Injury Severity Score (ISS) | Medical Algorithm

Description

The Injury Severity Score can be used to assess patients involved in traffic accidents. It makes use of the Abbreviated Injury Scale (AIS) and its value correlates with the risk of mortality.

Patient selection:

(1) Patients are those involved in a motor vehicle accident.

(2) Patients with immediately or rapidly fatal injuries are excluded.

Patient examination:

(1) Injuries are assigned to 5 body regions (general, head & neck, chest, abdominal, extremities & pelvis)

(2) Each type of injury encountered is assigned a value from 1 to 6, with:

Injury Severity	Abbreviated Injury Score
minor injury	1
moderate injury	2
severe but not life-threatening	3
potentially life-threatening but survival likely	4
critical with uncertain survival	5
unsurvivable injury (maximal possible)	6
severity unknown	9

General

aches all over	general	1
minor laceration, contusion and abrasions (simple closure)	general	1
1st degree burns	general	1
small 2nd or 3rd degree burns	general	1
extensive contusion or abrasion	general	2
large laceration	general	2
avulsion less than 3 inches wide	general	2
2nd or 3rd degree burn involving 10-20% BSA	general	2
large lacerations involving more than 2 extremities	general	3
large avulsions, >= 3 inches wide	general	3
2nd or 3rd degree burn involving 20-30% of BSA	general	3
severe lacerations and/or avulsion with dangerous hemorrhage	general	4
2nd or 3rd degree burns involving 30-50% of BSA	general	4
2nd or 3rd degree burns involving > 50% of BSA	general	5

Head and Neck

cerebral injury with headache or dizziness but no loss of consciousness	head and neck	1
whiplash complaint with no anatomical or radiological evidence	head and neck	1
abrasions and contusions of ocular apparatus (lids, conjunctivae, cornea, uveal injuries)	head and neck	1
vitreous or retinal hemorrhages	head and neck	1
fractures and/or dislocation of teeth	head and neck	1
cerebral injury with/without skull fracture, less than 15 minutes unconsciousness, no post-traumatic amnesia	head and neck	2
undisplaced skull or facial bone fractures or compound fracture of nose	head and neck	2
laceration of the eye and appendages	head and neck	2
retinal detachment	head and neck	2
disfiguring lacerations	head and neck	2
whiplash severe complaints with anatomical and radiologic evidence	head and neck	2
cerebral injury with or without skull fracture, with unconsciousness more than 15 minutes, without severe neurological signs, brief post-traumatic amnesia (less than 3 hours)	head and neck	3
displaced closed skull fracture without unconsciousness or other signs of intracranial injury	head and neck	3
loss of eye	head and neck	3
avulsion of optic nerve	head and neck	3
displaced facial bone fractures or those with antral or orbital involvement	head and neck	3
cervical spine fractures without cord damage	head and neck	3
cerebral injury with or without skull fracture with unconsciousness of more than 15 minutes, with definite abnormal neurological signs; post-traumatic amnesia 3-12 hours	head and neck	4
compound skull fracture	head and neck	4
cerebral injury with or without skull fracture with unconsciousness of more than 24 hours; post-traumatic amnesia more than 12 hours	head and neck	5
intracranial hemorrhage	head and neck	5
signs of increased intra-cranial pressure (decreasing state of consciousness, bradycardia under 60, progressive rise in blood pressure, or progressive pupil inequality)	head and neck	5
cervical spine injury with quadraplegia	head and neck	5
major airway obstruction	head and neck	5

Chest

muscle ache or chest wall stiffness	chest	1
simple rib or sternal fracture	chest	2
major contusion of chest wall without hemothorax or pneumothorax or respiratory embarrassment	chest	2
multiple rib fractures without respiratory embarrassment	chest	3
hemothorax	chest	3
pneumothorax	chest	3
rupture of diaphragm	chest	3
lung contusion	chest	3
open chest wounds	chest	4
flail chest	chest	4
pneumomediastinum	chest	4
myocardial contusion without circulatory embarrassment	chest	4
pericardial injuries	chest	4
chest injuries with major respiratory embarrassment (laceration of trachea, hemomediastinum, etc.)	chest	5
aortic laceration	chest	5
myocardial rupture or contusion, with circulatory embarrassment	chest	5

