Effect of rocuronium vs succinylcholine on endotracheal intubation success rate among patients undergoing out-of-hospital rapid sequence intubation: a randomized clinical trial
Guihard B, Chollet-Xémard C, Lakhnati P, et al. JAMA. 2019;322(23):2303-2312.
SUMMARY:
Succinylcholine is a depolarizing paralytic agent that was long the mainstay of rapid sequence intubation because of its rapid-on, rapid-off pharmacology. However, it causes a transient rapid rise in potassium, which can be exacerbated in some neuromuscular disorders and lead to hyperkalemic arrest. Rocuronium does not have any such contraindications and causes a fairly similar onset of paralysis but a longer duration of paralysis that can be reversed by suggamadex.
Most studies, including RCTs, have shown that succinylcholine provides better intubating conditions than rocuronium, but these studies have been criticized because they occurred in the OR and typically used the cord view rather than the actual intubation as the outcome.
This study appears to be the first RCT examining rocuronium versus succinylcholine for first-pass intubation success in an emergency situation, in this case a prehospital setting, which probably exacerbated any differences. The study occurred in France, and intubations were performed by anesthesiologists or emergency specialists in the field according to their usual practice.
This individual-level RCT included patients with any condition except cardiac arrest (no need for rapid sequence intubation) and excluded those with a contraindication for either rocuronium or succinylcholine. Participants were sedated with either 0.3 mg/kg etomidate or 2 mg/kg ketamine (at the discretion of the treating MD) and paralyzed with either 1 mg/kg succinylcholine or 1.2 mg/kg rocuronium.
Intubating physicians filled out a case-report form. The key outcome measure was first-pass success, and the study was set up with a noninferiority design. Secondary outcomes included assessment of glottic view, vital-sign disturbances, and other outcomes. The noninferiority margin was 7%, meaning that the CI of the difference in success rates between rocuronium and succinylcholine could not include values <7%.
The study enrolled 1,226 patients; half were intubated for neurologic conditions, 8% for trauma, and 15% for acute respiratory failure. First-pass success occurred in 79.4% of the succinylcholine group and 74.6% of the rocuronium group (−4.8% with CI down to −9%), indicating that rocuronium was not non inferior to succinylcholine. There was a slight increase in the use of mild rescue airway in the rocuronium group (bougie or laryngeal mask airway) but no difference in the need for cricothyroidotomy (essentially 0% in both groups).
As seen in previous studies, the intubating conditions might have been slightly better with succinylcholine than rocuronium; however, complications were higher in the succinylcholine group (23% versus 18%) and were mostly driven by a difference in hypotensive episodes (10% versus 6%) and arrhythmia (4% versus 2%). Death occurred in 1% of the rocuronium group and 0.5% of the succinylcholine group. Importantly, this study probably makes succinylcholine seem to perform slightly better than it would in real-world conditions, because under research conditions, systematic exclusions are more likely, thus avoiding people with succinylcholine contraindications who might otherwise receive succinylcholine under more routine clinical conditions. In addition, the fairly low dose of succinylcholine might have affected both the first-pass success rate and the complication rate in that group.
This is a study that will be interpreted as favoring whatever position one initially had, and it does not support avoiding either succinylcholine or rocuronium. If the provider assesses the airway as particularly difficult or the patient as being at particularly high risk of hypotension or arrhythmia, that could sway the choice, but routinely either is fine.
EDITOR’S COMMENTARY: This large prehospital RCT suggests that the choice of paralytic agent results in a trade-off between first-pass success and complications. Rocuronium was not found to be non-inferior to succinylcholine according to the first-pass success rate. However, the risk of arrhythmia and hypotension associated with rocuronium was significantly lower than that with succinylcholine. Clinicians will have to make a personal decision as to which outcome is more important to them, and this may vary according to patient characteristics.
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