A 28-year-old woman is brought to the trauma bay following a stab wound to the left lower abdomen. On examination, she is restless, BP 92/58 mmHg, HR 128/min, RR 24/min, and has severe abdominal pain with guarding and rebound tenderness. FAST examination shows free fluid in the pelvis and left paracolic gutter. What is the most appropriate immediate next step?

Explanation

## Clinical Context This patient presents with haemodynamic instability (hypotension, tachycardia), peritoneal signs (guarding, rebound), and a positive FAST after penetrating abdominal trauma. ## Indications for Immediate Laparotomy **Key Point:** Haemodynamic instability combined with peritoneal signs in penetrating abdominal trauma is an absolute indication for immediate exploratory laparotomy. No further imaging or investigation is warranted. **High-Yield:** In penetrating trauma, the presence of peritonitis (guarding, rebound, rigidity) mandates operative exploration regardless of imaging findings. Delay for imaging increases morbidity and mortality. ## Laparotomy Indications in Trauma | Indication | Penetrating | Blunt | Urgency | |---|---|---|---| | Haemodynamic instability + peritoneal signs | Yes | Yes | Immediate | | Peritoneal signs alone | Yes | Yes | Immediate | | Haemodynamic instability + positive FAST | Yes | Yes | Immediate | | Stable + positive FAST | No | No | CT imaging | | Evisceration | Yes | Yes | Immediate | **Clinical Pearl:** In penetrating abdominal trauma with peritoneal signs, the sensitivity of clinical examination for intra-abdominal injury is >95%. Operative exploration is safer than delayed imaging in an unstable patient. **Mnemonic: STAB** — **S**table + positive FAST → CT; **T**achycardia/hypotension + peritonitis → laparotomy; **A**bdominal signs → operate; **B**lunt or penetrating, if unstable → OR. ## Decision Algorithm ```mermaid flowchart TD A[Penetrating abdominal trauma]:::outcome --> B{Haemodynamically stable?}:::decision B -->|No| C{Peritoneal signs?}:::decision B -->|Yes| D{Peritoneal signs?}:::decision C -->|Yes or No| E[Immediate laparotomy]:::urgent D -->|Yes| E D -->|No| F[CT abdomen/pelvis]:::action E --> G[Operative management]:::action ```