Which grading system is used to classify the severity of hepatic injuries in blunt abdominal trauma according to the American Association for the Surgery of Trauma (AAST)?

Explanation

## AAST Organ Injury Scaling for Hepatic Trauma **Key Point:** The American Association for the Surgery of Trauma (AAST) uses the Organ Injury Scale (OIS) with 5 grades (I–V) to classify the severity of liver injuries in blunt abdominal trauma. This is the standard classification used worldwide and in NEET PG / ATLS curricula. ### AAST Liver Injury Grading (OIS) | Grade | Injury Type | Description | Prognosis | |-------|-------------|-------------|----------| | I | Hematoma | Subcapsular, <10% surface area | Excellent; conservative management | | II | Hematoma | Subcapsular, 10–50% surface area; intraparenchymal <10 cm | Excellent; conservative management | | III | Hematoma | Subcapsular, >50% surface area; intraparenchymal >10 cm; expanding hematoma | Good; monitor closely; may require intervention | | IV | Laceration | Parenchymal disruption involving 25–75% of hepatic lobe or 1–3 Couinaud segments | Fair; high risk of bleeding; consider angioembolization | | V | Laceration | Parenchymal disruption >75% of lobe or >3 Couinaud segments; juxtahepatic venous injuries | Poor; often requires operative intervention | **High-Yield:** Grade I–III injuries are managed **non-operatively** in hemodynamically stable patients with serial clinical examination, bed rest, and ICU monitoring. Grade IV–V injuries often require **angiographic embolization** or **operative intervention** (hepatic resection, packing, or damage control). **Clinical Pearl:** The OIS is used not only for the liver but also for other solid organs (spleen, kidney, pancreas, duodenum), with slight modifications in the number of grades depending on organ anatomy. ### Why Other Scales Are Not Used for Organ-Specific Injury - **AIS (Abbreviated Injury Scale):** A general injury severity scale (0–6) used for overall trauma assessment, not organ-specific grading - **TRISS (Trauma and Injury Severity Score):** A predictive model combining ISS, RTS, and age; used for outcome prediction, not organ classification - **ISS (Injury Severity Score):** A composite score derived from AIS; used for overall trauma severity, not specific organ grading