A 32-year-old man is brought to the emergency department following a motor vehicle collision with blunt abdominal trauma. On primary survey, he is haemodynamically stable with a systolic BP of 118 mmHg and HR 92/min. FAST examination is performed. Which of the following findings on FAST does NOT mandate immediate exploratory laparotomy in a haemodynamically stable patient?

Explanation

## FAST Examination and Laparotomy Indications in Blunt Abdominal Trauma ### FAST Protocol Overview **Key Point:** FAST (Focused Assessment with Sonography for Trauma) is a rapid, non-invasive bedside ultrasound with four views: pericardial, right upper quadrant (Morrison's pouch), periumbilical (free fluid), and pelvic. ### Indications for Immediate Laparotomy in Haemodynamically Stable Patients | Finding | Indication for Laparotomy | Rationale | |---------|---------------------------|----------| | **Positive pericardial view** (free fluid in pericardium) | **YES — Urgent** | Suggests haemopericardium; risk of tamponade even if currently stable | | **Positive Morrison's pouch** (perihepatic free fluid) | **YES — Urgent** | Indicates intra-abdominal bleeding; even stable patients need operative intervention | | **Positive pelvic view** (free fluid in pelvis) | **YES — Urgent** | Suggests significant intra-abdominal or pelvic bleeding | | **Minimal free fluid, haemodynamically stable, no peritoneal signs** | **NO — Observe** | Can be managed conservatively with serial examination, serial labs, and imaging | ### Clinical Decision-Making **High-Yield:** In a haemodynamically stable patient, the **presence and amount of free fluid** on FAST, combined with **clinical examination findings** (peritoneal signs) and **haemodynamic stability**, determines management: - **Positive FAST + haemodynamic instability** → Immediate laparotomy - **Positive FAST + haemodynamic stability + no peritoneal signs** → Serial FAST, clinical examination, CT imaging (if available and patient stable) - **Minimal free fluid + haemodynamic stability + no peritoneal signs** → Conservative management with observation **Clinical Pearl:** A single positive FAST view in an otherwise stable patient does not automatically mandate laparotomy. Serial FAST examinations (repeat at 15–30 min intervals) and clinical correlation are essential. However, **pericardial involvement always warrants urgent intervention** due to tamponade risk. **Warning:** Do not confuse "positive FAST" with "mandatory laparotomy." Haemodynamic stability and absence of peritoneal signs allow selective non-operative management (NOM) in many centres, especially with CT confirmation available. ### Why Option 3 Is Correct Minimal free fluid in a haemodynamically stable patient without peritoneal signs can be managed conservatively. Serial examination, serial labs (Hb trend), and imaging (CT if stable) guide further management. This patient does NOT require immediate laparotomy. ### Why Options 1, 2, and 4 Mandate Laparotomy - **Option 1 (Positive Morrison's pouch):** Indicates hepatic/upper abdominal bleeding; unstable or stable, operative intervention is typically needed. - **Option 2 (Pericardial fluid + muffled heart sounds):** Signs of haemopericardium and early tamponade; immediate laparotomy (or pericardiocentesis/surgical drainage) is mandatory. - **Option 4 (Free fluid in pelvis):** Even without peritoneal signs, pelvic free fluid indicates bleeding; most guidelines recommend laparotomy or CT + observation depending on stability. [cite:ATLS 10th Edition]