Abstract & Commentary
Source: Sakles JC, et al. Rocuronium for rapid sequence intubation of emergency department patients. J Emerg Med 2004;17:611-616.
This paper reports the University of California at Davis Medical Center’s emergency department (ED) experience with rocuronium, a rapid-onset, non-depolarizing paralytic agent available as an alternative to succinylcholine for rapid sequence intubation (RSI).
Before the study began, emergency physicians (EPs) were given educational instruction on the drug, with suggested indications for its use (essentially contraindications to succinylcholine) as well as dosage recommendations (1 mg/kg). Choice of paralytic agent in individual cases was left to the discretion of the treating EPs. A variety of demographic and physiologic data was collected. During the six-month study period, 261 patients underwent RSI, with 200 receiving succinylcholine, three receiving vecuronium, and 58 (22%) getting rocuronium. The most commonly cited indication for use of rocuronium was clinical concern for hyperkalemia (31/58, 53%), with 16 patients ultimately proven to have elevated serum potassium levels at the time of intubation; another four patients subsequently were found to be hyperkalemic, but had received rocuronium for other reasons.
The mean dose used in this study was 1.0 +/- 0.2 mg/kg (range 0.6-1.1 mg/kg). Onset of time-to-paralysis was precisely timed in 34/58 (60%) of patients, and was found to be 45 sec (+/- 15 sec; range 20-90 sec). In those 24 patients in whom the clinical situation prevented precise timing, the estimated times to paralysis were most commonly 45-60 sec, with none being longer than 90 sec. The most commonly used induction agent was etomidate (50/58, 86%). The authors report that previous literature reflects variation in onset of action of rocuronium, with more rapid onset related to higher doses of rocuronium and larger doses of induction agent. Complications and adverse events were few, and judged not to be due to the use of rocuronium; these included four esophageal intubations, three main-stem intubations, and one patient who vomited. In those patients in whom oxygen desaturation data were recorded (79%), desaturation was not overly dramatic and relatively rare. The authors conclude that rocuronium is a good alternative to succinylcholine for neuromuscular blockade in ED RSI, with a desirable, short onset of action and few complications.
Commentary by Richard Harrigan, MD
Succinylcholine serves as the workhorse paralytic agent in ED RSI; its appeal lies principally in its rapid onset of action (approximately 1 minute) and short duration of effect (3-5 minutes). As a depolarizing agent of the post-synaptic myoneural junction, it carries with it several undesirable side effects, some of which are linked to the resultant muscle fasciculations: hyperkalemia, malignant hyperthermia, autonomic ganglionic stimulation, and increased intracranial and intraocular pressure—although the clinical significance of these latter two pressure issues is open to debate. These side effects, especially real or anticipated fear of worsening hyperkalemia and thus precipitating potentially fatal dysrhythmias, can take the "rapid" out of RSI as the EP considers whether it is safe to use succinylcholine in certain scenarios, such as the patient in need of emergent intubation who may have missed hemodialysis. Defasciculating doses of non-depolarizing paralytic agents do not prevent hyperkalemia. Of further note, succinylcholine is not contraindicated in normokalemic renal failure patients.
Suggested contraindications to succinylcholine employed in this study are reasonable, and worthy of mention: history of malignant hyperthermia or allergy to succinylcholine, known or suspected hyperkalemia, muscular dystrophy, subacute spinal cord injury, any denervation syndrome, extensive burns more than 48 hours old, severe crush injury, penetrating globe injury, or avoidance of administering a second dose of succinylcholine. One other point worthy of mention, yet not stressed in this paper, is the relatively long duration of action of rocuronium; although its onset of action is comparable to succinylcholine, its duration of action is approximately 30-110 min.1
Dr. Harrigan, Associate Professor of Emergency Medicine, Temple University Hospital and School of Medicine, Philadelphia, PA, is Editor of Emergency Medicine Alert.
1. Hopson LR, Dronen SC. Pharmacologic adjuncts to intubation. In: Roberts JR, Hedges JR (eds). Clinical Procedures in Emergency Medicine. 4th ed. Philadelphia: Saunders /Elsevier; 2004:100-114.