21: Kinematics of Trauma

1. 21: Kinematics of Trauma

2. Cognitive Objectives • Describe the “three collisions” associated with motor vehicle crashes. • Relate how the fundamental principles of physics apply to motor vehicle crashes and other types of accidents. • State Newton’s three laws.

3. Psychomotor Objectives • There are no affective objectives for this chapter. • Observe various high-energy injuries and identify potential damage to the patient.

4. Kinematics of Trauma • Injuries are the leading cause of death among children and young adults. • Kinematics introduces the basic physical concepts that dictate how injuries occur and affect the human body.

5. Energy and Trauma • Work • Force acting over distance • Kinetic energy • Energy of moving object • Potential energy • Product of weight, gravity, and height

6. Traumatic Injuries • Blunt trauma • Caused by a force to the body • Injuries do not penetrate soft tissue or organs • Penetrating trauma • Caused by objects such as knives and bullets • Injuries pierce the surface of the body

7. Mechanism of Injury (MOI) • MOI is the way in which traumatic injuries occur. • Different MOIs produce many types of injuries. • Isolated to one body system • Injuries to many body systems

8. Vehicular Crashes and MOI • By assessing the crash, the MOI may be determined. • By determining the MOI, you may be able to predict the types of injuries that may have happened at the time of impact.

9. Vehicular Collisions • Three types of crashes • Collision of car against another car or object • Collision of passenger(s) against interior of car • Collision of passenger’s internal organs against the solid structures of the body

10. Significant MOI • Severe deformities to the frontal part of the vehicle • Moderate intrusion from a T-bone accident • Severe damage from the rear • Collisions in which rotation is involved

11. Types of Motor Vehicle Collisions • Frontal • Lateral • Rear-end • Rollovers • Spins

12. Frontal Collisions (1 of 2) • Evaluate seat belts and airbags. • Remember that supplemental restraint systems cannot prevent all injuries. • You should still suspect that serious injuries have occurred.

13. Frontal Collisions (2 of 2) • Check for contact points. • Steering wheels can also cause chest injuries, especially if no airbag is present.

14. Rear-End Collisions • Commonly cause whiplash-type injuries • Unrestrained passengers will be thrust forward into the dashboard. • Back seat passengers wearing only lap belts might have a higher incidence of lumbar and thoracic spine injury.

15. Lateral Collisions • Responsible for the highest incidence of deaths. • Lateral whiplash injury is the result. • There may be intrusion into the passenger compartment.

16. Rollover Crashes • Injury patterns differ if patients are unrestrained. • The most unpredictable injuries are to unrestrained passengers. • Ejection is the most common life-threatening injury.

17. Spins • Vehicle is put into rotational motion. • Vehicle often strikes a fixed object, combining forces of rotation with lateral impact.

18. Car-Versus-Pedestrian Collisions • Often cause serious injuries to body systems • Evaluate MOI to determine: • Whether patient was thrown and how far. • Whether patient was struck and pulled under car. • Presume injury to the spinal cord and maintain immobilization.

19. Falls • Injury potential is related to the height of the fall. • A fall either 15' or three times the person’s height is considered significant. • Suspect internal injuries from a significant fall.

20. Considerations for Falls • The height of the fall • The surface struck • The part of the body that hit first, followed by the path of energy displacement • Always consider syncope or other medical conditions as an underlying cause.

21. Penetrating Trauma • Second largest cause of death in the United States after blunt trauma • Penetration can be low-energy, or medium- or high-velocity. • The greater the speed of penetration, the greater the injuries.

22. Low-Energy Penetrating Trauma • Caused accidentally by an object or intentionally with a weapon • Injury caused by the sharp edges of the object moving through the body

23. Medium-Velocity and High-Velocity Penetrating Trauma • Usually caused by bullets • Bullets can change shape and ricochet within the body. • Pressure waves cause cavitation. • If possible, identify weapon caliber and shooting distance.

24. High-Velocity Penetrating Trauma

25. Newton’s First Law Objects at rest tend to stay at rest, and objects in motion tend to stay in motion, unless they are acted upon by some force.

26. Newton’s Second Law Force (F) equals Mass (M) times Acceleration (A) F=MA

27. Newton’s Third Law For every action, there is an equal and opposite reaction.

28. Injuries to the Head • Bruising or tearing of the brain • Bleeding or swelling inside the skull is often life threatening. • Some patients may not have signs and symptoms.

29. Injuries to the Neck • Tearing or swelling of trachea can cause life-threatening airway problems. • Injury to large blood vessels in the neck may produce swelling that prevents blood flow to the brain. • Open wounds to neck vein bleed heavily or allow air to enter the circulatory system.

30. Injuries to the Chest • Broken ribs may interfere with chest’s ability to expand normally. • Large vessels may tear, causing massive bleeding.

31. Pneumothorax • Air collecting between lung tissue and chest wall • Compression of lung tissue interferes with oxygen exchange. • May also interfere with the functioning of the heart (tension pneumothorax)

32. Abdominal Injuries • Solid organs can tear, lacerate, or fracture, causing serious bleeding and death. • Hollow organs can leak digestive fluids. • Trauma patients who complain of abdominal pain may have abdominal bleeding.

