Special Issue: Anesthesiologists Now Must Prepare for Biologic, Nuclear, or Chemical Terrorism

Michael J. Murray, MD, PhD, FCCM; C. George Merridew, MBBS, FANCZA

You are the on-call anesthesiologist and receive a page from the chief of staff notifying you that a chemical terrorist attack has just occurred in your community. The disaster plan is being initiated and hundreds of critically ill and injured patients will be descending on your hospital. What do you need to know?

Disaster Readiness Provides Response Infrastructure

In keeping with the tenets of the Anesthesia Patient Safety Foundation (APSF), this newsletter has 4 articles dedicated to the care of patients who might be victims of weapons of mass destruction or of natural disasters. We hope to also educate anesthesiologists on how to protect themselves when such catastrophes occur as they may find themselves either at ground zero or in healthcare facilities caring for the victims. While much of the information is basic, because of ongoing developments, we have also included selected URLs for websites that could be used for future updates or to gain additional information. Healthcare facilities have contact information for county and state public health agencies. We have also included telephone numbers for the Centers for Disease Control (CDC) and other federal government agencies that might play a role in coordinating any disaster response.

The goal of these articles is to provide information to assist in the care of victims of nuclear, biologic, or chemical (NBC) weapons. However, anesthesiologists involved in the events of September 11 found themselves confronted with none of the above. The few event survivors had blast, burn, and crush injuries, and less severe injuries similar to the types of injuries commonly seen in mass casualty situations. Therefore, this first article deals with how to provide care for such victims.

We all hope that such preparation is unnecessary, but we also know that it is not a matter of if, but when. Even if it were not necessary to anticipate such future terroristic attacks, major natural catastrophes continue to occur with disturbing frequency—be it a jumbo jet crashing in a corn field in Iowa, earthquakes in California, weather-related events (hurricanes, tornados, and floods) throughout the United States, industrial explosions, or motor vehicle accidents such as the recent 125 car pile-up in Georgia.

We all assume that given such events, we would help provide care in emergency departments (EDs), operating rooms, or intensive care units (ICUs). Yet the reality is that each of us could find himself or herself present at the site of the catastrophe for any number of reasons. Furthermore, depending on the extent of the catastrophe, the healthcare facilities in which we work may themselves be destroyed or incapacitated because of flooding, loss of power, or physical damage. In such scenarios, federal agencies would transport medical facilities to the site, but even in the best of circumstances, these take 8 to 24 hours to arrive. We could find ourselves without the high-level resources and facilities that we are accustomed to having. Even in an austere environment, our medical education and level of expertise still enable us to provide high quality medical care.

It is vitally important that all of us become familiar with the information contained in these articles. We often assume that local agencies or the federal government or the military will coordinate and provide an adequate response. The military generally has little involvement in the U.S. disaster response system. However, there have been recent examples of domestic military disaster response, such as the U.S. Airforce providing medical support and transportable healthcare facilities during the floods in Houston, Texas, in the summer of 2000, and in New York City at the World Trade Center.

Overview

The response to any disaster begins locally, but depending on the severity and type of event, the federal government becomes involved very quickly. At that level, the Department of Health and Human Services (DHHS) is the department with primary responsibility for coordinating the medical response. The Office of Emergency Preparedness (OEP) coordinates the activities of several agencies including the Federal Emergency Management Agency (FEMA) (http://www.fema.gov/) and any efforts by the Department of Justice or Department of Defense. If the disaster is the result of terrorism, the Department of Justice, in which the Federal Bureau of Investigation (FBI) (http://www.fbi.gov/) is located, coordinates the federal response to the specific threat, a response that may involve many law enforcement agencies.

FEMA is in charge of managing the consequences of any natural disaster or terrorist action to include protection of public health, coordinating rescue and medical treatment of casualties, evacuating people from the scene, protecting first responders, and preventing subsequent illness by contamination of first responders or healthcare workers with infectious, chemical, or radiation agents.

