Medical Triage for WMD Incidents: Incidents an adaptation of daily triage

 

 
 
 

Dave Donohue, MA, EMT-P | From the May 2008 Issue | Wednesday, September 3, 2008


Scenario

It's 2000 HRS on a Friday evening. You're assigned to an ALS engine company, and you're just settling down after a busy day when you're dispatched along with a BLS ambulance to a report of a sick person outside a local club where they're holding a concert. During your response, dispatch advises that they're receiving multiple calls on the incident and are dispatching a second BLS ambulance to the call. * As you turn the corner and approach the scene, you notice a haze in the air coming from an industrial site on the same side of the street and see approximately 200 people exiting the club in haste. Several dozen patrons line the street between the club and the subway station. They're coughing and crying, and several are vomiting. * The driver stops the engine in front of the subway entrance, which is located approximately 500 feet from the club and uphill and upwind from the haze. The scene is overwhelming, even to the captain, who turns to youƒas the paramedic on the crewƒand asks what you want done first. Your first thought is,Triage. But you know that triaging these patients is more complicated than your everyday two-car collision.

Evolution of Triage

The ability to rapidly identify the most seriously injured soldiers on the battlefield and prioritize their medical treatment was identified by the French Army during the Napoleonic Wars as a key element to troop survival and returning troops to the battlefield. During the past two centuries, this concept has been tested and honed.

As with other aspects of trauma care, civilian emergency medicine has borrowed lessons on triage from the military experience. The method of sorting medical casualties that has been taught to emergency responders in theU.S. for more than 20 years is START (simple triage and rapid transport). It's a simple, basic method of identifying life-threatening injuries and determining the order in which multiple patients will receive treatment. This method has been the key to the survival of countless trauma victims, particularly in cases of rapid triage at large mass casualty incidents (MCIs).

Our world is currently characterized by a focus on anti-terrorism tactics and preparedness. Thus, we must be prepared to perform triage during an incident involving a weapon of mass destruction (WMD). By utilizing the START system as a base and applying slightly different criteria, the emergency responder can effectively identify life-threatening conditions and prioritize medical treatment during a WMD event.

Start with the Basics

The START system allows the emergency responder to manage the patient load when presented with multiple patients. The emergency responder utilizes the results of three simple, rapid assessments to classify victims into one of four categories (seeTable 1). Based on the patient's medical condition, responders can then allocate available resources and request additional resources based on the patient load and need.

The key to the START system's success is itssimplicity. The responder completes rapid patient assessments, identifies patients with a tagging system and moves on to the next patient. Although the START system was originally used by EMTs and paramedics, it's now taught as part of the CERT (Community Emergency Response Team) program, first aid and similar basic responder programs.

The system requires the responder to assess three areas on each patient they encounter. Thefirst assessment performed by the responder is to determine if the patient is conscious and able to answer a few simple questions. If the patient is unconscious, the responder moves to the second assessment. If the patient is conscious, the responder asks one or two simple questions.

If the victim is unable to answer the questions appropriately, or shows other signs of diminished mental status, they're classified as a patient in need of immediate medical attention and the responder moves to the next patient. Identification of patient priority is done using triage tags, surveyors tape or a similar marking system.

Thesecond assessment is the patient's respiratory status. The responder simply opens the patient's airway and determines if they're breathing. If the patient isn't breathing, they're classified as Expectant (Priority 4ƒBlack), indicating they're dead or not expected to survive. If the patient is breathing, the number of breaths is counted for 15Ï30 seconds.

If the patient is breathing fewer than 12 times per minute or more than 30 times per minute, they're marked as being in need of immediate medical assistance (Priority 1ƒRed). (SomeEMS protocols allow the responder to also perform a simple invasive maneuver at this point, such as placing an oral-pharyngeal airway, to assist in maintaining a viable airway.)

Thethird assessment is the adequacy of patient circulation. Circulation is considered adequate to perfuse a patient's organs if a pulse is present at the wrist. A radial pulse is generally accepted as corresponding with a systolic blood pressure of approximately 80 mm/Hg, the minimum pressure needed to adequately perfuse the kidneys and other oxygen- sensitive organs for a short period of time.

If the victim does not have a radial pulse, and does have a carotid, they're classified as being in immediate need of treatment and classified as a Priority 1 patient. While the adequacy of patient circulation is being assessed, the responder can also rapidly address any significant hemorrhage. SeeTable 2 for an overview of these steps.

Application to WMD Events

During emergencies involving chemical agents, radiological agents or explosive devices, the responder will likely be faced with multiple patients, regardless of the cause of the incident. Applying the same rapid-assessment principals but with different benchmarks will allow you to rapidly identify and prioritize victims, and ensure that the greatest good can be done for the greatest number of victims.

As with any emergency, responders must remember that safety is first. Ensure personal safety by donning appropriate personal protective clothing, keeping improperly dressed personnel out of the danger area, decontaminating victims and confirming the area is free of secondary devices. Then, responders can attempt to identify the type of agent or device involved.

