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The threat of an IED is somewhat foreign to most Americans, who typically associate these “homemade bombs” with the wars in Iraq and Afghanistan. However, such events as the Oklahoma City and Centennial Olympic Park bombings and the attempts made by the Unabomber show that IED attacks are possible in the U.S.
Any medical first responder could one day encounter a large number of patients who have been injured by the explosion of one or more IEDs. The detonation could occur almost anywhere.
The range of injuries at IED incidents could vary from cuts and bruises to loss of limbs and could be compounded by release of a toxic substance as part of the attack, complicating efforts to administer treatment. First responders also must be prepared to treat additional injuries should secondary IEDs be detonated during the response.
IEDs are homemade bombs built using materials at hand. They come in many forms, ranging from a small pipe bomb to a sophisticated device capable of causing massive damage and loss of life. They can be delivered in a vehicle; carried, placed, or thrown by a person; delivered in a package; or concealed on the roadside.
When an IED is detonated in a combat situation, U.S. soldiers are ordinarily equipped with training, protective gear and armored vehicles to protect them from the blast. But in the civilian population, there is rarely an expectation of an IED and therefore little protective gear.
Injuries caused by an explosion can be difficult to treat, especially for civilian responders operating in the aftermath of a bomb blast for the first time. What’s more, few such personnel have seen the complex combination injuries that can result from an IED attack.
Types of Blast Injuries
EMS personnel must be able to recognize and treat blast injuries, which fall into four main categories.
Fragmentation injuries: These are the most common traumas that result from an explosion. They are caused by the impact of blast debris, such as implanted screws, nails, ball bearings or wood splinters, or objects in the environment that become projectiles.
These injuries turn the blunt force trauma of blast injuries into a mix of blunt and penetrating trauma. Hemorrhage is an immediate concern for penetrating trauma. Direct pressure to intensely bleeding wounds is of paramount importance in the field.
Overpressure damage: These injuries, which result from the force caused by the explosion, affect gas-containing bodily structures. Pulmonary injuries, also called blast lung injuries, feature tearing, hemorrhage and edema. Auditory injuries manifest as a tympanic membrane rupture leading to hearing loss and inner ear pain. Abdominal injuries typically display pain secondary to tearing or disruption of the hollow viscus.
After the initial primary survey of airway, breathing and circulation, asking a patient if he or she can hear is an important part of the secondary survey. Patients who have sustained enough blast pressure to rupture their eardrums also have sustained enough pressure to rupture alveoli. This means the patient is at risk of developing adult respiratory distress syndrome, which is secondary to disruption of alveolar tissue as well as diffuse pulmonary contusions. Such a patient may become hypoxic over the next hour, and airway and ventilator support may be necessary.
If a patient with difficulty hearing is also wheezing, you must be prepared to intervene quickly with oxygen, airway support and positive pressure ventilation. However, because weakened or air-filled alveoli are also prone to disruption, be alert for tension pneumothorax and seek to rule it out in your primary surveys.
Impact injuries: IED detonation produces a blast wind that can throw nearby individuals, causing impact injuries. Such an injury can affect any part of the body and commonly takes the form of cuts, fractures and open and/or closed brain injuries.
Head injuries require further discussion because the head and brain are subjected to a multitude of injury patterns from blasts. First, the sudden blast wave, sudden movement and jarring of the brain inside the skull places the brain at risk for coup and contra-coup injuries—the brain colliding with the skull, causing damage on one end, and the disruption of vessels on the opposite end of the brain. In addition, the neurons themselves can be disrupted, causing diffuse axonal injury.
The best field treatment in these cases remains the ABCs with cervical spine control. Hyperventilation is no longer an accepted treatment method. Protect the patient’s airway, especially in patients who have a GCS reading of less than 8.
Thermal injuries: IED detonation can produce thermal injuries through the explosive release of dust, debris and caustic substances. Exposure to, and inhalation of, airborne particles may result in burns, eye irritation and exacerbation of preexisting conditions like asthma, COPD and angina.
It is also important to note that if the perpetrator was bold enough to make an IED, then that perpetrator will likely be bold enough to contaminate it. Assume contamination may be present and wear PPE, which can protect from alpha and beta particle contamination, as well as chemical contamination.
Safety is the biggest concern when first entering the scene of a blast. Secondary explosives aimed at prehospital responders have happened, and securing the scene should be the first priority. Although it is important to supply expedient care to the victims of a blast, it is more important to avoid becoming an additional victim.
The use of universal precautions and PPE are also imperative to avoid the complications of blood-borne illnesses or exposures and to avoid contamination of the provider. Responders should suspect any structure that surrounds the blast and take precautions against secondary collapse.
A blast in an enclosed space should raise prehospital responders’ concerns about serious injuries to occupants in the area. Much as a wave of water collides against the wall of a pool and bounces back toward the center, so does a blast wave reflect off of walls and surfaces to some degree. Therefore, a victim may be exposed to both the initial blast wave, and the subsequent reflective blast wave. Such situations can significantly increase the potential for severe injury in a patient.
Response to an IED blast scene is intensely complex. Any blast that falls outside of the realm of accidental occupational or industrial blast has the potential for contamination or a secondary device. Prehospital responders must assume victims of a blast injury have blunt and penetrating trauma. The ABCs are extremely important in this patient class. The treatment of both blunt and penetrating trauma does not change in this case, but responders need to consider the potential of hollow viscus injury and the possibility of rapid respiratory decline. Vigilance and frequent re-assessment are key principles in the management of blast victims.
The CDC has created training products and just-in-time informational materials to explain the various blast injuries and how to treat them. Visit www.bt.cdc.gov/masscasualties for comprehensive information on this topic.