ABSTRACT
How do we train for the entire spectrum of potential emergency and crisis scenarios? Will we suddenly face large numbers of combat casualties, an earthquake, a plane crash, an industrial explosion, or a terrorist bombing? The daily routine can suddenly be complicated by large numbers of patients, exceeding the ability to treat in a routine fashion. Disaster events can result in patients with penetrating wounds, burns, blast injuries, chemical contamination, or all of these at once. Some events may disrupt infrastructure or result in loss of essential equipment or key personnel. The chaos of a catastrophic event impedes decision-making and effective treatment of patients. Disasters require a paradigm shift from the application of unlimited resources for the greatest good of each individual patient to the allocation of care, with limited resources, for the greatest good for the greatest number of patients. Training and preparation are essential to remain effective during crises and major catastrophic events. Disaster triage and crisis management represent a tactical art that incorporates clinical skills, didactic information, communication ability, leadership, and decision-making. Planning, rehearsing, and exercising various scenarios encourage the flexibility, adaptability, and innovation required in disaster settings. These skills can bring order to the chaos of overwhelming disaster events.
Introduction
The purpose of triage is to do the most good for the greatest number of people. Triage uses a set of principles that guide the sorting and assignment of treatment priorities. This directs the greatest amount of care to the largest number who will benefit, to salvage the greatest number while preserving scarce resources. Triage comes from the French word “trier,” meaning “to sort.” Triage methods can be traced to the pioneering work of Baron Larrey, a surgeon in Napoleon's army who developed a system to evaluate the wounded and to evacuate patients while the battle was still in progress.
Principles of triage and patient treatment evolved further during each successive war. In World War II, the U.S. Army Medical Corps developed a tiered triage system such that lifesaving procedures were performed closer to the battlefield and more-complex care was delivered as the casualty moved through the system to higher echelons of care. Portable field hospitals that used this system are credited with contributing to the greater survival rates of patients with abdominal wounds.1 The military continued to improve the tiered triage system, which has led to a significant improvement in survival rates of patients.2 Triage advances directed the appropriate patients into echelons of care so that the most good could be accomplished for the most casualties. The chaotic situation of large numbers of injured is brought under control so that effective care can be properly directed to each casualty.3
The Tactical Art of Triage
Triage is driven by the real-time events and the constraints of the evolving scenario. Different settings drive different management options. Triage conducted while under hostile fire from the enemy is different from triage at the scene of a car accident and different again from that performed with a medical team in the emergency department of a hospital. Tactical application of medical care shifts from the optimal highest level of care for each individual patient to providing the greatest good to the greatest number.4
Triage is a tactical art that requires situational awareness, decisiveness, and clinical expertise. Management of each triage setting or type requires planning, training, experience, leadership, and flexibility. A triage decision that all agree is appropriate in one setting may be inappropriate in another.
Only a small number of casualties in a mass casualty setting require urgent resuscitation and prompt operative intervention.5,6 The majority of the injured can tolerate varying degrees of delay before surgery.5 Application of sound decision-making criteria makes the treatment of large numbers of casualties more manageable, while minimizing confusion, conserving scarce resources, and maximizing patient salvage.3
The most experienced physician with casualty care experience and a surgical background should perform triage in a disaster setting.7,8 In a hospital, that likely is the chief of surgery or someone with commensurate experience in identifying wounds, assessing physiological impact, determining the requirement for resources, availability of operating rooms and teams, and length of proposed procedures, and predicting patient survival rates (see accompanying article).6,–8 Nurses, dentists, and physician assistants with training and experience have historically performed triage in exemplary fashion. The surgeons may all need to be operating where critical medical resources are thinnest, such as close to the battle in smaller field hospitals.3 In combat, it may be a medic/corpsman who has the medical knowledge and leads the triage at the scene.
