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  • The physics of motion, the science of motion that is what kinematics is. It uses all the laws of physics from gravity, energy, water & air compression.

Transcript

  • 1. KINEMATICS An Introduction to the Physics of Trauma CMSgt John Jonckers, Superintendent 141 st MDG Medical SMEE - Thailand
  • 2. Trauma Statistics
    • 100,000 trauma deaths/year
    • One-third are preventable
    • Unnecessary deaths often caused by injuries missed because of low index of suspicion
    • Raise index of suspicion by evaluating scene as well as patient
  • 3. Kinematics
    • Physics of Trauma
    • Prediction of injuries based on forces and motion involved in injury event
    • Mechanism of Injury
    • Index of suspension
  • 4. Physical Principles
    • Kinetic Energy
    • Newton’s First Law of Motion
    • Law of Conservation of Energy
  • 5. Kinetic Energy
    • Energy of motion
    • K.E. = 1/2 mass x velocity 2
    • Major factor = Velocity
    • “ Speed Kills”
  • 6. Newton’s First Law of Motion
    • Body in motion stays in motion unless acted on by outside force
    • Body at rest stays at rest unless acted on by outside force
  • 7. Law of Conservation of Energy
    • Energy cannot be created or destroyed
    • Only changed from one form to another
  • 8. Conclusions
    • When moving body is acted on by an outside force and changes its motion,
    • Kinetic energy must change to some other form of energy.
    • If the moving body is a human and the energy transfer occurs too rapidly,
    • Trauma results.
  • 9. Types of Trauma
    • Penetrating
    • Blunt
      • Deceleration
      • Compression
  • 10. Motor Vehicle Collisions
    • Five major types
      • Head-on
      • Rear-end
      • Lateral
      • Rotational
      • Roll-over
  • 11. Motor Vehicle Collisions
    • In each collision, three impacts occur:
      • Vehicle
      • Occupants
      • Occupant’s organs
  • 12. Head-on Collision
    • Vehicle stops
    • Occupants continue forward
    • Two pathways
      • Down and under
      • Up and over
  • 13. Rear-end Collision
    • Car (and everything touching it) moves forward
    • Body moves, head does not, causing whiplash
    • Vehicle may strike other object causing frontal impact
    • Worst patients in vehicles with two impacts
  • 14. Lateral Collision
    • Car appears to move from under patient
    • Patient moves toward point of impact
  • 15. Rotational Collision
    • Off-center impact
    • Car rotates around impact point
    • Patients thrown toward impact point
    • Injuries combination of head-on, lateral
    • Point of greatest damage = Point of greatest deceleration = Worst patients
  • 16. Roll-Over
    • Multiple impacts each time vehicle rolls
    • Injuries unpredictable
    • Assume presence of severe injury
  • 17. Restrained vs Unrestrained
    • Ejection
      • 27% of motor vehicle collision deaths
      • 1 in 13 suffers a spinal injury
      • Probability of death increases six-fold
  • 18. Pedestrians
    • Child
      • Faces oncoming vehicle
      • Waddell’s Triad
        • Bumper Femur fracture
        • Hood Chest injuries
        • Ground Head injuries
  • 19. Pedestrians
    • Adult
      • Turns from oncoming vehicle
      • O’Donohue’s Triad
        • Bumper Tib-fib fracture Knee ligament tears
        • Hood Femur/pelvic fractures
  • 20. Falls
    • Critical Factors
      • Height
        • Increased height = Increased injury
        • Always note & report
      • Surface
        • Decreased stopping distance = Increased injury
        • Always note & report type of surface
  • 21. Stab Wounds
    • Damage confined to wound track
      • Four-inch object can produce nine-inch track
    • Gender of attacker
      • Males stab up; Females stab down
    • Evaluate for multiple wounds
      • Check back, flanks, buttocks
  • 22. Stab Wounds
    • Chest/abdomen overlap
      • Chest below 4th ICS = Abdomen until proven otherwise
      • Abdomen above iliac crests = Chest until proven otherwise
  • 23. Gunshot Wounds
    • Damage to be determined by location of entrance/exit wounds
      • Missiles tumble
      • Secondary missiles from bone impacts
      • Remote damage from
        • Blast effect
        • Cavitation
  • 24. Gunshot Wounds Severity cannot be evaluated in the field or Emergency Department Severity can only be evaluated in Operating Room
  • 25. Blast Mechanics
    • Three types of explosions
      • Mechanical
        • Compressed gas cylinders
      • Nuclear
        • Sustained atomic reaction
      • Chemical
        • Small amount of solid or liquid material converted into a very large amount of gas in a very short time.
