Review Question - QID 1061

Injury Severity Score (ISS) scores are used to define injury severity for research purposes. The score is based on anatomic and severity indicies. Injury severity is based upon the AIS (abbreviated injury scale). AIS scores range from 1-6 where 1 is a minor laceration or contusion and 6 is a unsurvivable severe injury. An example of a 6 is a crushed head or brain whereas a 5 is a crushed larynx. Open pelvic fracture and femoral shaft fracture come in at 3 and large joint dislocations are a level 2 injury. ISS is the sum of the squares for the highest AIS grades in the three most severely injured ISS body regions. An ISS greater than 18 reflects multiply injured patients and that a transfer to a trauma center is indicated. So in this case, it would be (4x4)+(4x4)+(3x3)= 16+16+9=41. The AIS table can be found in Miller Review on page 699.

Recently, the New Injury Severity Score (NISS) has been developed and found by some authors (Lavoie et al & Balogh et al) to be more reliable indicator of length of stay and ICU stay. The NISS differs from the ISS in that the NISS sums the squares of the 3 most significant injuries (even if they occur in the same anatomic area). The ISS sums the 3 most significant injuries in 3 separate anatomic areas.