Introduction
Rapid sequence intubation (RSI) is a process whereby an induction agent and a neuromuscular blocking agent are given in rapid succession to facilitate endotracheal intubation The selection of a specific sedative depends on multiple factors: the clinical scenario, which includes patient factors (includes cardiorespiratory and neurologic status, allergies, comorbidity) and the clinician’s experience/training and institutional factors, as well as the characteristics of the paralytic
Succinylcholine remains the most commonly used paralyzing agent, however, it does have pharmacologic considerations The use of rocuronium continues to increase due to its unique pharmacologic profile and its niche is becoming prevalent in situations where the risk of hyperkalemia and bradycardia are high
Key Points
- RSI gives an induction agent and a neuromuscular blocking agent in rapid succession to facilitate endotracheal intubation.
- The two most commonly used paralytics are succinylcholine (a depolarizing agent) and rocuronium (a non-depolarizing agent).
- Succinylcholine remains the most commonly used paralytic but carries important pharmacologic considerations.
- Rocuronium use is increasing, especially where the risk of hyperkalemia or bradycardia is high.
Clinical Detail
The two agents most commonly used for neuromuscular blockade in RSI are succinylcholine (a depolarizing agent) and rocuronium (a non-depolarizing agent). The table below compares their dosing, pharmacokinetics, and safety profiles.
Agent Comparison
| Succinylcholine | Rocuronium | |
|---|---|---|
| Dose | IV: 1.5 mg/kg; IM: 3–4 mg/kg (ABW) | 1–1.2 mg/kg (IBW) |
| Administration | IV push | IV push |
| Formulation | 200 mg / 10 mL vial (must be refrigerated) | 100 mg / 10 mL vial (non-refrigerated) |
| Onset | 40–60 seconds | IV ~45–90 seconds |
| Duration | 4–10 minutes | 30–90 minutes |
| Metabolism | Rapidly hydrolyzed by plasma pseudocholinesterase to inactive metabolites | N-demethylation |
| Renal excretion | 10% | — |
| Adverse effects | Bradycardia, hyperkalemia, fasciculations, ↑ intraocular pressure, transient ↑ ICP ~5–10 mmHg, malignant hyperthermia (rare) | Very few reported; increased peripheral vascular resistance (abdominal aortic surgery) |
| Drug interactions | No major reactions | No major reactions |
| Compatibility | Incompatible with sodium bicarbonate, nafcillin, oxacillin, phenytoin, phenobarbital | Incompatible with furosemide, regular insulin, lorazepam, phenytoin, pantoprazole, and piperacillin/tazobactam |
Contraindications
| Succinylcholine | Rocuronium | |
|---|---|---|
| Contraindications | Hypersensitivity to succinylcholine or any component of the formulation; personal or familial history of malignant hyperthermia; skeletal muscle myopathies; >3–5 days following major burns, intra-abdominal sepsis, multiple trauma, extensive denervation of skeletal muscle, or upper motor neuron injury. | Hypersensitivity to rocuronium |
Evidence
Comparative trials and meta-analyses evaluating succinylcholine versus rocuronium (and vecuronium) for intubating conditions and first-pass success in RSI.