The CDC has established the national pharmaceutical stockpile (NPS) program with two phases. In the first phase, there are 8 separate prepackaged caches stored around the United States that are ready to be shipped within 12 hours. These push packs contain antibiotics, chemical antidotes, life support medications, airway maintenance supplies, and even dozens of mechanical ventilators. Should a situation be necessary to use such equipment, who is better trained in intravenous therapy, airway management, and mechanical ventilators than we as anesthesiologists? If the catastrophe requires an even larger response, there are vendor-managed inventory (VMI) packages that contain even more material that will be shipped to the site within 24 to 36 hours after the initial push package is sent.

Each of us has a responsibility to educate ourselves on how to treat victims of natural disasters or weapons of mass destruction. The Association of American Medical Colleges (AAMC) and the American Medical Association (AMA) (http://www.ama-assn.org/) have been advocating education of all physicians on biological, chemical, and nuclear terrorism. The AAMC is advocating its “first contact/first response” (http://www.aamc.org/bioterrorism/) plan to ensure that medical students, physicians in training programs, and practicing physicians are adequately educated on these topics. Legislation has been introduced in Congress to establish education programs sponsored by the Veterans Affairs Administration and the Department of Defense based on the existing programs at the F. Edward Hebert School of Medicine of the Uniformed Services University of the Health Sciences (USUHS). However, it is unlikely that Congress will mandate any change in medical school curriculum or in the credentialing and continuing education process for physicians. We, therefore, have a responsibility to educate ourselves.

In addition to these national medical associations’ responses, several medical schools and other professional associations have developed their own programs. For example, the New York University School of Medicine, in conjunction with the New York Harbor Veterans Affairs Medical Center, has created a “Joint Center for Bioterrorism Research,” and the school has opened a new “Center for Health Information and Preparedness (CHIP).” This special issue contains information for anesthesiologists relevant to roles they may be asked to assume in the event of a terrorist attack on their community.

Basic Tenets of Emergency Response

In almost all disaster cases, the first responder is not typically a member of the emergency response community, but a bystander who rushes to the site and begins either extracting victims from the scene or administering basic first aid or life support. The formal medical response is initially coordinated locally and includes emergency medical technicians and paramedics working with local ambulance services and hospitals. The National Disaster System can be subsequently activated to include county, state, and federal agencies, and even the military.

At the scene, one needs to assess any additional threats to patients, the safety of the environment, the risk to oneself and coworkers, and the immediate treatment steps necessary to care for patients. Simultaneously, one should activate the area’s disaster plan if necessary.

A basic tenet of any emergency response plan is to establish a command center with clear lines of communication (though the latter are very difficult to establish as several recent scenarios have borne out). If one is going to best assist, it is important that one contact the command center and offer one’s services to work with the center to become fully integrated into the disaster response.

It is also important to be familiar with the principles of triage. Triage is supposed to occur at the scene of the accident (this rarely occurs). Emergency medical technicians should triage patients, sending the most severely ill first and those with less severe injuries later. As the events of September 11 and many other catastrophes through the United States have borne out, individuals are often picked up on a first-identified basis and transported to the nearest facility. There is frequently very little prehospital triage. Many patients either transport themselves or are transported by friends, family, or coworkers to the ED. Therefore, it is frequently mandatory that a triage system be established outside the ED. Triage is designed to identify those individuals who are most critically wounded and who will most likely benefit from emergency intervention and surgery. In ideal circumstances there may be critically ill individuals one might be able to resuscitate and save, but if there are several hundred casualties, patients with ASA status 5E may be classified as “expectant,” i.e., expected to die from their injuries, and should be separated from the main patient flow and kept in a quiet reassuring environment with attention to providing analgesia and comfort. Trauma surgeons must deal with the onslaught of casualties and prioritize their efforts, focusing on those patients and surgical interventions that are most likely to have the greatest benefit. Burn, crush, or blast injuries are common, but one must also be prepared to treat chemical, biologic, or radiation injuries, while decontaminating the patient and protecting oneself.

