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ISS: anatomical score using AIS; 1–75; >15 = major trauma. RTS: physiological score (GCS, SBP, RR); <4 = poor survival. ISS for research/benchmarking, RTS for triage. Both complementary: anatomy + physiology.
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Polytrauma refers to the presence of multiple traumatic injuries involving different body regions, often associated with significant physiological derangement. Accurate assessment of injury severity is essential in trauma care for predicting mortality, guiding treatment priorities, and enabling comparison of outcomes across trauma centers.
Several trauma scoring systems have been developed to quantify injury severity. Among the most widely used systems are the Injury Severity Score (ISS) and the Revised Trauma Score (RTS). These scoring systems assist clinicians in triage decisions, evaluation of trauma care systems, and research studies involving trauma patients.
ISS is primarily an anatomical scoring system based on the Abbreviated Injury Scale, while RTS is a physiological scoring system based on vital parameters such as Glasgow Coma Scale, blood pressure, and respiratory rate.
The Abbreviated Injury Scale (AIS) is an anatomical scoring system used to classify individual injuries according to severity. Each injury is assigned a score from 1 to 6 based on its threat to life.
| AIS Score | Severity | Description |
|---|---|---|
| 1 | Minor | Superficial injury or minor fracture |
| 2 | Moderate | Injury requiring medical treatment |
| 3 | Serious | Significant injury but not life threatening |
| 4 | Severe | Life threatening injury |
| 5 | Critical | Critical survival uncertain |
| 6 | Maximum | Currently untreatable injury |
The Injury Severity Score (ISS) is one of the most widely used trauma scoring systems. It is derived from the Abbreviated Injury Scale and provides an overall score for patients with multiple injuries.
The body is divided into six anatomical regions:
The highest AIS score in each region is identified. The three most severely injured regions are selected, and their AIS scores are squared and added together.
ISS = (AIS1² + AIS2² + AIS3²)
The maximum ISS value is 75. If any injury has AIS score 6, the ISS is automatically assigned as 75.
| ISS Range | Interpretation |
|---|---|
| 1 to 8 | Minor trauma |
| 9 to 15 | Moderate trauma |
| 16 to 24 | Severe trauma |
| Greater than 25 | Critical trauma |
The Revised Trauma Score (RTS) is a physiological scoring system used during the initial assessment of trauma patients. It incorporates three clinical parameters which reflect the physiological status of the patient.
| Parameter | Measurement |
|---|---|
| Glasgow Coma Scale | Neurological status |
| Systolic blood pressure | Circulatory status |
| Respiratory rate | Ventilatory status |
Each parameter is assigned a coded value between 0 and 4 depending on severity. The weighted RTS is calculated using the following formula:
RTS = (0.9368 × GCS) + (0.7326 × SBP) + (0.2908 × RR)
| Feature | ISS | RTS |
|---|---|---|
| Type | Anatomical score | Physiological score |
| Based on | AIS injury severity | Vital parameters |
| Use | Outcome prediction | Initial triage |
| Maximum score | 75 | 7.84 |
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