapse

  • Sports stadium disaster

Explosion

  • Influenza

  • Hemorrhagic fever

Natural Disasters

The United States is relatively fortunate because the effects of natural disasters have not been as severe as seen elsewhere in the world, where millions of people are affected each year. Those who have experienced first hand the effects and sequelae of hurricanes, tornadoes, earthquakes, or floods, or who have worked in an ICU providing care to patients with SARS, avian flu, or Ebola know well the impact that these events have had on their communities and themselves.

Meteorological Disasters

In August 2005, hurricane Katrina struck New Orleans, Louisiana. Hurricane Ike struck Galveston, Texas, in September 2008, and in October 2012 hurricane Sandy came ashore just northeast of Atlantic City, New Jersey. Hurricane Sandy was barely a Category 2 hurricane (sustained winds of 96–110 mph) when it made landfall but because it struck during high tide, however, its storm surge caused significant flooding in New Jersey, New York, and other states along the Eastern seaboard. All three hurricanes flooded hospitals, and many were incapacitated because electrical power was lost or functioning at partial capacity because employees were unable to commute to the hospital. Mass transit ceased, roads were flooded, and the subway system was closed in New York. The United States was fortunate because there were far fewer casualties than those experienced by low-income countries. The economic impact, however, was staggering; the economic damage from hurricane Sandy alone was approximately $65 billion. Moreover, people still develop common ailments during such disasters. Individuals who develop appendicitis still require treatment, women in labor may require a cesarean section, and patients with coronary artery disease may have an acute myocardial infarction either de novo or caused by stress precipitated by the storm. Patients often somehow make their way to the closest health care facility, but if that facility is closed and is in the process of transferring its patients to other hospitals, the newly arriving patients will become part of that exodus. The receiving hospital is then faced with an influx of patients, some of whom are stable and some of whom require emergency intervention. Anesthesiologists practicing at the receiving hospitals or at outlying hospitals, must implement their family and personal emergency response plans, anticipate arrival at the hospital before the hurricane makes landfall, and have the ability to remain self-sufficient for as long as 48–72 hours.

The tornado that struck Joplin, Missouri in 2011 destroyed much of the town, including one of its two hospitals. Paramedics and EMTs worked out of their ambulances to render aid. On May 20, 2013, an EF5 tornado, with peak winds estimated at 210 mph struck Moore, OK, and adjacent areas, killing 24 people and injuring 377 others. Those 377 individuals sought aid wherever possible, and many who could not find a hospital asked for help in pharmacies, and free-standing surgery centers. Whatever the circumstance, anesthesiologists must be prepared to render aid.

Geological Disasters

Earthquakes are not as common as weather-related disasters but still claim more than 1 million victims a year. Because of a lack of building codes, low-income countries tend to have the highest morbidity and mortality. Even developed countries such as the United States can experience significant damage and loss of life, as happened in Northridge, California in 1994. Coastal regions of Indonesia and Japan experienced significant destruction from tsunamis that were caused by earthquakes. Casualties and patients requiring emergency treatment for non–disaster-related problems (e.g., appendicitis) might need to be transported out of the earthquake zone of hospitals are destroyed or rendered unsafe because of structural damage. Crush injuries and amputations are the most commonly seen injuries in patients who have sustained trauma. Anesthesiologists may be asked to assist at the site of a collapsed building to care for a patient who needs a surgical amputation in order to be extracted from a collapsed building. The aim in such a situation is to provide an anesthetic that is quick and effective (e.g., intramuscular or intravenous ketamine and midazolam) while recognizing that the usual standard of care may be impossible to achieve.

Biological Disasters

Diseases such as SARS and influenza are highly contagious and are as likely to disrupt a community as would be the dissemination of anthrax or smallpox by a terrorist group. The Spanish influenza virus infected approximately 500 million people during the pandemic of 1918–1919, and of those between 50 and 100 million died. Many of those who died were young adults 20–30 years of age, and they died within days of becoming ill. The H1N1 influenza epidemic in 2009 also resulted in considerable morbidity and mortality and placed enormous demands on many hospitals. More recently, the outbreak of Ebola Viral Disease (EVD) in West Africa has attracted worldwide interest, and though there were few cases outside of Africa, hospitals and healthcare personnel in high income countries spent considerable time and energy preparing for the worst.

