Anesthesia and Disaster Medicine: Part II [back]
Framework for Mass Casualty Management and the Role of the Anesthesiologist

By Ernesto A. Pretto, MD, MPH

Injury or trauma may be defined as physical or psychological harm resulting from adverse environmental factors or circumstances. The terms injury and trauma can be used interchangeably, but I prefer to use the word trauma. The mechanisms of physical trauma can be classified into broad categories such as intentional or unintentional, blunt or penetrating. Intentional trauma is further subdivided into suicide (self-inflicted trauma) or homicide from violence, a major health problem in our world today. Disasters, however, constitute special emergencies characterized by mass trauma or illness, and requiring extraordinary emergency response capability. As I mentioned in the first part of this series, medical disasters can be classified into two main types: natural (e.g. earthquakes, hurricanes, etc.) or man-made (e.g. weapons of mass destruction, armed conflict, wars, and complex humanitarian emergencies, etc.). In a temporal perspective, disasters also can be classified as chronic or protracted, as in drought or war (Ethiopia 1986, Somalia 1998, Bosnia 1993), or sudden-impact, as in earthquakes or terrorism (Armenia 1988, Kobe, Japan 1995, New York 2001). Response will vary according to type.

What makes a disaster different from other medical emergencies?

Immediately after a disaster such as an earthquake or terrorist attack strikes in a densely populated area, large numbers of people can be expected to suffer serious or life-threatening injuries or illnesses. The survival rate for these individuals declines rapidly unless prompt emergency medical assistance is provided within minutes to a few hours of their injuries. While the pattern and extent of injuries and illnesses will vary depending on the type and magnitude of the disaster, most disaster response experts agree that the main window of opportunity for saving lives of the critically injured but treatable victims is the first few hours.

Unfortunately, no matter how well prepared is the community, expected and unexpected problems arise that hamper the response effort causing delays in the treatment of victims. These barriers to prompt response are usually related to infrastructure damage (i.e. roadways, lifeline, communications, community services, etc.), which are directly caused by the disaster, contributing to the disorganized or haphazard delivery of medical and health care. This fact coupled with poor pre-planning, organization, and coordination of mass casualty management can further impede the ability of medical assistance from within or without the stricken region to deploy, set-up, and begin to treat casualties in time to impact on survival. As a result, a second disaster unfolds. This is an important difference that distinguishes a disaster from other medical emergencies.

Since, by definition, a disaster inflicts injury or illness sufficient to overwhelm the local ability to respond, reinforcements must be called in from outside, and some of the injured must be removed to unaffected areas. Response usually takes place at the lowest possible (local) level, because there are less logistical hurdles to overcome, and also because immediate, lower-level care is more effective in saving lives. For example, data from Emergency Medical Services (EMS) Systems in the United States suggest that the more rapidly and effectively the application of initial life supporting first aid (LSFA) by uninjured bystanders and Advanced Trauma Life Support (ATLS) by professional rescuers, more lives are saved and less expensive are the medical consequences in terms of reduced morbidity, mortality, and long term disability of patients. But because of the large number of casualties requiring immediate care simultaneously in a disaster or because of the destruction of the health care infrastructure, professional search and rescue and the pre-hospital response is hampered. This is a key distinction between a medical disaster and a multi-casualty incident (MCI).

How can we prevent or mitigate the human impact of trauma or illness in a disaster?

