Chapter 29 Trauma Systems and Mechanism of Injury
Unit Summary
Basic concepts of the mechanics and biomechanics of trauma will help you analyze and manage
your patient’s injuries. Analyzing a trauma scene is a vital skill because at the scene you are the
eyes and ears of the emergency department physicians. Your paramedic-written patient history is
the only source for physicians and surgeons to understand the events and mechanisms that led to
your trauma patient’s chief complaint. Your information is critical as a foundation to visualize
and search for injuries that may not be apparent on physical examination.
National EMS Education Standard Competencies
Trauma
Integrates assessment findings with principles of epidemiology and pathophysiology to formulate
a field impression to implement a comprehensive treatment/disposition plan for an acutely injured
patient.
Trauma Overview
Pathophysiology, assessment, and management of the trauma patient
• Trauma scoring (p 1503)
• Rapid transport and destination issues (pp 1507-1508)
• Transport mode (pp 1508-1511)
Multisystem Trauma
Recognition, pathophysiology, assessment, and management of
• Multisystem trauma (pp 1503-1511)
Pathophysiology, assessment, and management of
• Blast injuries (pp 1499-1503)
Knowledge Objectives
1. Define the term “trauma,” and explain its relationship to energy, kinetics, and
biomechanics. (pp 1483-1486)
2. Describe some of the factors that affect types of injury. (p 1484)
3. Define the terms “mechanism of injury” and “index of suspicion,” and explain their
relationship to the paramedic’s assessment of trauma. (p 1484)
4. Define the term “blunt trauma,” and provide an example of the mechanism of injury that
would cause it to occur. (pp 1486-1497)
5. Describe how impact patterns can help the paramedic to determine or predict types of
injury following motor vehicle crashes. (pp 1488-1493)
6. Describe the five types of motor vehicle crashes and the injury patterns associated with
each one. (pp 1488-1493)
7. Describe the benefits of seat belt restraints during a motor vehicle crash. (p 1493)
8. Describe the four types of motorcycle crashes. (pp 1494-1495)
9. Describe the three predominant mechanisms of injury during a pedestrian versus
automobile collision. (pp 1495-1496)
10. Discuss five specific factors to consider during assessment of a patient who has been
injured in a fall. (pp 1496-1497)
11. Define the term “penetrating trauma,” and provide examples of the mechanisms of injury
that would cause low-, medium-, and high-velocity injuries to occur. (pp 1497-1499)
12. Describe the factors to consider during the assessment of a patient who has sustained a
gunshot wound. (pp 1498-1499)
13. Discuss primary, secondary, tertiary, quaternary (miscellaneous), and quinary blast
injuries, and describe the anticipated damage each one will cause to the body. (pp 14991503)
14. Describe the components of a blast shock wave. (p 1501)
15. Discuss considerations in the assessment and management of a patient with a blast injury.
(pp 1502-1503)
16. Describe multisystem trauma and the special considerations that are required for patients
who fit this category. (p 1503)
17. Outline the major components of trauma patient assessment, including considerations
related to multisystem trauma. (pp 1503-1506)
18. Provide a general overview of trauma management, including considerations related to
multisystem trauma. (pp 1507-1511)
19. Summarize the American College of Surgeons Committee on Trauma and Centers for
Disease Control and Prevention triage decision scheme for referral to a trauma center. (p
1507-1509)
20. Describe the American College of Surgeons Committee on Trauma classification of
trauma centers and how it relates to making an appropriate destination selection for a
trauma patient. (pp 1507-1509)
21. Describe trauma patient management in relation to scene time and transport selection,
and list the Association of Air Medical Services criteria for the appropriate use of
emergency air medical services. (pp 1508-1511)
Skills Objectives
There are no skills objectives for this chapter.
Readings and Preparation
• Review all instructional materials including Chapter 29 of Nancy Caroline’s Emergency Care in
the Streets, Seventh Edition, and all related presentation support materials.
• Review all chapters in Section 7 of Nancy Caroline’s Emergency Care in the Streets, Seventh
Edition, to prepare for questions that may arise with specific injuries.
Support Materials
• Lecture PowerPoint presentation
• Case Study PowerPoint presentation
Enhancements
• Direct students to visit the companion website to Nancy Caroline’s Emergency Care in the
Streets, Seventh Edition, at http://www.paramedic.emszone.com for online activities.
• Obtain trauma statistics from your closest trauma ccenter. These can be a valuable learning tool
to demonstrate types of injuries found in your local area.
• Many states utilize a trauma triage criteria that is standard for all providers. If this is the case in
your area, distribute it as a reference.
• You may wish to contact a physics/science instructor to obtain ideas for demonstrating the
principles of kinetics.
Content connections: All chapters in Section 7 of Nancy Caroline’s Emergency Care in the
Streets, Seventh Edition, are relevant to this chapter.
Teaching Tips
This chapter has a wealth of visual learning opportunities for your students. Kinematics is a
difficult topic to read and understand. Do not be afraid to enlist the help of a physics or science
instructor for ideas.
Unit Activities
Writing activities: Provide students with a scenario that will include a critical trauma patient
who is in a given location within your local area. Students should be required to discuss
tranportation options for the patient and what mode of transportation will be the most effective
for patient care.
Student presentations: Students may present their writing assignment or you may chose to use
the group activity.
Group activities: Divide students into groups. Assign each group one of the physics topic
covered in Chapter 29 of Nancy Caroline’s Emergency Care in the Streets, Seventh Edition. The
purpose of the activity to to visually demonstrate these concepts.
Visual thinking: See “Group activities.”
Medical terminology: Many terms in this chapter relate to physics and science. Make sure to
discuss these terms as needed.
Pre-Lecture
You are the Medic
“You are the Medic” is a progressive case study that encourages critical-thinking skills.
Instructor Directions
Direct students to read the “You are the Medic” scenario found throughout Chapter 29.
• You may wish to assign students to a partner or a group. Direct them to review the
discussion questions at the end of the scenario and prepare a response to each question.
Facilitate a class dialogue centered on the discussion questions and the Patient Care Report.
• You may also use this as an individual activity and ask students to turn in their comments
on a separate piece of paper.
Lecture
I. Introduction
A. Trauma is the primary cause of death and disability in people between ages 1 to
44 years.
1. Analyzing a trauma scene is a vital skill.
a. You are the eyes and ears of the emergency department physicians.
b. Your patient history is the only source for physicians to understand the events that
led to the trauma.
II. Trauma, Energy, and Kinetics
A. Trauma: Injury that occurs when an external source of energy affects the body
beyond its ability to sustain and dissipate it
1. Different forms of energy produce different kinds of trauma.
a. Mechanical energy
i. Energy from motion (kinetic energy [KE])
(a) Example: Two moving vehicles colliding
ii. Energy stored in an object (potential energy)
(a) Example: A brick sitting on a building ledge
b. Chemical energy
i. Energy released as a result of a chemical reaction
(a) Example: An explosive or an acid
c. Electrical energy
i. Example: Electrocution or lightning strike
d. Barometric energy
i. Sudden radical changes in pressure
(a) Example: Scuba diving or flying
2. Biomechanics: Study of physiology and mechanics of living organisms using tools of
mechanical engineering
a. Can be used to help analyze the mechanisms and results of trauma
3. Kinetics: Study of the relationship among speed, mass, direction of force, and physical
injury caused by these factors
a. Can be used to help predict injury patterns
B. Factors affecting types of injury
1. The kind of injury sustained will be determined by the ability of patient’s body to
disperse the energy delivered.
