Trauma and Injury Severity Score - (TRISS)

Combines both anatomical and physiological measures of injury severity:

• ISS

• RTS

• Patient age

TRISS  predicts probability of survival (Ps) using this formula:
 

Ps=1/(1+e^-b)
 

`b' is calculated from: b=b0+b1(RTS)+b2(ISS)+b3 (Age Index).
The coefficients b0–b3 (table below) are derived from multiple-regression analysis of the Major Trauma Outcome Study database.

The Age Index is 0 if the patient is below 54 years of age or 1 if 55 years and over.

The coefficients (b0–b3) are different for blunt and penetrating trauma.

If the patient is less than 15 years old, the blunt coefficients are used regardless of the actual mechanism of injury.
 

TRISS appears to be valid for both adult and paediatric trauma.

Limitations:

• Limitations of ISS apply to TRISS inability to account for multiple injuries to the same body region.

• Limitations of RTS , intubated patients are excluded from TRISS because respiratory rates and verbal responses are not obtainable.

• Physiological data, may be unreliable or unavailable, affected by degree of resuscitation.

• TRISS takes no account of pre-existing medical conditions
  
   

Boyd CR, Tolson MA, Copes WS: "Evaluating Trauma Care: The TRISS Method", J Trauma 27:370-378;1987

Predicting outcome after multiple trauma: which scoring system?; Injury, Volume 35, Issue 4, April 2004, Pages 347-358; M. N. Chawda , F. Hildebrand , H. C. Pape and P. V. Giannoudis

http://www.trauma.org/scores/triss.html

Last updated 11/09/2015