There are four categories of warfare agentsƒchemical, blood, choking and radiologicalƒand many common hazardous materials that may be used. Each of these agents require alterations to the triage standard.

Chemical Agents

Nerve agents: Military nerve agents, such as sarin, tabun and V agents, are persistent liquids that cause the body's nerves to fire continuously. Nerve agents are acetylcholinesterase inhibitors, preventing the reabsorption of acetylcholine, resulting in continual stimulation of the nervous system. Victims of nerve-agent attacks may be exposed through inhalation, ingestion and/or absorption of the agent through their skin.

Patients may experience a number of symptoms, including loss of vision; shortness of breath; tremors and seizures; loss of consciousness; sudden urination, defecation and vomiting; and stomach pain.

The mnemonicSLUDGEM is often used to remember the symptoms.

  • Salivation
  • Lacrimation
  • Urination
  • Defecation
  • Gastric distress
  • Emesis
  • Meiosis

Common chemicals, such as readily available pesticides and herbicides, cause similar symptoms and may be as deadly.

Triage of these patients should focus on the patient's level of consciousness, the number of body systems exhibiting symptoms, the victim's reaction to initial treatment and if a chemical antidote treatment is used, such as the new DuoDote injector (which replaced the Mark I injector).

Patients who are breathing and are unconscious, are displaying convulsive movements, or have two or more body systems exhibiting symptoms, are classified as being in immediate (Priority 1) need of treatment. If the patient begins to show signs of improvement, with or without antidote therapy, they should be placed in the Delayed (Priority 2) category.

As with the START system, patients who are ambulatory and alert and oriented are classified as Minor. Patients who are unconscious and exhibit no breathing or signs of circulation are classified as Expectant.

Blister agents: Vesicants (blister agents) are a class of materials that have been used as warfare agents, but are primarily industrial acids or bases (alkalis). Warfare agents include mustard, phosgene oxime and lewisite, while commercial chemicals that may cause similar symptoms include phenol, dimethyl sulfate, as well as commonly available acids and caustic materials.

As with nerve agents, these materials may be inhaled, absorbed or ingested. Symptoms of exposure include shortness of breath, eye irritation, skin irritation and blister formation. The speed at which symptoms appear is dependent on the water solubility of the agent used; water-soluble materials, such as acids, tend to exhibit symptoms more quickly.

Materials that are chemically alkaline (or basic) tend to cause deeper tissue injuries and require significantly longer decontamination times. Caution must be taken during decontamination because some of these materials should not be combined with water.

Triage of patients exposed to blister agents focuses on the presence of pulmonary symptoms and the amount of body surface area (BSA) that has been affected. If any patient exposed to a blister agent is experiencing severe pulmonary symptoms, such as stridor, wheezing or tripod positioning, they should be placed in the Immediate category.

If the patient is breathing without serious respiratory symptoms, has eye symptoms, and/or burns covering 2Ï50% of BSA, they're considered Delayed.

Patients with less than 2% of their BSA affected and burns not within the critical areas of the face, hands, groin or feet are considered to be Minor. Any patient displaying burns on more than 50% of their BSA should be considered for placement in the Expectant category.

Blood Agents

Seen in routine industrial use, such as auto repair, metal work and pest control, and because of their ease of use, blood agents may be the chemical agent class most likely to be seen by first responders during a WMD event. Both military and commercial blood agents are easily obtained and include such chemicals as cyanide agents, hydrogen cyanide and cyanide salts, arsine, hydrogen sulfide and carbon monoxide.

These agents may attack the body through any route, but the respiratory route is most likely. They either attack and inhibit the body's ability to take oxygen from the air into the blood stream, or they prevent oxygen from moving from the blood into the cells.

Due to the speed at which these materials act, as well as the limited availability of antidote treatments and aggressive oxygen therapy (including hyperbaric treatment), patients suffering from blood-agent exposure are placed into one of only three triage categoriesƒImmediate, Delayed or Expectant. Patients suffering from convulsions or sudden loss of consciousness are classified as Immediate. Patients suffering other symptoms are classified as Delayed. And any patient exhibiting apnea, in the absence of sufficient resources to provide respiratory support, is classified as Expectant.

Choking Agents

Most commonly, chemical agents are industrial chemicals that cause severe respiratory distress. As with blood agents, warfare choking agents are commercial, industrial chemicals and include chlorine, ammonia, phosgene, hydrogen chloride, hydrogen fluoride and chloropicrin.

Due to their respiratory effects, triage of these victims in the field will focus on respiratory response. Patients who present with severe respiratory distress or unstable vital signs will be classified as Immediate patients.

Patients who have minimal or no respiratory distress and stable vital signs will be classified as Minor. Those who exhibit signs between Immediate and Minor should be classified as Delayed and triaged every 10Ï15 minutes.

Lastly, those patients experiencing severe respiratory distress from choking agents and who will not be able to receive aggressive respiratory support within four to six hours should be classified as Expectant.