2. External factors that determine types of injury include force and energy.
a.
b.
c.
d.
Size of object delivering force
Velocity (how fast the object is traveling)
Acceleration or deceleration (how fast the object speeds up or slows down)
Body area affected by application of force
3. Duration and direction are also important factors.
a. The larger the area of force dissipation, the more pressure is reduced to a specific
spot on the body.
b. Blunt trauma: Spreading of impact without breaking the skin
i. Difficult to diagnose
(a) Often little external damage
c. Rapidly applied amounts of energy are less tolerated than the same amount of energy
delivered over a longer period of time.
d. The position of the trauma victim at the time of the event is another external factor.
i. Seat belt use has reduced lethal injuries by keeping victims in safer positions.
4. The impact resistance of body parts has a bearing on types of tissue disruption.
a. Often determined by what is inside the patient’s organs.
i. Organs that have gas inside will scatter energy more than liquid or solid
boundaries and are easily compressed.
(a) Lungs
(b) Intestinal tract
ii. Liquid-containing organs are less compressible.
(a) Vascular system
(b) Liver
(c) Spleen
(d) Muscle
5. Understanding the effects of forces will help to assess the mechanism of injury (MOI).
a. Can help predict most likely type of injury
6. Paramedics should have a high index of suspicion for injuries that may be undetected.
a. Be aggressive in your primary assessment and interventions.
C. Kinetics
1. Velocity (V): Distance an object travels per unit of time
2. Acceleration (a): Rate of change of velocity an object is subjected to
3. Gravity (g): Downward acceleration imparted to any object moving toward Earth
a. During each second of a fall, the velocity or speed of the falling object increases by
9.8 m/sec².
4. Kinetic energy is associated with an object in motion.
a. Reflects the relationship between the weight (mass) of the object and the velocity at
which it is traveling
i. Kinetic energy = mass/2 × velocity²
b. Velocity has a much greater effect on KE than weight.
i. An object increases its KE more by increasing its velocity than by increasing its
mass.
5. The KE of a car in motion that stops suddenly must be transformed or applied to another
object.
a. Modern cars have crumple zones to maximize the amount of energy absorbed by
deformation before the passenger is involved.
6. Other factors that will affect the amount of energy dissipation in a crash include:
a. Vehicle’s angle of impact
i. Front impact versus side impact
ii. How the patient hits the inside of the automobile
b. Differences in sizes of the two vehicles
c. Restraint status and protective gear of the occupants
7. Each vehicle involved contributes KE to the crash.
8. Law of conservation of energy: Energy can neither be created nor destroyed; it can only
change form.
9. Energy dissipation: Process by which KE is transformed into a form of mechanical
energy
a. If a car stops slowly, KE is converted to thermal energy.
b. If a car crashes, KE is also converted to mechanical energy.
i. Mechanical energy is further dissipated in the form of injury.
c. Protective devices can manipulate the way in which energy is dissipated.
i. Seat belts
ii. Air bags
iii. Helmets
10. Newton’s first law of motion: A body at rest will remain at rest unless acted on by an
outside force.
a. Similarly, a body in motion tends to stay in motion unless acted on by an outside
force.
11. Newton’s second law of motion: The force an object can exert is the product of its mass
times its acceleration.
a. Force = mass (weight) x acceleration (or deceleration)
b. The higher an object’s mass and acceleration, the higher the force needed to make a
change of course.
c. Deceleration: Slowing down or slowing to a stop
i. Rapid deceleration dissipates tremendous forces.
d. Deceleration and acceleration can be measured in numbers of g force.
i. One g force = normal acceleration due to gravity
ii. Two or three g force = two or three times the force associated with gravity
iii. The human limit to deceleration is 30 g.
e. In a head-on crash, transferred energy is represented as the sum of both vehicles’
speed.
III. Blunt Trauma
A. Blunt trauma: Injuries in which the tissues are not penetrated by external
objects.
1. Commonly occurs in:
a.
b.
c.
d.
e.
f.
Motor vehicle crashes
Pedestrians hit by vehicle
Motorcycle crashes
Falls from heights
Sports injuries
Blasts when no shrapnel involved
B. Motor vehicle crashes
1. There are five phases of trauma tied to the effects of progressive deceleration when a
vehicle collides with another object.
a. Phase 1: Deceleration of the vehicle
i. Vehicle strikes another object and is brought to an abrupt stop
ii. Vehicle motion continues until KE is dissipated
b. Phase 2: Deceleration of occupant
i. Starts during sudden braking and continues during impact of the crash
ii. Results in deceleration, compression, and shear trauma depending on:
(a) Mass of each occupant
(b) Protective mechanisms in the vehicle
(c) Body parts involved
(d) Points of impact
c. Phase 3: Deceleration of internal organs
i. Body’s supporting structures and movable organs continue forward momentum
until stopped by anatomic restraints.
ii. May result in tears and shearing injuries
d. Phase 4: Secondary collisions
i.
Occupant hit by objects moving within the auto
(a) Loose objects
(b) Packages
(c) Animals
(d) Other passengers
ii. Known to cause severe spine and head trauma
e. Phase 5: Additional impacts received by the vehicle
i. Vehicle hit by a second vehicle
ii. Vehicle deflected into another vehicle, tree, or other object
iii. May increase severity of original injuries or cause further injury
2. Impact patterns
a. Frontal or head-on impacts
i. The front end of the car distorts as it dissipates KE and decelerates its forward
motion.
ii. Passengers decelerate at the same rate as the vehicle.
iii. Forces applied to the driver will differ based on:
(a) Car design
(b) Materials
(c) Safety features of the vehicle
iv. Abrupt deceleration injuries are produced by a sudden stop of a body’s forward
motion.
(a) Can induce shearing, avulsing, or rupturing of organs
(b) Injuries are often invisible during examination.
v. The head is vulnerable to deceleration injuries.
(a) Can cause the brain to strike the inside of the skull, causing bleeding,
bruising, or tearing injuries.
(1) Will not show up on a physical examination
(2) Index of suspicion should be high.
vi. The aorta is the most common site of deceleration injury in the chest.
(a) Often torn away from its points of fixation in the body
(b) Can result in loss of the total blood volume and immediate death.
vii. Internal organs that continue their motion after the motion of the body stops may
result in tearing or shearing injuries.
(a) Commonly affected organs include:
(1) Liver
(2) Kidneys
(3) Small intestine
(4) Large intestine
(5) Pancreas
(6) Spleen
viii. Crush and compression injuries are the result of forces applied to the body by
things external to the body at the time of impact.
(a) Often caused by:
(1) Dashboards
(2) Windshields
(3) The floor
(4) Heavy objects falling on the body
(5) The body or one of its parts getting trapped between two objects
(b) Assume spinal cord injuries and severe injury to the brain.
ix. Compression injuries of the chest may produce fractured ribs.
(a) A sign of lung injury is flail chest.
(1) Results from multiple consecutive rib fractures
(2) The chest wall moves paradoxically with respirations.