Abdomen

muscle ache	abdominal	1
seat belt abrasion	abdominal	1
major contusion of abdominal wall	abdominal	2
contusion of abdominal organs	abdominal	3
extraperitoneal bladder rupture	abdominal	3
retroperitoneal hemorrhage	abdominal	3
avulsion of ureter	abdominal	3
laceration of urethra	abdominal	3
thoracic or lumbar spine fracture without neurological involvement	abdominal	3
minor laceration of intra-abdominal contents (to include ruptured spleen, kidney and injuries to tail of pancreas)	abdominal	4
intraperitoneal bladder rupture	abdominal	4
avulsion of genitals	abdominal	4
thoracic and/or lumbar spine fracture with paraplegia	abdominal	4
rupture, avulsion or severe laceration of intra-abdominal vessels or organs, except kidney, spleen or ureter	abdominal	5

Extremities and Pelvis

minor sprains and fractures	extremities or pelvic girdle	1
dislocation of digits	extremities or pelvic girdle	1
compound fracture of digits	extremities or pelvic girdle	2
undisplaced long bone or pelvic fractures	extremities or pelvic girdle	2
major sprains of major joints	extremities or pelvic girdle	2
displaced simple long bone fractures	extremities or pelvic girdle	3
multiple hand and foot fractures	extremities or pelvic girdle	3
pelvic fracture with displacement	extremities or pelvic girdle	3
dislocation of major joints	extremities or pelvic girdle	3
multiple amputations of digits	extremities or pelvic girdle	3
laceration of the major nerves or vessels of extremities	extremities or pelvic girdle	3
multiple closed long-bone fractures	extremities or pelvic girdle	4
amputation of limbs	extremities or pelvic girdle	4
multiple open limb fractures	extremities or pelvic girdle	5

The highest score, indicating the most severe injury, for each region is selected. These are then ranked from the highest to lowest value. The 3 highest values are then used to calculate the injury severity score.

injury severity score =

= ((highest region score) ^2) + ((second highest region score) ^2) + ((third highest region score) ^2)

Interpretation:

• minimum score: 0

• maximum score: 75

The mortality rate increases:

(1) with score

(2) with age

Score	Mortality Rate If Age <=49	Mortality Rate If Age 50-69	Mortality Rate If Age >=70
5	0	3	13
10	2	4	15
15	3	5	16
20	6	16	31
25	9	26	44
30	21	42	65
35	31	56	82
40	47	62	92
45	61	67	100
50	75	83	100
55	89	100	100

data extrapolated from Figure 4, Baker et al (1974)

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Description

Specialty

Objective

ICD-10

Score	Mortality Rate If Age <=49	Mortality Rate If Age 50-69	Mortality Rate If Age >=70
5	0	3	13
10	2	4	15
15	3	5	16
20	6	16	31
25	9	26	44
30	21	42	65
35	31	56	82
40	47	62	92
45	61	67	100
50	75	83	100
55	89	100	100

Score	Mortality Rate If Age <=49	Mortality Rate If Age 50-69	Mortality Rate If Age >=70
5	0	3	13
10	2	4	15
15	3	5	16
20	6	16	31
25	9	26	44
30	21	42	65
35	31	56	82
40	47	62	92
45	61	67	100
50	75	83	100
55	89	100	100

Abbreviated Injury Scale (AIS) & Injury Severity Score (ISS)

Purpose: To assess a patient following a traffic accident using the Injury Severity Score.

Description

Specialty

Objective

ICD-10

Score	Mortality Rate If Age <=49	Mortality Rate If Age 50-69	Mortality Rate If Age >=70
5	0	3	13
10	2	4	15
15	3	5	16
20	6	16	31
25	9	26	44
30	21	42	65
35	31	56	82
40	47	62	92
45	61	67	100
50	75	83	100
55	89	100	100