MCHENRY WESTERN LAKE COUNTY EMS SYSTEM
OPTIONAL CE – BASIC ONLY (EMTB)
October 2013
Blast Injuries
Blast injuries can occur as a result of explosions from for example: natural gas, gasoline, fireworks,
improvised (man-make) explosive devices and grain elevators.
A blast or explosion happens when a chemical conversion occurs that changes a solid or liquid to highly
pressurized gases in an extreme manner with substantial instantaneous release of gas and heat. This
rapid expansion of gases compresses the surrounding air, creating incredible waves of pressure that
moves out from the point of explosion. This blast wave dissipates and disperses as it encounters more
stable air and moves across solid or liquid surfaces. The friction of the blast wave encountering the
stable air and other stationary objects aid in slowing and dispersing it. However, the closer an object or
person is to the point of the explosion, the more likely this incredible energy (which has a thermal
component) will be absorbed by that person or item.
If the blast wave is limited in the area where it can rapidly expand, the pressure it produces can be
concentrated or amplified. Examples of this scenario include blasts in confined spaces like in a building,
in a narrow street between two tall buildings, on is a hallway with closed doors. Even in a semi-open
area such as a street, if a blast occurs next to a building, the remaining area of less resistance (the street
and sidewalk) will be hit with a concentrated or amplified blast wave. Another way to look at this is that
a patient is far more likely to survive a car-bomb blast 100 feet away if it explodes in an open field rather
than an alley between two tall buildings.
There are two parts to a blast: a shock wave that travels at supersonic speed, and compressed air, which
travels in front of the shock wave. Both can cause considerable damage to the human body, but the
exact effects are unclear.
Although most commonly associated with military conflict, blast injuries are also seen in civilian practice
in chemical plants, factories, mines, shipyards and increasingly in association with terrorist activities.
Injuries resulting from a blast are categorized into one of 4 categories.
Primary Blast Injuries: These are due to the pressure wave of the blast. They primarily affect the gascontaining organs and include: Tympanic membrane rupture of the ear, pulmonary damage (blast lung)
and air embolism and hollow viscus injury.
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Ear Injury: Tympanic membrane rupture is the most common primary blast injury. Signs of ear
injury are usually evident on presentation and include: hearing loss, tinnitus (ringing in the ear),
otalgia (ear pain), vertigo, bleeding from the external canal and otorrhea (fluid from the ear).
Isolated tympanic membrane rupture is not a marker for morbidity.
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Blast lung injury: Symptoms may include dyspnea, cough, hemoptysis (coughing up blood) or
chest pain following a blast. Signs may include tachypnea, hypoxia, cyanosis, apnea, wheezing,
decreased breath sounds and hemodynamic instability. Signs and symptoms are usually present
at the time of initial evaluation, but may be delayed up to 48 hours. It is reported to be more
common in patients with skull fractures, greater than 10% BSA burns, and penetrating injury to
the head or torso. Due to pulmonary or vascular tearing, air may enter the arterial circulation
(air emboli) and present as a stroke, MI, acaute abdomen, blindness, deafness or spinal cord
injury.
Abdominal Injury: Gas-filled (hallow) organs are most vulnerable especially the colon.
Presentation may include bowel perforation, hemorrhage, mesenteric shear injuries, solid
organ lacerations or testicular rupture. It should be suspected in anyone with abdominal pain,
nausea, vomiting, hematemesis, rectal pain, tenesmus (the feeling that you need to pass stool),
testicular pain or unexplained hypovolemia. Clinical signs can be initially subtle until acute
abdomen or sepsis is advanced.
Secondary Blast Injuries: These are due to flying debris (such as shrapnel from the device or from glass
or splinters) that have been propelled by the force of the blast, or blast wind. These objects may travel
great distances and can be propelled at tremendous speeds, up to nearly 3000 mph for conventional
military explosives.
A blast wind occurs as the shock wave applies force to air molecules. Although less forceful than the
pressure wave, the blast wind is longer lasting and can hurl projectiles at high velocities. Projectiles
present serious hazards – flying debris may cause blunt and penetrating injuries. With bombs, the
casing fragments rip apart with monumental force, spreading in all directions. Structural elements can
break apart and travel at high rates of speed. Nails, wood splinters and glass shards can impale victims
located in the area of the blast. In contrast to primary blast injuries the secondary injuries are obvious.
Most common are lacerations, impaled objects, fractures and burns.
