Recognition and Management
Order the Operational Medicine CD, developed
by the US Navy and US Special Operations Command
Direct secondary blast injury.
The wound shown was made by a fragment of a 105-mm shell.
From the Textbook of Military Medicine, part I, volume 5, page 125,
2: Indirect secondary
The wounds shown were caused by a booby trap made from several hand
grenades surrounded by assorted pieces of scrap metal.
From the Textbook of Military Medicine, part I, volume 5, page 47,
3: Multiple burn wounds of the lower extremities caused
by hot metal spall
from the inside of an armored vehicle struck by a shape-charged weapon. From the Textbook of Military Medicine, part I, volume 5, page 32, figure
5: Car across the street from the bombing that occurred
behind the US Embassy in Nairobi, Kenya, in 1998. Note that all
surfaces backed by air are crushed in inward from the force of pressure
differentials created by the blast wave external to the vehicle and stress
waves internal to the materials. There is also significant thermal
damage created by the fireball from the explosion. From Lt Col
Wightman’s personal photographs. A similar acceleration of
surfaces occurs on the tympanic membrane, chest wall, and abdomen of the
human body resulting in stress
waves and the potential for primary
blast injury of these air-containing structures.
High-explosive (HE), thermobaric, and nuclear
detonations cause extreme compression of molecules in surrounding air or
water creating thin bands of locally high overpressure, which are
propagated away from the origin of the explosion as a blast shock wave.
Most casualties within the injury radius of a HE detonation will
have common penetrating (Figure 1
& Figure 2), blunt, and burn (Figure
3) injuries managed no differently than similar non-blast
the blast wave arrives at the surface of an object (vehicle, structure, or
human body), it is transmitted into that object as a stress wave (Figure
4). As the blast
wave separates from the stress wave due to the latter moving slower
through objects than the blast wave moves around them, pressure
differentials cause forces that accelerate surfaces (Figure
transmitted into the human body, the shock wave causes
stress-induced tears at air-tissue interfaces (Figure
6), which result in internal bleeding, weakening of tissue
resistance to additional insults, and possible rupture with escape of air
from the respiratory tract or spillage of gastrointestinal (GI) contents.
hemoptysis can compromise the airway. Management of any associated
penetrating, blunt, and thermal trauma will not be discussed in this
Worldwide. In addition to its association with combat and acts of
terrorism, blast injuries may occur as a result of industrial or training
The closer a casualty is to an explosion, the more likely he will receive
primary blast injury (PBI) from the effects of blast overpressure alone,
particularly if behind cover and shielded from ballistic trauma.
in enclosures (buildings, ships, armored vehicles, etc.) are at
greater risk, regardless of whether detonation occurred inside or
outside the enclosure.
treading water are at higher risk for abdominal than thoracic blast
injury from underwate explosion.
submerged personnel are at equal risk of combined thoracic and
abdominal blast injury, as are personnel in open air, but equivalency
occurs at three times distance from explosion underwater compared to
armor increases the risk of PBI, but decreases the risk of secondary
blast injury from fragments, shrapnel, and debris due to its ballistic
protection of vital structures.
blast injury occurs when the high-velocity blast wind generated by
pressure differentials accelerate personnel to tumble along the
ground, strike solid objects (Figure 7), or impale themselves on other
objects. Secondary and tertiary mechanisms result in
conventional blunt and penetrating trauma.
Acute (0-2 Hours)
Sub-Acute (2-48 Hours)
Chronic (>48 Hours)
Pleuritic Chest Pain
Cardiac Chest Pain
Persistent Hearing Loss
Chest x-ray showing small fragment wounds and primary
of the lung resulting in pulmonary contusions demonstrated as infiltrates
under the left chest wall. From
the Textbook of Military Medicine, part I, volume 5, page 302, figure 9-2.
Picture of the inside of an office space overlooking the rear of
the US Embassy after the bombing in Nairobi, Kenya, in 1998. Several
casualties were near the window at the moment of detonation.
Thus, they received primary
from the blast wave itself, secondary
from fragments of the truck carrying the device and glass, and tertiary
from being propelled into objects.
Note the head-high, arcing blood smear on the wall.
