How do you grade a liver injury in an adult patient with no pre-existing liver conditions?

Grading Liver Injury in Adults

Use the WSES (World Society of Emergency Surgery) classification system, which integrates both anatomic severity (AAST grade) and hemodynamic status to guide management decisions—this is superior to anatomic grading alone because hemodynamic status trumps anatomic injury grade in determining treatment. 1

Two-Step Grading Approach

Step 1: Determine Anatomic Grade (AAST Classification)

First, establish the anatomic severity using CT imaging with IV contrast in hemodynamically stable patients 1, 2:

• Grade I: Subcapsular hematoma <10% surface area OR capsular tear <1 cm parenchymal depth 2
• Grade II: Subcapsular hematoma 10-50% surface area OR intraparenchymal hematoma <10 cm diameter OR laceration 1-3 cm parenchymal depth 2
• Grade III: Subcapsular hematoma >50% surface area OR expanding/ruptured hematoma OR laceration >3 cm parenchymal depth 2
• Grade IV: Parenchymal disruption involving 25-75% of hepatic lobe OR juxtavenous hepatic injuries (retrohepatic vena cava/central major hepatic veins) 2
• Grade V: Parenchymal disruption >75% of hepatic lobe OR juxtavenous hepatic injuries 2
• Grade VI: Hepatic avulsion 2

Step 2: Assess Hemodynamic Status and Apply WSES Classification

Hemodynamic instability is defined as: systolic blood pressure <90 mmHg with clinical evidence of hemorrhagic shock (cool, clammy skin, decreased capillary refill), altered consciousness, shortness of breath, OR requiring bolus infusions/transfusions/vasopressors OR base excess >-5 mmol/L OR requiring ≥4 units packed red blood cells within first 8 hours 1.

Now integrate hemodynamics with anatomic grade 1:

• WSES Grade I (Minor): AAST Grade I-II + hemodynamically stable 1, 2
• WSES Grade II (Moderate): AAST Grade III + hemodynamically stable 1, 2
• WSES Grade III (Severe): AAST Grade IV-V + hemodynamically stable 1, 2
• WSES Grade IV (Severe/Critical): ANY AAST Grade (I-VI) + hemodynamically unstable 1, 2

Critical Management Implications Based on WSES Grade

The WSES grade directly determines treatment strategy 1:

• WSES I-III (stable patients): Attempt non-operative management with intensive monitoring, serial clinical/laboratory evaluation, and immediate access to interventional radiology, operating room, and blood products 1, 2

• WSES IV (unstable patients): Immediate operative management regardless of anatomic injury grade—do NOT delay for additional imaging 1, 2

Common Pitfalls to Avoid

Do not assume low anatomic grades are safe if the patient is hemodynamically unstable—even AAST Grade I-II injuries require immediate operative management when associated with instability, as they become WSES Grade IV 1, 3. Research demonstrates that 7 of 12 patients requiring emergency operation had minor hepatic injuries, but all were hemodynamically unstable 3.

Do not attempt non-operative management without proper resources—facilities lacking immediate surgical/interventional capabilities, intensive monitoring, and blood products should transfer patients rather than attempt NOM 1, 2.

Recognize that physiologic behavior dictates management more than anatomic grade—hemodynamic status is the primary determinant of operative versus non-operative management, not the CT appearance of the injury 3, 4.