The most critical lesson to be learned from these epidemics is that infected patients or those considered to be infected must be isolated from contact with others in order to achieve the best outcomes. Moreover, health care workers must take the necessary steps to protect themselves. The experience with SARS in Canada emphasizes this point. When the first patients with SARS arrived in Toronto, no one appreciated the etiology of their illness and other patients and health workers contracted the disease. The spread stopped when the scope of the problem was recognized, patients were isolated, and health care workers began to use protective equipment. Because of the experience in Toronto, hospitals in Vancouver were on the alert. Patients with a respiratory illness recently arrived from Asia, were isolated, and the spread of SARS in Vancouver was much less than was observed in Toronto. Implementing strict infection control techniques can also stop the spread of EVD, which is very contagious and associated with a high mortality rate. Because of the social norms in western Africa, however, the person-to-person spread has been significant.

Anesthesiologists may be called upon to use their skills in airway and ventilator management and may also be involved in the management of patients who are candidates for extracorporeal membrane oxygenation. Providing care to such patients is problematic, however, when wearing personal protective equipment. The suits are not ventilated and are therefore uncomfortable to wear. Providers are unable to work for >60–90 minutes at a time because of heat accumulation, at which point they must decontaminate themselves, disrobe, and rehydrate.

Unintentional Disasters

Crashes

Most crashes, whether of an airplane, bus, or train, do not create a mass casualty event but may create a mass casualty incident. Paramedics and EMTs transported patients to several hospitals, all of which experienced a mass casualty incident, after the Asiana Flight 214 accident in San Francisco in 2013. All of the hospitals that received casualties were, however, able to provide care in a timely fashion. Later that year, after 72 tank cars filled with crude oil derailed and caused a firestorm in Lac-Mégantic, Québec, Canada, the sole local hospital responded appropriately. Recognizing that there were insufficient personnel to handle a mass casualty incident, calls were made to nearby hospitals to request additional medical personnel. Despite the fact that one-half of the downtown was destroyed, 42 people were killed, and five were never accounted for, every casualty received appropriate care. In each of these cases, the emergency response system and the affected hospitals responded appropriately.

Fires

Appropriate management of the airway is one of the most critical components after an industrial accident or fire. Health care facilities near large industrial complexes must be prepared to manage patients with thermal injuries from chemical explosions and must therefore anticipate or know the types of chemicals to which patients may have been exposed.

One hundred people died immediately in a fire that struck a Rhode Island nightclub on February 20, 2003; 200 more were injured and required treatment at the nearby small community hospital. No neuromuscular blocking agents were used to intubate patients who required mechanical ventilation for surgery or to treat pulmonary insufficiency caused by smoke inhalation; the anesthesiologists realized only afterward this was the correct approach, as several patients had glottic edema that made intubation of the trachea difficult.

Patients with thermal injury require intravenous access as soon as possible for administration of intravascular fluids. Multiple protocols exist for the management of patients with thermal injury, but in essence Ringers Lactate solution should be administered during the first 24 hours at a rate of 1–2 mL/kg/percent body surface area burn. Avoid giving boluses if possible, adjusting the rate of administration of fluids to the urine output. Decrease or increase the Ringers Lactate infusion 20% per hour to maintain a urine output of 30–50 mL/h. Over-resuscitation is as harmful as under-resuscitation; during the 24 hours management of fluids on an hourly basis is critically important.

In patients with soft tissue and skeletal muscle damage, very high creatinine phosphokinase levels correlate with the degree of myoglobinemia. Alkalinizing the urine, along with intravascular volume resuscitation and promotion of diuresis, may protect the kidneys from injury.

Industrial Disasters

Health care workers, especially those who live or work near large industrial complexes, must be prepared to deal with industrial accidents. The Bhopal, India gas tragedy in December,1984, was one of the worst industrial accidents in recent memory. Methyl isocyanate gas was released into the atmosphere from a tank, killing approximately 3800 people and injuring several thousand more, many of whom required assistance with oxygenation and ventilation. The aftereffects are felt to this day.

