Mechanism of injury Flashcards
(62 cards)
1
Q
introduction
A
- trauma is primary cause of death and disability between ages 1-44 years
- analyzing a trauma scene is a vital skill
2
Q
trauma
A
-injury occurs when an external source of energy affects the body beyond its ability to sustain and dissipate the energy
3
Q
forms of energy
A
- different forms of energy produce different kinds of trauma
- mechanical energy
- chemical energy
- electrical energy
- barometric energy
4
Q
biomechanics
A
Study of physiology and mechanics of living organisms
5
Q
kinetics
A
Study of the relationship among speed, mass, direction of force, and physical injury caused by these factors
6
Q
mechanism of injury (MIO)
A
- physical cause of the injury
- what happens outside the body
- assessment of how energy was introduced to the body
- suggest which organs/systems may be affected
- can direct assessment and treatment
7
Q
biomechanics of trauma
A
- explains the physical results of the MOI
- what happens inside the body
8
Q
factors affecting types of injury
A
- Ability of body to disperse energy delivered
- Force and energy
- duration and direction
- position of victim
9
Q
force and energy: factors affection types of injury
A
− Size of object
− Velocity
− Acceleration or deceleration
− Affected body area
10
Q
duration and direction: factors affecting types of injury
A
− The larger the area of force dissipation, the more pressure is reduced to a specific spot.
11
Q
impact resistance
A
- impact resistance of body parts has a bearing on types of tissue disruption
- organs that have has inside are easily compressed
- liquid containing organs are less compressible
12
Q
understand the effects of forces to help assess the mechanism of injury (MOI)
A
13
Q
velocity (V)
A
distance per unit of time
14
Q
acceleration (a)
A
rate of change of velocity
15
Q
gravity (g)
A
downward acceleration imparted to any object moving toward earth
16
Q
kinetic energy
A
1/2 (mass x velocity^2)
17
Q
kinetics
A
- the KE of a car in motion that stops suddenly must be transformed or applied to another object
- other factors that will affect energy dissipation in a crash include:
- vehicles angle of impact
- differences in sizes of the 2 vehicles
- restraint status and protective gear of occupants
18
Q
law of conservation of energy
A
-energy can neither be created nor destroyed
19
Q
energy dissapation
A
- process by which KE is transformed into mechanical energy
- protective devices can manipulate the way in which energy is dissipated
20
Q
newtons first law of motion
A
-a body at rest will remain at rest unless acted on by an outside force
21
Q
newtons second law of motion
A
- the force of an object can exert is the product of its mass times its acceleration
- f= ma
22
Q
force
A
- force = mass (weight) x acceleration (or deceleration)
- deceleration and acceleration can be measured in numbers of g force
23
Q
blunt trauma
A
-injuries in which tissues are not penetrated by external object
24
Q
motor vehicle crashes
A
- 5 phases of trauma
- phase 1- deceleration of the vehicle
- phase 2- deceleration of occupant
- phase 3- deceleration of internal organs
- phase 4- secondary collisions
- phase 5- additional impacts received by the vehicle
25
impact patterns: frontal or head on impacts
- front end of the car distorts
- passengers decelerate at same rate as vehicle
- abrupt deceleration injuries are produced by a sudden stop of a body forward motion
- unrestrained occupants usually follow one of 2 trajectories:
- down and under pathway
- up and over pathway
26
impact patterns: lateral or side impacts
- impart energy to the near side occupant
- seat belt offer little protection
- the body is pushed in 1 direction, while the head moves towards the impacting object
27
-impact patterns: rear impacts
- have the most survivors
- whiplash injury is common
- energy is imparted to the front vehicle
28
impact patterns: rotational or quarter panel impacts
- occurs when a lateral crash is off center
| - the vehicle forward motion stops, but the side continues in rotational motion
29
impact patterns: rollovers
- patients may be ejected
- patients may be struck hard against the interior of the vehicle
- worst scenario bc no protection
30
restrained vs unrestrained occupants
- seat belts stop the motion of an occupant traveling at the same speed as the vehicle
- associated injuries include cervical fractures and neck sprains
31
air bags
- have reportedly reduced deaths in direct frontal crashes by about 30%
- can also result in secondary injuries:
- direct contact
- chemicals
32
motorcycle crashes
- any structural protection afforded to victims is derived from protective devices worn by the rider
- helmet
- leather or abrasion resistant clothing
- boots
- attention should be given to:
- deformity of motorcycle
- side damaged
- distance of skid
- deformity of objects or vehicles
- helmet deformity
33
four types of motorcycle impact
- head on impact
- angular impact
- ejected