The medical providers on a ship at sea, in an isolated disaster locale, or in a combat zone may have little or no evacuation opportunity and must triage and treat patients accordingly. Each decision in such scenarios is driven by factors such as the personnel versus casualty ratios, provider skill sets, accessibility of equipment, and availability of evacuation, communication, and supplies. Time, distance, and weather may also play significant roles, as does fatigue, confusion, or panic.
Triage is not democratic, and very tough decisions must be made. The “return to battle” or a “fight to save the ship” is a tactical scenario that may take precedence over “best practices” medical care. Some call this “reverse triage,” where the lightly wounded are treated first so that they can return to the action. Resources must be conserved and allocated in an optimal fashion to do the most good, such as winning the battle, putting out the fire, evacuating the falling building, or saving the ship.
Phases of Casualty Management
There are dynamic and distinct phases of casualty management. Butler et al.9 described extremely useful categorizations for the special operations community. This construct provides a great framework for thinking about this challenge. Three phases are detailed, including care under fire (or triage on the scene), where danger may persist and interfere with care, which transitions to tactical triage and field care that can be rendered in relative safety. When the tactical situation permits and assets are available, then casualty evacuation to definitive care is performed with additional personnel and equipment. Triage should take place at each setting where the casualties are staged and should be repeated upon arrival at a medical care facility for definitive care, which is discussed in the accompanying article.
Triage on the Scene
Triage and prioritization of care are essential when the number of casualties exceeds the ability of available medical personnel to effectively deal with and provide full attention and optimal treatment to each patient. Confronted with a scenario of large numbers of casualties, the first step may be to establish a call for notification and to seek additional help from nearby resources or higher authority.
Tactical considerations must always prevail. First responders who rush to treat the injured must avoid injury so that they themselves do not become ineffective. This was seen with the tragic loss of fire personnel during the September 11 event at the World Trade Center. Hazards can include falling debris, fire and products of combustion, unexploded ordnance, mines, hostile fire, and chemical or biological contamination (Fig. 1). Flooding in a compartment, exposed live wires, and hazardous contamination add complications to shipboard care.
Removing weapons and ordnance and checking for chemical weapon contamination (Foxtrot Medical Detachment, 1st Medical Battalion, 1st Force Service Support Group, U.S. Marine Corps, Operation Desert Storm, 1991).
Movement of the casualty and medical provider out of danger may take precedence over a lifesaving procedure or other medical care. It is best to move the casualty to safety by dragging the casualty on a poncho or pack frame in line, rather than lifting the casualty, when under fire if a move to safety is needed urgently. Cervical stabilization may risk more than is gained except when the mechanism of injury or physical examination suggests a high likelihood of neck or back injury; performance must be deemed worth the time spent and the risk to the provider.3,10,11
The most senior rescuers must step up and identify themselves and their skill sets. Management of the complex scene with many injured might start with a verbal order for casualties to get up and physically move to the rescuer. These are patients with salvageable minor injuries, who can be directed to a specific area to await treatment. They can also assist as providers for buddy aid.
Rapid but limited evaluation and basic treatment are then directed to the seriously injured who have not moved or could not move. A quick assessment is performed and, if an airway can be opened or quickly cleared or hemorrhage stopped, then this is performed before moving on to assess the next casualty. Priority goes to simple procedures that can be performed rapidly. Opening airways, stopping bleeding, and stabilizing injured limbs save lives and reduce further injury. Pressure dressings and tourniquets are very useful tools that prevent exsanguination, which is a leading cause of preventable death on the battlefield.9,12,13
Cardiopulmonary resuscitation probably has no role in a battlefield under fire or at a mass casualty scene.12 It may hamper treatment of salvageable casualties to perform futile efforts, while putting providers at risk.
The tactical situation may require reverse triage when the situation demands that individuals be returned to action as rapidly as possible. Those with minimal injuries are treated first and then returned to activity before more seriously wounded patients are treated. Fire superiority may be the best medicine on the battlefield and saving the sinking ship may outweigh best medical practices, as does control of other situations where ongoing danger threatens.