The community in which one lives influences the kinds of natural disasters for which planning and preparation are necessary (e.g., a hurricane, a tornado, or an earthquake) and also influences the types of industrial accidents for which one should be prepared. For example, personnel who work at a hospital that is close to a chemical plant should be prepared to provide care for the accidents that might occur at that plant. Although the number of affected people may be fewer than in Bhopal, anesthesiologists might be called upon to render assistance to plant workers who have been injured by toxic fumes.

It is not always possible to anticipate the kinds of casualties that might arise from an industrial accident if there are main line railroad tracks, petrochemical plants or nuclear power plants in the vicinity. However, following an incident, emergency response personnel should be queried for any information about the chemicals to which patients might have been exposed. Railroad tank cars are required to have information about their contents clearly displayed. Most first responders also carry Geiger counters and should be able to provide some information about the need for decontamination of patients arriving from a nuclear power plant accident. On April 17, 2013, only 2 days after the Boston Marathon bombing, an explosion occurred at a fertilizer storage and distribution facility in a small town close to Waco, TX, while emergency personnel were responding to a fire at the facility. At least 15 people were killed and more than 160 were injured. On June 14, 2013, a chemical-plant explosion killed two people and injured more than 100 at the Williams Olefins petrochemical plant in Geismar, LA. Another explosion the same day killed one and injured seven at the CF Industries nitrogen production plant in Donaldsonville, LA, a small city on the Mississippi River 10 miles south of Geismar. Several of those injured had burns of sufficient degree that they required transfer to the burn unit in Baton Rouge, LA. Anesthesiologists who work in areas such as these should learn the specific hazards posed by the industries in the area and make specific preparations to manage large numbers of patients who will present with the most likely types of injuries.

Intentional Disasters (Terrorism)

Chemical Agents

Chemicals have been used as weapons for millennia and as weapons of mass destruction for more than 100 years. Their effectiveness has recently been “discovered” by terrorist groups, who have used chemical weapons to attack their perceived enemies. The Aum Shinrikyo terrorist organization poured a nerve agent, sarin, on the floor of subway cars in Tokyo, Japan in 1995, injuring thousands, and had planned the simultaneous release of cyanide gas into the same subway station. Fortunately, the device for creating and releasing the gas malfunctioned. It is not well known, but the cult sent members to Africa in the late 1990s during an outbreak of EVD to bring back virions to be used as a biologic weapon; fortunately, their efforts were unsuccessful.

Nerve Agents

After the sarin gas attack in Tokyo, >5000 persons required emergency medical evaluation, with approximately 1000 manifesting exposure to the nerve agent; 18 people died. Anesthesiologists have a unique understanding of how to manage chemical nerve agents, irreversible anticholinesterases, because they administer a reversible anticholinesterase drug (neostigmine) on a daily basis. The excess acetylcholine that accumulates in cholinergic nerve terminals accounts for the toxicity of the nerve agents. (A cholinergic drug such as glycopyrrolate is administered at the same time as neostigmine to antagonize the muscarinic effects of the excess acetylcholine.) Excess acetylcholine (at preganglionic muscarinic and postganglionic muscarinic and nicotinic receptors) causes copious lacrimal and nasal secretions, meiosis, bronchospasm, arrhythmias, and tonic muscle contractions leading to respiratory paralysis. Central nervous system toxicity causes seizures. The combination of status epilepticus and respiratory paralysis results in death.

If several patients arrive simultaneously in an emergency department complaining of shortness of breath and who exhibit rhinorrhea, miosis, and an irregular cardiac rhythm, it is possible that they have been exposed to a nerve agent as a result of a terrorist attack (Table 16.2). The differential diagnosis includes opioid overdose, but opioids do not cause rhinorrhea, bronchospasm, or diarrhea. A pneumonic to help remember unopposed parasympathetic activity is DUMBELS (D-diarrhea, U-urination, M-miosis, B-bronchorrhea and bronchoconstriction, E-emesis, L-lacrimation, and S-salivation).

