Trauma Scoring Systems

Reviewed and revised 24 May 2014

OVERVIEW

• 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

• AIS
• ISS
• modified ISS
• Anatomic profile
• ICISS

Combined scoring systems

• TRISS
• Polytrauma-Schussel
• Trauma Index
• ASCOT
• HARM

USES

• 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

GCS	Score
13-15	4
9-12	3
6-8	2
4-5	1
3	0

SBP	Score
>89	4
76-89	3
50-75	2
1-49	1
0	0

RR	Score
10-29	4
>29	3
6-9	2
1-5	1
0	0

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
• RTSc
  • 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

Limitations:

• 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.

Limitations:

• 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

• see Glasgow Coma Scale (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

AIS Code		Description
1		Minor
2		Moderate
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:
  • Thorax
  • Abdomen and visceral pelvis
  • Head and neck
  • Face
  • 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

Limitations:

• 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

ANATOMIC PROFILE

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:

1. Patient age
2. Anatomical injury – ISS
3. Physiological status – RTSc
4. Type of Injury – Penetrating vs blunt

• Standard methodology for outcome assessment
• Valid for both adult and pediatric patients
• Limitations:
  • 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

Journal articles

• 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.