Ballistics for the EMS Ballistics for the EMS Provider Provider How guns work, what they How guns work, what they

can do, and how to treat gun shot woundscan do, and how to treat gun shot wounds

Jeff Brosius,

B.S., NREMT-P, CCEMT-P

Basic Principles of BallisticsBasic Principles of Ballistics

PhysicsFirearm mechanicsBullet propertiesTissue response to forceTreatment

Basic Principles of Physics Basic Principles of Physics

Kinetic Energy is a function of mass and velocity

Force is a function of mass and acceleration/deceleration

Energy can not be created or destroyed, only changed from one form to another

Newton’s Laws of EnergyNewton’s Laws of Energy

Kinetic Energy = ½ Mass x Velocity²Force = mass x G (where G = Gravity ForceA body in motion will continue in motion

until acted upon by an outside force (tissue, gravity, friction, solid object, etc.)

Firearm MechanicsFirearm Mechanics

All firearms share some basic principles.There is a barrel, which functions to direct

the projectile in a certain direction.There is a pin, which causes the powder in

the bullet to ignite.There is a trigger, which causes the pin to

strike the bullet.

Firearm Mechanics, cont.Firearm Mechanics, cont.

The bullet contains powder, which will burn rapidly, creating gas vapors.

These vapors expand inside the barrel, creating pressure.

The pressure forces the bullet out of the barrel.

The speed of the bullet depends on several factors (size, friction, etc.)

Bullet CharacteristicsBullet Characteristics

Caliber of the bullet (.22, .45, .357, 9mm, etc.)

Blunt vs. Hollow vs. Pointed endCasing (unjacketed/full metal jacket)Density of material

Handguns, by the NumbersHandguns, by the Numbers

Caliber Velocity Muzzle Energy Energy at 45 feet

Ft/sec

.25 810 73 60

.32 745 140 120

.357 1410 540 475

.38 855 255 255

.40 985 390 365

.44 1470 1150 875

.45 850 370 350

9 mm 935 345 315

Rifles, by the NumbersRifles, by the Numbers

Caliber Velocity Muzzle Energy Energy at 300 ft

.22 Hornet 3770 1735 1262

.243 3500 1725 1285

M-16 3650 1185 805

Uzi 1500 440 277 (150 ft)

AK-47 3770 1735 1262

Tissue ResponseTissue Response

Cavities – temporary and permanent– Temporary is larger than the size of the bullet,

and is caused by compression of air around the projectile.

– Permanent is the destroyed tissue from the bullet itself.

CavitiesCavities

The size of the cavity is not simply a factor of the bullet size. Other factors are important, but often unknown– Deflection– Yaw of bullet at impact– Speed of bullet at impact– Angle of impact– Range from gun to target

Cavity FormationCavity Formation

Tissue

Temporary Cavity

M-16 Rifle WoundM-16 Rifle Wound

NATO 7.62 WoundNATO 7.62 Wound

.22 Long Rifle Wound.22 Long Rifle Wound

AK-74 Rifle WoundAK-74 Rifle Wound

.22 cal Hollow Point Wound.22 cal Hollow Point Wound

Tissue ResponseTissue Response

Dense tissue will suffer more damage than hollow tissue. (Bone vs. lung)

Elastic tissue will suffer less damage than rigid tissue. (Muscle vs. liver)

Strong tissue will withstand damage better.

Treatment GoalsTreatment Goals

Safety!!!!!!!!!!!!!!!!!!ANY penetrating trauma should be treated

with the utmost urgency.A small hole on the outside might be hiding

a large hole inside.A large hole outside can mask massive

internal damage.

Treatment GoalsTreatment Goals

ABCs, as always.Rapid scene times… grab ‘em and get

moving to the hospital.Airway support to include intubation (more

often needed for thorax injuries.)Ventilatory support as needed.IV enroute, fluids as protocol/Med Control

requests.

Treatment GoalsTreatment Goals

Hemorrhage control if possible.Occlusive dressings for sucking chest

wounds.Needle Thoracostomy as needed for tension

pneumothorax.Bilateral needle decompression ONLY in

an intubated patient.

Treatment GoalsTreatment Goals

Early notification of the hospital.Constant reassessment…A GSW to the

chest can cause the patient’s condition to change RAPIDLY. Be vigilant.

Again, rapid transport is the single best method for treating a gunshot victim.

Nothing else will be as helpful as a physician and hospital trauma care.

Treatment PitfallsTreatment Pitfalls

Wasting time looking for the bullet or shell casing. Thinking that a small hole is not a major issue. Wasting time trying to classify wounds as

entrance or exit. Closest facility vs. Closest appropriate facility. Delaying transport for ANY reason, other than

EMS crew safety.

Controversial IssuesControversial Issues

Cervical Spine Immobilization.Large volumes of fluid replacement.Traumatic cardiac arrest treatment.

Pictures of injuries from Pictures of injuries from firearms….firearms….

AcknowledgementsAcknowledgements

Andres M. Rubiano, MD David H Livingston, MD, FACS Manuel Sotelo, MD Errington C. Thompson, MD Eric D. Ladenheim, MD M.L. Fakler, MD Grady Memorial Hospital, Atlanta, GA Emory University School of Medicine,

Department of Surgery

Web SitesWeb Sites

ww.umds.ac.uk http://medstat.med.utah.eduhttp://igm.nlm.nih.gov/http://www.vnh.org/EWSurg/EWSTOC.htmlhttp://internet.cybermesa.com/~jbm/ballistics

/calculations.htmlhttp://www.firearmstactical.com

Web SitesWeb Sites

http://www.iwba.com/http://www.milnet.com/milnet/weapons.htmhttp://www.wwa.com/~dvelleux/htmlhttp://www.vnh.org/EWSurg/EWSTOC.html

Final Words….Final Words….

Don’t waste time. What you can’t see will kill the patient.

Be safe. Treat the patient. Do not treat the bullet, and don’t waste time on

details that don’t matter. Understand that a .22 is just as lethal as a .357. Don’t waste time.

Questions?Questions?