Prehospital Care

From an anesthesia perspective, the situation most frequently encountered at the disaster site, short of extraction of individuals from rubble or vehicles, providing first aid, and triaging patients, has to do with airway management and ensuring adequate ventilation and oxygenation. One may be asked to assist with an amputation of a limb to facilitate the extraction of an individual who is trapped. Under these circumstances, ketamine, with or without benzodiazepines or opioids, is the anesthetic of choice. One must recognize the increased risk for awareness and potentially for hallucination in these scenarios. However, the use of a benzodiazepine or opioid in these circumstances must be done with caution as many of these patients may be hypovolemic from hemorrhage. Any central nervous system depressant, by abating the sympathetic response, has the potential to produce profound hypotension with resultant morbidity or mortality.

Patients who are already extracted from buildings or vehicles may need more invasive support of ventilation. Intubations in this setting are frequently difficult for a variety of reasons. An awake, blind, nasal intubation is the preferred technique because these individuals have to be assumed to have a full stomach. The use of medications to facilitate intubation is rarely recommended. There is debate in the literature, however, because patients who can be successfully intubated without anesthesia or muscle relaxants frequently are so obtunded that their outcome is extremely poor.1 The decision to facilitate intubation with medication should be based on the situation, expertise of the provider, and availability of drugs.2

Hospital Care

Although anesthesiologists may be deployed in the ED, their expertise will most often be required in the operating rooms where the majority of surgical procedures may be limited to life-saving and limb-salvage operations. When anesthetizing these individuals, there are many reasons why it may not be possible to meet our usual standard of care (Table 1). Frequently, there is no preoperative assessment and often times volume resuscitation is limited. In certain circumstances, supplies may be extremely limited, and we must improvise. Depending on the scope of the disaster, there may be an inadequate number of trained personnel and one must rely on “on-the-job training” to enlist bystanders in the delivery of care.

There are a variety of anesthetic techniques that may be available and appropriate, but ketamine is the drug most frequently prescribed, with or without a benzodiazepine. If possible, a local anesthetic can be the primary technique, and depending again on the environment, an inhalation anesthetic might be used. Central neuraxial anesthetics should be avoided and may be frankly contraindicated because of concerns about volume status and the potential for exacerbation of hemorrhagic shock.

Even when using ketamine, one has to be cognizant of comorbidity that could affect anesthetic management. We must assume that these patients have a full stomach, hypovolemia, and anemia. Their care may be complicated by extensive burns that limit IV access, by chest and head injuries, and by undiagnosed injuries. These patients may not give an adequate history and their examinations are frequently rushed. Depending on the scenario (e.g., earthquake), up to 10% of patients will have chest injuries requiring surgical intervention.3 However, if one is caring for flood victims, surgery is usually noncavitary and interventions are usually focused on limb trauma.

If general anesthesia is required, a rapid sequence induction is generally recommended. There may be an increased risk of awareness, but the consequences of over-sedation with a benzodiazepine or opioid are readily recognized and may lead to increased mortality. If one is unable to secure the airway, then a laryngeal mask airway (LMA) may be used and, if need be, a surgical airway may be required. The intraoperative care of trauma patients is fairly standardized and is well documented in the literature.4

Similarly, the postoperative care of these patients is frequently the same as for any other trauma patient who has undergone major surgery. One must not assume that all medical and surgical problems have been resolved. These patients may require continued volume resuscitation, intubation, mechanical ventilation, and frequent reassessment. Similarly, they may require invasive monitoring, additional analgesia or sedation, or transport to another facility, frequently with the assistance of anesthesiologists.5 During the postoperative period, attention to certain details can greatly facilitate the overall disaster response and the post-hoc analysis of how to improve future responses. Initial documentation is often inadequate and, if time permits, documentation of the patient’s name, injuries, and pertinent information on mechanism of injury (in addition to completion of the anesthetic record), may be extremely helpful. Currently there are no such guidelines for uniform reporting of data, but the development of guidelines is underway.6

