Multi-Trauma

Injury Severity Score, (ISS)

• an anatomical scoring system that provides an overall score for patients with multiple injuries.
• Each injury is assigned an Abbreviated Injury Scale (AIS) score from 1-5 and is allocated to one of six body regions (Head, Face, Chest, Abdomen, Extremities (including Pelvis), External). Only the highest AIS score in each body region is used.
• 3 most severely injured body regions have their score squared and added together to produce the ISS score
• ISS scores = 0 to 75.
• If an injury is assigned an AIS of 6 (unsurvivable injury), the ISS score is automatically assigned to 75.
• ISS >16 =10% mortality
• ISS <30 –good prognosis unless associated with severe head injury
• ISS >60 usually fatal
• ISS  virtually the only anatomical scoring system in use and correlates linearly with mortality, morbidity, hospital stay and other measures of severity.
• It's weaknesses are that any error in AIS scoring increases the ISS error, many different injury patterns can yield the same ISS score and injuries to different body regions are not weighted. Also, as a full description of patient injuries is not known prior to full investigation & operation, the ISS (along with other anatomical scoring systems) is not useful as a triage tool.
• Baker SP et al, "The Injury Severity Score: a method for describing patients with multiple injuries and evaluating emergency care", J Trauma 14:187-196;1974
• Copeland, CE AR:Mortality in patients with bilateral femoral fractures. J Orthop Trauma  1998:12 :315-319.