Disaster Medicine: Impact on Critical Care Operations

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Chapter 74 Disaster Medicine

Impact On Critical Care Operations

John R. Benjamin, MD, MSc , Edward E. George, MD, PhD

Disaster medicine encompasses extraordinarily wide and disparate scenarios. Despite the heterogeneity of scope and nature, many components are common to virtually all situations. The impact on health care resources at all levels of care most often requires adjusting the routine manner(s) of delivering care in response to these challenges. Better appreciation of the generic components of disaster medicine may help individuals involved in critical care medicine prepare and optimize response to these challenging situations.

1 What are the two general categories of disasters?

Natural and manmade

2 What are the most commonly encountered disasters?

Hurricanes, earthquakes, industrial accidents, acts of terror

3 How does the public health sector plan for disaster medicine–related events?

The Department of Homeland Security (DHS) in conjunction with the Department of Health and Human Services (HHS) bears a prominent role in the National Response Plans of the federal government. In the National Preparedness Guidelines issued by the DHS are listed 15 National Planning Scenarios (Box 74-1).

Box 74-1 United States National Planning Scenarios

From Department of Homeland Security: National Preparedness Guidelines September 2007: www.dhs.gov/xlibrary/assets/National_Preparedness_Guidelines.pdf.

In reviewing the various situations listed by government agencies exercising oversight for the public welfare, it is apparent that many of the envisioned scenarios could or would result in victims requiring medical care in facilities ranging in echelon from community hospitals to tertiary-level academic institutions.

For a comprehensive discussion of disaster planning from the level of the federal government please refer to the National Preparedness Guidelines website: www.dhs.gov/xlibrary/assets/National_Preparedness_Guidelines.pdf.

4 What mechanisms are commonly employed in acts of terror?

Explosives, chemical agents, biologic agents

5 What are common categories of injuries encountered in the disaster victim?

Cardiopulmonary: Commonly seen with inhalation agents such as mustard or blistering agents causing both a direct insult to pulmonary tissue(s) and indirect as a result of marked pulmonary edema with potential compromise of cardiac function.

Systemic (biologics or chemicals): Infectious agents, such as anthrax and smallpox, present obvious systemic effects, with an appreciable delay between exposure and manifestation of systems, thereby presenting a further challenge in timely therapy. Chemical agents (e.g., cyanide) with direct effects on cellular respiration and nerve gases (e.g., sarin) by inhibition of acetylcholinesterase exhibit systemic effects ranging from respiratory collapse to paralysis.

6 What are the four phases of disaster response?

See Table 74-1.

Table 74-1 Four Phases of Disaster Response

Personnel responding to disasters vary in training and experience, in part as a function of the phase of response. After the chaotic component, initial response is almost exclusively local personnel. Specifically police, fire, and emergency medical assets (emergency medical technicians and paramedics) will be the first trained personnel arriving at the scene. As on-scene assessments are conducted and contingency plans engaged, the process of bringing additional specially trained personnel and equipment into the area and establishing a coordinated process of command and control for triage and evacuation relies more heavily on teams trained in the management of disaster scenes, as well as coordination with evacuation centers. Training and exercise for such contingencies are ongoing at the municipal, state, and federal level with guidance and oversight provided by numerous federal agencies to include the Federal Emergency Management Agency, as well as the DHS and HHS. With training directed and coordinated at the national level, personnel from every tier of the response system benefit from understanding the overall approach to a specific disaster, as well as expectations and capabilities of support at and from all levels.

7 What are the four categories of blast injury?

Primary: Injuries resulting from the overpressurization wave that affects gas-filled structures such as the lungs, gastrointestinal tract, and middle ear

Secondary: Injuries resulting from flying debris affecting any body part

Tertiary: Resultant injuries from personnel being thrown by the blast wind

Quaternary: Exacerbations from existing conditions (i.e., chronic obstructive pulmonary disease exacerbations, myocardial infarctions) or complications from blast injuries (i.e., burns, crush injuries, closed head injuries)

8 Describe blast lung.

Lung injury is a result of a blast wave passing through lung tissue, causing tissue disruption at the capillary-alveolar interface. Effectively a pulmonary contusion caused by the traversing of a shock wave (associated with a blast) through the various structures of the lung, the process can be magnified as a result of the blast occurring in a confined structure thereby magnifying the effect with the pressure wave rebounding from the walls, floor, and ceiling. This type of injury may be mimicked by a shotgun blast to the thorax; however, injuries associated with high-velocity projectiles and knives do not present a similar pattern of injury.

