What are the first-line medications for Repetitive Strain Injury (RSI) in the Emergency Room (ER)?

First-Line Medications for Rapid Sequence Intubation (RSI) in the Emergency Department

Core RSI Medication Regimen

For rapid sequence intubation in the emergency department, administer a sedative-hypnotic induction agent (etomidate or ketamine) immediately followed by a neuromuscular blocking agent (succinylcholine or rocuronium). 1, 2

Sedative-Hypnotic Induction Agents

Etomidate vs. Ketamine Selection

Both etomidate (0.2-0.4 mg/kg IV) and ketamine (1-2 mg/kg IV) are appropriate first-line induction agents, with no significant difference in mortality or hypotension rates. 1, 2

• Etomidate 0.2-0.4 mg/kg IV (maximum 20 mg) is preferred for patients with head injury or increased intracranial pressure, as it lowers ICP while maintaining hemodynamic stability 1, 2

• Ketamine 1-2 mg/kg IV is the preferred agent for hemodynamically unstable patients due to its sympathomimetic effects, though recent retrospective evidence suggests etomidate may produce less hypotension than ketamine in patients with shock or sepsis 1, 2, 3

• The Society of Critical Care Medicine found no difference between etomidate and other induction agents regarding mortality (OR 1.17,95% CI 0.86-1.60) or incidence of hypotension in the peri-intubation period 1

• Midazolam 0.2 mg/kg IV is a less desirable alternative due to longer onset of action and potent venodilation at RSI doses, though it can be used when other agents are contraindicated 1, 2

Etomidate and Adrenal Suppression Controversy

• Etomidate inhibits 11-beta-hydroxylase, but multiple RCTs show no mortality benefit from administering hydrocortisone after etomidate use for RSI 1

• Routine corticosteroid administration following etomidate for RSI is not recommended, though specific populations (cirrhosis with septic shock, noncardiac surgery patients) may benefit 1

Neuromuscular Blocking Agents

Succinylcholine vs. Rocuronium

Either succinylcholine or rocuronium can be used as first-line neuromuscular blocking agents when there are no contraindications to succinylcholine. 1, 2

• Succinylcholine 1-1.5 mg/kg IV has rapid onset (45-60 seconds) and short duration (5-10 minutes), making it ideal for RSI 1, 2

• Rocuronium 0.9-1.2 mg/kg IV (high-dose for RSI) provides similar first-pass success rates to succinylcholine, with onset in 1-2 minutes but longer duration (30-60 minutes) 1, 2

• A large RCT of 1,248 patients showed first-pass success rates of 74.6% with rocuronium versus 79.4% with succinylcholine (difference -4.8%, inconclusive for noninferiority) 1

• Critical caveat: The longer duration of rocuronium may delay post-intubation analgosedation provision, potentially increasing risk of patient awareness during neuromuscular blockade 1

Contraindications to Succinylcholine

• Hyperkalemia (risk of cardiac arrest) 4
• Known or suspected malignant hyperthermia
• Neuromuscular disorders
• Severe burns or crush injuries (>24-48 hours old)
• When these contraindications exist, rocuronium is the preferred alternative 1, 2

Neuromuscular Blocking Agent Use: Essential Recommendation

Always administer a neuromuscular blocking agent when using a sedative-hypnotic induction agent for intubation. 1

• Use of NMBAs significantly improves first-pass success rates: 80.9% with NMBA versus 69.6% without (p=0.003) 1

• NMBAs provide optimal intubating conditions by eliminating muscle tone and preventing patient movement 1

• The concern about "cannot intubate, cannot ventilate" scenarios should not prevent NMBA use, as intubations without NMBAs have lower success rates and potentially higher complication rates 1

Pretreatment Medications (Limited Role)

Pretreatment medications have fallen out of favor in adult RSI due to limited evidence, but specific scenarios may warrant their use. 3

• Lidocaine 1-2 mg/kg IV may be considered 30 seconds to 5 minutes before intubation in patients with increased intracranial pressure, though evidence is low quality 2

• Fentanyl pretreatment is not routinely recommended in the ED setting 3

• Atropine is not routinely used in adult RSI 3

Post-Intubation Analgosedation: Critical Pitfall

Immediately provide post-intubation sedation and analgesia after successful intubation, especially when rocuronium is used. 1

• Studies show post-intubation analgosedation is provided more rapidly when succinylcholine is used compared to rocuronium, likely because rocuronium's longer duration masks patient movement that would otherwise prompt sedation 1

• Seven of 10 patients reporting post-intubation awareness had received a longer-acting NMBA 1

• Consider implementing protocolized post-intubation analgosedation protocols and involving clinical pharmacists to improve timeliness 1

Special Population: Pediatric Considerations

For pediatric patients requiring RSI, the medication approach differs slightly:

• Atropine 0.01-0.02 mg/kg IV (maximum 0.5 mg) should be administered before intubation in children aged 28 days to 8 years, particularly with septic shock, hypovolemia, or when succinylcholine is used, to prevent bradycardia 2, 4

• Pediatric succinylcholine dosing is age-dependent: 1-1.5 mg/kg for children >10 years, 1.2 mg/kg for ages 1-10 years, 2.0 mg/kg for infants 1 month to 1 year 2, 4

Reversal Agents: Must Be Available

• Sugammadex should be rapidly available when rocuronium is used for potential reversal in "cannot intubate, cannot ventilate" scenarios 2, 4

• Flumazenil can reverse benzodiazepine-induced respiratory depression but will also reverse anticonvulsant effects 1, 2