Which neuromuscular blocking agent is preferred for rapid sequence induction due to its rapid onset and is administered at a dose of 1.2 mg/kg IV?

Explanation

## Neuromuscular Blocking Agents in Rapid Sequence Induction **Key Point:** The stem specifies a dose of **1.2 mg/kg IV** — this is the hallmark high-dose RSI regimen for **Rocuronium**, not succinylcholine. Rocuronium at 1.2 mg/kg achieves intubating conditions in 60–90 seconds and is increasingly preferred for RSI in modern anesthesia practice. ### Rocuronium at 1.2 mg/kg: The RSI Dose **High-Yield:** Rocuronium is a non-depolarizing aminosteroid NMBA with the following RSI-relevant properties: - **Standard dose:** 0.6 mg/kg (onset ~3 min) - **RSI dose:** **1.2 mg/kg IV** (onset ~60–90 sec — approaches succinylcholine speed) - **Duration at RSI dose:** ~60–70 minutes - **Reversal:** Sugammadex 16 mg/kg for immediate reversal, 4 mg/kg for deep block - **Advantage:** No contraindications related to hyperkalemia, malignant hyperthermia, or fasciculations ### Why Not Succinylcholine Here? Succinylcholine's RSI dose is **1.0–1.5 mg/kg** (typically 1.5 mg/kg for RSI in many protocols, with 1.2 mg/kg also used). However, the stem's phrasing — "preferred for RSI due to rapid onset and administered at 1.2 mg/kg" — is the **canonical description of high-dose Rocuronium** in contemporary RSI protocols, particularly when succinylcholine is contraindicated. ### Comparison: Rocuronium vs. Succinylcholine for RSI | Feature | Rocuronium (RSI dose) | Succinylcholine | | --- | --- | --- | | **Dose** | **1.2 mg/kg IV** | 1.0–1.5 mg/kg IV | | **Onset** | 60–90 sec | 30–60 sec | | **Duration** | 60–70 min | 5–10 min | | **Type** | Non-depolarizing | Depolarizing | | **Reversal** | Sugammadex | Spontaneous only | | **Contraindications** | Few | Burns, crush, denervation, MH risk | **Clinical Pearl:** According to Morgan & Mikhail's Clinical Anesthesiology (6e) and current NAP4/DAS guidelines, Rocuronium 1.2 mg/kg is the preferred alternative to succinylcholine for RSI and is now considered first-line in many institutions due to the availability of sugammadex for rapid reversal. The 1.2 mg/kg dose is specifically cited as the RSI dose for rocuronium. **Warning:** Succinylcholine carries risks of severe hyperkalemia (burns >24h, crush injuries, denervation syndromes), malignant hyperthermia, and increased intragastric/intraocular/intracranial pressure from fasciculations — making rocuronium the preferred agent in many clinical scenarios. **Mnemonic:** **ROCK** = **R**apid **O**nset with **C**omplete reversal by sugamma**dex** at **1.2 mg/K**g [cite: Morgan & Mikhail's Clinical Anesthesiology 6e Ch 13; Miller's Anesthesia 8e Ch 34]