Preventive measures are by far the most cost effective means to prepare for a disaster. Methods to prevent or reduce morbidity and mortality from trauma caused in an earthquake, chemical, nuclear or bio-terrorism attack, or efforts to prevent or mitigate the disruption of health services and deteriorating sanitary conditions following these, depend on a number of factors. However, there are ten basic elements of disaster prevention and mitigation that, when applied before the event, can greatly reduce the adverse health consequences of disasters:

1. Prudent land use (location of human settlements in safe – low risk areas).
2. Limited land or building occupancy density (low population/building density).
3. Good quality infrastructure (building stock and materials for shelters).
4. Early warning systems and pre-designated evacuation routes for populations at risk (such as in coastal areas at risk for hurricanes).
5. Epidemiological or disease surveillance systems (especially in preparing for bio-terrorism).
6. Well-equipped and trained first responders (EMS, Police, Fire) and other emergency health workers and services capable of rapid deployment and field operations in the local community (see 16 EMS disaster functions below).
7. A significant proportion of the civilian population (>30%) knowledgeable in what to do in disaster and trained in life supporting first aid. In addition, an organized citizen response component such as the Community Emergency Response Teams (CERT), volunteers trained in providing effective support to EMS operations (see below).
8. Hospitals with structural and nonstructural integrity capable of operating under disaster conditions (see criteria for hospital disaster preparedness below).
9. A disaster ‘resistant’ telecommunications infrastructure (with backup systems such as amateur radio network) designed to allow multi-jurisdictional coordination (police, fire, EMS, hospital, etc.) and enhanced by robust information management and decision support systems.
10. The organizational flexibility to escalate the delivery of health resources to effectively match resources with demand for those services (needs), as the disaster unfolds, and the early identification of secondary hazards (e.g. Fires produced by ruptured gas lines in earthquakes).

What is the framework for mass casualty management?

The basic unit of medical response in a disaster is the local pre-hospital EMS/trauma and hospital system. In large-scale disasters where the local community is overwhelmed, health services are backed-up by regional, state or federal resources, depending on the magnitude of the needs. However, it is beyond the scope of this paper to describe state and federal roles or assets currently available to support local jurisdictions during disaster response (please see: FEMA: Federal Response Plan - ESF#8 - Health and Medical Services Annex). I will also not describe the specialized federal medical teams belonging to the Department of Health and Human Services (DHHS) such as the Metropolitan Medical Response System (Federal Medical Response Teams), the Disaster Medical Assistance Teams NDMS DMATs of the National Disaster Medical System 2001.01.25: (Fact Sheet) Medical Response in Emergencies: HHS Role that are specially designed and trained for mass casualty management. I will also not discuss in detail resources for bio-terrorism response APIC Bioterrorism Resources, which differ from other types of disaster responses.

Instead I will describe a general framework for local emergency medical response or mass casualty management by outlining basic emergency medical services or emergency support functions that apply to all multi-casualty incidents and disasters. I will also present strategies to improve the delivery of emergency medical services in times of disaster.

In general terms the phases and concomitant activities and the timing of the delivery of emergency medical services will vary according to disaster type. In sudden-impact disasters such as earthquakes or in terror attacks using conventional weapons such as in the 9/11 event the following phases and medical services are commonly observed:

Pre-hospital Response

Once a disaster has occurred preventive measures are inoperative and emergency medical services and public health measures remain the only means to reduce morbidity and mortality. The management of the injured or ill casualties of disaster in the pre-hospital setting requires, at minimum, the prompt delivery of the following 16 emergency support functions. Medical disaster plans at local, regional and state levels should be standardized in format and content to define when, who, and how the following services will be provided:

1. Alert/notification/communication:

Involves the process of alerting local, and if judged necessary regional, or state authorities to the fact that a disaster situation is unfolding. It includes the communication network and back up systems needed to ensure rapid notification. I have included a good example of an EMS plan for communication at this link http://www.njcommunity.com/sites/682/FSLO-942689685-985682.pdf

2. Establishment of the EMS incident command:

The incident command system (ICS) is the management structure through which EMS response to a disaster is organized and carried out in an orderly manner DOT/IncidentCommandSystem.pdf.

3. Needs assessment:

The mechanism through which disaster responders become informed of the health and medical needs generated by a disaster. Also, it is the amount of material and manpower resources required to effectively meet demand. Pan American Health Organization

4. Casualty identification, clearing, evacuation (search and rescue):

Is the process through which victims of a disaster are located, identified, and evacuated from the disaster area.

