›Shock index and transfusion triggers
›Shock index (HR/SBP)
›> 1.0 indicates significant hemorrhagic shock
›> 1.4 associated with massive transfusion requirement
›ABC score for massive transfusion
›Penetrating mechanism, SBP <= 90 mmHg, HR >= 120 bpm, positive FAST
›Score >= 2: activate massive transfusion protocol
›MRI role in pelvic fracture
›Limited acute utility for VS fractures
›Long acquisition time incompatible with unstable patients
›CT remains gold standard for acute trauma
›Problem-solving indications (subacute and elective)
›Posterior ligamentous complex assessment
›Sacral stress fracture vs acute fracture differentiation
›Nerve root injury characterization post-stabilization
›Sacral fracture nerve involvement
›MRI superior to CT for neural foraminal impingement
›Guides decompression decision-making
›Contraindications
›Hemodynamic instability (absolute contraindication acutely)
›Incompatible metallic implants or pelvic fixation hardware
›CT pelvis with IV contrast (CTA)
›Gold standard for definitive fracture characterization
›Posterior ring anatomy: sacral fractures, SI joint disruption
›Anterior ring: symphyseal and rami fractures
›Active arterial extravasation (contrast blush)
›Contrast blush on CTA
›Predicts need for angioembolization
›Sensitivity ~72%, specificity ~91% for arterial hemorrhage
›ACEP Level B recommendation for CTA as primary imaging in stable patients
›CT abdomen and pelvis combined
›Concurrent visceral injury assessment
›Retroperitoneal hematoma characterization
›Kidney, liver, spleen, bowel survey
›CT protocol specifics
›IV contrast required for vascular assessment
›Arterial phase: active bleeding detection
›Portal venous phase: visceral injury assessment
›Inlet and outlet reformats
›Inlet view: AP displacement of posterior ring
›Outlet view: vertical displacement quantification
›Renal function and contrast precautions
›GFR threshold per local protocol
›Benefit-risk favors CT in unstable pelvic trauma
›Plain radiography role
›AP pelvis X-ray (first-line, performed in trauma bay)
›Cephalad migration of hemipelvis pathognomonic for VS
›Symphyseal widening > 2.5 cm: significant anterior disruption
›Fracture lines through sacrum, rami, ilium
›Inlet and outlet views (supplemental)
›Quantify anterior-posterior and vertical displacement
›May be obtained in OR preoperatively
›FAST examination
›Focused assessment with sonography in trauma
›Morrison's pouch (hepatorenal)
›Splenorenal recess
›Pelvic free fluid (suprapubic)
›Pericardial window
›Positive FAST with hemodynamic instability
›Competing intraperitoneal hemorrhage source
›Emergent laparotomy decision
›Negative FAST with hemodynamic instability
›Pelvic source hemorrhage dominant
›Preperitoneal pelvic packing pathway
›FAST sensitivity 63-96% for intraperitoneal free fluid
›Retroperitoneal hemorrhage not detected by FAST
›ACEP Level A recommendation for FAST in trauma
›Extended FAST (eFAST)
›Thoracic assessment added
›Pneumothorax: absent lung sliding
›Hemothorax: pleural effusion pattern
›Pericardial tamponade screen
›Concurrent cardiac injury or penetrating mechanism