| Glasgow Coma Scale | 13-15 9-12 6-8 4-5 3 |
| Systolic BP | > 89 mm Hg 76-89 mm Hg 50-75 mm Hg 1-49 mm Hg 0 mmHg |
| Resp. rate | >29/min 10-29/min 6-9/min 1-5/min 0/min |
The TRISS score utilizes the Injury Severity Score (Baker, et al) and the Revised Trauma Score (Champion, et al) along with patient age to calculate a predicted death rate for blunt or penetrating trauma.
Injury Severity Score (ISS)
The injury severity score (ISS) relates to injuries to 6 body areas:
These 6 body areas have injury severities of 0-6 with:
Specific coding of injury severity is via the abbreviated injury scale (AIS 90 or AIS 98) via a manual that gives specific guidelines for scoring of injuries by body region into category 1-6.
The total ISS ranges from 0-75 points.
Only the most severe injury from each body area is used in the total score, with each body area score being squared (e.g. a score in one body area of 4 = 16 points as 4 is squared). Any score of 6 in any body area gives a maximum score of 75 points, regardless of other injuries.
The total ISS score comes from the 3 most injured areas ONLY and is the square of each of these scores summed.
The ISS has a limitation in that severity 4 head injury with no other injuries would only score 16 points, but having a severity 3 injury to the extremities and a severity 2 injury each to the abdomen and chest would score 17 points; however, mortality would likely be higher in the head trauma case.
In one survey, ISS corresponded to following rates of mortality:
| Score: | %Mortality |
|---|---|
| 0-8 | 5% |
| 9-15 | 8% |
| 16-24 | 17% |
| 25-40 | 64% |
| 41-66 | 88% |
| 75 | 100% |
Revised Trauma Score (RTS)
The RTS considers 3 items:
An RTS (the sum of the points) of less than 11 indicates need for transport to a designated trauma center.
The RTSc is the RTS coded which weights the individual components.
RTSc = Resp Rate pts × 0.2908 + SBP pts × 0.7326 + GCS points × 0.9368
In one survey, RTS corresponded to following rates of mortality:
| Score: | %Mortality |
|---|---|
| 0 | 94% |
| 1-3 | 67% |
| 4-6 | 59% |
| 7-9 | 39% |
| 10-11 | 27% |
| 12 | 9% |
Trauma Injury Severity Score (TRISS)
This score gives a predicted death rate for blunt or penetrating trauma and takes into account the ISS, RTS and patient age.
Blunt injury is defined as trauma that is not penetrating, but can include crush injuries, simple lacerations, amputation or asphyxia.
Penetrating injury includes injury by bullets, knives or other penetrating trauma (pick, spikes, etc).
Points are assigned based upon patient age:
The predicted death rate = 1/(1+e X )
X (penetrating) = -2.5355 + RTS × 0.9934 + ISS × -0.0651 + age pts × -1.1360
X (blunt) = -0.4499 + RTS × 0.8085 + ISS × -0.0835 + age pts × -1.7430
** Note that for age <15 years, the X (blunt) is used for both penetrating and blunt trauma.
References:
The injury severity score (ISS) relates to injuries to 6 body areas:
These 6 body areas have injury severities of 0-6 with:
Specific coding of injury severity is via the abbreviated injury scale (AIS 90 or AIS 98) via a manual that gives specific guidelines for scoring of injuries by body region into category 1-6.
The total ISS ranges from 0-75 points.
Only the most severe injury from each body area is used in the total score, with each body area score being squared (e.g. a score in one body area of 4 = 16 points as 4 is squared). Any score of 6 in any body area gives a maximum score of 75 points, regardless of other injuries.
The total ISS score comes from the 3 most injured areas ONLY and is the square of each of these scores summed.
The ISS has a limitation in that severity 4 head injury with no other injuries would only score 16 points, but having a severity 3 injury to the extremities and a severity 2 injury each to the abdomen and chest would score 17 points; however, mortality would likely be higher in the head trauma case.
In one survey, ISS corresponded to following rates of mortality:
| Score: | %Mortality |
|---|---|
| 0-8 | 5% |
| 9-15 | 8% |
| 16-24 | 17% |
| 25-40 | 64% |
| 41-66 | 88% |
| 75 | 100% |
References:
The Revised Trauma Score (RTS) considers 3 items:
An RTS (the sum of the points) of less than 11 indicates need for transport to a designated trauma center.
The RTSc is the RTS coded which weights the individual components.
RTSc = Resp Rate pts × 0.2908 + SBP pts × 0.7326 + GCS points × 0.9368
In one survey, RTS corresponded to following rates of mortality:
| Score: | %Mortality |
|---|---|
| 0 | 94% |
| 1-3 | 67% |
| 4-6 | 59% |
| 7-9 | 39% |
| 10-11 | 27% |
| 12 | 9% |
References: