Accident Injury Severity - Indian Institute of Technology...

Accident

Injury Severity

Accident Severity

Collision severity

Injury severity

Early Severity Scales

Burden of injury – live or dead

Live - bleeding or not bleeding

Injured – treated or not treated

Treated – physician, doctor’s office

emergency room

released or admitted

Injury Severity

Department of Transport

Fatal Injury - injuries which caused death in

less than 30 days after the accident.

Serious Injury - inpatient or fracture,

concussion, internal injuries, crushings,

severe cuts, severe shock type of injury or

death after 30 days.

Slight Injury - minor sprain, bruise, cut, or

requiring only roadside attention

WORKING DEFINITIONS OF

A FATALITY Greece, Portugal, Spain use within 24

hours.

France uses within 6 days.

Italy uses within 7 days.

Most other states use within 30 days.

Correction Factors applied to get 30 day

equivalent, range from 1.3 (Spain) to

1.078 (Italy).

Serious & Slight

Prone to error

severity assessed and

assigned by police at the

scene

Correct in ≈ 60% of cases

Therefore a better scale is

needed which could be

used by non medics and

the scale that is

anatomically based

Abbreviated Injury Scale

Developed in the 1960’s by a group of 75

specialists from around the world.

Introduced in 1971

Revised in 1980, 1985, 1990,1998 & 2005

Abbreviated Injury Scale

Probability of threat to

life scale based on

individual injury

7 digit code

used to classify an injury.

123456.7

The code describes

type of injury

location of injury

severity of injury

Abbreviated Injury Scale

123456.7

1 Body Region

2 Type of Anatomical Structure

3/4 Specific Anatomical Structure

5/6 Level

7 Severity Score

1 Body Region 123456.7

1 Head

2 Face

3 Neck

4 Thorax

5 Abdomen

6 Spine

7 Upper Extremity

8 Lower Extremity

9 Unspecified

2 Type of Anatomic Structure 123456.7

1 Whole Area

2 Vessels

3 Nerves

4 Organs (inc. muscles/ligaments)

5 Skeletal (inc. joints)

6 Loss of Consciousness (head only)

3/4 Specific Anatomic Structure 123456.7

Whole Area

02 Skin Abrasion

04 Contusion

06 Laceration

08 Avulsion

10 Amputation

20 Burn

30 Crush

40 Degloving

50 Injury - NFS

60 Penetrating

Head - Loss of Consciousness (LOC)

02 Length of LOC

04-08 Level of Consciousness

10 Concussion

Spine

02 Cervical

04 Thoracic

06 Lumbar

Vessels, Nerves, Organs, Bones, Joints

These are all assigned consecutive

two digit numbers beginning with 02

5/6 Level

123456.7

Specific Injuries are assigned

consecutive two-digit numbers

beginning with 02

Fractures, rupture, laceration, etc

Injury Severity

Abbreviated Injury Score

1 Minor

2 Moderate

3 Serious

4 Severe

5 Critical

6 Maximum

AIS

AIS Example

1 superficial laceration

2 fractured sternum

3 open fracture of humerus

4 perforated trachea

5 ruptured liver with tissue loss

6 total severance of aorta

AIS – Threat to life

AIS % prob. of death

1 0

2 1 – 2

3 8 – 10

4 - 5 50 – 50

6 100

Organ injuries

Skeletal injuries

Measures of Injury Severity

• Maximum Abbreviated Injury Score (MAIS) - Maximum AIS for an occupant or body region

- Frequently used for assessing overall severity

- Non-linear relationship with the probability of death

Body region AIS MAIS

Head 4

Neck 2

Thorax 5 5

Abdomen 1

Lower limb 3

Injury Severity Score (ISS)

Gives a better fit between overall severity &

probability of survival than MAIS

The ISS is the sum of the squares of the

highest AIS code in each of the three most

severely injured ISS body regions.

There six ISS body regions.

Six ISS body regions

Head or Neck

Face

Thorax

Abdominal or Pelvic content

Extremities or Pelvic Girdle

External

Injury Severity Score (ISS)

Body region AIS MAIS Head 4 Neck 2 Thorax 5 5 Abdomen 1 Lower limb 3

ISS = (5x5)+(4x4)+(3x3) = 50

ISS range 0 – 75

Proviso : AIS 6 = ISS 75

Linear scale 0 - 75

Examples

Uses

of

Injury Severity Data

• Eppinger et al (1999) (NHTSA)

• Foret-bruno et al (1998) 42nd STAPP

• Mertz

(1971??)