Blast lung is clinically diagnosed by the presence of respiratory distress, hypoxia, and butterfly or batwing infiltrates (perihilar infiltrates caused by the reflection of the blast wave of mediastinal structures).

If patients require mechanical ventilation, the Acute Respiratory Distress Syndrome Network (ARDSNet) protocol is appropriate.

Triage

9 Describe the history of triage

Triage is a concept originating with the French (trier, to sort) during the Napoleonic Wars, although the principles have been applied for centuries. Napoleon’s surgeon, Baron Dominique-Jean Larrey, also credited with establishing the ambulance corps, popularized a system for sorting wounded soldiers in the field and prioritizing which casualties to evacuate first. Military and disaster triage differs from standard civilian emergency medical service (EMS) systems because often the most critically ill patients are evacuated last to ensure that injured casualties who have a greater chance of survival receive expedited medical treatment.

10 What are the secondary triage categories?

Priority I: immediate, life-threatening injuries requiring simple urgent intervention

Priority II: delayed, not life-threatening but urgent injuries that can tolerate a delay before further medical care is needed

Priority III: minimal, not life-threatening and not urgent injuries; also known as the walking wounded

Priority IV: expectant, unsalvageable injuries due to either severity or limits to resources

Priority V: dead

11 What is overtriage?

Sending low-priority patients to major trauma centers because they are incorrectly assigned as priority I or II. This triage error leads to increased mortality in mass casualty incidents.

12 How can overtriage be reduced or prevented?

Secondary and tertiary triage sites set up away from the disaster scene allow for a more methodical process to prioritize casualties.

Although primarily designed to reduce overtriage, reevaluating patients may also identify deteriorating casualties. This process is also known as dynamic triage.

A vital component to the triage process is the means and manner of patient evacuation, from the perspective of both personnel involved in the process and the assets used for transport. Initial casualty staging areas are commonly evacuated by ground ambulance or helicopter, with the bulk of personnel associated in this process drawn from local assets (police, fire, EMS, local Red Cross). However, given the magnitude of the disaster and the requirements for more extensive evacuation, additional assets are provided by state and federal institutions to assist in both local transport and secondary evacuations to more specialized (and often more distant) treatment facilities. In that a local disaster can easily overwhelm the resources of care facilities proximal to the scene of the disaster, contingency plans exist at the municipal, state, and federal levels to redistribute the burden of casualties to more remote and/or more specialized treatment facilities. Given the special care requirements of critically injured victims, a coordinated process with close collaboration between public health and military assets may be employed to use civilian personnel, with specialized training in the evacuation by air transport of critically ill patients, in conjunction with the Department of Defense to provide aircraft, facilities, and additional personnel.

13 What is the second-hit phenomenon of disaster scenes?

This describes the additional events that occur after the initial disaster and may result in significant loss of life and equipment.

A well-known example of this is the collapse of the World Trade Center towers on September 11, 2001.

This also applies to a common terrorist strategy where a second attack is planned to target first responders. For example, a vehicular bomb may be detonated in a marketplace, with additional explosive devices strategically placed around the initial explosion site, either set with delayed timers or remotely detonated by an observer to injure responding rescue personnel.

Planning and Response

14 Does the Joint Commission require hospitals to engage in disaster drills?

Hospitals are required to conduct disaster drills twice a year and annually test the integration with the local community.

15 How has Walmart affected hospital disaster preparedness?

Walmart’s pioneering supply system, known as just-in-time inventory, has revolutionized the way businesses resupply inventory. As a result, many hospitals no longer have significant stores of supplies. A hospital near a disaster zone and receiving a large number of casualties may quickly experience a material crisis if the supply chain is interrupted. This leaner philosophy of resupply operation reinforces the need to examine institutional contingency plans with a distinct focus on the impact of logistics.

16 What is the Incident Command System (ICS)?

The ICS was first introduced in the 1970s in an effort to more effectively coordinate the response to large-scale wildfires in the West.

The ICS is a modular system that provides a command structure to disaster scenes. It assembles the key components of a response (i.e., fire, EMS, law enforcement) to an individual event at a location in close proximity to the scene.

Although the size and scope of an ICS vary, five functional requirements are inherent to the organization. They are command, operations, planning, logistics, and finance and administration.

Although the ICS is commonly a prehospital concept, many medical centers have a hospital emergency ICS (HEICS) set up in the event of a disaster or mass casualty situation.

