A 48-year-old man with a history of hypertension and type 2 diabetes presents to the emergency department with a perforated duodenal ulcer. He is hemodynamically stable (BP 132/88 mmHg, HR 102/min) but in severe pain. He last ate 4 hours ago. On examination, he has a rigid, board-like abdomen with rebound tenderness. He requires emergency laparotomy under general anesthesia. Which of the following is the MOST appropriate muscle relaxant to use during rapid sequence intubation in this patient?

Explanation

## Muscle Relaxant Selection in Rapid Sequence Induction ### Why Succinylcholine in RSI **Key Point:** Succinylcholine is the gold standard muscle relaxant for rapid sequence induction because of its rapid onset (30–40 seconds) and ultrashort duration (5–10 minutes), allowing quick intubation and recovery if intubation fails. **High-Yield:** In emergency airway management, speed is critical. Succinylcholine's rapid onset and offset make it ideal for RSI, even though it has side effects like hyperkalemia and malignant hyperthermia risk—these are outweighed by the need for rapid airway control. ### Comparison of Muscle Relaxants in RSI | Agent | Onset (sec) | Duration (min) | Metabolism | Use in RSI | Advantages | Disadvantages | | --- | --- | --- | --- | --- | --- | --- | | **Succinylcholine** | **30–40** | **5–10** | **Pseudocholinesterase** | **GOLD STANDARD** | Rapid onset, short duration, reversible | Hyperkalemia, MH risk, fasciculations, ↑ ICP | | Vecuronium | 60–90 | 30–40 | Hepatic | Avoid | Slower onset | Prolonged paralysis | | Atracurium | 60–90 | 30–40 | Hofmann elimination | Avoid | Organ-independent | Slower onset, histamine release | | Pancuronium | 90–120 | 60–90 | Renal/hepatic | Contraindicated | Long-acting | Tachycardia, prolonged paralysis | ### RSI Protocol with Succinylcholine 1. **Pre-oxygenation** (3 min, 100% O₂) 2. **Cricoid pressure** (Sellick maneuver) 3. **Induction agent:** Etomidate 0.2 mg/kg IV (or propofol if hemodynamically stable) 4. **Paralysis:** Succinylcholine 1–1.5 mg/kg IV 5. **Intubation** within 30–40 seconds (before paralysis wears off) **Clinical Pearl:** Succinylcholine causes visible muscle fasciculations (uncoordinated contractions) that increase intracranial pressure and serum potassium. Pre-treatment with a small dose of non-depolarizing agent (e.g., vecuronium 0.01 mg/kg) can attenuate fasciculations if time permits, but in true RSI, this is often omitted. **Warning:** Succinylcholine is contraindicated in: - Malignant hyperthermia susceptibility - Acute hyperkalemia (risk of cardiac arrhythmias) - Severe burns or crush injuries (>24 hours post-injury) - Prolonged immobilization or denervation injuries - Pseudocholinesterase deficiency (prolonged paralysis) In this patient, none of these contraindications are present, making succinylcholine safe and appropriate. **Mnemonic — RSI Relaxant:** **S**uccinylcholine = **S**peed (fastest onset, shortest duration).