Anesthesia in Austere Environments

We all assume that we would do whatever we could to help in any such disaster, but there is also naïveté in that we believe we will continue to work in our own hospital environments. The reality, based on the extent of the disaster, is that we may have to work in a field hospital established by the military, or a situation may arise where we as anesthesiologists are transported to another site and practice anesthesia in an austere environment.7 In this circumstance the principles that are advocated above continue to hold true with respect to the use of ketamine. Depending on the severity of the situation and the availability of medications, other induction agents (e.g., propofol or etomidate) can be used, if titrated to effect. Draw-over anesthesia machines have the most stability and are the most frequently used in austere environments.8 With our education in the basics of anesthesia, we should be able to quickly become familiar with the delivery of an inhalation agent using a draw-over machine, which may have added safety, particularly with inexperienced personnel or limited monitoring equipment.

Conclusion

From past experience, we know that anesthesiologists will be involved in response to future catastrophes.9 While we may be practicing in austere environments, the hallmarks of a good anesthesiologist or anesthetist are clinical expertise and ability to improvise using all five senses, vigilance, and commitment to excellence. Even though monitoring devices may be unavailable, such monitoring only supports what we commonly do and is not a substitute for experience and our commitment to excellence. We hope that these treatises facilitate your ability to respond to any future catastrophes and to contribute to an effective medical response that optimizes outcome and minimizes injury to oneself. In such situations, rest-work cycles must be established, again to protect oneself and to assure the availability of competent, focused healthcare providers.

Michael J. Murray, MD, PhD, FCCM, is Chair and Professor, Department of Anesthesiology, Mayo Clinic, Jacksonville, Florida, Chair of the American Society of Anesthesiologists’ Critical Care Medicine and Trauma Medicine Committee, Colonel, USAR Medical Corp., and Guest Editor of this special edition of the APSF Newsletter. C. George Merridew, MBBS, FANCZA, is Chair of the Anaesthesia Section, Australian Defense Force, Brisbane, Australia.

References

  1. Lockey D, Davies G, Coats T: Survival of trauma patients who have prehospital tracheal intubation without anaesthesia or muscle relaxants: observational study. Br Med J 2001;323:141.
  2. Yamamoto LG, Yim GK, Britten AG: Rapid sequence anesthesia induction for emergency intubation. Pediatr Emerg Care 1990;6:200-13.
  3. Özdoóan S, Hocaoólu A, Caólayan B, et al: Thorax and lung injuries arising from the two earthquakes in Turkey in 1999. Chest 2001;120:1163-66.
  4. Hardman JG, Wilson JMA, Yeoman PM, Riley B: Anaesthetic management of severely injured patients: general issues. Br J Hosp Med 1997;58:19-21.
  5. Leslie CL, Cushman M, McDonald GS, et al: Management of multiple burn casualties in a high volume ED without a verified burn unit. Am J Emerg Med 2001;19:469-73.
  6. Dick WF, Baskett PJF, Grande C, et al: Recommendations for uniform reporting of data following major trauma—the Utstein style. An International Trauma Anaesthesia and Critical Care Society (ITACCS) initiative. Br J Anaesth 2000;84:818-19.
  7. Taylor PRP, Emonson DL, Schlimmer JE: Operation Shaddock—the Australian defence force response to the tsunami disaster in Papua New Guinea. Med J Australia 1998;169:602-6.
  8. Olson KW, Kingsley CP: Drawover anesthesia. A review of equipment, capabilities, and utility under austere conditions. Anesthesiology Rev 1990;17:19-29.
  9. Gyamfi-Adu Y: The Gulf War: the experience of a department of anesthesiology in the management of scud missile casualties. Prehosp Disaster Med 1997;12:109-13