Tactical Triage and Field Care
More-thorough evaluation and care can be provided when there is no imminent danger to the provider or the casualties. The ABC's of casualty management provide a useful algorithm during this phase.14,–16 The algorithm outlines management of the airway, breathing, and supporting circulation, disability/ deformity evaluation, and exposure. This is a rapid primary survey, in which simultaneous treatment of life-threatening injuries can be performed.
Airway management is the first step in assessment. Symptoms of stridor (noisy breathing), hoarse voice, obvious direct neck trauma, and extensive maxillofacial injury with blood, teeth, or vomitus in the airway signify the need for establishing airway control. Agitation or unresponsiveness may be signs of airway problems and hypoxia. If the airway cannot be established by maneuvers such as chin lift or jaw thrust, digital clearing of an airway, or insertion of a nasal or oral airway, then death will result unless intubation is performed or a surgical airway is created. With many casualties needing care, there may be limited time to stop at an individual casualty for this step.
Intubation of the trachea requires significant training, special equipment, and ongoing experience. Surgical cricothyroidotomy is a simple lifesaving technique that can be performed expeditiously and should be part of most triage training regimens.12,17
Breathing assessment requires recognition that the patient has difficulty moving air into and out of the lungs effectively. Inspection, palpation, percussion, and auscultation are classic techniques for physical evaluation. Clinical signs such as decreased breath sounds and hyperresonance to percussion may be difficult to determine even in an emergency room and are much more difficult to determine on the scene.12 Clinical evidence includes obvious respiratory distress, tachypnea (>30 breaths per minute), paradoxical or asymmetric chest motion, and bubbles at the site of a chest wound. Palpation may demonstrate crepitus, subcutaneous emphysema, tenderness, or deformity.17
Intervention at this step includes recognition and treatment of open chest wounds that should be sealed (on three sides if possible, allowing periodic venting of resultant pneumothorax via the fourth side). Recognizing and treating tension pneumothorax is a clinical decision that must be made well before symptoms of tracheal shift and distended neck veins (signs of impending cardiac arrest) are seen. Unilateral chest injuries, especially penetrating wounds, with respiratory distress should suggest this diagnosis and require action, at least needle thoracostomy.12,17 A chest tube is usually necessary, when time, circumstances, and equipment permit it to be inserted.
Circulation at this stage of triage and field treatment requires stopping overt bleeding. Direct wound pressure and tourniquets provide control until definitive correction (Fig. 2). This is probably the single most effective step in saving lives on the battlefield.9,12,17,–20
Captain Nelson Realo intubating a patient and a corpsman preparing the chest, abdomen, and leg. The tourniquet placed on the right leg by a corpsman in the field prevented blood loss before definitive surgery (Foxtrot Medical Detachment, 1st Medical Battalion, 1st Force Service Support Group, U.S. Marine Corps, Operation Desert Storm, 1991).
Certain injuries do not stop bleeding with direct pressure, and sometimes tourniquets do not work. These wounds may require some additional intervention for bleeding control, such as large scalp wounds that must be sutured to stop the bleeding.21
The Food and Drug Administration has approved new hemostatic agents that can be used in conjunction with direct pressure. They are indicated when conventional techniques of controlling the bleeding have not been effective.3 HemCon dressings (Hemcon Medical Technologies, Inc., Portland, Oregon) use a glucosamine (chitosan) derivative, and QuikClot (mineral zeolite; Z-Medica Corporation, Wallingford, Connecticut) and human fibrin dressings have been introduced into current care doctrine.3,22,23 HemCon is carried by army medics, and QuikClot is carried by all U.S. Marines.
Disability/deformity is the next assessment. A rapid neurological examination to determine whether the patient is awake, responsive to voice or pain, or unconscious is of value. The AVPU mnemonic (awake, verbal response, painful response, or unresponsive) is faster and simpler than the Glasgow Coma Scale.3 Providers should perform a quick assessment for gross deformity; the ability to move all extremities and the presence of fractures and dislocations effect subsequent steps.
