Which neuromuscular blocking agent is preferred during rapid sequence induction due to its rapid onset and lack of histamine release?

Explanation

## Neuromuscular Blocking Agents in Rapid Sequence Induction **Key Point:** Rocuronium is the preferred NMBA for RSI because it combines rapid onset (60 seconds at standard dose), intermediate duration, and absence of histamine release. ### Why Rocuronium for RSI? 1. **Rapid onset**: 60 seconds (fastest non-depolarizing agent) 2. **Intermediate duration**: 30–40 minutes 3. **No histamine release**: Unlike atracurium and mivacurium 4. **Predictable neuromuscular blockade**: Reliable intubating conditions 5. **Reversible with sugammadex**: Newer reversal option available ### Comparison of NMBA Agents | Agent | Onset | Duration | Histamine Release | Metabolism | Use in RSI | |-------|-------|----------|-------------------|------------|----------| | **Rocuronium** | 60 s | 30–40 min | No | Hepatic | **Preferred** | | Atracurium | 90–120 s | 30–45 min | **Yes** | Ester hydrolysis | Avoid (histamine) | | Mivacurium | 60–90 s | 12–20 min | **Yes** | Pseudocholinesterase | Avoid (histamine) | | Vecuronium | 90–120 s | 30–40 min | No | Hepatic | Alternative if rocuronium unavailable | | Succinylcholine | 30–40 s | 5–10 min | Yes | Pseudocholinesterase | Depolarizing; hyperkalemia risk | **High-Yield:** Rocuronium at **1.2 mg/kg IV** achieves intubating conditions in ~60 seconds. Higher doses (1.5 mg/kg) may shorten onset by 5–10 seconds but prolong duration. **Clinical Pearl:** Sugammadex (rocuronium reversal agent) allows rapid reversal of neuromuscular blockade, which is particularly valuable in difficult airway scenarios where re-intubation may be needed. **Warning:** Atracurium and mivacurium release histamine, which can cause bronchospasm, hypotension, and tachycardia — dangerous in RSI where airway compromise is already a risk. Succinylcholine causes hyperkalemia and is contraindicated in crush injuries, burns, and prolonged immobilization.