Lt Col Wightman’s personal photographs.
you short of breath? (Pulmonary contusion inhibits oxygen
diffusion and requires more effort to inhale. Pneumothorax and
hemothorax decrease the volume of air that can be inspired.
Shock will cause the sensation of dyspnea due to poor tissue
you have chest pain? (Chest pain indicates the possibility of
penetrating or blunt trauma, pneumothorax, or myocardial ischemia or
infarction due to coronary AGE.)
you have abdominal or testicular pain, nausea, urge to defecate, or
blood in your stools? (Penetrating and blunt abdominal trauma
cause pain, but PBI of air-containing structures in the GI tract may
cause any of the listed symptoms.)
you have eye pain or problems with your vision? (Evaluate for
penetrating or blunt eye trauma as described in the chapter on
you have ear pain or problems with your hearing? (Ruptures of
TMs occur commonly but are not life-threatening, unless the casualty
cannot hear life-saving commands or communications.)
or Aggravating Factors –
much exertion is required to cause any shortness of breath? (Dyspnea
at rest indicates shock due to external or internal hemorrhage,
pneumothorax, or serious pulmonary contusion. The more exertion
required to elicit dyspnea, the less lung injury is likely.)
Asymmetric Breath Sounds
Altered Mental Status
Focal Neurologic Deficit
Using Basic Tools
of the foot caused by a small anti-personnel mine. Although
this picture was taken in Vietnam, this injury is typical of small
landmines scattered throughout the Balkans and other parts of the world.
Because there are no metal parts, virtually all effects are due to
the stress wave fracturing the bone and the blast
ripping off the foot. From
the Textbook of Military Medicine, part I, volume 5, page 46, figure 1-65.
of both lower extremities caused by a large anti-personnel mine.
Ballistic and thermal trauma can be seen, as well as massive
contamination from dirt and straw. From
the Textbook of Military Medicine, part I, volume 5, page 172, figure 5-9.
This Ranger has been placed in the coma
his left side down, his body rotated halfway between the left-lateral
decubitus and prone positions, and his head at same the same level as his
places his airway in a position of protection such that his tongue will
naturally fall away from his oropharynx and blood, secretions, or emesis
may drain by gravity. There
is minimal restriction of his respiratory efforts.
If he has a pulmonary contusion, more posterior alveoli may be
aerated in this or the supine position.
also places his coronary arteries in their lowest position to protect
against coronary AGE and his head at lowest risk for both cerebral AGE and
how his right elbow and knee provide support, so that he does not have to
be actively maintained in this position by an attendant.
Lt Col Wightman’s personal photographs.
sites of life-threatening external hemorrhage first.
(#1 cause of preventable death on battlefield.)
dyspnea by its severity at rest or by the degree of exertion
that causes it. (Do not
purposefully exert the casualty just to see how much exertion elicits
mental status may be transient or not.
(May be due to head trauma, shock, or cerebral AGE.)
indicates stress from external or internal hemorrhage, hypoxia,
exertion, dehydration, or anxiety.
is inappropriate but may be transient following a blast-induced vasovagal
reaction stimulated by suddenly increased intra-pulmonary
heart rhythm may indicate cardiac irritability from shock or coronary
AGE. Rapid, shallow
respirations are common after blast exposure, regardless of the degree
of lung injury, but can also indicate other thoracic damage, shock,
exertion, or anxiety.
may result from hemorrhage, other causes of shock, or a vasovagal
external abrasions, contusions, penetrating wounds
1 & Figure 2), and traumatic
amputations (Figure 8 & Figure 9)
for inadequate chest-wall movement.
for central and peripheral cyanosis (indicating hypoxia)
and well-demarcated mottling or blanching of the tongue or areas of
skin (indicating AGE).
or bleeding from the ears indicates TM rupture or basilar
emphysema indicates an open external wound or rupture of an
air-containing internal structure.
tenderness may indicate internal hemorrhage or GI tract rupture.
of the spine or extremities may be appropriate to decide if the
casualty can move under his own power or needs to be transported in an
SPO2 < 95% on room air indicates some degree
of lung injury, inadequate respirations, shock, or exposure to a
chemical agent such as cyanide.
the Assessment section of this chapter on using pulse oximetry
to categorize the severity of blast lung injury.