Table 16.2 Symptoms and Treatment of Patients with Nerve Agent Exposure

Minimal

Moderate

Severe

Miosis, headache

Severe rhinorrhea

Respiratory failure

Rhinorrhea, salivation

Dyspnea/bronchospasm

Seizures/flaccid paralysis

Chest tightness

Muscle fasciculations

Incontinence

Remove from exposure

Wet decontamination

Decontaminate/atropine

Remove clothes

Atropine

2-PAM CL, ventilate

Patients who may have been exposed to a nerve agent must undergo decontamination (if that has not already been performed). The primary goals are to remove the nerve agent to prevent further injury and contamination of others. After donning personal protective equipment (PPE), remove the patient’s clothes, and if the patient has been exposed to a liquid nerve agent (as opposed to vapor), wash the patient with copious amounts of water in 0.5% hypochlorite (household bleach). The bleach is not as critical as washing with copious amounts of water. The only exception is if the patient is in extremis; treat these patients first and then decontaminate the patient and oneself. Patients who are in respiratory arrest or in status epilepticus should be treated as any other patient with these diagnoses. Antagonize the excess acetylcholine with a cholinergic agent (e.g., atropine at a dose beginning at 0.4 mg and repeated at 5-minute intervals until symptoms and signs have resolved; doses of 1–2 g are sometimes required) intravenously to attenuate and block the muscarinic side effects of the agents. Consider also administering pralidoxime chloride (2-PAM chloride). Pralidoxime chloride is an oxime that reactivates acetylcholinesterase by removing the nerve agent from its binding site on the enzyme. Spontaneous reactivation of acetylcholine esterase is variable and depends on the nerve agent used, the concentration of the agent to which the patient has been exposed, and the amount of time that has elapsed since exposure. Therefore, 2-PAM-CL should be administered as soon as possible to a patient if exposure to a nerve agent is suspected.

Pulmonary Agents

Pulmonary agents are gases at room temperature that damage the lungs. Any gas (e.g., otherwise harmless gases such as helium or nitrogen) could be considered a pulmonary agent because if released into a closed space in sufficient volume it could displace O2 and cause asphyxiation. Chlorine and phosgene, however, are the two classic pulmonary agents, and are most likely to be used by terrorists. Both gases are extremely toxic to the lungs and often cause acute respiratory distress syndrome even if small quantities are inhaled. Treatment is no different than that of silo filler’s disease or farmer’s lung (caused by exposure to nitrogen dioxide when a farm worker opens or enters a silo that has inadequate ventilation). Management of the resulting noncardiac pulmonary edema from NO2 or the pulmonary agents is symptomatic: mechanical ventilation using small tidal volumes (6–8 mL/kg) while maintaining peak airway pressures <30 cm H2O, positive end expiratory pressure and inspired oxygen concentrations of 50%–60% or less.

Blood Agents

The blood agents, hydrogen cyanide and cyanogen chloride, are the third class of chemicals that could be used as WMD. Because of the instability of cyanogen chloride, hydrogen cyanide is more likely to be delivered as an aerosol in a closed environment inducing cyanide toxicity to those who inhale the agent. Cyanide toxicity is an entity with which anesthesiologists are familiar because sodium nitroprusside, if administered at a high-dose for extended periods of time, also causes cyanide toxicity. Cyanide interrupts the electron transport chain in mitochondria, inhibiting aerobic metabolism. Untreated patients die rapidly. Cyanide poisoning is treated with an initial small, inhaled dose of amyl nitrite, followed by intravenous sodium nitrite and then intravenous sodium thiosulfate. The sulfur moiety of the thiosulfate serves as a receptor for the metabolic degradation of cyanide ions to thiocyanate, which is then excreted by the kidneys. Thiocyanate has few side effects until plasma levels exceed 10 mg/dL. Sulfanegen TEA, under investigation as an alternate to thiosulfate, can be administered by intramuscular injection and also converts cyanide into thiocyanate. Hydroxocobalamin, approved in 2008 is effective for the treatment of cyanide poisoning because its cobalt moiety binds cyanide ion rendering it inactive. Depending upon the severity of the poisoning, tracheal intubation, mechanical ventilation with 100% oxygen, and inotropes and vasopressors may be required.

Biologic Agents

Biologic agents are chosen for their ability to cause mass casualties because they are highly contagious or easily distributed over a large geographic area, because of the high morbidity and mortality associated with infection, and because of their ability to cause panic and disruption of normal social behavior. Several agents that fit this description have been used by military forces and terrorists in the past. Category A agents are those that are highly contagious, have a high mortality rate, along with other characteristics that make them ideal WMD (Table 16.3).

