What is the most appropriate initial step in management for a patient with severe pelvic and back pain, transient hypotension, and free fluid in the lower abdomen after a roll-over accident?

CT Abdomen and Pelvis with IV Contrast

In this hemodynamically stable patient (BP 100/60 after initial resuscitation) with severe pelvic trauma and free fluid on FAST, proceed directly to CT abdomen and pelvis with IV contrast—this is the most appropriate initial step. 1, 2

Rationale for CT as Initial Step

The patient's current hemodynamic status is the critical decision point. With a BP of 100/60 after a single 500 mL NS bolus and no ongoing hypotension, this patient meets criteria for hemodynamic stability. 2

For hemodynamically stable patients with pelvic trauma and free fluid, the American College of Radiology recommends proceeding directly to thoraco-abdomino-pelvic CT scan with IV contrast as the primary imaging modality. 1, 2 This approach:

• Provides complete inventory of all injuries including hepatic, splenic, renal, and pelvic vascular injuries 3, 1
• Identifies active sources of bleeding with 93.9% positive predictive value and 87.5% negative predictive value compared to angiography 3, 1
• Detects 35.6% more pelvic fractures than plain pelvic X-ray 2
• Allows characterization of solid organ injury and active bleeding when performed in portal venous phase 1

Why Not the Other Options

Pelvic X-ray (Option A)

Pelvic X-ray should not delay CT scanning in stable patients, as it adds no clinical value and provides no additional management guidance. 2 In hemodynamically stable patients, pelvic X-ray does not influence patient management since normal images only exclude pelvic injuries as sources of bleeding, while CT provides far superior information. 3

Retrograde Urethrogram (Option B)

Retrograde urethrography is not indicated as the initial step. 3 While lower urinary tract injuries occur in 3.5-19% of pelvic fractures, systematic dedicated imaging for urethral injury is not warranted initially because these injuries never jeopardize patient outcome in the initial phase and their repair is never an emergency. 3 Retrograde urethrography should only be performed if clinical symptoms of lower urinary tract injury are present (inability to urinate, gross hematuria, blood at the meatus), particularly before attempting urinary catheterization in men. 3

Back MRI (Option D)

MRI has no role in acute trauma management and would cause dangerous delays in a patient with free intraperitoneal fluid and potential ongoing bleeding. 1, 2

Critical Management Algorithm

1. Confirm hemodynamic stability (BP adequate after initial resuscitation, no ongoing hypotension) 2
2. Transport directly to CT scanner without delay for plain radiographs 1, 2
3. Perform CT abdomen/pelvis with IV contrast in portal venous phase 1
4. Consider arterial phase imaging to assess for active arterial bleeding and pseudoaneurysm formation 1
5. If CT demonstrates active bleeding, proceed to angiography/embolization as needed 3, 2

Common Pitfall to Avoid

Do not delay CT imaging to obtain pelvic X-rays in stable patients—this adds no clinical value and wastes precious time. 1, 2 The decision to proceed with CT should be based solely on hemodynamic stability, not on obtaining preliminary plain films first. 1