What is the recommended anesthetic agent and dosage for a rapid induction sequence?

Rapid Sequence Intubation: Recommended Anesthetic Agents and Dosages

For rapid sequence intubation in critically ill adults, administer etomidate 0.2-0.4 mg/kg IV followed by either succinylcholine 1-1.5 mg/kg IV or rocuronium 0.9-1.2 mg/kg IV, as etomidate provides the most favorable hemodynamic profile with no mortality difference compared to other agents. 1

Induction Agent Selection

First-Line: Etomidate

• Etomidate (0.2-0.4 mg/kg IV) is the preferred induction agent for critically ill patients due to its superior hemodynamic stability 1
• The Society of Critical Care Medicine guidelines confirm no significant mortality difference between etomidate and other induction agents, making hemodynamic considerations the primary selection criterion 1
• Most studies demonstrate favorable peri-intubation hemodynamics with etomidate compared to alternatives 1
• Etomidate is readily available, clinicians have extensive experience with it, and it has low cost 1

Alternative: Ketamine

• Ketamine (1-2 mg/kg IV) serves as an alternative when etomidate is contraindicated or unavailable 1, 2, 3
• Ketamine's sympathomimetic properties theoretically maintain hemodynamic stability, but evidence shows higher rates of peri-intubation hypotension compared to etomidate (18.3% vs 12.4%, OR 1.4) 1
• In septic patients specifically, ketamine caused hypotension in 51% versus 73% with etomidate in one propensity-matched study, though other registry data showed the opposite pattern 1
• In patients with depleted catecholamine stores (severe sepsis, cardiogenic shock), ketamine may paradoxically cause hypotension despite its sympathomimetic effects 3

Avoid: Propofol

• Propofol causes significant vasodilation and should be avoided in hemodynamically unstable patients 4, 5
• Propofol requires dose reduction in elderly and debilitated patients (1-1.5 mg/kg vs 2-2.5 mg/kg in healthy adults) 4

Neuromuscular Blocking Agent Selection

First-Line: Succinylcholine

• Succinylcholine 1-1.5 mg/kg IV is the first-line neuromuscular blocking agent when no contraindications exist 2, 3, 6
• Provides fastest onset and shortest duration of action 2, 3
• Intubation can be attempted after muscle fasciculation is completed 1

Alternative: Rocuronium

• Rocuronium 0.9-1.2 mg/kg IV should be used when succinylcholine is contraindicated 2, 3, 6
• At 0.6 mg/kg, rocuronium provides 99% excellent/good intubating conditions at 60 seconds, comparable to succinylcholine 6
• Higher doses (≥0.9 mg/kg) are required for optimal rapid sequence conditions 3, 6
• Sugammadex must be immediately available when using high-dose rocuronium for reversal in "cannot intubate, cannot ventilate" scenarios 3, 6
• Wait at least 60 seconds after rocuronium administration before attempting intubation 3

Critical Sequencing and Timing

Medication Administration Order

• The sedative-hypnotic agent (etomidate or ketamine) MUST be administered before the neuromuscular blocking agent to prevent awareness during paralysis 2, 3
• Failure to provide adequate sedation before paralysis results in awareness in approximately 2.6% of emergency department intubations 2
• Administer the NMBA as early as practical after induction to minimize apnea time and risk of coughing 3

Dosing Technique

• Titrate etomidate in 20 mg increments every 10 seconds until loss of consciousness, rather than rapid bolus 1
• Rapid bolus increases likelihood of undesirable cardiorespiratory depression including hypotension, apnea, and oxygen desaturation 4

Special Population Considerations

Hemodynamically Unstable Patients

• Etomidate 0.3 mg/kg IV is strongly preferred in hemodynamically unstable patients 3
• Consider lower end of ketamine dosing range (1 mg/kg) if used as alternative 3
• Have vasopressors immediately available regardless of agent chosen 3

Septic Patients

• Avoid etomidate in pediatric septic shock; use ketamine instead 3
• In adult septic patients, evidence is mixed regarding hypotension risk between agents 1
• Corticosteroid administration following etomidate is NOT recommended despite transient adrenal suppression 1, 3

Obese Patients

• Dose rocuronium based on actual body weight, not ideal body weight 6
• Dosing by ideal body weight results in longer time to maximum block and shorter clinical duration 6

Obstetric Patients (Cesarean Section)

• Rocuronium is NOT recommended for rapid sequence induction in Cesarean section patients 6
• Poor or inadequate intubating conditions occurred in 5 of 13 women when intubation was attempted at 60 seconds 6

Elderly/Debilitated Patients

• Reduce etomidate dose to approximately 1-1.5 mg/kg (20 mg every 10 seconds) 4
• Avoid rapid bolus as this population has reduced clearance and higher blood concentrations 4

Common Pitfalls and How to Avoid Them

Inadequate Neuromuscular Blockade

• Ensure full neuromuscular blockade before attempting intubation to prevent coughing or movement that increases aspiration risk 3
• Use peripheral nerve stimulator to confirm adequate blockade if uncertain 3

Etomidate-Specific Issues

• Etomidate may cause pain on injection, myoclonic movements, and transient adrenal suppression 7
• The adrenal suppression after single-dose etomidate has NOT been shown to cause clinically significant negative outcomes 1

Ketamine-Specific Issues

• In critically ill patients with depleted catecholamine stores, ketamine may cause paradoxical hypotension 3
• Registry data shows conflicting results on hypotension rates, requiring clinical judgment based on individual patient physiology 1

Inadequate Preoxygenation

• Position patient in semi-Fowler position (head and trunk inclined) to improve first-pass success 3
• Use high-flow nasal oxygen when challenging laryngoscopy is anticipated 3
• Use noninvasive positive pressure ventilation in patients with severe hypoxemia (PaO2/FiO2 < 150) 3