Exposure enables a search for hidden injuries such as unsuspected penetrating wounds, blunt trauma, or bleeding that had not been evident. This also allows for removal of weapons and ordnance to prevent catastrophe. Clothing removal or destruction, and the environmental exposure that may then occur, must taken into consideration.
If time and circumstance permit, then intravenous access should be established. This allows resuscitation and administration of medication. It is more expedient in field care to insert an 18-gauge catheter that is “locked” and used as needed.9,24 In difficult-to-access cases, an alternative is the interosseous device.25 This is safer and less cumbersome in field conditions than performing a saphenous vein cutdown or central vein cannulation.17,21
Immediate fluid resuscitation may not be necessary in cases in which the casualty is in hemodynamically stable condition.3 If significant hemorrhage has occurred, as evidenced by hypotension and tachycardia or a decreased level of consciousness, then fluid resuscitation may “buy time” and be lifesaving. A minimal systolic blood pressure of 70 mm Hg should be a relative target. Heavy volume infusion and higher blood pressures may be counterproductive until definitive care is reached and operative intervention can control bleeding.20,25,26
Infusion is most often initiated with a balanced salt solution. Hespan (6% hetastarch; Bristol-Myers Squibb, New York, New York) is a large molecule that is retained in the intravascular space and may be a good alternative, because a longer effect is maintained with smaller volumes and less weight to carry.26,–28 Albumin, plasma, and other expanders including blood may be used, but the future will likely involve stroma-free hemoglobin that can carry oxygen without antibody problems.
Preparation for Evacuation
Cleaning, dressing, splinting, and protecting wounds decreases tissue destruction and wound infection.29 Antibiotic administration should be performed as soon as reasonable. Parenteral administration provides rapid antibiotic delivery to the tissues, but there is evidence that oral antibiotics with a broad spectrum, such as fourth-generation fluoroquinolones, can be used if the gastrointestinal tract is intact. These provide good bioavailability and reduced dosing schedules with an excellent safety profile.30
Splinting injured areas decreases tissue damage, limits further injury, and reduces pain.29 Splints may have to be improvised from available materials, such as cardboard or pillows. Fractures of the pelvis can be stabilized by tying a sheet tightly around the hips. It is essential to check pulses and sensation distal to extremity injuries and wounds before and again after bandaging and splinting.29,31
Intravenous pain medicine administration may be beneficial for conscious patients at this point. Oral medication administration is an alternative for minor injuries.3
Identification, Medical Records, and Communication
Casualties are tagged for identification, to describe the injury, to place in a care priority, and to list medication or treatment given. This is essential in treating, tracking, and maintaining continuity. Colored tags are often used when casualties are sorted and identified in the field. A recent proposal suggests a geometric pattern similar to that used by ski patrols, to enhance readability in low-light settings. A diamond for immediate, square for delayed, circle for minimal, and X for expectant was proposed.32 Combining techniques using colored tags with a raised geometric pattern that can be felt in low-light settings might be the optimal approach for the future. Tags with radio-frequency identification devices or other “wireless intelligent tags” may be future systems for both identification and tracking of the injured.33,34
Immediate
These patients have life-threatening injuries that can be treated quickly, with minimal use of resources. They should be treated first because potentially simple interventions can positively affect outcomes. These cases may include airway obstruction, significant external hemorrhage, shock, sucking chest wounds, pneumothorax, and partial- or full-thickness burns of the face and neck.
Delayed
This group includes wounded who are badly in need of time-consuming surgery but whose general condition permits delay in surgical treatment without unduly endangering life or worsening outcomes. Sustaining measures are required (e.g., stabilizing intravenous fluids, splinting, administration of antibiotics, catheterization, gastric decompression, and relief of pain). These injuries include large soft-tissue wounds, fractures of major bones, and intra-abdominal and/or thoracic injuries that may be hemodynamically stable.
