CAISS Injury Severity Scoring 3 — Questions and Answers
Question 1: How many body regions does the AIS/ISS system recognize for ISS calculation?
- 4
- 6 (Correct answer)
- 8
- 9
Correct answer: 6
ISS uses six body regions: head/neck, face, chest, abdomen, extremities/pelvis, and external.
Question 2: A patient with an isolated splenic laceration coded AIS 4 and no other injuries would have an ISS of:
- 4
- 8
- 16 (Correct answer)
- 64
Correct answer: 16
With only one injury, ISS = 4² = 16; the other two terms are zero.
Question 3: Which body region in the ISS framework includes pelvic ring fractures?
- Abdomen
- External
- Extremities/Pelvis bony (Correct answer)
- Face
Correct answer: Extremities/Pelvis bony
Pelvic ring fractures are classified under the Extremities/Pelvis bony region in ISS coding.
Question 4: Probability of survival (Ps) in trauma scoring is most directly calculated using:
- ISS alone
- AIS alone
- Revised Trauma Score and ISS combined (TRISS) (Correct answer)
- GCS alone
Correct answer: Revised Trauma Score and ISS combined (TRISS)
TRISS combines the Revised Trauma Score (physiologic) and ISS (anatomic) to estimate survival probability.
Question 5: In AIS coding, which descriptor best defines an AIS 3 injury?
- Minor
- Moderate
- Serious (Correct answer)
- Severe
Correct answer: Serious
AIS 3 is defined as 'serious' on the severity scale from 1 (minor) to 6 (unsurvivable).
Question 6: A trauma patient has two chest injuries coded AIS 3 and AIS 4. For ISS calculation, which chest value is used?
- AIS 3 (lower)
- AIS 4 (higher) (Correct answer)
- Average of both (3.5)
- Both are added (7)
Correct answer: AIS 4 (higher)
Only the highest AIS score from each body region is used; the AIS 4 chest injury is selected.
Question 7: The ISS was originally validated primarily using data from which type of trauma registry?
- Military combat trauma
- Major Trauma Outcome Study (MTOS) (Correct answer)
- National Trauma Data Bank
- NTDB Pediatric Registry
Correct answer: Major Trauma Outcome Study (MTOS)
The ISS and TRISS methodologies were validated using the Major Trauma Outcome Study database in the 1980s.
CAISS Injury Severity Scoring 3
How many body regions does the AIS/ISS system recognize for ISS calculation?