Abbreviated Injury Scale (AIS)
- Introduced in 1969
- Injuries ranked 1-6 (1 minor and 7 unsurvivable)
AIS Score | Injury
1: Minor
2: Moderate
3: Serious
4: Severe
5: Critical
6: Unsurvivable
AIS ranking system is used to create an ISS score
Injury Severity Score (ISS)
- An anatomic scoring system that grades the severity of an injury as a whole
- 6 body regions each given its own AIS score
- Top 3 AIS scores squared and added together to give final ISS score
- ISS is automatically 75 if any AIS is 6 (unsurvivable)
- Rising ISS score does correlate with mortality
- ISS >25 indicates a severe injury
- Should be considered for transfer to a trauma centre
- ISS >40 indicates a life-threatening injury
Disadvantages of ISS
- Any error in AIS increases the ISS
- Does not weight body areas independently
- Many different injury patterns give the same ISS score
- Only one score per body area is allowed – excludes multiple injuries within one area
Body Region | Injury Description | AIS | Square of Top 3
- Head & Neck: Cerebral contusion | 3 | 9
- Face: No injury | |
- Chest: Flail chest | 4 | 16
- Abdomen: Liver laceration | 4 | 16
- Extremity: Femur fracture | 3 |
- External: No injury | 0 |
- Total ISS score | | | 41
NISS
- Modification to the ISS
- Allows top AIS scores to come from the same body segment
- E.g., Splenic, pancreatic, and liver injuries are scored separately and can be used individually to generate the NISS score disregarding lesser injuries elsewhere
- This is more realistic in determining the patient's survival