Which neuromuscular blocking agent is preferred for rapid sequence induction due to its rapid onset and short duration, and is unaffected by pseudocholinesterase deficiency?

Explanation

## Neuromuscular Blocking Agents in Rapid Sequence Induction **Key Point:** Rocuronium is the modern standard NMBA for RSI, offering rapid onset comparable to succinylcholine without the risk of pseudocholinesterase deficiency or hyperkalemia. ### Rocuronium in RSI 1. **Onset time:** 60–90 seconds at standard dose (0.6 mg/kg); 30–40 seconds at high dose (1.2 mg/kg) 2. **Duration:** 30–40 minutes (context-sensitive half-time ~15 min) 3. **Metabolism:** Hepatic and renal elimination; independent of pseudocholinesterase 4. **Reversibility:** Can be reversed with sugammadex (encapsulation) or neostigmine + glycopyrrolate 5. **Hemodynamic stability:** Minimal cardiovascular effects ### Comparison of NMBAs for RSI | Agent | Onset | Duration | Metabolism | Hyperkalemia Risk | Pseudocholinesterase Dependent | RSI Role | |-------|-------|----------|-----------|-------------------|--------------------------------|----------| | **Rocuronium** | 60–90 s (or 30–40 s high-dose) | 30–40 min | Hepatic/renal | No | **No** | **First-line** | | Succinylcholine | 30–40 s | 5–10 min | Plasma esterase | **Yes** | **Yes** | Avoided if deficiency | | Atracurium | 90–120 s | 30–45 min | Hofmann/ester | No | No | Too slow for RSI | | Vecuronium | 90–120 s | 30–40 min | Hepatic | No | No | Too slow for RSI | **High-Yield:** Rocuronium at **1.2 mg/kg IV** achieves intubating conditions in 30–40 seconds, matching succinylcholine's speed without pseudocholinesterase risk. **Mnemonic:** **ROCURONIUM = Rapid Onset, Consistent, Unaffected by cholinesterase, Reversible** — the modern RSI agent. **Clinical Pearl:** In patients with pseudocholinesterase deficiency (genetic variant, liver disease, pregnancy, organophosphate exposure), rocuronium is the ONLY rapid-onset NMBA option; succinylcholine would cause prolonged paralysis. **Warning:** ~~Atracurium and vecuronium~~ are NOT suitable for RSI due to slower onset (90–120 s), which exceeds the critical desaturation window in apneic oxygenation.