Using Advanced Tools
casualties with primary bowel injury have bleeding, it is usually gross hematochezia,
but guaiac-positive stool indicates possible occult penetrating, blunt, or
allows close inspection of the possibility of penetrating anterior-eye
hemorrhage or a foreign body on funduscopic examination or the absence of a red
reflex indicates posterior-eye trauma.
air is noted in retinal vessels, it proves AGE.
Prediction of Respiratory Problems
pulmonary injury may be defined as no dyspnea with exertion after 1 hour
of rest. Significant pulmonary
blast injuries may be classified as mild, moderate, or severe based on pulse
oximetry. This may help predict
the likelihood of complications, requirement for positive-pressure
ventilation (PPV), and need for higher-than-normal positive
end-expiratory pressure (PEEP).
90% on 100% oxygen
to need conventional PPV
of 5-10 cmH2O usually needed
< 90% on 100% oxygen
to need unconventional PPV
10 cmH2O usually needed
more likely to be initiated or exacerbated by decreased ambient external
pressure on the casualty are pneumothorax, AGE, and bowel-wall stretching.
Rapid Unconsciousness –
Airway Compromise –
or internal hemorrhage
from pulmonary injury
bleed (more often lower)
Focal Neurological Deficits –
or spinal AGE
Ruptured TMs –
IV fluid is administered for controlled hemorrhage with shock or uncontrolled
hemorrhage with altered mental status, bolus with one quarter the usual amount
(crystalloid or hetastarch) and reevaluate to avoid exacerbating lung or brain
injury. Repeat boluses as
Procedures for Suspected Arterial Gas
high-flow supplemental oxygen. Use
an aviator’s mask for extra pressure, if needed and available.
Evacuate to a hyperbaric chamber as soon as possible.
Pressurize the evacuation aircraft’s cabin to the atmospheric
pressure at the destination, if using air transportation and it is
technically possible in the aircraft used.
the casualty in the coma position with his left side down (halfway
between the left-lateral decubitus and prone positions) and his head at the
same level as his heart (Figure 10).
Procedures for Massive Hemoptysis
Procedures for Suspected Tension Pneumothorax
thoracentesis to relieve life-threatening shock.
(chest tube), if air is aspirated during
but respiratory difficulty and hemodynamic compromise are not relieved.
Although tube thoracostomies are generally not recommended during
Tactical Field Care for penetrating trauma, severe pulmonary blast injuries
can cause direct communications between large airways and the pleural space
(bronchopleural fistula) where a 14-gauge catheter cannot evacuate
air out of the pleural space faster than it enters.
Treatment of Suspected Pulmonary
all activity. Administer
high-flow supplemental oxygen, if it is available.
Initiate PPV only if absolutely necessary.
at least 1 hour. Resume tasks
undertake activities at the lowest practical level of exertion (slower
movement, less weight carriage, etc.).
Procedures for Ventilatory Assistance
open pneumothorax (sucking chest wound).
Allow spontaneous breathing whenever possible.
Place casualty in the position he can breathe best.
positive-pressure ventilation (PPV) becomes required, use
mouth-to-mask or bag-valve-mask/tube with slower and less-forceful delivies
than are often used with other traumatic causes of respiratory problems.
Impact 750M Portable Ventilator
(if available and operator qualified)
high-pressure hose from oxygen source to 50-psi inlet
will be 1.00 (100%) unless blender is used
mode to synchronized intermittent mandatory ventilation (SIMV)
respiratory rate to 12 breaths/minute (1 breath every 5 seconds)
tidal volume as 8 mL/kg
inspiratory time to 1 second (I:E ratio equals 1:4 over 5 seconds)
inspiratory flow to 8 mL/second for every kg of body weight
PEEP valve to exhalation port, if needed
on balloon before attaching to airway adjunct
Double-check that the definitive airway is still in place and
its cuff is intact. Ensure
oxygen is being delivered to the ventilator unit. Change the PEEP valve to a greater PEEP (up to 10 cmH2O).
Peak Inspiratory Pressures > 35 cmH2O:
that the definitive airway is in place. Evaluate
for tension pneumothorax, and correct if present.