Radiological Agents

It's not inconceivable that the response community will some day soon face a response to a radiological dispersal device, including one that does not use explosives as its means of dissemination. Simply placing a highly radioactive source within a public space may result in a large number of victims of radiation exposure.

Unfortunately, radiation exposuresƒunless accompanied by some warning, such as an explosionƒare clandestine and may result in symptoms appearing from days to weeks after the initial exposure. Consequently, many patients may not be salvageable.

Patients who present with traumatic injuries, burns to the face or burns to the respiratory tract should be classified as Immediate. These patients would present after the detonation of a nuclear device or explosive radiological dispersal device (i.e., dirty bomb), and the rapid treatment of trauma will be the primary concern.

Patients who present with non-life-threatening injuries and less than 25% BSA burns should be classified as Delayed. This includes patients with less than 10% BSA burns and minimal radiation symptoms. These patients should be triaged again prior to treatment and transportation.

Patients presenting with a high fever, disorientation, bloody diarrhea and vomiting should be classified as Expectant, because they have likely received a high dose of radiation and have a poor survival prognosis.

According to the Centers for Disease Control and Prevention, the first symptoms of acute radiation sickness (ARS) are nausea, vomiting, diarrhea and skin damage (i.e., swelling, itching and redness). The symptoms will begin to present within minutes to days after the exposure and can last for minutes up to several days. The symptoms may be present and then absent, with patients feeling and appearing healthy for a short period and then becoming sick again. At its most serious stage, ARS can present with seizures and coma and may last from a few hours to several months.

Explosions

The most common terrorist weapon has been explosives. Commercial high explosives (e.g., dynamite and TNT) can be legally purchased or stolen from commercial sites, such as a quarry or blasting sites. Low explosives, such as gunpowder and fireworks, which decompose at a slower rate and require containment, can also be legally purchased. In addition, improvised explosives may be made from a variety of materials, including compressed gases, fertilizers and urine.

Because of the ability to disrupt the body's internal organs, explosions tend to result in serious internal injuries that are easily overlooked when faced with multiple patients with obvious injuries. Identifying such signs as bleeding from the ear or hearing loss, which may indicate that the victim has been exposed to an over-pressurizing injury, is critical when triaging victims of explosions.

Patients who present with any hearing loss, shortness of breath, penetrating or traumatic injuries to the torso or head, or who demonstrate disorientation should be classified as being in need of Immediate medical attention. If the patient is not demonstrating any of these signs, then the responder should follow the normal START triage or their protocol triage system.

Conclusion

Although not frequent, MCIs do occur on a regular basis. Emergencies involving WMDs, on the other hand, have an extremely low occurrence rate, but are high-impact events. Responders should already be familiar with the concepts of triage and should practice triage whenever faced with two or more patients. This routine practice helps us maintain proficiency with this skill.

Once mastered, the skills used for managing an MVC with three victims can be applied to manage the victims of a chemical-plant accident, a chemical release from a derailment, or a criminal or terrorist attack. Mastery of basic triage will enable you to rapidly determine the number of victims, their medical conditions and the resources needed to properly treat them.

Dave Donohue, MA, EMT-P, has more than 28 years of emergency response experience and is currently employed with a federal hazardous materials response team in Washington, D. C. He's also active in the emergency response community inWest Virginia, serving as an emergency responder and instructor inJeffersonCounty. He's a U.S. Coast Guard Reserve Chief Petty Officer assigned to U.S. Coast Guard Sector Baltimore in the Incident Management Division, where he instructs Coast Guard personnel in incident management, hazardous materials and CBR He previously served as a firefighter, paramedic, company officer and battalion chief with several fire departments.

Resources

Centers for Disease Control and Prevention. Centers for Disease Control and Prevention.www.cdc.gov

U.S. ArmyU.S. Army:Textbook of Military Medicine: Medical Aspects of Chemical and Biological Warfare.

www.bordeninstitute.army.mil/published_volumes/chemBio/chembio.html

Agency for Toxic Substances and Disease Registry. Agency for Toxic Substances and Disease Registry:Medical Management of Chemical Casualties Handbook:U.S. Army Medical ManagementGuidelines.www.atsdr.cdc.gov/mhmi/mmg.html




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Related Topics: Major Incidents, Airway and Respiratory, Medical Emergencies, Natural Disasters, Special Operations, WMD and Terrorism, Jems Features

 

Dave Donohue, MA, EMT-PDave Donohue, MA, EMT-P, has more than 28 years of emergency response experience and is currently employed with a federal hazardous materials response team in Washington, D. C. He's also active in the emergency response community in West Virginia, serving as an emergency responder and instructor in Jefferson County. He's a U.S. Coast Guard Reserve Chief Petty Officer assigned to U.S. Coast Guard Sector Baltimore in the Incident Management Division, where he instructs Coast Guard personnel in incident management, hazardous materials and CBR He previously served as a firefighter, paramedic, company officer and battalion chief with several fire departments.

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