Bledsoe et al., Paramedic Care: Principles & Practice, Volume 4: Trauma Emergencies, 3rd. Ed. ©...

Bledsoe et al., Paramedic Care: Principles & Practice, Volume 4: Trauma Emergencies, 3rd. Ed.© 2009 by Pearson Education, Inc. Upper Saddle River, NJ

Paramedic Care:Principles & Practice

Volume 4Trauma Emergencies


Chapter 2 Blunt Trauma


Topics

Introduction to Blunt Trauma

Kinetics of Impact

Biomechanics of Trauma



Blunt trauma is the most common cause of trauma-related death and disability. – Results from an energy exchange between an

object and the human body, without intrusion through the skin.

True nature of the injury is often hidden.


Kinetics of Impact


Kinetics of Impact

Kinetics is a branch of physics dealing with objects in motion and the energy exchanges that occur as objects collide.

Two basic principles of kinetics:– Laws of inertia – Energy conservation

Kinetic energy and force formulas quantify the energy exchange process between the moving object and the human body.


Law of Inertia

Newton’s first law: – “A body in motion will remain in motion unless

acted upon by an outside force.” – “A body at rest will remain at rest unless acted

upon by an outside force.”


Energy Conservation

Law of Energy Conservation – “Energy can neither

be created nor destroyed. It can only be changed from one form to another.”

– All the energy of motion converts to other energy forms.

© Mark C. Ide


Kinetic Energy

Kinetic energy of an object while in motion is measured by the following formula:

KE = mass (weight) x velocity (speed)2

2


Kinetic Energy

When you double an object’s weight, you double its kinetic energy.

As speed (velocity) increases, there is a larger (squared) increase in kinetic energy.

Releasing energy slowly, as occurs with braking, results in a tolerable transfer of energy while stopping.


Force

Newton’s second law of motion explains the forces at work during a collision:

Force = Mass (Weight) X Acceleration (or Deceleration)


Force

The formula emphasizes the importance of the rate at which an object changes speed. – Gradual changes in speed are usually uneventful.

When significant kinetic energy is applied to human anatomy, we call it trauma.



The biomechanics of trauma describes the actual injury process. The biomechanics of trauma are bound by the laws of physics: – Inertia, energy conservation, and force

Trauma is divided into two general categories: – Blunt– Penetrating



Blunt– Closed injury– Indirect injury to

underlying structures– Transmission of

energy into the body– Stretch forces – Shear forces



Penetrating– Open injury– Direct injury to

underlying structures


Automobile Collisions

44,000 people die each year on U.S. highways.Events of Impact:– Vehicle collision– Body collision– Organ collision– Secondary collisions– Additional injuries

Vehicle receives a second impact



Restraints– Seatbelts– Airbags (SRS)

Reduce blunt chest trauma

Cause: hand, forearm, and facial injury

Check for steering wheel deformity

Side airbags

– Child Safety Seats



Types of Impact– Frontal– Lateral– Rotational

Left and right – front and rear

– Rear-end– Rollover


Frontal Impact

Up-and-Over– Tenses legs = bilateral femur fracture– Hollow organ rupture and liver laceration– Similar chest trauma– Axial loading

Down-and-Under– Knee, femur, and hip fracture– Chest trauma – steering wheel

Paper bag syndrome

Ejection


Lateral Impact

15% of MVCs but 22% of deaths

Upper extremity injury

Rib, clavicle, humerus, pelvis, femur fracture

Lateral compression– Ruptured diaphragm – Spleen fracture – Aortic injury


Rotational Impact

Vehicle struck at oblique angle

Less serious injuries unless strike a secondary object

© Mark C. Ide


Rear-End Collisions

Rear-end– Seat propels the

occupant forward– Head is forced

backwardStretching of neck muscles and ligaments

Hyperextension and hyperflexion

© Mark C. Ide


Rollover

Rollover– Multiple points of

impact– Ejection or partial

ejection– Less injury with

restraints

© Mark C. Ide



Click here to view an animation on collisions.


Vehicle Collision Analysis

HazardsCrumple zonesIntrusionDeformity of vehicleUse of restraints

Undeployed airbags should be deactivated by trained fire/extrication personnel

Intoxication– Fatal collisions: >50% involve legal intoxication– Recreational accidents



Vehicular Mortality– Head: 48%– Internal (torso): 37%– Spinal and chest fracture: 8%– Extremity fracture: 2%– All other: 5%


Automobile Collision Evaluation

Collision Questions– How did collision occur?– Direction?– Speed?– Similar/different sized?– Secondary collisions?

Cause of Collision– Weather and visibility?– Alcohol involved?– Skid marks?

Auto Interior– Starring of windshield?– Steering wheel

deformity?– Dash deformity?– Intrusion?


Automobile Collision Evaluation

© Ray Kemp/911 Imaging


Motorcycle Collisions

Serious injuries can occur with high- and low-speed collision

Types of Impact– Frontal– Angular– Sliding– Ejection

Initial bike/object collision

Rider/object

Rider/ground


Pedestrian Collisions

Adults– Adults turn away– Bumper strikes

lower legs first– Victim rolls up and

over and thrown


Pedestrian Collisions

Children– Children turn toward– Femurs, pelvis often

injured– Thrown away or run

over


Recreational Vehicle Collisions

Lack structure and restraint system

Types of Vehicles– Snowmobiles– Personal watercraft– ATVs

Often see injuries in children due to lack of skills and training


Blast Injuries


Explosion

Pressure Wave– Structural collapse– Blast wind

Burns

Projectiles– Terrorist devices may contain nails, screws, or

other materials meant to cause additional injury and destruction.

Personnel Displacement


Explosion

Blast Injury Phases– Primary: Heat of the explosion– Secondary: Trauma caused by projectiles– Tertiary: Personnel displacement and structural

collapse


Explosion

Blast Injury Assessment– Be alert for secondary device– Initial scene size-up important– Establish Incident Command System (ICS)– Evaluate for secondary hazards– Injury Patterns:

Rupture of air- or fluid-filled organsLung: Late manifestation (heat and pressure)

Hearing loss


Explosion

Lungs– Forceful compression and distortion of chest cavity

Compression and decompression

– Pulmonary embolism, dyspnea, hemoptysis, pneumothorax

Abdomen– Compression and decompression– Release of bowel contents– Diaphragm rupture from pushing of organs up into

thorax area


Explosion

Ears– Initial hearing loss– Injury improves over time

Penetrating Wounds– Care as any serious open wound or impaled object

Burns– Treatment consistent with traditional management


Other Types of Blunt TraumaFalls– The initial impact may

involve other body surfaces with the forces of deceleration

– Evaluating a fall Determine the point of impact

The fall height

The impact surface

The transmission pathway of forces along the skeleton


Other Types of Blunt Trauma

Sports Injuries– Sports injuries are most commonly produced by

extreme exertion, fatigue, or by direct trauma forces.

Injuries can be secondary to acceleration, deceleration, compression, rotation, hyperextension, or hyperflexion.


Other Types of Blunt Trauma

Crush Injury– Cause

Structural collapse, explosion, MVC, industrial, or agricultural

– Great force to soft tissue and bonesTissue stretching and compression

Extended pressure results in anaerobic metabolism distal to compression

Return of blood flow, toxins to entire body

Severe hemorrhage due to severe damaged blood vessels


Summary


Kinetics of Impact


Bledsoe et al., Paramedic Care: Principles & Practice, Volume 4: Trauma Emergencies, 3rd. Ed. ©...

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