Is succinylcholine, ketamine, and midazolam (Versed) appropriate for Rapid Sequence Intubation (RSI) induction?

Succinylcholine, Ketamine, and Midazolam for Rapid Sequence Intubation

Yes, the combination of succinylcholine, ketamine, and midazolam is appropriate for Rapid Sequence Intubation (RSI), with each medication serving a specific purpose in the intubation process. 1

Medication Components for RSI

Neuromuscular Blocking Agents (NMBA)

• Succinylcholine (1.5 mg/kg IV) is an appropriate NMBA choice for RSI when there are no contraindications 1, 2
• The Society of Critical Care Medicine guidelines specifically recommend administering either rocuronium or succinylcholine for RSI 1
• Caution is needed in pediatric patients as succinylcholine has been associated with cardiac arrest in undiagnosed myopathies 2

Induction Agents

• Ketamine (1-2 mg/kg IV) is an appropriate induction agent for RSI due to its:
  • Quick onset and short duration of action 1
  • Preservation of respiratory drive 1
  • Sympathomimetic properties that help maintain hemodynamic stability 1, 3
• Guidelines advise administering a sedative-hypnotic induction agent when an NMBA is used for intubation (best practice statement) 1

Sedative Agents

• Midazolam (0.1-0.2 mg/kg IV) can be used as an adjunctive sedative 4, 5
• While midazolam has a longer onset of action compared to other induction agents and is a potent venodilator, it can be beneficial when combined with ketamine 1, 6

Important Considerations

Medication Sequence and Timing

• A sedative-hypnotic agent (ketamine) should be administered before the neuromuscular blocking agent (succinylcholine) 1
• Failure to provide adequate sedation before paralysis can result in awareness during paralysis, which occurs in approximately 2.6% of emergency department intubations 1

Hemodynamic Considerations

• Ketamine's sympathomimetic properties make it particularly valuable in hemodynamically unstable patients 1, 4
• Midazolam doses should be reduced in hemodynamically unstable patients due to its vasodilatory effects 1, 5
• Drug interactions should be monitored as midazolam metabolism can be affected by other medications (e.g., erythromycin, diltiazem) 5

Contraindications and Special Populations

• Succinylcholine should be used with caution in pediatric patients due to risk of cardiac arrest in undiagnosed myopathies 2
• Pregnant patients may have decreased plasma cholinesterase levels, potentially leading to prolonged apnea with succinylcholine 2
• Elderly patients may require lower doses of midazolam due to altered pharmacokinetics 5

Protocol Implementation

• Standardized RSI protocols using ketamine and neuromuscular blockers have been shown to:
  • Decrease time from drug administration to intubation 3
  • Reduce the need for medication redosing 3
  • Facilitate efficient airway management in critically injured patients 3

This medication combination provides effective conditions for intubation while balancing the need for sedation, analgesia, and muscle relaxation during this critical procedure.