(b) May cause blood or air to enter the chest cavity
(1) Leads to a pneumothorax or hemothorax
x. Compression of the heart may cause dysrhythmias and direct injury to the heart
muscle.
xi. Compression of the lungs can result in acute respiratory distress syndrome.
xii. Compression against the seat belt may result in:
(a) Bowel rupture
(b) Bladder rupture
(c) Diaphragm tearing
(d) Spinal injuries
b. Unrestrained occupants usually follow one of two trajectories:
i. Down-and-under pathway
(a) Occupant slides under the steering column or dash
(b) The knees hit the dashboard
(c) Look for:
(1) Fracture-dislocation of the knee
(2) Hip and pelvic fractures
(3) Hip dislocation
(4) Spinal injuries
(5) Rib fractures
(6) Pulmonary and cardiovascular injuries
ii. Up-and-over pathway
(a) The lead point is the head.
(b) The head impacts the windshield, roof, mirror, or dashboard
(c) Can include significant head and cervical spine trauma.
(d) Ejection is possible if the windshield does not stop the body.
(e) A dangerous lung injury may occur if your patient reflexively takes a deep
breath just before impact.
(f) Lower leg fractures could be present.
c. Lateral or side impacts
i. Impart energy to the near-side occupant almost directly to the pelvis and chest.
ii. Seat belts offer little protection because they are designed to limit forward
hinging injuries.
iii. Injury results from:
(a) Direct trauma to the affected side
(b) Tension developed on the far side
iv. The shoulder frequently rotates outward, exposing the chest and ribs to injury.
v. The passenger’s body is pushed in one direction, while the head moves toward
the impacting object.
(a) May result in disruption and dislocation of the spine
vi. Passengers travel in opposite directions, colliding with each other.
vii. The typical pattern of pelvic injury that occurs in this scenario is a lateral
compression injury (pelvic ring disruption).
viii. Death is usually the result of associated torso or head injuries.
d. Rear impacts
i. Have the most survivors if properly restrained
ii. Whiplash injury
(a) Sudden forward accelerating force causes the body to move forward but not
the head.
(b) The head is snapped back and then forward.
iii. Energy is imparted to the front vehicle.
e. Rotational or quarter-panel impacts
i. Occurs when a lateral crash is off center
(a) The vehicle’s forward motion stops, but the side continues in rotational
motion.
ii. The point of greatest speed loss of the vehicle is the site where the greatest
damage to the occupant will occur.
iii. Occupants tend to receive frontal and lateral injuries.
iv. Three-point seat belts are effective in preventing injury in angled crashes of up to
45°.
f. Rollovers
i. Greatest potential for lethal injury
(a) Patients may be ejected.
(b) Patients may be struck hard against the interior of the vehicle.
ii. Ejection increases the chance of death by 25 times.
3. Restrained versus unrestrained occupants
a. Seat belts stop the motion of any automobile occupant who is traveling at the same
speed as the vehicle.
i. Limit the contact of the occupants with the interior of the vehicle.
ii. Prevent ejection.
iii. Distribute deceleration energy over a greater surface.
iv. Prevent the occupants from violently contacting each other.
b. Specific injuries associated with seat belt use include cervical fractures and neck
sprains.
i. Most serious injuries occur because the patient did not use the seat belt correctly.
c. Air bags have reportedly reduced deaths in direct frontal crashes by about 30%.
i. Front air bags will not activate in side impact crashes or impacts to the front
quarter panel.
ii. Can also result in secondary injuries from direct contact or from the chemicals
used to inflate it.
iii. Small children can be severely injured or killed if air bags inflate while they are
in the front seat.
C. Motorcycle crashes
1. Any structural protection afforded to victims is derived from protective devices worn by
the rider.
a. Helmet
i. Protects against impact forces to the head
ii. Transmits impact into the cervical spine
b. Leather or abrasion-resistant clothing
i. Protects against road abrasion
ii. Does not protect against blunt trauma from secondary impacts
c. Boots
2. When assessing the scene, attention should be given to:
a.
b.
c.
d.
e.
Deformity of motorcycle
Side of most damage
Distance of skid in road
Deformity of stationary objects or other vehicles
Extent and location of deformity in helmet
3. There are four types of motorcycle impact.
a. Head-on impact
i. Motorcycle strikes another object and stops its forward motion.
ii. Rider continues forward until stopped by an outside force.
(a) Causes rider to go over the handlebars
iii. For motorcycles with a low riding seat, the gas tank can act as a wedge on the
pelvis.
(a) Can result in:
(1) Severe anterior-posterior compression injuries
(2) Open pelvic fractures
b. Angular impact
i. Motorcycle strikes an object or another vehicle at an angle
ii. Rider sustains direct crushing injuries to the lower extremity between the object
and the motorcycle.
iii. May result in:
(a) Severe open and comminuted lower extremity injuries
(b) Traumatic amputation
(c) Severe thoracoabdominal torsion and lateral bending spine injuries
c. Ejected
i. Rider will travel at high speed until stopped by a stationary object, by another
vehicle, or by contact with the road.
ii. Severe abrasions down to the bone can occur.
d. Laying the bike down
i. A technique used to separate the rider from the body of the motorcycle and the
object to be hit.
ii. Developed by motorcycle racers as a means of controlling the crash
iii. Motorcycle is turned flat and tipped sideways at 90° to the direction of travel so
that one leg is dropped to the ground.
(a) Slows occupant faster than motorcycle, allowing for rider to become
separated from motorcycle
4. The helmet should be removed carefully if:
a. Airway management techniques cannot be performed with the helmet in place.
b. Helmet does not fit snuggly to the head.
5. The helmet should be cut if it cannot be removed without introducing further deformation
to the neck.
D. Pedestrian injuries
1. Almost 87% of pedestrians are struck by a vehicle’s front end.
a. Adult injuries are generally lateral and posterior.
i. Tend to turn to the side or away from impact
ii. Children face forward into the oncoming vehicle
2. There are three predominant MOIs.
a. First impact: auto strikes an adult body with its bumpers.
i. Creates lower extremity injuries, particularly to knee and leg
b. Second impact: adult is thrown on the hood and/or grille of vehicle.
i. Results in head, pelvis, chest, and coup-contrecoup traumatic brain injuries
c. Third impact: body strikes the ground or some other object after it has been subjected
to a sudden acceleration by the colliding vehicle.
3. Pediatric patterns of pedestrian injury are different from patterns in adults.
a. Waddell triad refers to pattern of injuries in children and people of short stature:
i. The bumper hits the pelvis and femur instead of knees and tibias.
ii. The chest and abdomen hit the grille or low on the hood of the car.
(a) Sternal and rib fractures
(b) Abdominal injuries
iii. The head strikes the vehicle and then the ground
(a) Skull and facial fractures
(b) Facial abrasions
(c) Closed head injury
E. Falls from heights
1. Usually involve children younger than 5 years of age.
a. Adult falls usually occur in the context of:
i. Criminal activity
ii. Attempted suicide
iii. Intoxication
2. A fall produces acceleration downward at 9.8 m/sec².
3. Severity of injuries affected by:
a. Height
i. The height will determine the velocity of the fall.
ii. Height plus stopping distance predicts the magnitude of deceleration forces.
b. Position
i. Will be a determinant of the type of injuries sustained and their survivability
ii. Children tend to fall headfirst, resulting in:
(a) Head injuries
(b) Injuries to the wrists and upper extremities
iii. Adults usually try to land on their feet.