  • 26. Blast Mechanics
    • Explosive Blasts are essential to our society:
      • Automobile engines
      • Mining & earth moving
      • Bonding dissimilar metals
        • Sandwiched copper in Quarters
      • Aircraft construction
        • Explosive rivets
      • Throwing life lines between boats
      • Preventing avalanches
  • 27. Blast Mechanics
    • Blast Overpressure
    • Blast winds
    • Burns
  • 28. Blast Mechanics Blast Overpressure
    • Expanding gases force out in all directions
      • Subsonic or supersonic speeds
        • not important to medical providers
      • Objects can be thrown at 2000 mph
  • 29. Blast Mechanics Blast Overpressure
    • Only chemicals are destroyed / incinerated
      • Bomb pieces are bent/twisted but remain intact
      • Important for evidence
    • Instantaneous increase in “Atmospheric Pressure”
      • Followed by instantaneous ‘vacuum’
      • Immediate return to normal pressure
  • 30. Blast Mechanics Blast Winds
    • Ever expanding air mass makes its own wind
      • 1500 mph after a 100 psi overpressure
      • Objects are blown into people
      • People are thrown against objects
  • 31. Blast Mechanics Thermal Burns
    • Burns?
    • High temps in expanding gas cloud
      • Lasts only a very short time
    • Burn injuries are rare
      • More common among the dead
      • Few victims admitted to burn centers
    • UNLESS A SUBSEQUENT FIRE !
  • 32. Blast Mechanics Mechanisms of Injury
    • Blast casualties are affected by
      • Open air or closed room
        • Distance from the blast
        • Size of room
        • Height of ceiling
      • Was there a building collapse?
      • Number of persons in the area
      • Was shrapnel used?
      • Was there a resultant fire?
  • 33. Blast Pathophysiology
    • Blast overpressure
    • Air filled organs most vulnerable
      • Lungs (injury threshold – 4.2 psi)
      • Alveoli can compress – fluid filled capillaries can not
      • Torn capillary membranes
        • Pulmonary contusion
        • ‘Blast Lung’
      • Pneumo-thorax if air escapes into pleura
  • 34. Blast Pathophysiology
    • Blast Lung:
      • Hypoxemia
        • possible hypotension, bradycardia, hemoptysis
      • May take 12-24 hours to develop
    • Treat similarly to other hypoxic situations
      • High flow O 2 by mask
      • Consider intubation if severe
      • No diuretics
      • Good long term outcomes without sequela
  • 35. Blast Pathophysiology
    • Blast overpressure
    • Air filled organs are most vulnerable to injury
      • Abdomen & GI tract (injury threshold 6 psi)
    • Air is compressed & balloons out in other areas
      • Ruptured intestinal wall
        • Ileo-cecal joint most common to burst
      • More common in underwater blasts
        • Possibility must be considered in all situations
  • 36. Blast Pathophysiology
    • Blast overpressure
      • Abdomen & GI tract:
    • As tissue layers are compressed & released;
      • Disrupts epithelial, mucosal, sub-mucosal tissues
        • Resultant hemorrhage, necrosis, possible emboli
      • Symptoms similar to abdominal trauma
      • Challenge in predicting future of lesion
        • Burst or spontaneous recovery?
