Kinematics of Trauma Kimberly Ann Holmes Kenney RN, CNS-Rx, MS(N), MS CCRN, CEN, CFRN, NREMT-P

Objectives Discuss the laws of energy and motion. Discuss trauma associated with blunt impact and penetrating injury. Overview of the effects of energy distribution in MVCs. Review the kinematics of blast and violent injuries. Use kinematics to predict injury patterns.

Kinetic Energy KE = or KE = Kinetic energy is the energy of motion. mass (weight) x velocity (speed)2 2 KE = or mv2 2 KE = Kinetic energy is the energy of motion.

Example of Kinetic Energy The KE of a 150-lb. person traveling at 30 mph would be: = 67,500 KE units 150 x 30 x 30 2

Velocity vs. Mass What is more important: velocity or mass? 150 lb. person traveling at 30 mph = 67,500 KE units 180 lb. person traveling at 30 mph = 81,000 KE units 150 lb. person traveling at 40 mph = 120,000 KE units What is more important: velocity or mass?

Velocity

Newton’s First Law of Motion A body at rest will stay at rest. A body in motion will remain in motion. Unless what?

Newton’s First Law and Blunt Trauma Car strikes pole. Driver continues moving forward. Anterior surface of body strikes steering wheel. Posterior body continues moving forward. Organs compressed within body.

Law of Conservation of Energy Energy cannot be created. Energy cannot be destroyed. But, energy can change forms and can be transferred. Can you give an example?

How does the Law of Conservation of Energy pertain to trauma? Can you give some examples?

Deceleration and Acceleration Compression Injury

Deceleration and Acceleration Shear Injury

Organ Injury In a 50 mph MVC, what types injuries would occur if the patient were to strike the windshield?

Head Injury Fractures. Ligamentous injuries. Soft tissue injury. Brain injury. Cord damage.

Torso Injury Rib fractures. Heart & lung damage. Abdominal organ damage. Major vessel damage.

Extremity Injury Fractures. Ligamentous injury. Soft tissue injury.

Types of Motor Vehicle Collisions Frontal impact. Lateral impact. Rotational impact. Rear impact. Rollover.

What type of injury patterns might you see in a frontal impact?

Frontal Impact - Occupant Pathways What injuries would you expect with an up and over pathway?

Injuries with Up & Over Pathway continued... Head injuries. Spine injuries. Chest injuries. Fractures. Pneumothorax. Hemothorax. Contusions. Great vessel injury.

Injuries with Up & Over Pathway continued... Abdominal injuries. Solid organs. Hollow organs. Diaphragm. Fractured pelvis.

Frontal Impact - Occupant Pathways What injuries would you expect with a down and under pathway?

Injuries with Down & Under Pathway Posterior knee/hip dislocations. Femur fractures. Lower extremity fractures. Pelvic/acetabular fractures.

What types of injuries would you expect? Rear Impact What types of injuries would you expect?

What types of injuries would you expect? Lateral Impact What types of injuries would you expect?

Body Motion during Lateral Impacts Neck Chest Pelvis

What types of injuries would you expect? Rotational Impact What types of injuries would you expect?

Rollover What injury patterns might you see following this collision?

Lap Restraint Device Properly positioned lap restraint. Improperly positioned lap restraint. What types of injuries should you anticipate?

Lap & Shoulder Restraint System Shoulder harness only; lap belt not used. (Victim moves down and under). Lap restraint only; shoulder harness not used. (Victim moves up and over) What types of injuries should you anticipate?

Airbag Deployment What types of injuries would you expect to see? What injuries would occur in a second collision?

Airbag Deployment What concerns would you have about a: Small patient? Child in a car seat?

Motorcycle Collisions Mandatory helmet laws have been associated with up to 300% fewer head injuries and deaths.

Types of Impact: Frontal/Ejection How many impacts did this collision involve? What types of injuries would you expect to see?

Types of Impact: Lateral How many impacts did this collision involve? What types of injuries would you expect to see?

Pedestrian vs. Motor Vehicle How would the injury patterns differ between the adult and the child?

Falls Impact surface. Height. (Harder surface = greater injury.) Height. (Greater height = greater injury.) Falls from a distance of more than three times the patient’s height produce critical injuries.

Falls Deceleration injuries. Liver. Aorta. Spleen. Kidney.

Landing Feet First (Don Juan Syndrome) Injuries seen in patients landing feet first: Bilateral heel fractures. Ankle fractures. Distal tibia/fibula fractures. Knee dislocations. Femur fractures. Hip injuries. Spine compression fractures.

Landing Arms/Hands First Physical findings: Colles’ fractures of wrists. Shoulder dislocations. Fractures of the clavicles.

Landing Head-First Physical findings: C-spine injuries. Facial injuries. CNS damage.

Sports & Recreational Activity Mechanisms Acceleration Deceleration Hyperextension Hyperflexion Twisting Falling What types of sporting or recreational injuries are common to your area?

Predicting Sports-Related Injuries Kinematics & forces involved. Equipment contributing to injury. Involvement of protective equipment. Nature of the sport.

Blast Injuries Warfare. Civilian areas. Mines. Shipyards. Chemical plants. Tank trucks. Refineries. Fireworks firms. Silos. LP gas tanks. Do you have any of these in your area?

Blast-Related Injuries Three mechanisms of injury: Primary. Secondary. Tertiary.

Primary Phase Injuries Cause: pressure wave from blast. Affected area: gas-containing organs. Injuries: Pulmonary bleeding. Pneumothorax. Air emboli. Perforation of the GI tract. Burns. Death may occur in absence of outward signs.

Secondary Phase Injuries Cause: flying debris. Affected area: Body surface. Skeletal system. Injuries: Lacerations. Fractures. Burns.

Tertiary Phase Injuries Cause: victim thrown against an object. Affected area: area of impact or referred energy. Injuries: similar to those sustained in a vehicle ejection.

Penetrating Trauma Physics. Weapon velocity. Bullet design.

Penetrating Trauma Newton’s First Law and ballistics: Bullet in brass cartridge is at rest. Bullet propelled by rapid combustion of powder. Bullet leaves barrel of gun. Bullet strikes a body. Bullet transfers energy to victim.

Low-Energy Injuries Low velocity. Usually hand-driven weapons. Less secondary trauma. Multiple wounds from a single weapon.

Low-Energy Penetrating Wounds How does the length of the weapon relate to the cone of damage?

Assessment of Low-Energy Injuries Type of weapon involved. Path of weapon. Depth of penetration. Number of wounds. Underlying anatomy.

Medium-Energy Penetrating Injuries

High-Energy Penetrating Injuries How do these weapons differ from handguns and shotguns? How do the wounds differ internally and externally?

Projectile - Frontal Area The larger the frontal area of the projectile, the greater the damage. The larger the cavitation and the greater the damage, the greater the exit wound.

Gunshot Wounds - Cavitation Reformation by elastic tissue Temporary cavity Direction of travel Bullet Permanent cavity Compression and crush

Gunshot Wounds Describe the difference between entrance and exit wounds.

Tumbling Projectiles Some projectiles are designed to tumble. Tumbling creates greater tissue damage and more tissue destruction.

Fragmentation The shotgun round is the ultimate in fragmentation.

Considerations for Penetrating Trauma Scene safety. Patient care is the priority! Weapon type. Range at which weapon was fired. Number of entrance and exit wounds. Underlying anatomy and track. Crime scene preservation.

Kinematics Summary The cornerstone of assessment is early consideration of kinematics to predict hidden injury.