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.
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.