Increase I:E ratio by proportionally increasing inspiratory time and
decreasing inspiratory flow (e.g., 4 mL/sec per kg of body weight
for 2 sec). Consider selective
intubation and independent lung ventilation with half the tidal volume.
Treatment of Vasovagal Syncope:
the casualty’s head at the level of his heart and elevate his lower
Wait until casualty awakens. Unlike
syncope from fright, this may take up to 2 hours in a blast-injured
Treatment of GI Bleeding: Same as outlined in the chapter on Gastrointestinal Problems.
Treatment of Possible GI Tract
Maintenance IV fluid. Cefoxitin
or ceftriaxone IV or IM.
Evacuate DELAYED for surgical care within 4 hours.
Monitor for peritonitis and sepsis.
or promethazine IV or IM,
if needed to prevent recurrent vomiting.
PO water, if no IV and evacuation time > 4 hours. Ciprofloxacin
and metronidazole PO, if
not carried or casualty is allergic to them.
Virtually any antibiotic coverage is better than nothing when time to
definitive care is prolonged.
of Mediastinitis, Peritonitis, or Sepsis
of two parenteral combinations: 1) cefoxitin
or 2) ampicillin/sulbactam
combination of ciprofloxacin
Treatment of TM Rupture
Do not attempt removal of foreign debris.
Prevent water and other non-sterile material from entering the ear
canal. Manage pain as
antibiotics are not indicated. If
infection of the TM (myringitis) develops, instill ophthalmological
(for the eye) gentamicin 4 drops (not ointment) 4 times
a day for 10 days. Otological
(for the ear) suspensions for otitis externa are contraindicated when
the TM is ruptured.
or ciprofloxacin PO, if
ophthalmological antibiotic drops are not available.
Inspect the area surrounding the ear, the external ear itself,
the ear canal, and the TM daily for redness, swelling, or purulent drainage.
Pain when gently pulling up and back on the pinna or pressing on the
cartilage just in front of canal also indicates otitis externa.
casualty should ideally be seen by an ear, nose, and throat (ENT) specialist
within 3 days, or sooner if significant debris is in the canal.
Up to 2 weeks is acceptable, if no infection develops.
from the tactical environment to a higher level of medical care, then
MEDEVAC to more definitive care. The
destination chosen should consider the following needs based on suspected
with neurosurgery – URGENT-SURGICAL.
Intensive care at the same facility is desirable.
with general surgery – URGENT-SURGICAL.
Cardiothoracic and vascular surgery are desirable.
with hyperbaric chamber – URGENT. Other
trauma services at the same facility are desirable.
with intensive care – URGENT. Pulmonary
and surgery services are desirable.
Tract Rupture: Facility
with general surgery – PRIORITY. A
pulmonary service is desirable.
facility with physician – ROUTINE. An
ENT service is desirable.
is most likely due to penetrating or blunt head trauma or shock from
bleeding, but two unique features of blast injury are less common causes: 1)
blast overpressure on the lungs can cause vasovagal syncope with bradycardia
and hypotension, which may last minutes to hours even with conventional
treatment; and 2) stress-induced tears in lung tissue may allow air into the
pulmonary veins, which can then be ejected to the cerebral or coronary
circulation causing a stroke or heart attack, respectively.
amnesia is common after any loss of consciousness caused by
petechiae (but not TM rupture) predict a higher likelihood of pulmonary
sure the casualty can be easily moved between sitting and lying positions
for respiratory management.
PPV unless absolutely necessary, because it increases the risks for pneumothorax
and arterial gas embolism. AGE
is the most common cause of death in immediate survivors and often occurs
when PPV is initiated.
is better to place a possibly unneeded chest
tube than have a tension pneumothorax during transportation.
of a tension pneumoperitoneum affecting respirations is rare, but may
require a 14-gauge needle paracentesis in the midline just above the
umbilicus for decompression.
is usually due to head injury, not blast effects on the inner ear.
Meclizine can improve
symptoms but can also sedate, thus impairing the casualty’s ability to
function and making assessment of AMS more difficult.
should be withheld in bradycardia and given with caution in
for the necessity of a tetanus
This section contributed by Lt Col John Wightman, USAF, MC