Reviewed and revised 24 May 2014
- There are various systems available for scoring trauma severity
- Some are based on anatomical descriptions of injuries, some on physiological parameters and others use combined data
- No ideal trauma scoring system is currently available
- The ideal trauma scoring system would provide an accurate, reliable and reproducible description of injuries and prediction of morbidity and mortality outcomes in any setting
- scores that combine anatomical and physiological data are likely to be most useful, but age and premorbid state are also important factors
- outcome = anatomical injury + physiological injury + patient’s reserve
EXAMPLES OF TRAUMA SCORING SYSTEMS
Physiological scoring systems
- Revised Trauma Score
- APACHE I, II, and III
- Glasgow Coma Scale and Paediatric Glasgow Coma Scale
- Prognostic Index
- Trauma Score
- Acute Trauma Index
- Triage Index
Anatomical scoring systems
- modified ISS
- Anatomic profile
Combined scoring systems
- Trauma Index
- Injury description
- Predict outcome/ mortality – resource allocation, end of life decisions
- Triage – transfer to trauma centers, use of helicopter transport
- Quality assurance – evaluation of trauma care within and between trauma centers
- Trauma care research
REVISED TRAUMA SCORE (T-RTS AND RTSc)
3 specific physiologic parameters
Code parameters from 0-4 based on magnitude of the physiologic derangement
Used in 2 forms:
- Triage revised trauma score: T-RTS
- When used for field triage
- Rapid identification of severely injured patients on arrival to hospital
- RTS is determined by adding each of the coded values together
- RTS ranges from 0-12 and is calculated very easily
- RTS < 11 = need for transport to a designated trauma center
- Coded form of the RTS
- Quality assurance and outcome prediction
- Emphasizes the significant impact of traumatic brain injury on outcome
- RTS = 0.7326 SBP + 0.2908 RR + 0.9368 GCS
- GCS estimation – especially in ventilated, intoxicated patients and children (GCS is no more predictive than motor score alone)
- may underscore rapidly resuscitated patients
- does not account for duration of physiological derangement
ACUTE PHYSIOLOGY AND CHRONIC HEALTH EVALUATION (APACHE I, II AND III)
Widely for the assessment of illness severity in ICUs
- introduced in 1981, has had 2 revisions since
- 2 components:
- Chronic health evaluation – presence of comorbid conditions (eg, DM, cirrhosis)
- Acute Physiology Score – neurologic, cardiovascular, respiratory, renal, gastrointestinal, metabolic, and hematologic variables.
- data used is that which are the most abnormal during the first 24 hours.
- Used mainly in ICU
- Trauma tends to affect a younger population with minimal co-morbidities
- Only ICU data used/ does not account for prior treatment – underestimates mortality
- GCS was not intended to reflect extracranial injuries
- Inferior to TRISS in predicting mortality in injured patients
- APACHE III not widely used as proprietary and expensive
GCS AND PAEDIATRIC GCS
ABBREVIATED INJURY SCALE (AIS)
- Developed and published in 1971, undergoes regular revision
- Every injury is assigned a code based on anatomical site, nature, and severity
- Injuries are grouped by body region
|3||Serious (non life-threatening)|
|4||Severe (life-threatening, survival probable)|
|5||Critical (survival uncertain)|
|6||Unsurvivable (with current treatment)|
Enables ranking of injury severity and correlates with patient outcome
INJURY SEVERITY SCORE (ISS)
- Derived from the AIS
- Defined as the sum of squares of the highest AIS grade in the 3 most severely injured body regions
- Six body regions are defined:
- Abdomen and visceral pelvis
- Head and neck
- Bony pelvis and extremities
- External structures (skin, burns)
- Only one injury per body region is allowed.
- The ISS ranges from 1-75, and an ISS of 75 is assigned to anyone with an AIS of 6.
- Correlates with mortality, morbidity and length of hospital stay
- Validated for the use of blunt and penetrating injuries in adults and children > 12
- Consistent risk factor predictor for post injury multiple-organ failure
- Inability to account for multiple injuries to the same body region
- Limits the total number of contributing injuries to only 3
- Impairs usefulness of ISS in penetrating injuries – multiple injuries common
- Weights injuries to each body region equally
- Ignores importance of head injuries in mortality from trauma
- Mortality is not strictly an increasing function of the ISS
- Mortality rate from ISS of 16 > mortality rate from ISS of 17, due to the different combinations of AIS scores that comprise each
- Many ISS values cannot occur
- Other ISS values can result from multiple different combinations of AIS scores
- Makes the ISS a heterogeneous score and reduces its predictive ability
MODIFIED ISS (NEW ISS OR NISS)
Based on the 3 most severe injuries regardless of body region
- Avoids many of its previous limitations
- Preserving AIS framework – NISS remains familiar and user-friendly.
- Preliminary studies suggest NISS more accurate predictor of trauma mortality than the ISS, particularly in penetrating trauma.
- Other researchers demonstrated NISS superior to the ISS as a measure of tissue injury in predictive models of postinjury multi-organ failure
Includes all serious injuries in a body region
- Weights head and torso injuries more heavily than other body regions
- Summarizes all serious injuries (AIS greater >3) into 3 categories
|Category A||head and spinal cord|
|Category B||thorax and anterior neck|
|Category C||all remaining serious injuries|
|Category D||all non-serious injuries|
- Practitioners calculate each component as the square root of the sum of squares of the AIS scores of all serious injuries within each region.
- A region with no injury receives a score of zero.
- Using logistic regression, the values are used to calculate a probability of survival.
- Performs better than the ISS in discriminating survivors from nonsurvivors
- Provides a more rational basis for comparing injury severity between patients
- Failed to garner interest due to its mathematical complexity and only modest improvement in predictive performance
INTERNATIONAL CLASSIFICATION OF DISEASES (ICISS)
- Based on the International Classification of Disease, Ninth Edition (ICD-9) codes
- Uses survival risk ratios (SRRs) calculated for each ICD-9 discharge diagnosis.
- SRRs are derived by dividing the number of survivors in each ICD-9 code by the total number of patients with the same ICD-9 code.
- ICISS is calculated as the simple product of the SRRs for each of the patient’s injuries.
- Advantages over ISS:
- Represents a true continuous variable that takes on values between 0 and 1
- Includes all injuries
- ICD-9 codes are readily available; do not require special training/ expertise to determine
- Better predictive power when compared to the ISS
- It accounts better for the effects of comorbidity on outcome
- ICISS outperforms the ISS in predicting other outcomes of interest (eg, hospital length of stay, hospital charges).
- However, it has not yet replaced other methods of outcome analysis.
- Further validation is needed before it can be used widely.
TRAUMA AND INJURY SEVERITY SCORE (TRISS)
- Estimates the probability of patient survival based on regression equation and takes into account:
- Patient age
- Anatomical injury – ISS
- Physiological status – RTSc
- Type of Injury – Penetrating vs blunt
- Standard methodology for outcome assessment
- Valid for both adult and pediatric patients
- It is only moderately accurate for predicting survival
- Problems already are noted with the ISS
- Does not take account of pre-existing conditions (eg, cardiac disease, etc)
- Similar to the RTS – intubated patients – RR and verbal responses not obtainable
References and Links
FOAM and web resources
- Trauma.org — Trauma Scoring
- Chawda MN, Hildebrand F, Pape HC, Giannoudis PV. Predicting outcome after multiple trauma: which scoring system? Injury. 2004 Apr;35(4):347-58. Review. PubMed PMID: 15037369.
- Yates DW. ABC of major trauma. Scoring systems for trauma. BMJ. 1990 Nov 10;301(6760):1090-4. PMC1664231.