5. Casualty triage and stabilization:

The method by which the type, extent and severity of injuries sustained by disaster victims is prioritized for treatment Perform Casualty Triage. During this time initial treatment is provided to casualties in order to prevent further or rapid deterioration in the patient’s status, and in the case of weapons of mass destruction perform decontamination in pre-designated areas to prepare the victim for transportation to a treatment facility and to protect rescuers and other individuals from toxic or infectious substances.

6. Casualty collection:

The process of gathering patients from a hazardous location or scene of injury to a staging area near the disaster zone where further harm is avoided and from which patients are prepared for transport and loaded onto transport vehicles Casualty Collection Points. First aid is initially applied at these areas.

7. Field medical care:

The provision of emergency medical or surgical care to patients at collection points whose severity of illness or injury preclude safe transport to a treatment facility

A- Bystander life supporting first aid (public):

Involves the delivery of basic first aid by uninjured co-victims and is aimed at initiating the trauma life support chain. Life supporting first aid entails the following basic maneuvers: calling for help; maintaining a patent airway; controlling external bleeding; positioning for shock; rescue pull, and; CPR (if indicated).

B- Basic trauma life support (EMT/paramedics):

Constitutes the second step in the life support chain and involves the administration of advanced first aid in the form of airway control, hemorrhage control, immobilization of unstable limb fractures, wound dressing, burn treatment, among other lifesaving maneuvers by trained first responders.

C- Advanced Trauma Life Support (physicians):

The administration of lifesaving emergency medical or surgical care to critically injured patients by physicians and usually includes the following:

Intravenous fluid resuscitation
Pleural drainage
Endotracheal intubation
Mechanical ventilation
Wound suturing
Other lifesaving medical/surgical interventions

8. Transport with life support (land, air, rail, or sea):

The evacuation of disaster victims from the scene of injury to treatment facilities accompanied by health care professionals with, at minimum, basic trauma life support capability.

9. Definitive medical/surgical care (medical facility):

The delivery of specialized in-hospital medical or surgical care by physicians, nurses, and other health care professionals for the purpose of correcting or reversing life-threatening illness or injury and/or to prevent long-term disability.

10. Medical and pharmaceutical supply management:

The process by which medical supplies, equipment, drugs, and other pharmaceuticals are delivered to treatment areas.

11. Personnel management:

The process of assigning manpower resources.

12. Volunteer management:

The process of assigning and supervising the roles and responsibilities of lay bystanders and others not directly involved in disaster response efforts but who have needed skills and to avoid convergence of excess personnel and chaos at the site of a disaster.

13. Planning and evaluation:

The activity of preparing for and assessing response to disaster so as to improve the efficiency of future disaster response operations

14. Education and training:

The activity that involves the transfer of knowledge, experience or skill to another individual for the purpose of facilitating the application of a learned set of facts or adequate performance of a given task or set of practical skills to achieve a desired objective.

15. Critical incident stress debriefing (CISD):

Stress management through psychological support of disaster-affected
response personnel.

16. Worker safety/security:

Providing a safe workplace for and ensuring safe access to victims by response personnel.

Hospital Response

Although the Joint Commission for Accreditation of Health Care Organizations (JCAHO) provides little detail about the structure or content of hospital disaster plans Emergency Management, I suggest that disaster preparedness guidelines for hospital organizations be designed around a set of specific and measurable objectives that would define the hospital’s performance in the event of a disaster. The goals should address tasks such as:

1. Establishing a clear chain of command or incident management system/Hospital Ermergency Incident Command Sytem.pdf to coordinate the hospitals response.

2. Provide for necessary medical equipment, supplies, and pharmaceuticals.

3. Provide emergency back-up lifeline (power, gas, water) and personnel (medical and non-medical) for, at minimum, 24 hours.

