What is the role of paralytic agents prior to rapid sequence intubation (RSI)?

Updated: Apr 07, 2020
  • Author: Keith A Lafferty, MD; Chief Editor: Guy W Soo Hoo, MD, MPH  more...
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Paralyzing agents provide neuromuscular blockade and are administered immediately after the induction agent.

Neuromuscular blockade does not provide sedation, analgesia, or amnesia; thus, administering a potent induction agent is important.

A depolarizing neuromuscular blocker (eg, succinylcholine [Anectine] at 2 mg/kg IV or 4 mg/kg IM) has a rapid onset (45-60 sec) and the shortest duration of action (8-10 min). It should be used with caution in patients with known or suspected hyperkalemia and those with chronic neuromuscular disease. Also use caution in patients with chronic renal failure or dialysis-dependent patients as they are prone to be hyperkalemic and this may be unsuspected. Zink's 1995 prospective study of 100 patients in the ED undergoing RSI did not find a change in serum potassium level from before to after RSI with succinylcholine. Exclusion criteria were minimal; a limitation was that postintubation potassium level was checked at only 1 time interval (5 min). [44]

A nondepolarizing neuromuscular blocker (NMB) (eg, rocuronium [Zemuron] at 1-1.2 mg/kg IV) has a slightly longer onset of action (60-75 sec) than succinylcholine and longer duration of action (30-60 min). Use with caution in patients in whom difficult intubation is possible. Does not result in muscle depolarization or defasciculation and does not exacerbate hyperkalemia. Sugammadex is a new NMB reversal agent that has been shown to be safe and effective for reversal of neuromuscular blockade induced by nondepolarizing agents. Reversal occurs at 1.5 minutes with a dose of 16 mg/kg and at 3 minutes with a dose of 4 mg/kg. It has been shown to induce full reversal of such agents faster than succinylcholine’s normal metabolic breakdown and for the first time in over 50 years offers a safe alternative and viable option for emergent RSI. [45]

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