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Overview :
A car passenger
involved in an accident can be triaged based on the type of impact, extent of
vehicular damage and estimated velocity change involved. The change in speed
that a vehicle undergoes during the crash shows the strongest correlation with
the severity of injury. The authors are from the Washington Hospital
Center in Washington, DC.
Types of impacts
for front seat passengers
(1) direct
frontal: damage extending more than 2/3 of frontal width of car
(2) offset
frontal: damage extending less than 2/3 of frontal width of car
(3) side, with
passenger on side struck
(4) side, with
passenger on side opposite the side struck
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Parameters
Predicting >= 10% Probability of Patient with Injuries ISS >= 16
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Type of Impact
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Estimated
Change in Speed
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Crush
Distance
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direct frontal
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>= 20 mph
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>= 20 inches
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offset frontal
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>= 22 mph
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>= 28 inches
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side impact
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>= 15 mph
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>= 15 inches
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Equations were
derived to predict the probability of injury with ISS >= 16. These are shown
in Figures 1 to 4 on pages 648-649.
percent of front
seat occupants with ISS >= 16 following direct frontal collision =
= 0.0262 *
((velocity change in mph) ^ 2.0035)
percent of front
seat occupants with ISS >= 16 following offset frontal collision =
= 0.0024 *
((velocity change in mph) ^ 2.6941)
percent of front
seat occupants with ISS >= 16 following side impact on same side =
= 0.0028 *
((velocity change in mph) ^ 2.7567)
percent of front
seat occupants with ISS >= 16 following side impact to opposite side =
= 0.0840 *
((velocity change in mph) ^ 1.9097)
If the equations
are solved for percent ISS = 10 (percent), then the data in the table above is
obtained.
Different
variables decreasing the risk to the passenger (associated with an increased
threshold velocity for serious injury):
(1) Using a seatbelt (increased the
threshold velocity for serious injury by about 5 mph).
(2) If
unrestrained: being the driver.
(3) In side impacts: being on the side
opposite to the impact.
Limitations:
• Cars designed to absorb the energy of
the impact (crumple zones, reinforced doors, etc.) would probably require a
higher velocity change and greater damage to produce the same degree of
passenger injury.
• I am unsure
how prevalent airbags were in the vehicles studied.
• The data did not appear to include
backseat passengers or accidents with rollover.
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