4. Establish mutual aid agreements with other hospitals (example of Hospital Mutual Aid Memorandum of Understanding.pdf)

5. Once alerted/activated rapidly reorganize resources to convert to disaster operations and reassign personnel to meet the special needs of disaster patients (internal and external disaster plans)

6. Coordinate and maintain open channels of communication with pre-hospital EMS systems, hospitals, local and state health authorities, families of casualties, the media, etc.

7. Provide a plan for the transfer of stable inpatients to other health care institutions.

8. Establish pre-designated treatment areas within the hospital with prioritization of care, as follows:
   
   a. Casualty reception and triage area (ER and adjacent areas)
   
   b. Decontamination area (in the event of casualties of weapons of mass destruction)
   
   c. Area for the diagnosis, treatment or stabilization of patients who have life-threatening conditions (Acute care areas such as OR, ICU)
   
   d. Area for the diagnosis, treatment or stabilization of patients having urgent conditions who will be referred for follow-up care
   
   e. Area for the treatment of patients with non-urgent conditions, with referral for later definitive diagnosis, treatment, and comprehensive care
   
   f. Area for the reception of hopeless moribund or dead casualties
   
   g. Alternative treatment area (outside the hospital) in the event the hospital cannot provide services
    
9. Perform evaluation of performance after the event
    
10. Revise disaster plan and provide training based on knowledge gained through experience, after action reports and evaluation

Hospital response to biological events will require additional planning, preparedness and specialized resources not covered in this discussion Guidelines for Hospital Bioterrorism Preparedness.

How can we further improve the delivery of medical services in disaster?

I present 3 strategies to strengthen the delivery of EMS in times of disaster. First, I suggest establishing a ‘critical time to treat’ guideline. Second, I propose a gradated emergency medical response scale, based on an estimate of the number of critically injured or ill casualties requiring intensive care and linked to universal and standardized response plans. Third, I emphasize the institutionalization of citizen response, and suggest ways to accomplish greater citizen involvement in emergency response.

How fast is fast enough in a disaster?

Currently, many well-developed urban EMS/Trauma and hospital systems in the US are able to cope with the demands of daily urban trauma that result in multi-casualty incidents not exceeding 5-10 critically injured casualties at any given time (a bus or train crash). However, casualties exceeding this number will require, in most communities, outside help to handle the extra demand. One of the major problems in disaster operations is how to swiftly and accurately determine the quantity and quality of the medical care needed, know when local resources are exceeded, or when to ask for outside help. These decisions are the responsibility of local authorities (i.e. the Mayor or his designee, the incident commander) in conjunction with health officials. The incident commander, however, may not always have the expertise to rapidly assess the level of medical response needed (needs assessment) in order to request appropriate support in a timely manner. Delays in performing needs assessments cause further delays in the delivery of emergency care and, as a result, predisposes to preventable deaths and disability.

One of the most important limiting factors in disasters is the ability to provide intensive care services. Intensive care resources are quickly overwhelmed in most communities because they are usually in limited supply on a daily basis. Therefore, outside aid to accommodate excess critically injured patients must be done with cooperation from neighboring hospitals. The threshold to initiate outside support for these services, and plans to transport patients must be determined in advance.

Normally EMS systems at the community/local level are designed to provide cost-effective emergency medical care to critically injured casualties within a defined time frame namely, the ‘Golden’ hour of trauma. This is based on outcome studies showing improved survival of trauma patients when definitive treatment is provided in this time frame. Definitive treatment encompasses all components of the life support chain from the scene of injury and pre-hospital response, to transport, stabilization and initial care in the emergency room, and surgical treatment in the operating room and intensive care, if necessary. This is an example of a critical pathway for the treatment of trauma patients. It has become the standard of care for trauma patients under normal conditions.

Unfortunately, the standard of care for victims of a disaster varies tremendously according to a number of limiting factors including the availability of medical resources, which is dictated by the number of casualties and the severity of their injuries, and other logistical limitations, such as the ability of responders to match resources with needs in an efficient manner.