Tertiary Blast Injuries: These occur when a person is hurled by the force of the explosion (or blast wind)
against stationary, rigid objects like the ground or a wall. The injuries that result are numerous and
result from both penetrating and blunt mechanisms. Fractures are common, and in some cases wind
injuries can amputate limbs. Injuries can also result from structural collapse resulting in crush injuries,
in addition to the other injures mentioned earlier.
Victims may also be injured from displacement away from the blast. Displacement occurs when a
person is in close proximity to the explosion, survival in this instance is highly unlikely.
Quaternary Injuries: These injuries result in the miscellaneous events that occur during an explosion.
These injuries can include burns, respiratory injury from inhaling toxic gases, and crush injuries. For
example, the heat generated during an explosion may cause burns, ranging from superficial flash burns
to full-thickness burns. There is also a risk for entrapment that may be prolonged for days.
In Addition:
Neurologic injuries and head trauma are the most common causes of death from blast injuries.
Subarachnoid (beneath the arachnoid layer covering the brain) and subdural (beneath the outermost
covering of the brain) hematomas are often seen. Permanent or transient neurologic deficits may be
secondary to concussion, intracerebral bleeding, or air embolism. Instant but transient unconsciousness
with or without retrograde amnesia, may be caused by not only head trauma, but also by cardiovascular
problems. Bradycardia and hypotension are common after an intense pressure wave from an explosion.
Scene Size-Up
When your response includes the report of an explosion, your scene size-up must include trying to
better understand possible causes and if it is the result of an accident or intentional act. Either situation
may pose a risk to responders. Additionally, explosion scenes will likely be chaotic, and this information
may not be initially available. Explosions may result in buildings, including nearby structures, becoming
unsteady and unsafe. In addition to possible structural instability, rubble and other debris may also
pose an airborne threat. Do no attempt a rescue you are not trained, equipped and prepared to
undertake. Always await the responders who have the equipment and expertise.
Initial Triage and Management
These do have the potential to be a multi casualty incident. In this case you would follow the mass
casualty protocol and patients would be triaged using the START or Jump Start (patients under 8 years of
age) system.
Your approach to assessing these patients should not differ from you normal assessment of a potential
trauma patient. There are however several key areas to focus on when assessing and managing a blast
victim.
1. Common life-threatening injuries to be aware of include closed head injuries and cervical spine
injuries
2. With the chest, pay close attention for the possibility of pneumothorax, hemothorax, or tension
pneumothorax (caused by rapidly changing pressures created by the blast wave).
3. For the abdominal area, it is important to note that hollow organs, such as the stomach and
colon, may be damaged by the rapidly changing pressure. If you suspect a solid organ injury
(for example signs and symptoms of a rupture spleen), it is reasonable to suspect and to
continue to evaluate for a hollow organ injury.
4. Assess the pelvis for stability and all extremities for deformity and stability. Additionally, the
blast wave can lead to fractures caused by propelled objects, the wave itself or a patient being
thrown against a fixed object.
5. An overall assessment should include looking for damage produced by shrapnel.
6. Depending on the source of the explosion, the blast wave may include very hot air that creates
critical burn injuries at the point of contact with the patient. For some of the more catastrophic
blast scenarios, this could create a profound number of burn-injured patients.
7. Blast-injured patients may have significant burns that can draw the focus of the provider.
Although burns can be life-threatening, do not lose sight of the principle concern for loss of life,
the underlying traumatic injury.
Initial trauma resuscitation and transport of patient involved in a blast injury should follow your
standard protocols for treatment of trauma patients.
McHenry Western Lake County EMS System
OPTIONAL CE – BASIC ONLY (EMTB)
October 2013
Blast Injuries
Name: ___________________________________ Dept: ___________________________________
Date: __________________________
1. Explain the physics of an explosion.
2.
What is the cause of primary blast injuries and list the three most common injuries seen in this
category.
3. List the signs and symptoms of blast lung injury.
4. List the cause of secondary blast injuries and the most common injuries seen in the category.
5. Explain the cause of tertiary blast injuries and common injuries you may see in this category.
6. Discuss what happens in a blast that results in quaternary injury and list three types of injuries
you would see in this category.
7. _________________and __________________ are the most common causes of death from
blast injuries.
8. Explain your scene size up upon arrival to the scene of a blast injury.
9. Gas-filled (hallow) organs, especially the colon are more commonly injured in a blast than solid
organs. True False
10. Initial trauma resuscitation and transport of patient involved in a blast injury should follow your
standard protocols for treatment of trauma patients.
True False