Stephen A. Ridella, Amanda Beyersmith National Highway Traffic Safety Administration Kristin Poland, PhD National Transportation Safety Board

Transcription

1 Stephen A. Ridella, Amanda Beyersmith National Highway Traffic Safety Administration Kristin Poland, PhD National Transportation Safety Board 1

2 Studies conducted on injury incidence by age Hanna and Hershman (NHTSA, 2009), 9, NASS CDS For frontal and side crashes: Incidence of serious rib fractures increases with age, but only after age 75 Welsh et al (Transportation Research, 2006), UK Case Study For similar crash characteristics, older occupants (65 years and older) have a significantly higher rate of fatality in frontal (and nearside) lateral impacts Same study found higher incidence of multiple rib fractures and thoracic organ injury older occupants (>age 65) compared to younger (<39 yrs) Newgard (Accident Analysis and Prevention, 2008) Injury risk versus age differs for men and women Most studies stop at body region injury incidence Not possible to go further in most datasets This paper describes more detailed age related factors related to injuries Risk of Chest and Head Injuries Increased for Older Occupants Male, Belted, Driver, BMI=24 kg/m 2, Pass Car, 20 mph DV (side 25.0% impact) Thorax Head (OR=5.53) 20.0% Thorax (OR=8.15) of AIS 3+ Injury (%) Risk o 15.0% 10.0% Abdomen (OR=7.48) Spine (OR=12.95) UX (OR=6.49) LX (OR=1.0) Head 5.0% Spine Abd LX UX 0.0% Age (yr) 2

3 Specific Injury Analyses for Older Occupants Required Effects of gender and body mass index Pre existing medical conditions and co morbidities Injury causation and mechanisms with respect to crash direction and severity Injury outcomes for almost every body region in every crash mode Crash Injury Research Engineering Network (CIREN) Data rich relative to crash description and occupant injury BioTab tool provides injury mechanism analysis Uses specific crash and injury data to inform on causation and mechanism Identifies source of energy, involved physical components and path to injured region Reports contributing factors that may have contributed to likelihood of specific injury (age, bone condition, obesity, belt use, posture, etc) 6 C ith Bi T b i j i id 1306 Cases with BioTab injuries were queried Age groups: <25, 25 44, 45 64, 65 74, 75 Injury frequency was tabulated by body region and analyzed by crash mode and gender Further analysis on specific injuries to head and chest with respect to crash and occupant information 3

4 Decreased Cortical Bone Bone Density Muscle Mass Increased AP diameter Cartilage ossification Vascular ossifications 45 YRS 75+ YRS 4

5 Number of Injuries Number of Injuries Lower Lower Number of Women's Injuries by Age Upper Upper Spine C, T, L Abdomen & Pelvic Thorax Neck Number of Men's Injuries by Age Spine C, T, L Abdomen & Pelvic Thorax Face Head Neck Face Head < < % of Women's Injuries by Age % of Injuries Lower Upper Spine C, T, L Abdomen & Pelvic Thorax Neck Face Head < % of Injuries Lower Upper % of Men's Injuries by Age Spine C, T, L Abdomen & Pelvic Thorax Neck Face Head <

6 Age Group Most Frequent AIS Code Description Second Most Frequent AIS Third Most Frequent AIS <25 Unilateral lung contusion Bilateral lung contusion 2 3 Rib fractures and w/wo hemo w/wo hemo Sternum fracture (6) /pneumothorax (20) /pneumothorax (8) Unilateral lung contusion w/wo hemo /pneumothorax (22) >3 Rib fractures on one side and <=3 on the other with hemo /pneumothorax (19) Sternum fracture (18) Sternum fracture (32) >3 Rib fractures on one side Unilateral lung and <=3 on the other (31) contusion w/wo hemo /pneumothorax (21) Sternum fracture (15) >3 Rib fractures on one side and <=3 on the other (11) 75+ Sternum fracture (25) >3 Rib fractures on one side and <=3 on the other (17) 2 3Rib fractures (6) Unilateral lung contusion w/wo hemo /pneumothorax (11) Age Group Delta V (kph) Involved Physical Component <25 66 wheel, seat belt, airbag wheel, seat belt Fatal: Non Fatal 0:20 2: Seat belt, steering 0:32 wheel Seat belt 1: Seat belt 6:19 6

7 Front Comorbidity 1 Comorbidity 2 Age <25 Intrusion (90) High Delta V (83) Unbelted (72) n/a n/a Intrusion (156) Unbelted (112) Comorbidity (68) Obesity (37) not significant sample size Osteoporosis/ Intrusion comorbidity Osteopenia (124) (102) Unbelted (72) Obesity (48) (10) Elderly (41) 75+ Elderly (126) Comorbidity (38) Intrusion (24) Comorbidity (58) Unbelted (17) Osteoporosis/ osteopenia (20) Obesity (7) Osteoporosis/ osteopenia (44) Obesity (12) 7

8 Case 1 Case 2 Side Impact 2005 Hyundai Sonata 24.8 mph Delta V 14.2 inches crush Impacted pick up truck Side Impact 2008 Honda Civic 29.8 mph Delta V 17.7 inches crush Impacted by pick up truck 8

9 Case 1 Case 2 21 year old female Injuries: Left pelvis fracture 78 year old male Injuries: 7 fractured ribs, pneumothorax Case 1 Case 2 21 year old female BMI 20.9 Maximum AIS 3 No Co morbidities 2 days $15, year old male BMI 25.7 Maximum AIS 4 Cardiac co morbidity 10 days $58,505 9

10 Head and chest injuries were most prominent Crash severity decreased with increasing occupant age Contributing factors included loss of bone density and obesity as age increased Outcome was often worse for the older occupant even for a similar crash or injury CIREN provided additional analysis on the injury and the likely contributing factors related to age As one ages, the factors related to injury change from high crash speed and intrusion to factors such as bone quality and obesity Lower crash severity for older occupants 10

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12 Most Frequent AIS Code Second Most Frequent AIS Code Third Most Frequent AIS Code Delta V Involved Physical Fatal: Non Delta V Involved Physical Fatal: Non Involved Physical Fatal: Non Age N (kph) Component fatal N (kph) Component fatal N Delta V Component fatal < Wheel, Seat Belt, Air Bag 0: Wheel, Seat Belt 0: Seat Belt 0: Seat Belt, Wheel, Instrument Panel 2: Wheel, Seat Belt 0: Seat Belt, Wheel 1: Seat Belt, Wheel 0: Seat Belt, Wheel 1: Seat Belt/ Wheel 0: Seat Belt 1: Seat Belt 0: Seat Belt 1: Seat Belt 6: Seat Belt 2: Seat Belt 4:7 12