Trauma Studies Lecture 1 PDF

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TRAUMA STUDIES – NOTES LECTURE 1 – KINEMATICS OF TRAUMA Kinematics: looking at the mechanism of the incident to determine the injuries from the forces & motions. Energy: ability to do work Potential Energy: energy stored by a object, from work done/position. *not in motion. PE=WV Object moves & PE becomes KE Kinetic Energy: energy associated with movement. KE=1/2mv2 Traumatic Event Phases/Haddon Matrix 1. PRE-EVENT: circumstances leading up to. 2. EVENT: moment of trauma. 3. POST-EVENT: outcomes of trauma event. *Host/human factors: gender, intelligence, health, personality, intoxication. *Agent/energy factors: velocity, shape, material, brakes, exposure time. *Environment factors: physical= weather etc., social= attitudes, belief etc. 1st Law of Motion: body at rest will remain at rest, body in motion will remain in motion unless acted on by an outside force. Eg. 1. Vehicle hits object 2. Occupant hits inside of vehicle. 3. Internal organs hit anterior body surface. 2nd Law of Motion: (conservation of energy) energy can’t be created or destroyed CAN change form. Acceleration of an object produced by a net force is directionally proportional to net force magnitude in the same direction as the net force, & inversely proportional to the mass of the object. Forces are unbalanced  acceleration  acceleration depends directly on net force & inversely on objects mass. Force= Mass x Acceleration Force= Mass x Deceleration *same force – small mass  greater acceleration - large mass  lesser acceleration 3rd Law of Motion: for every action/force there is an equal & opposite reaction. Energy Exchange: number of body tissue particles impacted determines the amount of energy exchanged  damage/injury. Number of particles is determined by: Density:  density =  particles =  energy exchange. Contact Area:  C.A of object =  particles impacted.  Small C.A &  force = penetration trauma ie. Bullet. Cavitation: impact  particles acceleration away from impact  partickes accelerate into other particles & so on  cavity/hole   energy =  cavitation. 1. Temporary: stretched tissues, some/all return to position. 2. Permanent: temporary cavity collapses, tissues don’t rebound. BLUNT TRAUMA : non-penetrating injury by rapidly moving object. Direction of the impact determines pattern of & potential injury. - 2 major parts: 1. Mechanical & structural effect of vehicle crash. 2. Internal effects on oragans & body structures. - On-scene observations: 1. Direction of impact. 2. External damage to vehicle. 3. Internal damage ie. Knee-dashboard impact. - Shear Injury/Shearing Forces: organ/structure (or part there of) changing speed faster than another  parts separating/tearing. - Compression Injury/Compression Forces: organ/structure (or part there of) being directly squeezed. Eg. Bowel between spinal column & anterior internal abdominal wall wearing seatbelt. 5 Types of Motor Vehicle Crashes 1) FRONTAL IMPACT: impact at front, stopping forward motion. a. Up & over path: body motion  up & over steering wheel. b. Down & under path: forward off seat & into dashboard. 2) REAR IMPACT: slower/stationary vehicle hit from behind by faster vehicle. 3) LATERAL IMPACT: intersection/’t-bone’ collision, vehicle veers off road & impact sideways. Vehicle moves in opposite direction of impact. 4) ROTATIONAL IMPACT: corner of vehicle strikes immovable object/another vehicle/slower vehicle/vehicle moving in opposite direction. 5) ROLLOVER: impacts in several angles.

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MV vs Pedestrian. Waddell’s Triad: 1. Femur fracture 2. Intra-abdominal/intra-thoracic injury. 3. Head injury. MV vs Adults 1. Initial impact to legs and hips. 2. Torso onto hood and possibly windshield. 3. Body onto ground, usually head 1st and c-spine. MV vs Child 1. Initial impact to legs 2. Bonnet into child’s throat. 3. Child thrown downward. Seatbelts: positioned properly  pelvis & chest absorb pressure  few/no serious injuries, pressure passes through restraint system. *worn improperly  spleen, liver & pancreas compression, diaphragmatic rupture & organ herniation, lumbar spine compression. Airbags: dangerous to children & small adults. Proper distance, driver = 25cm, passenger = 45cm,  small abrasions. MOTORCYCLE CRASHES 3 types: 1. HEAD ON IMPACT: solid object stops forward motion. Center of gravity above & behind front axle/pivot point  bike tipping forward & driver into the handle bars  - thighs  handle bars  bilateral femur fractures. - pelvis  handle bars  open book pelvic fracture. 2. ANGULAR IMPACT: hit object at an angle  bike collapsing in rider OR rider crushed between bike and object  fractures, soft tissue & abdominal organ injury. 3.

EJECTION IMPACT: lack of restraints  injury at point of impact & energy absorbed by body.

FALLS : Multiple impacts, energy exchange indication = height of fall, landing surface & body part 1st to impact. Landing surfaces & compressibility: effects stopping distance & pattern of injury Don Juan Syndrome: landing feet 1st  bilateral calcaneous fractures, ankle fractures, tibia & fibula fractures, thoracic & lumbar compression fractures. Outstretched hands: bilateral compression & flexion fractures of wrists. Head 1st: entire weight & force of torso, pelvis & legs  head & c-spine. PENETRATING TRAUMA : KE = 1/2mv2 3 Factors influencing energy exchange 1. PROFILE: objects initial size & if it changes at impact   Drag =  impact  Deformity at impact =  particle damage 2. TUMBLE: object turning over and assuming different angles inside body.  Wedge shape = center of gravity further back  tumble   particle damage 3. FRAGMENTATION: object breaks up   drag & energy exchange.  Can occur after leaving weapon or after entering body  Active = explosive detonates, Passive = breaks on impact BLAST INJURIES – 5 Types 1. 2. 3. 4. 5.

PRIMARY: shock wave with body  stress & shear waves  waves reinforce/reflected at tissue density interface *gas filled organs at risk*  tympanic membrane rupture, blast lung, concussion, eye injuries. SECONDARY: projectiles, ballistic wounds from pieces of exploding weapon & secondary environmental fragments  penetrating injuries, traumatic amputations, lacerations. TERTIARY: propulsion of body into another object  body translocation. Crush injuries by structural damage/collapse.  Blast injuries, crush syndrome, compartment syndrome. QUANTERNARY: heat, flames & other explosive related injuries, illnesses & disease  burns, toxic gas, inhalation injury, injury/infection from environmental contamination. QUINARY: radiation, chemicals, bacteria, “dirty bomb”

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LECTURE 2: SCENE ASSESSMENT

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