(a) Don Juan syndrome or lover’s leap: Group of potential injuries from a
vertical fall to a standing position
(1) Foot and lower extremity fractures
(2) Hip, acetabular, and pelvic ring and sacral fractures
(3) Vertebral compression and burst fractures
(4) Vertical deceleration forces to organs
(5) Fractures of the forearm and wrist
c. Area
i. The larger the area of contact, the greater the dissipation of force.
d. Surface
i. The degree to which the surface can deform under the force of the falling body
can help dissipate forces of sudden deceleration.
ii. If the surface does not conform, the body will.
e. Physical condition
i. Preexisting medical conditions could influence injuries sustained.
(a) Osteoporosis is the most notable.
(1) Predisposes to fractures even with minimal falls
(b) Hematologic conditions are prone to ruptured spleen in fall.
IV. Penetrating Trauma
A. Penetrating trauma involves a disruption of the skin and underlying tissues in a
small, focused area.
1. Usually caused by firearms, knives, and other devices used as a means to cause
intentional or accidental harm.
2. Classified as low, medium, or high velocity
a. Low velocity: Caused by sharp edges of object moving through body
b. Medium and high velocity: Path of the object might not be easy to predict because it
might flatten out, tumble, or even ricochet within the body
3. In the United States, the most common sources of penetrating injuries are firearms.
a. In 2009, 31,285 people died by gunfire in the United States.
B. Stab wounds
1. Severity depends on:
a.
b.
c.
d.
Anatomic area involved
Depth of penetration
Blade length
Angle of penetration
2. Neck wounds can involve critical anatomic structures
a. Deep neck wounds can result in spinal cord involvement and cervical fracture.
3. Lower chest or upper abdominal wounds have the potential of involving the thoracic and
abdominal cavities.
4. The pattern of a stab wound closely relates to the mechanism involved and should be
documented in detail.
a. Record the direction of the wound.
C. Gunshot wounds
1. The severity of a gunshot wound depends on several factors.
a.
b.
c.
d.
e.
Type of firearm (rifle, shotgun, or handgun)
Velocity of projectile
Physical design and size of projectile
Distance of the victim from the muzzle of firearm
Type of tissue that is struck
2. Shotguns
a. Fire round pellets
i. From half a dozen to several dozen at a time
b. Shot density (separation between any two pellets) is determined by distance traveled.
c. Can induce destructive injuries at a very close range.
3. Rifles
a. Fires single projectile at a very high velocity.
b. Grooved barrel imparts a spin to the projectile for accuracy.
4. Handgun
a. Revolver holds 6 to 10 rounds of ammunition.
b. Pistol holds up to 17 rounds of ammunition.
c. Rifled barrel imparts spin to bullet, but accuracy is limited.
i. Barrels are shorter.
d. Ammunition is generally less powerful than rifles and fires at lower velocity.
5. The most important factor for seriousness of a gunshot wound is the type of tissue
through which the projectile passes.
a. Tissue of high elasticity is better able to tolerate stretch.
6. The entry wound is characterized by the effects of the initial contact and implosion.
a. Skin and tissues are pushed in, cut, or abraded.
b. At close range, tattoo marks from powder burns can occur.
c. At closer range, burns can occur from muzzle blast.
7. Deformation and tissue destruction is based on a combination of factors.
a.
b.
c.
d.
Density
Compressibility
Missile velocity
Missile fragmentation
8. The projectile crushes the tissue during penetration, creating a permanent cavity.
a. May be straight line or irregular pathway
b. Pathway expansion: Tissue displacement that occurs as the result of lowdisplacement sonic pressure waves that travel at the speed of sound in tissue
c. Bowel, muscle, and the lungs are relatively elastic, resulting in fewer permanent
effects of temporary cavitation.
d. The liver, spleen, and brain are relatively inelastic, resulting in more permanent
effects of temporary cavity.
e. Missile fragmentation: Projectile sends off fragments that create their own separate
paths through tissues.
9. Exit wounds occur when the projectile has sufficient energy that is not entirely dissipated
along its trajectory through the body.
a. The size depends on the energy dissipated and the degree of cavitation at the point of
exit.
b. Usually have irregular edges
c. May be larger than entry wounds
10. Shotgun wounds are the result of tissue impact by numerous projectiles.
a. The greater the distance from the muzzle to the target, the more dispersion the
projectiles will have.
b. Wounding potential depends on:
i. Powder charge
ii. Size and number of pellets
iii. Dispersion of the pellets
(a) Determined by:
(1) Range at which the weapon was fired
(2) Barrel length
(3) Type of choke at the end of the barrel
11. Try to obtain the following:
a. What kind of weapon was used?
b. At what range was it fired?
c. What kind of bullet was used?
12. Look for:
a. Powder residue around the wound
b. Entrance and exit wounds
V. Blast Injuries
A. Primary blast injuries
1. Damage to the body is caused by the pressure wave generated by the explosion.
a. Concentrated pressure results from air displacement and heat originating from the
center of the blast.
2. Organs generally affected are:
a. Lungs
b. Eardrums
c. Other compressible organs
3. Burns also may occur.
4. Close proximity to the origin of the pressure wave carries a high risk of injury or death.
B. Secondary blast injuries
1. Result from being struck by flying debris
a. Objects can travel great distances and can be propelled at tremendous speeds.
i. Up to nearly 3,000 mph for conventional military explosives.
2. A blast wind occurs as the shock wave applies force to air molecules.
3. Flying debris may cause blunt and penetrating injuries.
C. Tertiary blast injuries
1. Occur when a person is hurled by the force of the explosion (or blast wind) against
stationary, rigid objects.
2. Ground shock: Physical displacement of the body when the body impacts the ground.
a. Resulting injuries are numerous and may be blunt and penetrating.
D. Quaternary (miscellaneous) blast injuries
1. Occur from the miscellaneous events that occur during an explosion.
2. May include:
a.
b.
c.
d.
Burns from hot gases or fires started by the blast
Respiratory injury from inhaling toxic gases
Crush injury from the collapse of buildings
Risks from entrapment
E. Quinary blast injuries
1. Caused by biologic, chemical, or radioactive contaminants that have been added to a
traditional explosive device.
2. Associated with “dirty bombs”
a. Increased concern due to the threat of its use by terrorist organizations.
F. The physics of an explosion
1. When a substance is detonated, it is converted into large volumes of gas under pressure.
a. Propellants are explosives designed to release energy relatively slowly compared
with high explosives.
2. Components of blast shock wave
a. Blast front: Leading edge of an explosion pressure blast wave
b. Positive wave pulse: Phase of the explosion in which there is a pressure front higher
than atmospheric pressure
c. Shock wave: High-explosive blast waves
i. Possess a characteristic brisance
ii. Tissue damage depends on the magnitude of the pressure spike and the duration
of force.
d. Negative wave pulse: phase in which pressure is less than atmospheric
i. May last 10 times as long as the positive wave pulse
ii. Occurs as air displaced by the positive wave pulse returns to fill the space
iii. Can lead to high-velocity winds
e. The speed, duration, and pressure of the shock wave are affected by:
i. Size of the explosive charge
(a) The larger the explosion, the faster the shock waves and the longer they will
last.
ii. Nature of surrounding medium
(a) Pressure waves travel more rapidly and are more effective in water.
iii. Distance from explosion
(a) The farther from the explosion, the slower the shock wave velocity and the
longer its duration.
iv. Presence or absence of reflecting surfaces
(a) If the pressure wave is reflected off a solid object, its pressure may be
multiplied several times.
f. An explosion is more damaging in closed spaces.
i. Limited dissipation environment
ii. Generation of toxic gases and smoke
iii. The shock wave is magnified when it comes into contact with a solid surface
g. Blast pressures cause destruction at:
i. Interface between tissues of different densities, or
ii. Interface between tissues and trapped air
G. Tissues at risk
1. Air-containing organs are more susceptible to pressure changes.
a.
b.
c.
d.
e.