In order to maximize lifesaving efforts in disasters emergency care should be provided as early as possible and certainly within a critical time period. This period of time can be defined as the ‘critical time to treat’, which translates into the amount of time an injured or ill patient in a disaster can wait before complications can be expected. This critical time to treat will vary for each individual and is determined by the severity of the injury or illness. For example, table 1 estimates ‘critical time to treat’ for injury types and mechanisms most commonly observed in earthquakes or building collapses from any cause, such as crush injury and hemorrhage. Delays in definitive treatment beyond the critical time to treat may cause complications such as loss of limb, other disability, or death.

Table 1:
Injury type	Critical time to Treat (hours)
Crush: Limb Chest/Abdomen Head	6-12 0-1 0- 0.1
Uncontrolled External Hemorrhage: Arterial: Venous:	0-1 1-6
Uncontrolled Internal Hemorrhage: Arterial: Venous: Viscera l:	0.5-1 1-6 3-8
2nd/3rd Degree Burns (>45% BSA*)	1-6
* BSA= Body Surface Area

In order to impact on lifesaving efforts and prevent unnecessary deaths and/or injury, the emergency response system must achieve definitive care within the specified time periods for each of the injury types illustrated. Therefore, the critical time to treat can be estimated according to injury type and severity by using the prognostic value of the injury severity score (ISS) as a guideline for emergency response planning.

Gradated Response Scale

How difficult is it to execute an organized and coordinated emergency medical response in time to prevent unnecessary deaths and disability? Normally, the response effort is guided by medical needs, and medical needs are based on types, numbers and severity of injury/illness. Initial casualty figures are determined based on the total affected population, injured and dead. Information on injured and killed in the early stages of a major disaster is incomplete. There is no method to immediately and accurately determine the numbers and severity of the injured. Needs assessment takes time to perform. A recent review of morbidity and mortality statistics in major disasters from 1970-2000 (unpublished data) found that the distribution of dead, seriously injured, and uninjured is relatively constant in most major disasters: 1/3 dead, 1/3 with severe injuries requiring hospitalization and intensive care, and 1/3 sustaining no injury or mild to moderate injury. Hence a reasonable estimate of expected numbers of critically injured could be extrapolated based on the total population in the immediate disaster affected area. This estimate could be linked to a level of response (Table 2).

Table 2:
Total Casualty Estimate		*Critical	Level of response	Incident/disaster
15-30	X 1/3 =	5-10	Local (city, county)	**MCI
30-300	=	10-100	Regional (>2 counties)	+Mass
>300	=	100-1000	State/Nation	++Catastrophic
* Requiring Intensive care bed ** MCI - Multi-Casualty Incident (by definition not a disaster). + Mass Casualty Disaster (regional resources required) ++ Catastrophic Casualty Disaster (State and Federal resources required)

 

The need for hospital beds, specifically, intensive care beds and the personnel and material resources to support those patients is one of the most important limiting factors of the emergency medical response.

Medical response levels, as color coded alert levels are now, should also be standardized throughout the USA to include 2 levels of disaster response: 1) for the regional or multi-county level, the mass casualty disaster plan (requiring regional resources to treat 10-100 critically injured patients (NYTimes.com Abstract) and, 2) the State level, or catastrophic casualty disaster plan (requiring the medical resources of an entire state, neighboring states or federal response to manage the excess number of casualties (>300 critically injured).

In a catastrophic casualty disaster scenario with a minimum of 300 critically injured casualties (ICU admissions) the basic standard of care based on the above critical time to treat guideline would be emergency and intensive medical care for all patients within 6 hours. However, 300 patients all requiring hospitalization and intensive care (i.e. burn beds) at once would quickly overwhelm the hospital resources of a large city of the US, as was the case on 9/11 in New York – even though New York is a high medical resource area and one of the best prepared cities in the US.