  • 37. Blast Pathophysiology
    • Blast overpressure
    • Auditory (injury threshold 5 psi)
      • Pressures cant equalize quickly enough
        • Ruptured tympanic membranes
          • most heal spontaneously
        • Dislocated/fractured ossicles
      • Multiple long term problems
        • Tinititis, vestibular, sensory loss
    • Not reliable indicator of concealed injuries!
      • Detailed additional exams recommended
  • 38. Blast Pathophysiology
    • Blast overpressure
    • Neurological
      • Air emboli may happen
        • Blast bends?
        • Air admitted through damaged lung capillaries?
      • May be a cause of death
      • Not significant pathology in survivors
    • Transient flattening of EEG waves in pigs
  • 39. Blast Pathophysiology
    • Blast forces and blast winds
      • Direct tissue trauma
        • Flying objects hitting victims (Shrapnel)
        • Victims hitting other objects (Tertiary contacts)
      • Amputation
  • 40. Blast Pathophysiology
    • Intentional Shrapnel
    • Ball bearings, nuts, bolts, nails etc.
      • Penetrating injuries similar to multiple small arms fire
      • Hundreds of objects may be seen on x-ray
      • Significant internal injuries
        • Objects may enter brain, spinal column
      • Nails enter head first (unlike bullets)
      • Objects are commonly retained in victims
        • Lifetime impairments
        • Long term disabilities
  • 41. Blast Pathophysiology
    • Blast forces and winds
      • Direct tissue trauma
  • 42. Blast Pathophysiology
    • Blast forces and winds
    • Amputations
  • 43. Blast Pathophysiology
    • Amputations
    • First: Blast forces shatter bone
      • Through bending type force
    • Second: Blast winds separate limb
      • Avulsion type of mechanism
    • Occurs to mainly long bones
        • Rarely at joints
    • High risk for exsanguination - Rarely re-attachable
        • Tourniquet
    • Amputation injuries more common among dead & expectant victims
  • 44. Blast Pathophysiology
    • Amputations
    • Tourniquet may be necessary
  • 45. Management of Blast Situations
    • Triage
    • #1 problem in patient management
      • Ongoing & continuous
        • NOT performed just once !
      • Victims re-evaluated & reclassified at hospital
        • Expect high demand for special procedures
        • Decisions about admission vs. discharge
          • Eardrum rupture NOT strict admission criteria
  • 46. Special considerations
    • Market place infection
      • Higher incidence of Candidema septicemia
    • Hepatitis vaccinations
      • Blood & body fluids exchange
      • Rate 10% Palestinian vs. 1-2% Israelis
    • Additional contamination
      • NBC material
      • Rat poison (coumarin types)
        • Anecdotal or myth ?
          • Incalculable dose
        • Vitamin K
        • Factor 7 injection
  • 47. Psychological & Long Term
    • Psychological Trauma to rescuers
  • 48. Psychological & Long Term
    • Psychological Trauma to rescuers
      • War wounds inflicted on civilians
  • 49. Conclusion
    • Look at mechanisms of injury
    • The increased index of suspicion will lead to:
      • Fewer missed injuries
      • Increased patient survival
  • 50. Summary
    • How people die in ground combat:
    • 31% Penetrating Head Trauma
    • 25% Surgically Uncorrectable Torso
    • Trauma
    • 10% Potentially Correctable Surgical Trauma
  • 51. Summary cont.
    • 9% Exsanguination from Extremity Wounds -1st
    • 7% Mutilating Blast Trauma
    • 5% Tension Pneumothorax - 2nd
    • 1% Airway Problems - 3rd
    • 12% Died of Wounds (Mostly infections and complications of shock)
  • 52. Closing statement
    • Three categories of casualties on the battlefield
    • Soldiers who will do well regardless of what we do for them
    • Soldiers who are going to die regardless of what we do for them
    • Soldiers who will die if we do not do something for them now (7-15%)
  • 53. References:
    • Mosby’s Paramedic Textbook, revised second edition – 2001, Chapter 18 Mick J. Sanders