[swatsurgeon]

with the significant increase in suicide bombers I thought this re-newed thread would be appropriate. Previous threads have touched on a few issues related to blast injuries, I wanted to start with a "guide" that was printable as a primer for care of the patient involved in a blast.
This will also hopefully begin a discussion of specific injuries and treatments. Most importantly is recognition of the pending/delayed injuries....the obvious ones are just that, obvious, my concern is the non-observable and how the medic can literally make the difference in the outcome by recognition of the potential problems. Here is the first part or summary then let the questions begin:

Explosion
 This wave of compressed air can be measured as overpressure or direct impulse.
 The magnitude of the overpressure is proportional to the amount and type of explosive used.

Overpressure
 Overpressure is measured in pounds per square inch.
 Relative power is calculated by multiplying PSI X duration in milliseconds of the impulse.
 overpressure of 58 – 80psi is 95% lethal.
 7 – 8psi can shear brick walls or overturn rail cars.
 5psi can rupture tympanic membranes.
 0.5 – 1psi can break windows and knock people down.

Injury Physiology
 Lung injury
– 0-48 hrs to manifest signs/symptoms!!!!!
 dyspnea, cough, hemoptysis, chest pain
 if going to O.R. or air transport, consider chest decompressions
 Ear Injury
 hearing loss, tinnitus, otalgia, vertigo, bleeding, otorrhea

 Abdominal injury
 abdominal pain, nausea, vomiting, hematemesis, rectal pain, testicular pain, shock state, peritonitis
 Brain injury
 concussion / TBI (and associated symptoms), headache, fatigue, reduced concentration, lethargy, depression, anxiety, insomnia, seizures, depressed GCS, pupil changes, weakness, paresthesias

Shock Wave
 The shock wave has 3 components:
– Positive phase
– Negative phase
– Mass air movement

 Positive phase.
– Velocity and duration of the blast head.
 Dependant upon:
– Size/type of the explosive
– Surrounding media
– Distance from the detonation.

Shock Wave
 Closed spaces magnify the effects of the direct impulse.
 “Shock Wave” “bounces” off hard surfaces and is referred to as a “Reflected Impulse.”
Shock Wave
 Shock waves all create similar rates of rise in pressures at the blast front.
 The magnitude of this “positive-phase impulse” becomes the important property in the generation of the Primary Blast Injury (PBI).
Shock Wave
 Negative phase.
– Partial vacuum is created near the epicenter after outward movement of air
– Consumption of oxygen by the burning process.

 The “reflected impulse” may combine with the “direct impulse” and increase injuries at a greater distance from the blast site than expected.

Shock Wave
 Effects are cumulative.
 Example:
– A blast that causes a 1% mortality when experienced once, causes a 20% mortality when experienced twice, and 100% mortality if experienced three times.

Primary Blast Injury
 Caused by shock wave from explosion
– tissues are disrupted at air/fluid interfaces in a process called “spalling”
 ears and lungs are most commonly injured
 bowel injuries more common with under water blasts
– degree of injury is related to the magnitude and duration of the peak overpressure of the blast shock wave
– death nearest to blast is usually caused by massive cerebral & coronary air embolism


Secondary Blast Injury
 Caused by debris set in motion by shock wave that impacts the body

Injuries - Penetrating
 Secondary blast injuries
– Injuries from devices that contain foreign bodies:
 Nails
 Rivets
 Ball bearings
 Nuts and bolts,
 Etc.
Injuries - Penetrating
 Medically, usually no different than other penetrating injuries seen.
 Complicated by the PBI’s.
 Bone and tissue from suicide bombers may be secondary missiles.
– Aids, hepatitis, etc.

Secondary Missiles
Injuries - Penetrating
 Secondary missiles created by container fragments or added missiles can have velocities of up to 1,500m/sec.
 Rapid deceleration seconday to poor ballistic properties.

Tertiary Blast Injury
 Displacement of victims body to crash into other objects

Injuries
 Tertiary injuries – Blunt trauma.
– Physically thrown through the air and strike or impale themselves on objects.
– Collapsing structures.
– Other objects propelled through the air striking the victim.

Tertiary Injuries
 Severe head injury is a leading cause of death in victims of blasts.
 Subdural and subarachnoid hemorrhages are the most common findings in fatalities.

Injuries
 Thermal injuries
 Primary or secondary incendiary.
– Inhalation
– Dermal

Scene
 Recent studies suggest the PBI victims do poorly when strenuous physical activity follows significant blast loading.
– Reduce activity of potential blast-exposed individuals.
– Provide history of activity to ED personnel receiving patient.
Medical Management
 On site treatment is VITALLY important
– rapid stabilization
– control of hemorrhage
– splinting of fractures
– cleaning and covering of wounds
 antibiotics
 analgesics
 med control contact
 transport initiation
Medical Management
 On site treatment is VITALLY important
– immediate determination of concomitant radiation, chemical or biological contamination
 decon if possible
– patient and you
Tactical Field Care
 CPR is not initiated if no signs of life
– no respirations
– no palpable pulse
– no response to any stimuli
 naso-pharyngeal airway is airway of choice for unconscious patient
 Severe respiratory distress = need for chest needle decompression
Tactical Field Care
 Controlled bleeding without signs of shock don’t need IV fluid
– controlled bleeding & in shock = 250-500mL NSS boluses
– uncontrolled bleeding & in shock, but mentating, no IVF
 if depressed mental status, give bolus

 Antibiotics for abdominal wounds