A 28-year-old man is brought to the trauma centre with a tension pneumothorax following blunt chest trauma. He is hypotensive (BP 90/60 mmHg), tachycardic (HR 128/min), with absent breath sounds on the left and tracheal deviation. After immediate needle decompression, a chest tube is placed. Which agent is the drug of choice for analgesia and sedation during chest tube insertion in this haemodynamically unstable patient?

## Sedation and Analgesia for Chest Tube Insertion in Shock **Key Point:** Ketamine is the induction agent of choice in haemodynamically unstable trauma patients undergoing chest tube insertion because it maintains airway reflexes, preserves spontaneous ventilation, and maintains or increases sympathetic tone. ### Why Ketamine is Preferred in Shock 1. **Sympathomimetic effect** — increases or maintains BP and HR through catecholamine release 2. **Preserves airway reflexes** — maintains protective airway mechanisms 3. **Maintains spontaneous ventilation** — does not suppress respiratory drive at sedative doses 4. **Analgesia + sedation** — provides both in one agent (dissociative state) 5. **Rapid onset** — suitable for emergency procedures ### Mechanism of Action Ketamine is an NMDA receptor antagonist that produces dissociative anaesthesia with sympathomimetic properties. It causes catecholamine release (noradrenaline, adrenaline) → ↑ BP, ↑ HR, ↑ cardiac output. ### Comparison of Induction Agents in Shock | Agent | BP Effect | Airway | Analgesia | Use in Shock | |-------|-----------|--------|-----------|-------------| | **Ketamine** | ↑ or → | Preserved | Yes | **BEST** | | **Propofol** | ↓↓ (severe) | Depressed | No | Contraindicated | | **Etomidate** | → (stable) | Depressed | No | Relative CI (adrenal suppression) | | **Midazolam** | ↓ | Depressed | No | Avoid in shock | **Clinical Pearl:** In a haemodynamically unstable trauma patient, the choice of induction agent can be life-saving. Propofol and midazolam cause vasodilation and myocardial depression — dangerous in shock. Etomidate causes adrenal suppression. Ketamine is the only agent that maintains or improves haemodynamics. **High-Yield:** Ketamine is the induction agent of choice for **rapid sequence intubation (RSI) in trauma, sepsis, and shock**. It is also suitable for procedural sedation (chest tube, central line, emergency ultrasound) in unstable patients. **Mnemonic:** **KETAMINE in SHOCK** — Keeps Everything Tolerable, Airway Maintained, Maintains Innervation, Noradrenaline Elevated. [cite:ATLS 10e Ch 4; Trauma.org Sedation in Shock]