- laying the bike down
34
when helmet should be removed
- helmet should be removed carefully if:
- airway management techniques cannot be performed with the helmet in place
- helmet should be cut if it cannot be removed without further deformation
35
3 predominant MOIs for pedestrains
- 1st impact- auto strikes body with its bumpers
- 2nd impact- adult is thrown on hood and/or grille of vehicle
- 3rd impact- body strike the ground or some other object
36
waddell triad
- pattern of injuries in children and people of short stature
- bumper hits pelvis and femur
- chest and abdomen hit grille
- head strikes vehicle and ground
- more likely to go under, hit head on ground, or hit grille
37
falls from heights
- severity of injuries impacted by:
- height
- position
- surface
- physical condition
38
penetrating trauma
- involves disruption of skin and tissues in a focused area
- low velocity- caused by sharp edges
- medium and high velocity- object might flatten out, tumble, or ricochet
- middle- handgun
- high- riffle
39
most common penetrating injury
-caused by firearms
40
stab wounds
- severity depends on:
- anatomic area involved
- depth of penetration
- blade length
- angle of penetration
41
gunshot wounds
- the most important factor for seriousness of wound is type of tissue involved
- entry wound is characterized by the effects of the initial contact and implosion
- severity depends on:
- type of firearm
- velocity of projectile
- physical design/size of projectile
- distance of victim from muzzle
- type of tissue struck
42
handgun wounds
- revolver holds 6-10 rounds of ammunition
- pistol holds up to 17 rounds of ammunition
- accuracy is limited
43
shotguns
- fire round pellets
| - shallower
44
rifles wounds
- fire single projectile at a very high velocity
- impart a spin for accuracy
- longer barrel = more accurate
- can go further into the body
- high velocity
45
deformation/tissue destruction: gunshot wounds
- deformation/tissue destruction is based on:
- density
- compressibility
- missile velocity
- missile fragmentation
46
projectile creates a permanent cavity
-may be straight line or irregular pathway
47
pathway expansion
-tissue displacement that results from low displacement sonic pressure
48
missile fragmentation
-projectile sends off fragments that create paths through tissues
49
exit wounds
- exit wounds occur when projectile energy is not entirely dissipated
- size depends on energy dissipated and degree of cavitation
- exit wound is larger, can be burns, more surface area
50
wounding potential
- wounding potential depends on:
- powder charge
- size and number of pellets
- dispersion of the pellets
- range at which the weapon was fired
- barrel length (long = more accuracy)
- type of choke at the end of the barrel
- shorter barrel -> more dispersion
51
when assessing gunshot wounds
- obtain weapon used, range fired, bullet used
- look for powder residue around the wound
- entrance and exit wounds
52
primary blast injuries
- damage is caused by pressure wave generated by explosion
- close proximity to the origin of the pressure wave carries a high risk of injury or death
- can rupture membranes and affect organs
53
-secondary blast injuries
- result from being struck by flying debris
- a blast wind occurs
- flying debris may cause blunt and penetration injuries
- most common
- b
54
tertiary blast injuries
- occur when a person is hurled against stationary, rigid objects
- ground shock
- amputations, broken bones, penetrations
55
ground shock
-physical displacement when the body impacts the ground
56
quaternary blast injury
- occur from the miscellaneous events that occur during an explosion
- may include:
- burns
- respiratory injury
- crush injury
- entrapment
57
quinary blast injuries
- caused by biologic, chemical, or radioactive contaminants added to an explosive
- associated with dirty bombs
58
physics of an explosion
- speed, duration, and pressure of the shock wave are affected by:
- size of the explosive charge
- nature of surrounding medium
- distance from explosion
- presence or absence of reflecting surface
59
explosion is more damaging in closed spaces
true
60
blast pressures cause destruction at
- interface between tissues of different densities
| - interface between tissues and trapped air
61
tissue at risk
- air containing organs are more susceptible to pressure changes (lungs) -> primary blast
- junctions between tissues of different densities and exposed tissue are prone
- the ear is most sensitive (pressure)
- primary pulmonary blast injuries occur as contusions and hemorrhages
- if there is any reason to suspect lung injury in a blast victim -> administer oxygen
62
assessment/management of blast injuries
- if scene safety cannot be ensured, evacuate until advised that it is safe
- assess for other hazards
- form a general impression as you approach
- assess breath sounds frequently
- examine for the presence of DCAP-BTLS
- establish a baseline pulse oximetry value