Table 16.3  Biologic Agents Used as Weapons of Mass Destruction

Category A

Category B

Category C

Bacillus anthracis (anthrax)

Coxiella brunetti (Q fever)

Encephalitic viruses

Variola major (smallpox)

Vibrio cholerae

Yersinia pestis (plague)

Burkholderia mallei (glanders)

Clostridium botulinum (botulism)

Enteric pathogens

Viral hemorrhagic fever (Ebola)

Cholera, cryptosporidium

Various biologic toxins

Smallpox

Smallpox

The last case of naturally occurring smallpox in the world was reported in 1977 in Somalia and in 1980, the World Health Organization announced that the world was free of this scourge. Routine vaccination for smallpox is no longer carried out, except in the military and for some public health care workers considered at high risk of contracting the disease (i.e., individuals who the government would rely on to staff vaccination stations if there were a breakout). Terrorists might consider using smallpox as weapon because an increasing number of people no longer have immunity. Smallpox is highly infective, with 40% to 80% of non-vaccinated individuals becoming affected after exposure to only 10 to 100 virions. Virions can be transmitted as an aerosol or on clothing or linen from an infected individual. Thirty to fifty percent of infected patients die. Immunity decreases over time in individuals who have been vaccinated, but the vaccine provides some protection even after 20 years.

Patients who are infected with smallpox present with malaise, headache, and backache with fever to as high as 40° C. The fever decreases over the next 3–4 days at which time the characteristic rash develops. Smallpox has a predilection for the distal extremities and face, although no part of the body is spared, with all lesions at the same stage. If a case of smallpox is identified, the Centers for Disease Control and Prevention has plans to quarantine the patient. That patient’s immediate contacts and individuals within the geographic area would be vaccinated. There are stockpiles of vaccines placed strategically throughout the United States just for such an event. The Centers for Disease Control and Prevention and the states’ departments of health will implement their quarantine and vaccination plans should an index case or several cases (a cluster) occur.

Anthrax

Anthrax (bacillus anthracis) spores clump in the nasopharynx when inhaled. For B. anthracis to be used as a weapon, therefore, it must finely ground so that it can be aerosolized, inhaled, and deposited in terminal bronchioles and alveoli. When inhaled, weaponized anthrax has very high infection and fatality rates. For example, one of the letters mailed in the anthrax attacks of 2001 contained 2 g of weapons-grade anthrax. With an LD50 of 1000 spores, under optimum conditions, this was enough material to infect 50 million individuals and cause a fatality rate as high as 80%. The accidental release of anthrax spores at a facility in Sverdlovsk in the former Soviet Union in 1979 killed 66 of the 77 people who were infected (i.e., an 86% mortality rate).

Anthrax presents in a manner similar to an influenza-like disease with fever, myalgias, malaise, and a nonproductive cough that may or may not be associated with chest pain. After a few days, the patient appears to improve, but then develops dyspnea, hemoptysis, stridor, chest pain, and cyanosis. Chest X-ray reveals a widened mediastinum. If untreated, death occurs in 1–2 days. Penicillin G was the treatment of choice before several countries engineered a resistant strain. Immunization against anthrax is undertaken for the US military but requires six subcutaneous injections administered over 2 years. Ciprofloxacin or doxacycline are the recommended antibiotic treatment for a patient with an active case of anthrax.

Plague

Yersinia pestis (bubonic plague) was the cause of the Black Death that killed one-third of the population of Europe in the 14th century. Rodents and fleas are the natural hosts for Y. pestis, and the infection is transmitted through fleas. Humans are an accidental host, usually acquiring the disease from a fleabite, although direct person-to-person transmission can occur from patients with pneumonic plague. The mortality rate for either bubonic or pneumonic plagues is as high as 50%.

After a 2- to 6-day incubation period, an infected patient presents with sudden onset of fever, chills, weakness, and headache. Buboes, intensely painful swelling of the lymph nodes in the groin, axilla, or neck, also develop at this time. Without treatment, patients develop septic shock with cyanosis and gangrene in peripheral tissues. Patients with bubonic plague can seed their lungs with organisms, developing pneumonic plague. Aerosolized secretions caused by coughing can then infect others. The diagnosis can be confirmed with a gram stain or culture of organisms from blood, sputum, or buboes. The treatment of choice is streptomycin, but chloramphenicol or tetracycline can also be used.