| Author, Year | Design / Sample Size | Intervention & Comparison | Outcome |
|---|---|---|---|
| April, 2018 | Prospective cohort study / n = 4,275 | Succinylcholine ≥ 1.5 mg/kg vs Rocuronium ≥ 1.2 mg/kg | First-pass intubation success rate showed no difference between the agents: 87.0% with succinylcholine versus 87.5% with rocuronium (adjusted OR 0.9; 95% CI 0.6–1.3). Incidence of any adverse events showed no difference. There was a difference in first-pass intubation success with rocuronium ≥ 1.2 mg/kg compared to < 1.2 mg/kg. |
| Tran, 2017 | Cochrane meta-analysis / n = 4,151 | Succinylcholine ≥ 1 mg/kg vs Rocuronium ≥ 0.6 mg/kg | Overall, succinylcholine was superior to rocuronium for achieving excellent intubating conditions (RR 0.86; 95% CI 0.81–0.92; n = 4,151) and clinically acceptable intubation conditions (RR 0.97; 95% CI 0.95–0.99; n = 3,992). A high incidence of detection bias was noted amongst the trials. |
| Patanwala, 2016 | Retrospective cohort study / n = 233 | Succinylcholine (dosing not reported) vs Rocuronium (dosing not reported) | In high-severity TBI patients, succinylcholine was associated with increased mortality compared with rocuronium (OR 4.10; 95% CI 1.18–14.12). |
| Patanwala, 2011 | Retrospective analysis / n = 327 | Succinylcholine 1.65 mg/kg vs Rocuronium 1.19 mg/kg | The rate of first-attempt intubation success was similar between the succinylcholine and rocuronium groups (72.6% vs 72.9%; p = 0.95). |
| Watt, 2012 | Retrospective cohort study / n = 200 | Succinylcholine 1.7 ± 0.7 mg/kg vs Rocuronium 1.3 ± 0.4 mg/kg | After intubation, 77.5% (n = 155) of patients were initiated on a sedative infusion of propofol (n = 148) or midazolam (n = 7). Mean time to post-intubation sedation was significantly greater with rocuronium compared to succinylcholine (27 min vs 15 min; p < 0.001). |
| Smith, 2002 | Prospective, blinded study / n = 100 | Rocuronium 1 mg/kg vs Vecuronium 0.15 mg/kg | Intubation was successful in 95% of patients in the vecuronium group and 100% in the rocuronium group. |
| Weiss, 1997 | RCT / n = 45 | Succinylcholine 1.5 mg/kg vs Rocuronium 0.7 and 0.9 mg/kg | Rocuronium at a dose of 0.9 mg/kg provided intubating conditions similar to succinylcholine 1.5 mg/kg at 1 minute. Intubating conditions at 1 minute following rocuronium 0.7 mg/kg were inferior to the higher dose of rocuronium or succinylcholine. |
| Magorian, 1993 | RCT / n = 50 | Succinylcholine 1 mg/kg vs Rocuronium 0.6, 0.9, and 1.2 mg/kg vs Vecuronium 0.1 mg/kg | Onset times of rocuronium 0.9 mg/kg and 1.2 mg/kg and succinylcholine 1 mg/kg were similar; onset times for rocuronium 0.6 mg/kg and vecuronium 0.1 mg/kg were much longer. Rocuronium 1.2 mg/kg had a mean onset time of 55 seconds, similar to the mean onset time of succinylcholine (50 seconds). |
Conclusions
Emergency medicine physician perspectives on agent selection are summarized below.
| Agent | Advantages per EM Physicians | Considerations per EM Physicians |
|---|---|---|
| Succinylcholine | Shorter duration of paralysis | Hyperkalemia can occur with CNS / spinal cord injury (>3 days), myopathies, burns (a few days later), intra-abdominal sepsis, critical illness, and occasionally with severe traumatic injury acutely. Avoid succinylcholine when possible in pediatric populations (<8 years). |
| Rocuronium | Has a reversal agent; not associated with malignant hyperthermia; not associated with hyperkalemia (no fasciculation); dosed on ideal body weight. Where available, sugammadex may be used for reversal as an alternative to neostigmine plus atropine. | Longer paralytic time, however has a reversal agent. |
References
Micromedex [Electronic version].Greenwood Village, CO: Truven Health Analytics. Retrieved September 6, 2018, from http://www.micromedexsolutions.com/
Magorian. Anesthesiology. 1993;79:913-918.
Smith CE. Air Med J. 2002;21:26-32.
Weiss JH. J Clin Anesth. 1997 Aug;9(5):379-82.
Patanwala S. Acad Emerg Med. 2011 Jan;18(1):10-4.
Patanwala S. Pharmacotherapy. 2016 Jan;36(1):57-63.
Tran DTT. Anaesthesia. 2017 Jun;72(6):765-777
April MD. Ann Emerg Med. 2018 Dec;72(6):645-653.
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