What is the most appropriate next step in management for a hemodynamically stable patient with severe lower abdominal pain and free intraperitoneal fluid after a motor vehicle accident?

Management of Hemodynamically Stable Trauma Patient with Positive FAST

Neither pelvic X-ray nor CT without contrast is appropriate—this hemodynamically stable patient with free intraperitoneal fluid after blunt trauma requires CT of the abdomen and pelvis WITH intravenous contrast to guide definitive management.

Rationale for CT With IV Contrast

In hemodynamically stable trauma patients with positive FAST, CT abdomen and pelvis with IV contrast is the definitive next step to characterize injuries, identify the source of bleeding, and determine whether operative or non-operative management is appropriate 1.

Why IV Contrast is Essential

• Active hemorrhage detection: IV contrast allows identification of active arterial extravasation, which appears with CT attenuation of 85-370 HU (mean 132 HU), significantly higher than clotted blood at 40-70 HU (mean 51 HU) 2
• Solid organ injury grading: Contrast enhancement is critical for accurately characterizing liver, spleen, and kidney injuries, which directly impacts management decisions 1
• Vascular injury identification: Contrast-enhanced CT can detect pseudoaneurysms, vascular occlusions, and intimal tears that may require angioembolization rather than surgery 1
• Selective non-operative management: Modern trauma care increasingly relies on CT findings combined with clinical examination to safely manage many injuries non-operatively, but this requires contrast-enhanced imaging 1

Why CT Without Contrast is Inadequate

CT without IV contrast is explicitly not recommended for trauma evaluation 1. The evidence is clear:

• Noncontrast CT may show trajectory but fails to demonstrate internal organ injuries adequately 1
• Solid organ injuries are "much more apparent with IV contrast" 1
• During the 2022 contrast shortage, unenhanced CT was used only as a last resort in emergency situations 1
• There is no relevant literature supporting noncontrast CT for initial penetrating or blunt trauma evaluation 1

Why Pelvic X-ray is Not the Answer

Pelvic X-ray is only indicated for hemodynamically UNSTABLE patients who cannot undergo CT scanning 1:

• In unstable patients requiring ongoing resuscitation, pelvic X-ray combined with chest X-ray and FAST helps rapidly determine bleeding control options 1
• For hemodynamically stable patients, pelvic X-ray should NOT be performed—they should proceed directly to CT with IV contrast 1
• This patient responded to IV fluids and is now stable, making him a CT candidate 1

Clinical Algorithm for This Patient

1. Confirm hemodynamic stability: Patient responded to fluids and is currently stable—this is the key decision point 1

2. Proceed directly to CT abdomen/pelvis with IV contrast: Do not delay with pelvic X-ray 1

3. CT findings will guide management:

   • Active arterial extravasation → angioembolization 1
   • Solid organ injury without active bleeding → non-operative management with serial exams 1
   • Hollow viscus injury or peritonitis → surgical exploration 1
   • Venous bleeding → supportive care 1

Important Caveats

If the patient becomes hemodynamically unstable while awaiting or during CT, immediately abort imaging and proceed to the operating room based on FAST findings 1, 3. Every 10-minute delay from admission to laparotomy in unstable patients increases mortality 3.

The positive FAST indicates free fluid but does not specify the source or severity—this is why contrast-enhanced CT is essential to characterize the injury and plan appropriate intervention 1.

Oral contrast is not necessary and would only delay definitive imaging without improving diagnostic accuracy in trauma patients 4, 5.