17 What are critical supply issues during Emergency Mass Critical Care (EMCC) events?

Institutions faced with responding to an EMCC will certainly experience shortages of supplies, equipment, space, and personnel. Although institutional resources may be capable of absorbing the initial requirements for support, the challenges associated with large-scale disaster will rapidly exhaust any reserve in place. Planning with local or municipal authorities in advance of any real event will facilitate any response to shortfalls. Systems such as HEICS will not only optimize the use of any institutional assets but also coordinate identified and anticipated needs with extramural resources commonly coordinated by state and federal agencies. Assets such as the Strategic National Stockpile for medications can be used, via regionalized distribution sites, to provide vital agents in a timely manner.

Ventilators: Most institutions have few ventilators not in use at any given time. Vendors supplying inventory on hand or shipments from hospitals not affected by a surge in patients may provide extra capacity. The United States has a strategic reserve of ventilators that may be shipped to hospitals. Adapting anesthesia machines as ventilators may be a possibility if the disaster has a low surgical patient population.

Oxygen: Many hospitals rely on liquid oxygen stores that must be replenished periodically. The limited number of producers of medical oxygen and the specialized transportation requirement hamper hospital resupply.

Medications: The United States has experienced numerous shortages of medications routinely used in the intensive care unit (ICU) including vasopressors, sedatives, and diuretics, to name a few. Such inherent shortages would be exacerbated during a sudden surge in critically ill patients. Contingency plans within the institution to utilize substitute medications (and equipment) in time of shortage can help attenuate the logistical challenges associated with shortages across the spectrum of operations.

Staff: Although major events and crises are often accompanied by a surge of volunteers and altruistic staff willing to work extended hours, high absenteeism commonly follows. It is vital to have established emergency staffing plans in place to ensure that all institutions maintain a longitudinal response and staffing capability. Although extended hours and physical demands are characteristic of disaster and emergency operations, it is critical that all personnel appreciate the potential compromise of care resulting from overstressed or exhausted personnel.

Beds: Critical care requires specialized equipment, medical gas access, suction, and electrical resources not available throughout most areas of the hospital. This requirement also limits the ability of an ICU standing up in a public space (i.e., gymnasiums) or a temporary shelter, such as a tent.

18 In what manner are hospital surge operations defined?

Surge operations are variable depending on not only the nature of the causative factor(s) but also the individual institution’s resources. Surge operations are characterized by the ability to rapidly expand the capacity of an institution to respond to an increased patient volume that would otherwise challenge or exceed routine capacity of the facility. These challenges may occur as the result of events ranging from day-to-day acute demands to the demands of an emergent event encountered in disaster medicine.

19 What is the estimated patient surge during a mass critical care illness?

Hospitals should prepare for triple their usual ICU capacity and not to expect significant resupply for 10 days.

20 How can a hospital, with an average census of 90%, expect to handle a significant patient influx?

Data indicate that up to 20% of hospital inpatients can be discharged home within a few hours. Another 40% could be quickly transported to other hospitals with community resources (buses, taxis, vans). What should not be overlooked with these data is that a hospital’s priority is to take care of its current patient load first.

Key Points Disaster Medicine

1. Disasters come in many shapes and sizes; however, an appreciation of commonalities of response can serve as the basis of an executable disaster plan.

2. Realistic on-scene training is vital to an efficient and effective disaster plan.

3. Caregivers may also be impacted (friends and family) by disasters, and contingency plans must be prepared and understood to ensure an adequate and sustainable response plan.

4. Although disasters by nature are chaotic and information may be limited and/or conflicting, reliance on training will always provide the best likelihood of a successful response effort.

1 Department of Homeland Security: National Preparedness Guidelines September 2007: www.dhs.gov/xlibrary/assets/National_Preparedness_Guidelines.pdf

2 Ritenour A.E., Baskin T.W. Primary blast injury: update on diagnosis and treatment. Crit Care Med. 2008;36:S311–S317.

3 Rubinson L., Hick J.L., Hanfling D.G., et al. Definitive care for the critically ill during a disaster: a framework for optimizing critical care surge capacity. Chest. 2008;133:18S–31S.

4 Stein M., Hirshberg A. Medical consequences of terrorism: the conventional weapons threat. Surg Clin North Am. 1999;79:1537–1552.

5 Wise R.A. The creation of emergency health care standards for catastrophic events. Acad Emerg Med. 2006;13:1150–1152.

6 Zoraster R.M., Amara R., Fruhwirth K. Transportation resource requirements for hospital evacuation. Am J Disaster Med. 2011;6:173–178.

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