Middle ear
Heart
Lungs
Major blood vessels
Gastrointestinal tract
2. Junctions between tissues of different densities and exposed tissues are prone as well.
3. The ear is most sensitive to blast injuries.
a. The tympanic membrane will rupture at pressures of 5 to 7 pounds per square inch
above atmospheric pressure.
b. The patient may complain of:
i. Ringing in the ears
ii. Pain in the ears
iii. Some loss of hearing
iv. Visible blood in the ear canal
4. Primary pulmonary blast injuries occur as contusions and hemorrhages.
a. The patient may have:
i. Tightness or pain in the chest
ii. Tachypnea or other signs of respiratory distress
iii. Subcutaneous emphysema (crackling under the skin) over the chest
(a) Indicates underlying pneumothorax
iv. Pulmonary edema
5. If there is any reason to suspect lung injury in a blast victim, administer oxygen.
a. Avoid giving oxygen under positive pressure.
b. Intravenous (IV) fluids may be poorly tolerated in patients with this lung injury.
6. Assessment and management of blast injuries
a. When you are at the scene of an explosion, expect significant trauma and multiple
victims.
b. If the explosion was intentional, examine the area for a secondary device.
i. If scene safety cannot be ensured, evacuate until qualified personnel advise you
that it is safe to approach the patient.
c. Assess the scene for other hazards.
d. After standard precautions have been taken, form a general impression as you
approach the patient.
i. Rapidly perform a primary assessment.
ii. Immobilize the cervical spine.
iii. Assess the airway by performing the jaw-thrust maneuver.
(a) Correct airway compromise immediately.
(b) Note gross respiratory pattern.
iv. Assess circulation by checking the carotid and radial pulses.
v. Reassess mental status.
e. Assess breath sounds frequently
f. Examine the patient rapidly for the presence of DCAP-BTLS.
g. Establish a baseline pulse oximetry value, and reassess frequently.
i. Administer high-flow supplemental oxygen even in the presence of a high
reading.
h. An absence of overt signs of abdominal injury should not lead you to conclude that
an injury is not present.
i. If patient reports abdominal pain, use OPQRST to guide your history taking.
ii. Examine all abdominal quadrants for the presence of DCAP-BTLS.
VI. Multisystem Trauma
A. Multisystem trauma: Injuries that involve several body systems.
1. The body has a much harder time dealing with multiple injuries that involve several
major body areas.
2. Generally caused by events that affect the entire body.
3. Often, both blunt and penetrating trauma occurs
B. If you suspect that multiple body systems are affected:
1. Assess the patient’s entire body.
2. Prioritize the treatment of the injuries.
3. Transport patients without delay.
VII. Trauma Score
A. Trauma scoring systems are often used to determine injury severity in the health
care profession.
1. There are several different systems.
2. The trauma score is used to determine the likelihood of patient survival.
a. Calculated on a scale of 1 to 16
i. 16 is the best possible score.
3. Takes into account:
a.
b.
c.
d.
e.
Glasgow Coma Scale (GCS) score
Respiratory rate
Respiratory expansion
Systolic blood pressure
Capillary refill
B. GCS: Evaluation tool used to determine level of consciousness
1. Scores are assigned for eye opening, verbal response, and motor response.
2. Can be used to predict patient outcome
3. Does not accurately predict survivability in patients with severe head injuries
a. In these instances, the Revised Trauma Score is used.
VIII. Revised Trauma Score
A. The Revised Trauma Score (RTS) is used to assess injury severity in patients
with head trauma.
1. Heavily weighted to compensate for major head injury without multisystem injury or
major physiologic changes.
2. Data used to calculate the score include:
a. GCS score
b. Systolic blood pressure
c. Respiratory rate
3. Also used to predict survival in patients with severe injuries.
4. Highest RTS is 12; the lowest is 0
IX. General Assessment of Trauma
A. Managing a trauma scene involves more consideration of external factors than a
typical scene with a medical patient.
1. Your observations are critical to the hospital staff.
2. Very few trauma injuries can be truly stabilized on scene.
B. Scene size-up
1. Attention to personal protective equipment is required.
a. Gloves
i. The likelihood of bleeding is much higher.
ii Keep an extra pair of gloves with you, in case one becomes torn and needs to be
replaced.
b. Protective eyewear
c. Helmets
d. Heavy coats
e. Boots
2. Anticipate possible scene hazards while en route.
a. Call for assistance before you move on to patient assessment and care.
3. Assess your environment carefully.
4. As you approach your patient(s), consider whether you will need additional medical
resources.
C. Primary assessment
1. Form a general impression.
a. Patients who look very ill or present with obvious bleeding injuries often have
serious injuries.
b. Do not make major patient decisions based strictly on your first impression.
c. Keep the MOI in mind as you approach the patient.
i. Consider whether spinal stabilization will be necessary.
ii. Be prepared to protect the patient from movement-induced spinal injury.
(a) Ask the patient not to move his or her head.
(b) Have your partner apply manual cervical stabilization.
d. Evaluate the patient using the AVPU.
i. If the patient is awake:
(a) Introduce yourself.
(b) Check pupil size and reactivity.
ii. If the patient does not appear to be awake:
(a) See if he or she responds to verbal or light painful stimulus.
2. Airway and breathing
a. If your patient is unconscious, ask your partner to open the airway using the jawthrust maneuver.
b. Observe for obvious oral or facial trauma that may contribute to airway obstruction.
c. If necessary, remove foreign objects and suction out blood or vomitus.
d. If the patient is unconscious, consider an oral or nasopharyngeal airway.
e. If you suspect blockage is due to a foreign object, apply the appropriate manual
airway clearing technique.
f. Once the airway is clear, assess the patient’s breathing.
i. Absence of breathing will require bag-mask ventilation and consideration of a
more advanced airway adjunct.
ii. If the patient is breathing, note:
(a) Rate and quality of respirations
(b) Patient’s ability to speak
g. Note the skin color,
i. Cyanosis is caused by inadequate oxygenation.
h. Observe chest wall movement with respirations.
i. If you observe a sucking chest injury, immediately seal the wound.
i. Assess the thorax and neck for:
i. Deviated trachea
ii. Tension pneumothorax
iii. Neck and chest crepitation
iv. Broken ribs
v. Fractured sternum
vi. Other problems that may inhibit breathing
j. Determine how best to support your patient’s breathing.
i. Most trauma patients will benefit from application of oxygen even in the absence
of dyspnea.
3. Circulation
a. Check both radial and carotid pulses simultaneously to estimate blood pressure and
pulse.
i. Note rate and quality of the pulse.
ii. If there is no pulse, begin CPR
b. Skin condition can also be a good indicator of circulation.
c. Quickly scan for significant external bleeding.