In such a scenario in order to provide appropriate and timely care to even the most seriously injured, immediate alert/notification of state and federal authorities is needed. After 9/11 federal medical teams were activated and deployed to the scene. About 1500 people sustained injuries and were treated and released from neighboring hospitals. Approximately 300 persons were more seriously injured and required emergency transport and intensive care in hospitals in New York, New Jersey, and Connecticut -- most of these for burn wound care (THREATS AND RESPONSES: THE WOUNDED; For Survivor, Home Is Still a Hospital). Approximately 3,000 people died in the collapse of the twin towers, far exceeding the number of critically injured -- an exception to the ratio of injured to dead commonly observed in disasters. Precise details of the extent and adequacy of the emergency medical response after 9/11, however, have, to this date, not been widely disseminated by New York health authorities, for unclear reasons.

Citizen Rescuers

In our nation, today, the average citizen has little knowledge of what to do or how to provide help to others in a disaster. In order to ensure proper and safe citizen response, public education programs and training must be developed and implemented by federal, state and local authorities. This should be done in conjunction with private and public educational organizations, who are experts in teaching bystander first response. The new Department of Homeland Security must undertake the task of preparing and training the public, not only about how to defend or protect against a terrorist attack with duct tape and plastic sheeting, but also on teaching the public how to become an effective member of an organized citizen emergency response effort.

A simple but effective way of accomplishing this task would be to provide all citizens of the United States, ages 9-92, the option of receiving (free of charge) a 2-hour life supporting first aid (LSFA) training course SALF - Save A Life Foundation. These courses are currently administered in elementary, middle and high school, in selected communities. They could be offered to all students, and to citizens seeking motor vehicle licensing. Citizens should also be encouraged to maintain first aid kits in their homes and cars. Only through full community involvement can maximum lifesaving potential in disasters be achieved.

Moreover, each neighborhood or community should have Citizen Emergency Response Teams LAFD - Community Emergency Response Team (CERT) Training, in the same way that ‘neighborhood watch teams’ are established to combat crime.

I stress the need for an organized and trained public as an essential element of disaster medical services because it is clear that no EMS system can rely solely on professional responders and expect to save many lives in large-scale disasters. If properly trained and organized, citizen rescuers can make a difference in times of crisis. Disaster medical response planners should plan for and include this resource as an essential element of disaster response. The training standards and programs needed to fulfill the goals described herein should be agreed upon in advance and taught to all citizens.

What is the role of Anesthesiologists in Emergency Response?

Anesthesiologists are acute care physicians with special expertise in airway management, physiologic monitoring, patient stabilization and life support, fluid resuscitation, and crisis management. These are the most important aspects of emergency medical care of the trauma or disaster patient. As such, anesthesiologists can serve crucial roles not only in the anesthetic management of civilian and combat casualties in the familiar setting of the operating room, but also, if called upon, can function adequately as team members in field medical teams, the emergency room, or in the management of intensive care patients. Other roles anesthesiologists are well qualified to perform in disaster include but are not limited to the following:

• Sort, triage, stabilize, and resuscitate casualties
  
• Establish definitive airway control
  
• Provide external hemorrhage control
  
• Diagnose and treat life-threatening conditions commonly observed in victims of disasters (i.e. acute respiratory failure, acute renal failure, poisoning with organophosphates, hemo-pneumothorax, etc.)
  
• Establish intravenous access
  
• Guide fluid resuscitation and blood component therapy
  
• Perform regional and general anesthesia wherever needed or feasible
  
• Transport critically ill patients
  
• Manage acute pain
  
• Alleviate pain and suffering among patients triaged to die
  
• Manage intensive care patients in the ICU or in non-intensive care areas when the number of intensive care patients exceeds ICU bed capacity

The ability of anesthesiologists to more effectively participate in emergency medical care in disasters is enhanced by the acquisition of competency in Advanced Trauma Life Support (ATLS), basic principles of mass casualty and disaster management (as described above), and knowledge of the anesthetic methods, techniques, and equipment commonly used outside the operating room environment. The latter will be discussed in the next and last part of this series.

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