Tularemia

Francisella tularensis (tularemia) has some similarity to anthrax and plague, but is not nearly as dangerous. Normally, humans acquire F. tularensis with direct contact of an infected animal or from the bite of an infected tick or deerfly. As few as 10 or 50 organisms can invade the body either through hair follicles or miniabrasions. After an incubation period of 2–6 days, swelling and ulceration is noted at the site of entry. As the swelling continues, the skin eventually breaks, creating an ulcer that develops a necrotic base that becomes black as it scars. F. tularensis would most likely be delivered as an aerosol from an airplane. There would then be a 3- to 5-day incubation period after inhalation. The onset of disease would then be marked with fever, pharyngitis, pneumonitis, and hilar lymphadenopathy with a mortality rate of 5% to 15%.

The treatment of choice for tularemia is streptomycin, although gentamicin, tetracycline, and chloramphenicol have been used.

Hemorrhagic Fevers

A number of viral hemorrhagic fevers are listed as Category A agents including the arenaviruses (Lassa fever), bunya viruses (hanta), flaviviruses (Dengue) and filoviruses (Ebola and Marburg). There are at least 18 viruses that cause human hemorrhagic fevers; they are characterized by viral replication in lymphoid cells with incubation between 2 and 18 days. Patients then develop fever (>38.6° C), headache, myalgias, abdominal pain, and vomiting, depending on the agent itself and the amount that is inhaled or inoculated across the skin. During the EVD pandemic that began in West Africa in December of 2013 symptoms appeared 8–10 days after an 8-year-old boy handled a bat, the only known reservoir for Ebola virus. Lessons learned in central Africa from the more than 20 epidemics that have occurred there since 1976 were forgotten. Control of the pandemic required implementation of practices that are important for managing any contagious infectious disease, but especially for any Class A agent. Patients with the disease must be quarantined, contacts must be identified and isolated from the rest of the population, health care workers providing care must follow strict infection control protocols, and safe burial practices must be implemented. Treatment of EVD is supportive and includes maintenance of intravascular volume and oxygenation and treating associated infections. Some patients have recovered more quickly after the intravenous administration of plasma obtained from survivors. Several vaccines are currently being studied.

Radiologic Agents

An industrial accident or the intentional use of radiologic agents by a terrorist group would be the most likely reason that a large population would be exposed to radiation. Terrorists have tried twice to detonate a “dirty bomb,” which is a conventional explosive device surrounded with radioactive material, but fortunately were unsuccessful. Although the use of a dirty bomb is of concern, an accident at a nuclear power plant is far more likely (see Table 6.2). After a nuclear power plant accident, patients are often externally radiated and, may or may not require decontamination and treatment depending on the type and amount of radiation exposure. Assessment may be difficult, but individuals who have no symptoms after 6 hours are unlikely to have received a dose of radiation that requires hospitalization. Those who are symptomatic are hospitalized if possible for serial measurement of white blood cell counts. If the white blood cell count remains stable for 48 hours, the patient may be discharged.

The current policy in the United States is that after any release of radiation, local public health departments will distribute potassium iodide tablets within 24 hours to protect the thyroid of all potentially exposed individuals. Those with the greatest exposure may require hospitalization for treatment of the sequelae of radiation exposure, which include bone marrow failure leading to infection and coagulopathy, gastrointestinal bleeding caused by mucosal damage to the lumen of the intestines, and thrombocytopenia. Treatment of infection, transfusion and volume resuscitation and treatment with G-CSF (granulocyte colony stimulating factor) may be lifesaving.

Nuclear Disasters

A nuclear bomb detonation is very unlikely, but significant planning for the management of such a catastrophe has occurred. Guidelines are in place and are available for use by health care professionals. Most survivors will present with traumatic injuries similar to those seen with conventional explosions. These injuries will be the immediate cause of morbidity and mortality; sequelae of radiation exposure may then appear days to years later depending on the degree of exposure.