4. Transport decision
a. Patients that should be categorized for immediate transport include those with:
i. Altered mental status
ii. Airway or breathing problems
iii. Multisystem trauma
iv. Significantly compromised circulation
b. If a patient needs immediate transport, continue your assessment en route to the
trauma center
i. On-scene time should be limited to 10 minutes or less.
(a) Referred to as the “platinum 10 minutes”
(b) After the first 60 minutes in shock, the body has increased difficulty
compensating.
(1) Referred to as the “Golden hour”
D. History taking
1. Obtain a SAMPLE history and OPQRST.
2. Medical history should be obtained as soon as possible in case the patient’s level of
consciousness deteriorates.
3. If the patient is unconscious, gather information from bystanders or family members.
4. Important information to obtain includes:
a.
b.
c.
d.
e.
Allergies
Medications
Past medical history
Patient’s last oral intake
Events leading up to the situation
E. Secondary assessment
1. Trauma patients are classified into two major groups:
a. Those with an isolated injury
i. Allows you to immediately focus on the main problem
b. Those with multisystem trauma
i. You must first find all of the various problems, then prioritize them by severity
and the order in which you plan to address them.
ii. Think about how each injury or condition relates to the others.
2. Vital signs
a. Obtain a full set of initial or baseline vital signs.
b. Should include an assessment of:
i. Pulse
ii. Respirations
iii. Auscultatory blood pressure
c. Other measurements that should be considered include:
i. Pulse oximetry
ii. Blood glucose level
iii. Cardiac monitoring
iv. Automatic blood pressure monitoring, if available
3. Physical examinations
a. Most traumatic injury patients should have a thorough physical exam prior to or
during transport.
b. The head-to-toe exam should be done in a systematic manner.
c. Head and neck
i. Palpate and visualize for injuries.
(a) Deformities
(b) Contusions
(c) Abrasions
(d) Penetrations
(e) Burns
(f) Tenderness
(g) Lacerations
(h) Swelling
ii. Look in the nose, mouth, and ears for bleeding.
iii. Check for jugular vein distension and tracheal deviation
iv. Press a finger down in the notch at the top of the sternum.
(a) If the trachea is palpated in this position, it is midline (normal).
(b) If it is off to one side, it is considered deviated.
(1) A sign of an advanced tension pneumothorax
v. Consider applying a cervical collar while you continue your assessment.
d. Chest, abdomen, and pelvis
i. Examine and palpate the chest wall.
ii. Look for penetrating injuries and assess for bruising.
iii. Use your stethoscope to listen to breath and heart sounds.
(a) Auscultate the same area on both sides of the chest to compare breath
sounds.
(1) Unequal breath sounds may indicate a pneumothorax.
iv. Palpate the abdomen across the upper and lower quadrants.
(a) A rigid and distended abdomen usually indicates significant internal
abdominal bleeding.
v. Press the iliac crests down and squeeze them inward to determine pelvic stability.
vi. Consider palpation of the pubic symphysis.
vii. Examine for signs of incontinence and/or bleeding from the groin area.
e. Extremities
i. Palpate the legs from top to bottom.
ii. Palpate each leg separately, and note any difference.
iii. Check both feet for:
(a) Distal pulse
(b) Motion
(c) Sensation
iv. Examine the arms in the same manner.
f. Back
i. While the patient is on his or her side, examine the back for injuries.
F. Reassessment
1. While en route to the hospital, consider performing another physical examination.
2. Repeat the primary assessment.
3. Reevaluate vital signs.
a. Every 5 minutes for patients in serious condition
4. Review the status of the interventions you have performed.
5. Notify the hospital staff as quickly as possible.
X. Management of Trauma
A. Management of trauma requires an accurate assessment of the patient and
knowledge of the mechanics of injury.
1. During transport, begin any necessary interventions.
2. Most trauma patients will need to be treated for shock, which may include:
a. Establishing IV access
b. Administering a fluid bolus
c. Rapid transport
3. Unresponsive trauma patients will most likely need an advanced airway placed.
a. Should be done before transport, if possible
4. Most patients who are in shock should be:
a. Given oxygen
b. Kept supine with extremities slightly elevated
c. Transported rapidly to a trauma center
5. Also consider fluid resuscitation for patients in shock.
a. If shock is caused by a large fluid shift, large quantities of fluid may be required.
b. If shock is caused by blood loss, too much fluid could dilute the blood and raise
blood pressure.
c. If shock is caused by vasodilation due to a spinal cord injury, consider administration
of medications instead of adding more fluid.
d. Consult with medical control.
e. Begin fluid resuscitation at volumes that maintain a minimum blood pressure.
i. Allows clots to form at sites of bleeding within the body
6. Several techniques can be used to treat multisystem trauma.
a. Multisystem trauma patients cannot be stabilized in the field.
b. Use a team approach to assess and transport your patient.
i. Many tasks can be done simultaneously.
ii. Requires extra attention on the part of the lead paramedic
7. Critical thinking is important when treating a patient with multisystem trauma.
a. Signs and symptoms may be related to different response mechanisms.
b. Analyze the MOI and the patient’s signs and symptoms.
B. Criteria for referral to a trauma center
1. The American College of Surgeons Committee on Trauma (ACS-COT) and the Centers
for Disease Control and Prevention published a field triage decision scheme.
2. Physiologic criteria
a. If one of the following is present, refer to the highest-level trauma center:
i. GCS (Glasgow Coma Scale) score of less than or equal to 13
ii. SBP (systolic blood pressure) of less than 90 mm Hg
iii. RR (respiratory rate) of less than 10 or more than 29 breaths/min (more than 20
breaths/min in infants) or need for ventilator support
3. Anatomic criteria
a. If one of the following is present, transport to the highest-level trauma center:
i. All penetrating trauma to the head, neck, torso, and extremities proximal to
elbow or knee
ii. Chest wall instability or deformity
iii. Two or more proximal long bone fractures
iv. Crushed, degloved, mangled, or pulseless extremity
v. Amputation proximal to wrist or ankle
vi. Pelvic fractures
vii. Open or depressed skull fractures
viii. Paralysis
4. MOI criteria
a. If one of the following is present, and depending on the MOI, transport to the closest
appropriate trauma center:
i. Adults: falls more than 20 ft
ii. Children: falls more than 10 ft or two or three times the height of the child
iii. High-risk auto crash
iv. Intrusion into passenger compartment
(a) More than 12 inches occupant site, or
(b) More than 18 inches any other site
v. Ejection (partial or complete) from automobile
vi. Vehicle telemetry data consistent with a high risk of injury
vii. Pedestrian/bicyclist thrown or run over or auto-pedestrian injury with significant
impact
viii. Motorcycle crash at more than 20 mph
5. Special considerations
a. Consider transfer to an emergency department or low-level trauma center if:
i. Patient’s age is more than 55 years
ii. Systolic blood pressure of less than 110 mm Hg in persons older than 65 years
iii. Children should be triaged to a pediatric-capable trauma center.
iv. Patient uses anticoagulants or has a bleeding disorder.
v. Patient is pregnant (more than 20 weeks of gestation).
vi. Low-impact mechanism in older adults may result in severe injury.
vii. Burns with other trauma
viii. EMS provider judgment
6. The ACS-COT publishes a list of criteria defining four separate levels of trauma centers
(Level I, II, III, and IV).
7. It is important to know which hospitals specialize in:
a.
b.
c.
d.
e.
f.
