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# Kinematics

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CMSgt John Jonckers, Superintendent 141st MDG …

CMSgt John Jonckers, Superintendent 141st MDG
Medical SMEE - Thailand

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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 &amp; air compression.

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• 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
• 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
• Bumper Femur fracture
• Hood Chest injuries
• Ground Head injuries
• 19. Pedestrians
• Turns from oncoming vehicle
• 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’
• 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
• 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
• 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
• 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