CAISS Injury Classification & Scoring 5 — Questions and Answers
Question 1: The TRISS methodology combines ISS with which additional variable to estimate probability of survival?
- GCS score alone
- Revised Trauma Score (RTS) and patient age (Correct answer)
- NISS and mechanism of injury only
- Shock index and respiratory rate
Correct answer: Revised Trauma Score (RTS) and patient age
TRISS uses the ISS, Revised Trauma Score (RTS, derived from GCS, systolic BP, and RR), and patient age to calculate probability of survival.
Question 2: When the mechanism of injury is blunt versus penetrating in TRISS, this distinction affects:
- The AIS body region assignments
- The regression coefficients used in the survival probability equation (Correct answer)
- Whether ISS or NISS is applied
- The definition of the AIS severity scale
Correct answer: The regression coefficients used in the survival probability equation
TRISS uses separate sets of regression coefficients (b0, b1, b2, b3) for blunt and penetrating mechanisms to reflect their different survival patterns.
Question 3: A patient presents with an open femur fracture (AIS 3), liver laceration grade III (AIS 3), and bilateral pulmonary contusions (AIS 3). What is the NISS?
- 27 (Correct answer)
- 18
- 9
- 36
Correct answer: 27
NISS = 3² + 3² + 3² = 9 + 9 + 9 = 27, using the three highest AIS scores regardless of body region.
Question 4: Which AIS edition introduced the current six AIS body regions as the standard framework?
- AIS 1971
- AIS 1985
- AIS 1990
- AIS 2005 (Correct answer)
Correct answer: AIS 2005
The AIS 2005 edition, with its 2008 update, established the contemporary standardized body region and coding structure widely used today.
Question 5: A spinal cord injury resulting in complete paraplegia below T6 would most appropriately receive which AIS severity code in the Spine region?
- AIS 3
- AIS 4
- AIS 5 (Correct answer)
- AIS 6
Correct answer: AIS 5
Complete paraplegia is a critical, life-altering injury and is coded AIS 5 (Critical) in the Spine region per AIS guidelines.
Question 6: Which of the following scenarios would make a patient INELIGIBLE for a standard ISS calculation?
- Injuries limited to a single body region
- Presence of an AIS 6 injury in any region (Correct answer)
- All injuries coded as AIS 1 or AIS 2
- More than three body regions involved
Correct answer: Presence of an AIS 6 injury in any region
An AIS 6 injury automatically assigns ISS = 75 by convention, bypassing the standard three-region square-and-sum calculation.
Question 7: In AIS coding, the Face body region specifically includes injuries to:
- Brain and cranial vault only
- Orbit, nose, zygoma, mandible, and facial soft tissue (Correct answer)
- Cervical spine and larynx
- Ear canal and temporal bone only
Correct answer: Orbit, nose, zygoma, mandible, and facial soft tissue
The AIS Face region covers facial bones (orbit, nasal, zygoma, mandible), facial soft tissue, and associated structures like the eye and parotid gland.
CAISS Injury Classification & Scoring 5
The TRISS methodology combines ISS with which additional variable to estimate probability of survival?