Neurology
Burns
Pediatric trauma
Cardiac care
Microsurgery
Hyperbaric therapy
8. Give the trauma center early notice of the patient’s arrival, including:
a.
b.
c.
d.
e.
f.
g.
h.
i.
Age
Sex
MOI
Vital signs
GCS
Intubation and airway status
SAMPLE history
Significant comorbidities
Estimated time of arrival
C. Mode of transport
1. When making the decision to transport by ground, several factors should be considered.
a. Can the appropriate facility be reached within a reasonable time frame?
b. What is the extent of injuries?
c. If in a congested area, can the patient be transported to a more accessible landing
zone for air medical transport?
2. The Association of Air Medical Services and MedEvac Foundation International identify
criteria for the appropriate use of emergency air medical services:
a. There is an extended period required to access or extricate a remote or trapped patient
that depletes the time frame to get the patient to the trauma center by ground.
b. Distance to the trauma center is greater than 20 to 25 miles.
c. The patient needs medical care and stabilization at the Advanced Life Support
(ALS)-level, and there is no ALS-level ground ambulance service available within a
reasonable time frame.
d. Traffic conditions or hospital availability make it unlikely that the patient will get to
a trauma center via ground ambulance within the ideal time frame.
e. There are multiple patients who will overwhelm resources at the trauma center(s).
f. EMS systems require that the patient be brought to the nearest hospital for initial
evaluation and stabilization.
g. There is a multiple-casualty incident.
3. You should always follow your local protocols when determining what type of
transportation is appropriate.
4. When making the transport decision, consider:
a. If the patient can be transported by ground within a reasonable amount of time
b. The time it will take for the aircraft to lift off, travel, and land
c. The terrain
XI. Summary
A. Trauma is the primary cause of death and disability in people between ages 1
and 44 years.
B. The amount of force and energy delivered are factors in the extent of trauma
sustained. Duration and direction of the force of application are also important.
C. Understanding the effects of forces and energy will help in developing a high
index of suspicion for the mechanism of injury and the likely types of injuries.
D. Kinetic energy (KE) of an object is the energy associated with that object in
motion. It reflects the relationship between the weight (mass) of the object and
the velocity at which it is traveling.
E. The law of conservation of energy states that energy can be neither created nor
destroyed; it can only change form.
F. Blunt trauma refers to injuries in which the tissues are not penetrated by an
external object, as commonly occurs in motor vehicle crashes, in pedestrians hit
by a vehicle, in motorcycle crashes, in falls from heights, in serious sports
injures, and in blasts when no shrapnel is involved.
G. In a motor vehicle crash, the angle of impact, mechanical characteristics of the
vehicle, and the occupant’s position at the time of impact will determine types of
injury.
H. Trauma in a crash is composed of five phases representing the effects of
progressive deceleration: deceleration of the vehicle, deceleration of the
occupant, deceleration of internal organs, secondary crashes, and additional
impacts.
I. There are five primary types of impacts: frontal or head on, lateral or side, rear,
rotational, and rollover.
J. The front seat occupants of vehicles during a frontal or head on crash usually
follow one of two trajectories, a down-and-under pathway or an up-and-over
pathway.
K. Protective devices such as seat belts, air bags, and helmets are designed to
manipulate the way in which energy is dissipated into injury.
L. In a motorcycle crash, any structural protection afforded to the victims is not
derived from a steel cage, as is the case in an automobile, but from protective
devices worn by the rider such as helmets and leather or abrasion-resistant
clothing.
M. There are four types of motorcycle impacts: head-on collisions, angular
collisions, ejected riders, or laying the bike down.
N. Adult pedestrians involved in a crash experience three predominant mechanisms
of injury: lower extremity injuries from the initial hit, second impact injuries
from being thrown onto the hood or grille, and third impact injuries when the
body strikes the ground or another object.
O. The severity of injuries from falls from heights depends on the height, position,
and orientation of the body at the moment of impact; the area over which the
impact is distributed; the surface onto which the person falls; and the physical
condition of the patient.
P. Penetrating trauma involves a disruption of the skin and underlying tissues in a
small, focused area, as commonly occurs with stab wounds and gunshot wounds.
Q. The severity of a stab wound depends on the anatomic area involved, depth of
penetration, blade length, and angle of penetration.
R. Firearms are the primary mechanism resulting in penetrating trauma. The
magnitude of tissue damage depends on the projectile’s velocity, the orientation
of the projectile as it entered the body, the distance from which the weapon was
fired, the design of the projectile, and the type of tissue through which the
projectile passed.
S. Blast injuries include primary, secondary, tertiary, quaternary (miscellaneous)
injuries.
T. A blast wave or shock wave is dependent on many factors including the size of
the explosive charge, the nature of the surrounding medium, the distance from
the explosion, and the presence or absence of reflecting surfaces.
U. Air-containing organs such as the middle ear, heart, lungs, major blood vessels,
and gastrointestinal tract are most susceptible to pressure changes and blast
injuries.
V. Multisystem trauma describes trauma that involves several body systems. Most
trauma affects more than one system, often includes both blunt and penetrating
trauma, and has a high level of morbidity and mortality.
W. Management of trauma patients requires a thorough and accurate assessment of
the patient as well as a good working knowledge of the mechanisms of injury. In
treating multisystem trauma, remember that if a generalized mechanism is
present, you should anticipate multisystem injuries. It is also important to
remember that multisystem trauma patients cannot be stabilized in the field.
X. The criteria for transport to a trauma center vary from system to system.
However, there are key variables for transport to a trauma center as defined by
the Centers for Disease Control and Prevention National Trauma Triage
Protocol.
Y. There are four categories of trauma centers. Your system may include a level I,
which is the highest level trauma center.
Z. The Association of Air Medical Services and MedEvac Foundation International
identify criteria for the appropriate use of emergency air medical services for
trauma patients. The criteria include situations in which there is extended
transport time by ground, mass-casualty incidents, prolonged extrication times,
critically injured patients, or when there is a long distance to an appropriate
facility.
Post-Lecture
This section contains various student-centered end-of-chapter activities designed as
enhancements to the instructor’s presentation. As time permits, these activities may be presented
in class. They are also designed to be used as homework activities.
Assessment in Action
This activity is designed to assist the student in gaining a further understanding of issues
surrounding the provision of prehospital care. The activity incorporates both critical thinking and
application of paramedic knowledge.
Instructor Directions
1. Direct students to read the “Assessment in Action” scenario located in the Prep Kit at the
end of Chapter 29.
2. Direct students to read and individually answer the quiz questions at the end of the
scenario. Allow approximately 10 minutes for this part of the activity. Facilitate a class
review and dialogue of the answers, allowing students to correct responses as may be
needed. Use the quiz question answers noted below to assist in building this review.
Allow approximately 10 minutes for this part of the activity.
3. You may wish to ask students to complete the activity on their own and turn in their
answers on a separate piece of paper.
Answers to Assessment in Action Questions
1. Answer: B.
continue with a secondary assessment.
Rationale: Continue with the secondary assessment, but be aware that the patient is
potentially unstable due to the MOI, the presence of chest injury, and possible hip/pelvic
injury. Constant monitoring of the patient is essential. Even vital signs that seem stable,
especially in the very young or very old, are not reliable indicators of the absence of
shock.
2. Answer: B.
The speed and lack of braking of the bicyclist
Rationale: Remember, velocity is a much more significant contributor to kinetic energy
than mass.