33. Mutisystem Trauma Patient • A patient whose injuries involve more than one body system

34. Review • A 20-year-old man has major open facial injuries after his vehicle struck a tree head-on. Which of the following findings within the car would MOST likely explain his injury pattern? A. Deployed airbag B. Bent steering wheel C. Nonintact windshield D. Crushed instrument panel

35. Review Answer: C Rationale: The mechanism of injury and condition of the vehicle’s interior suggest likely areas of injury. Head and neck injuries are likely to result when the head and face impact the windshield.

36. Review • A 20-year-old man has major open facial injuries after his vehicle struck a tree head-on. Which of the following findings within the car would MOST likely explain his injury pattern? • Deployed airbag Rationale: This typically results in abrasions of the face, head, and arms. B. Bent steering wheel Rationale: This typically indicates the presence of chest injuries. C. Nonintact windshield Rationale: Correct answer D. Crushed instrument panel Rationale: This typically indicates the presence of leg and hip injuries.

37. Review 2. Which of the following would MOST likely result from the third collision in the “three-collision” effect that occurs during a high-speed, frontal impact, motor vehicle crash? A. Extensive damage to the automobile B. Flail chest and lower extremity fractures C. Massive external trauma with severe bleeding D. Aortic rupture or compression injury to the brain

38. Review Answer: D Rationale: During the third collision, the body's internal organs collide with the inside of the body. These injuries are usually not as obvious, but are often the most life-threatening. Injuries that may result from this include internal injuries of the brain (compression injuries) and aortic tears, resulting in massive internal bleeding.

39. Review 2. Which of the following would MOST likely result from the third collision in the “three-collision” effect that occurs during a high-speed, frontal impact, motor vehicle crash? • Extensive damage to the automobile Rationale: This would occur in the first collision. B. Flail chest and lower extremity fractures Rationale: This would occur in the second collision. C. Massive external trauma with severe bleeding Rationale: This would occur in the second collision. D. Aortic rupture or compression injury to the brain Rationale: Correct answer

40. Review 3. Death from a rollover motor vehicle crash is MOST often secondary to: A. crushing injuries. B. airbag related trauma. C. multiple collisions to the interior of the car. D. ejection of the patient from the motor vehicle.

41. Review Answer: D Rationale: Rollover crashes are the most unpredictable with regard to injuries sustained by the patient. An unrestrained passenger may have struck multiple points within the vehicle. However, the most life-threatening event in a rollover is ejection or partial ejection of the patient from the vehicle. Death is 25 times more likely if a person is ejected from the vehicle.

42. Review 3. Death from a rollover motor vehicle crash is MOST often secondary to: • crushing injuries. Rationale: These injuries occur during ejection or partial ejection. B. airbag related trauma. Rationale: Airbags significantly reduce the risk of death in motor vehicle crashes. C. multiple collisions to the interior of the car. Rationale: Thismakes the prediction of injury patterns difficult, but is not the most common life-threatening event in a rollover. D. ejection of the patient from the motor vehicle. Rationale: Correct answer

43. Review 4. A young male experienced severe blunt chest trauma when his passenger car struck another vehicle head-on. During your inspection of the interior of his vehicle, you would MOST likely find: A. deployed airbags. B. steering wheel deformity. C. starring of the windshield. D. a crushed instrument panel.

44. Review Answer: B Rationale: Blunt chest injuries during a motor-vehicle crash typically occur when the chest impacts the steering wheel. Therefore, your inspection of the vehicle’s interior will most likely reveal a deformed steering wheel.

45. Review 4. A young male experienced severe blunt chest trauma when his passenger car struck another vehicle head-on. During your inspection of the interior of his vehicle, you would MOST likely find: • deployed airbags. Rationale: Typically, this will cause abrasions to the face, head, and arms. B. steering wheel deformity. Rationale: Correct answer C. starring of the windshield. Rationale: Typically, this indicates the presence of head, face, and neck injuries. D. a crushed instrument panel. Rationale: Typically, this indicates the presence of leg and hip injuries.

46. Review 5. Kinetic energy is a calculation of: A. weight and size. B. weight and speed. C. mass and weight. D. speed and force.

47. Review Answer: B Rationale: Kinetic energy is a calculation of mass (weight) and velocity (speed). Energy cannot be destroyed, only converted.

48. Review 5. Kinetic energy is a calculation of: • weight and size. Rationale: Weight is part of the formula, but size would also mean weight. B. weight and speed. Rationale: Correct answer C. mass and weight. Rationale: Mass and weight are the same. D. speed and force. Rationale: Force is the product of mass times acceleration, all part of Newton’s Second Law.

49. Review 6. Whiplash injuries are MOST common following _________ impacts. A. rear-end B. rollover C. frontal D. lateral

50. Review Answer: A Rationale: Whiplash injuries of the neck are a common occurrence following rear-end collisions. As the vehicle is suddenly thrust forward, the occupant’s head is thrust backward. Properly positioned headrests can minimize the severity of whiplash injuries.