Explosive (High Energy) Agents

Detonation of an improvised explosive device (IED) is by far the most widely used weapon by terrorists. On April 15, 2013, at the finish line of the Boston Marathon, two IEDs—pressure cookers loaded with gunpowder, nails, and ball bearings—were detonated, killing three bystanders at the scene (Fig. 16.1). Another 264 runners and bystanders were injured and transported to 29 local hospitals, underscoring what was discussed previously: Casualties do not preferentially go to Level I trauma centers (the greater Boston area has 11 Level 1 adult and pediatric trauma centers). Sixteen patients had traumatic amputations; their limbs were either severed during the explosion or sustained such severe damage that they were not salvageable. Three patients had more than one traumatic amputation. An IED detonation may cause lacerations, thermal injury, multiple penetrating wounds from shrapnel, fractures, blunt soft issue injury, traumatic amputations, and traumatic brain injury from the primary, secondary, and tertiary blast effects. Although a “dirty” bomb has not yet been detonated by terrorists, this could happen in the future. These patients require decontamination prior to evaluation, stabilization, and treatment, unless the patient has life-threatening injuries that require treatment before decontamination.


Figure 16.1 The finish line at the Boston Marathon as the improvised explosive device exploded.

Figure 16.1 The finish line at the Boston Marathon as the improvised explosive device exploded.

Photo by Dan Lampariello. Reprinted with permission.

Patients with any evidence of burns to the face or airway should be intubated, awake if possible, because a significant number of these patients will have mild to moderate glottic edema at the time of intubation. Patients with burns must be managed aggressively with fluid resuscitation. Because these patients will have other injuries from shrapnel and amputations, intravascular volume may be significantly decreased and a very liberal fluid resuscitation policy must be followed. Many patients will require more fluid than is commonly given with either the Parkland or Brook Army Burn Center formulae. In addition to volume resuscitation, forced diuresis with alkalinization of the urine in patients with a crush injury or extensive soft tissue and skeletal muscle damage may be organ and lifesaving. Patients with the most severe injuries are likely to have had significant blood loss and are at risk of developing acute traumatic coagulopathy. Rapid, acute blood loss leads to deceased O2 delivery because left ventricular end diastolic volume and cardiac output are decreased, and the decreased blood hemoglobin levels results in a decreased arterial O2 content. Hemorrhagic shock is the end result manifested by hypotension, tachycardia, lactic acidosis, and hypothermia. The latter two predispose the patient to developing acute traumatic coagulopathy. After an incident such as the Boston Marathon bombing, the blood bank should be alerted to the possibility that the hospital’s massive transfusion protocol may need to be activated for multiple patients. The operating rooms should be warmed and measures taken to maintain patients’ temperature during surgery. Damage control resuscitation is commonly used in these cases, so the infusion of crystalloid should be very limited, with a goal of replacing what was lost using thromboelastography or one of its surrogates to guide blood component therapy. Tranexamic acid has been shown to improve outcome but the improvement in outcome is moderate at best. The best outcomes are achieved by stopping the bleeding as soon as possible by whatever means necessary, for example, by placing a tourniquet in the field or by rapid transport of a patient to the hospital and an operating room for damage control surgery. With planning and preparedness, patients who arrive at a hospital may have a 98% chance of survival.

Conclusion

Few physicians who work in the community or at an academic center are experienced in the management of mass casualties. However, one can prepare for one by developing a family care plan, a personal care plan, and a professional plan that includes a review of the anesthesiology department’s emergency response plan and knowing where to find information that would be of great importance in managing patients injured by WMD.

Further Reading

Baker DJ. Management of casualties from terrorist chemical and biological attack: a key role for the anaesthetist. Br J Anaesthes. 2002; 89(2): 211–214.Find this resource:

Ball CG. Damage control resuscitation: history, theory and technique. Can J Surg. 2014; 57(1): 55–60.Find this resource:

Rice MJ, Gwertzman A, Finley T, Morey TE. Anesthetic practice in Haiti after the 2010 earthquake. Anesthes Analges. 2010; 111(6): 1445–1449.Find this resource:

Shamir MY, Weiss YG, Willner D, et al. Multiple casualty terror events: the anesthesiologist’s perspective. Anesthes Analges. 2004; 98(6): 1746–1752.Find this resource: