swatsurgeon
12-15-2004, 07:59
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
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