Minimal
This group includes patients with minor lacerations, contusions, sprains, superficial burns, and behavioral aberrations. These patients will not suffer significant morbidity even if no immediate medical intervention is performed, or they can be cared for by themselves or physician extenders.
Expectant
This group includes patients for whom there are signs of impending death or massive injuries with poor likelihood of survival, such as unresponsive patients with penetrating head wounds, high spinal cord injuries, mutilating explosive wounds involving multiple anatomical sites and organs, second- and third-degree burns involving >60% of total-body surface area, profound shock with multiple injuries, or agonal respiration.3
Essential to the best care of patients is rapidly conveying the information available, along with physical findings, as the patients transit. Verbal reports and written records must be simple and somehow durable. This remains an ongoing area of intense technological research, development, and testing.33,34
Casualty Evacuation and Care en Route
Triage at this stage is performed to prioritize casualties for movement, on the basis of need for further definitive surgical intervention. The likely outcome of the individual casualty must be factored into the decision-making process before the commitment of limited transportation assets and medical resources when a large number of casualties compete for care. Difficult decisions may be called for in sending less injured patients who are more likely to survive ahead of grievously wounded patients who are less likely to survive. Initial triage and casualty evacuation follow the commander's intent and the need to control the tactical outcome of the event.
Medical knowledge is crucial for line officers and mission commanders to understand what care can and cannot be provided in field settings.35 Communication between medical staff members and line commanders requires knowledge of the tactical setting, resources, evacuation platforms, and mission capability for both parties. Mission completion may compete with best medical care practices, requiring flexibility, innovation, and leadership.
Knowledge of time, distance, transportation assets, receiving facility capability, and two-way communication affects every decision. Every effort should be made to ensure that the existing resources are expended for optimal outcomes for the most-salvageable patients.
The presence of more personnel and additional equipment when a casualty evacuation platform arrives may allow improved interventions. Better airway management, chest decompression, fluid management, and protection from the environment may be possible.
Traditional casualty evacuation has not included care underway. One significant issue with potential for controversy is the use of field medical personnel from a tactical unit to accompany the critically wounded for care underway. This deprives the tactical unit of a crucial team member and medical asset for an unknown length of time, may cause a dip in morale, and potentially deprives others of urgent medical care.36,37 Adding additional medically trained personnel to the casualty evacuation platform to provide care during transit is an issue of importance in this phase. This has led to the establishment of casualty evacuation teams in special operations and use of critical care nurses and corpsmen for Marine Corps evacuations from forward resuscitation surgical units.38 This medical support during casualty evacuation is a long-overdue improvement.
It is important to retriage casualties at each stop in their travel, because their medical condition can alter over time. Vital signs can deteriorate, the level of consciousness can change, airways can become obstructed, pneumothorax can develop, and tourniquets or splints can become dislodged. Lifesaving interventions may need to be instituted or repeated to again stabilize the casualty. Tourniquets can be removed and direct pressure applied or hemostatic agents used. Triage priority may be altered by new findings, necessitating assignment to a new category. Verbal comfort and reassurance, along with pain medication, can ease the rigors of casualty evacuation.
Conclusions
Training and preparing for a disaster is a way to impose order in an overwhelming situation of chaos. The purpose of casualty triage is to do the most good for the greatest number of people. Triage uses a set of principles that guide the sorting and assignment of treatment priorities to various categories of casualty types and enables providers to effectively provide the greatest amount of care to the largest number likely to benefit.
Triage is driven by the unfolding events and must be performed within the constraints of the scenario and environment. Different settings have issues that drive different management options. Triage in mass casualty and disaster response represents a tactical art that includes many skills, including leadership, communication, flexibility, and adaptability. Military and field survival skills, as well as an understanding of the tactical setting and commander's intent, are essential. Flexibility and adaptability are essential when the loss of fixed facilities, communication, crucial supplies, or key personnel alters execution. The goal is to prioritize, to stabilize, and to move the injured to definitive care in the proper order, to impose order on chaos.
