A 28-year-old man is brought to the emergency department following a high-speed motor vehicle collision. On primary survey, he is alert, breathing spontaneously at 22/min, with a BP of 110/70 mmHg and HR of 98/min. During secondary survey, you note severe abdominal distension, bruising over the left flank, and tenderness in the left upper quadrant. There is no external bleeding. Which investigation is most appropriate to assess the extent of intra-abdominal injury?

Explanation

## Investigation of Choice in Blunt Abdominal Trauma **Key Point:** In a haemodynamically stable trauma patient with suspected intra-abdominal injury, contrast-enhanced CT abdomen and pelvis is the gold standard investigation during the secondary survey. ### Why CT is Optimal Here The patient meets the criteria for CT imaging: - Haemodynamically stable (BP 110/70, HR 98) - Alert and cooperative (can lie flat and hold breath) - Mechanism of injury (high-speed MVC) warrants imaging - Clinical signs suggest solid organ injury (left flank bruising, LUQ tenderness) **High-Yield:** CT provides: 1. Identification and grading of solid organ injuries (spleen, liver, kidney) 2. Detection of active bleeding (contrast extravasation) 3. Assessment of retroperitoneal injuries 4. Evaluation of hollow viscus and mesenteric injuries 5. Guides conservative vs. operative management ### Comparison of Investigations | Investigation | Best Use | Limitation | |---|---|---| | **FAST** | Rapid screening in unstable patients; detects free fluid | Cannot grade organ injury; operator-dependent; poor specificity | | **DPL** | Rapid assessment when FAST unavailable; unstable patient | Invasive; cannot localize bleeding; poor specificity for solid organ injury | | **CT** | Stable patient; detailed organ assessment; guides management | Requires transport; radiation; time-consuming if patient unstable | | **Diagnostic laparoscopy** | Therapeutic intervention; selective penetrating trauma | Not first-line investigation; reserved for specific indications | **Clinical Pearl:** The "holy trinity" of imaging in blunt trauma: - **FAST** = rapid triage in unstable/shocked patients - **CT** = comprehensive assessment in stable patients - **DPL** = alternative when ultrasound unavailable and patient unstable **Mnemonic: STABLE = CT** — Stable patient → Comprehensive imaging → CT abdomen-pelvis [cite:ATLS 10th Edition Ch 5]