3. Answer: C.
kinetic energy.
Rationale: Kinetic energy is the energy associated with bodies in motion.
4. Answer: C.
significant because of reduced bone and muscle mass.
Rationale: Bone and muscle mass decrease significantly with age. Energy is not as well
dissipated, and more traumatic damage occurs as a result.
5. Answer: C.
based on the mechanism of injury.
Rationale: You would treat this patient for shock due to the mechanism of injury (the
velocity of the bike hitting the elderly patient full force). This patient should also be
monitored frequently for any changes.
6. Answer: D.
the impact speed at which the bike hit the patient.
Rationale: Remember the criteria for transport to a trauma center. It includes any
significant impact between a pedestrian and bicycle.
Additional Questions
7. Rationale: Start with the mental status. The brain requires adequate tissue perfusion.
Inadequate perfusion will appear as confusion, combativeness, unreasonable behavior. A
“normal” blood pressure of 118/60 mm Hg in an elderly patient may be very low as
compared to the baseline. Always rely on changes in blood pressure based on your
baseline measurement.
Assignments
A.
B.
Review all materials from this lesson, and be prepared for a lesson quiz to be
administered (date to be determined by instructor).
Read Chapter 30, Bleeding, for the next class session.
Unit Assessment Keyed for Instructors
1. What is the definition of “trauma”?
Answer: Trauma is the acute physiologic and structural change (injury) that occurs in a
patient’s body when an external source of energy affects the body beyond its ability to
sustain and dissipate it.
(p 1483)
2. Identify and describe the five types of energy that may produce trauma.
Answer: Mechanical energy is energy from motion (kinetic energy [KE])—such as a
moving vehicle) or energy stored in an object (potential energy—a brick sitting on a
building ledge). KE would be found in two moving vehicles colliding. Potential energy
would be present in an object sitting at a height. In that case, gravity would be the
potential source of energy that converts to KE if the object falls. Chemical energy is the
energy released as a result of a chemical reaction and can be found in an explosive or an
acid or even from a reaction to an ingested or medically delivered agent or drug.
Electrical energy comes in the form of high-voltage electrocution or a lightning strike.
Barometric energy can result from sudden and radical changes in pressure, as can occur
during scuba diving or flying.
(p 1484)
3. Compare and contrast biomechanics and kinetics.
Answer: Biomechanics is the study of the physiology and mechanics of a living
organism using the tools of mechanical engineering. Biomechanics provides a way of
analyzing the mechanisms and results of trauma sustained by the human body. Kinetics
studies the relationships among speed, mass, direction of the force, and, for paramedics,
the physical injury caused by speed, mass, and force. Knowledge of kinetics can help you
predict injury patterns found in a patient.
(p 1484)
4. What are Newton’s laws of motion?
Answer: Newton’s first law of motion states that a body at rest will remain at rest unless
acted on by an outside force. Similarly, a body in motion tends to remain in motion at a
constant velocity, traveling in a straight line, unless acted on by an outside force. Most
bodies in motion (without the assistance of a motor or other propulsion device) tend to
eventually stop due to the action of forces of friction, wind resistance, or other forces
resulting in deceleration. Newton’s second law of motion states that the force that an
object can exert is the product of its mass times its acceleration. The higher an object’s
mass and acceleration, the higher the force that needs to be applied to make a change of
course or stop the object.
(p 1486)
5. What are the five phases of injury that are tied to progressive deceleration?
Answer: When a motor vehicle collides with another object, trauma in the crash is
composed of five phases tied to the effects of progressive deceleration. The first phase,
deceleration of the vehicle, occurs when the vehicle strikes another object and is brought
to an abrupt stop. The second phase is deceleration of the occupant, which starts during
sudden braking and continues during the impact of the crash. This results in deceleration,
compression, and shear trauma to the occupants. The third phase, deceleration of internal
organs, involves the body’s supporting structures (skull, sternum, ribs, spine, and pelvis)
and movable organs (brain, heart, liver, spleen, and intestine) that continue their forward
momentum until stopped by anatomic restraints .The fourth phase is the result of
secondary collisions, which occur when a vehicle occupant is hit by objects moving
within the auto such as loose objects, packages, animals, or other passengers. These
objects may continue to travel at the auto’s initial speed and then hit a passenger who has
come to rest. These types of collisions have been known to cause severe spine and head
trauma. The fifth phase is the result of additional impacts that the vehicle may receive,
such as when it is hit by a second vehicle, or is deflected into another vehicle, tree, or
other object.
(p 1487)
6. Why are seatbelts ineffective in side impact collisions?
Answer: Lateral impact, “T”-bone, and side impacts impart energy to the near-side
occupant almost directly to the pelvis and chest. Unrestrained occupants will remain
almost motionless, literally having the car pushed out from under them. Seat belts do
little to protect these passengers because they are designed to limit forward hinging
injuries, not side impacts.
(p 1490)
7. What is a quarter-panel impact?
Answer: Rotational or quarter-panel impact occurs when a lateral crash is off center. In
this case, rotation occurs as part of the car continues to move and part of the car comes to
a stop. The vehicle’s forward motion stops at the point of impact, but the side continues
in rotational motion around the impact point. The point of greatest speed loss of the
vehicle is the site where the greatest damage to the occupant will occur.
(p 1492)
8. Discuss how falling from a height determines velocity.
Answer: The height from which the patient has fallen will determine the velocity of the
fall. A person falling one story (12 ft) onto concrete, for example, will fall at about 28 ft
per second (fps) and experience an impact force of about 48 g. A person falling from the
second story (24 ft) will reach a velocity of 39 fps and experience an impact force of 95 g
on the same surface. Height plus stopping distance predicts the magnitude of deceleration
forces. A fall greater than 15 ft or 2.5 to 3 times the height of the patient will have a
greater incidence of morbidity and mortality, although it is usually assumed that a fall
from four stories may be survivable. At five stories, survival is questionable; at six
stories, survival is unlikely, and a fall from seven stories or higher is rarely survivable.
(p 1496)
9. What information should you provide to hospital personnel about a gunshot wound?
Answer: To give the trauma team at the hospital as much information as possible, try to
obtain the following information: What kind of weapon was used (handgun, rifle, or
shotgun; type and caliber, if known? At what range was it fired? What kind of bullet was
used? (Ideally, see if the police can find an unfired cartridge.) Is there powder residue
around the wound and entrance and exit wounds (the exit wound is usually larger and
more ragged)?
(p 1499)
10. What is a “trauma score”?
Answer: The trauma score is used to determine the likelihood of patient survival, which
is calculated on a scale of 1 to 16, with 16 being the best possible score. It takes into
account the Glasgow Coma Scale (GCS) score, respiratory rate, respiratory expansion,
systolic blood pressure, and capillary refill.
(p 1503)
Unit Assessment
1. What is the definition of “trauma”?
2. Identify and describe the five types of energy that may produce trauma.
3. Compare and contrast biomechanics and kinetics.
4. What are Newton’s laws of motion?
5. What are the five phases of injury that are tied to progressive deceleration?
6. Why are seatbelts ineffective in side impact collisions?
7. What is a quarter-panel impact?
8. Discuss how falling from a height determines velocity.
9. What information should you provide to hospital personnel about a gunshot wound?
10. What is a “trauma score”?