What is the recommended dosing of etomidate (amidate) for routine induction of anesthesia and rapid sequence intubation (RSI)?

Etomidate Dosing for Routine Induction and Rapid Sequence Intubation

For routine anesthesia induction in adults and children >10 years, administer etomidate 0.3 mg/kg IV over 30-60 seconds; for rapid sequence intubation, use the same dose (0.2-0.3 mg/kg) as part of a modified RSI protocol with immediate muscle relaxant administration. 1

Standard Dosing Protocol

Routine Induction of Anesthesia

• The FDA-approved dose for routine induction is 0.2-0.6 mg/kg IV, with 0.3 mg/kg being the standard dose for adults and pediatric patients >10 years old, administered over 30-60 seconds 1
• Pediatric patients <10 years have inadequate safety data and routine use is not recommended by the FDA 1
• However, the American Academy of Pediatrics supports 0.2 mg/kg IV as an initial dose in pediatric patients for procedural sedation, which provides adequate sedation in 60-67% of cases 2, 3
• Maximum total dose should not exceed 0.3 mg/kg in pediatric patients to minimize respiratory depression risk 2, 3

Rapid Sequence Intubation

• For RSI, use etomidate 0.2-0.3 mg/kg (typically midazolam 2-5 mg with etomidate 10-20 mg in adults) followed immediately by succinylcholine 1 mg/kg or rocuronium 0.9-1.2 mg/kg after loss of consciousness 4
• The Chinese Society of Anesthesiology recommends midazolam 2-5 mg combined with etomidate 10-20 mg for induction, with fentanyl 100-150 µg or sufentanil 10-15 µg to suppress laryngeal reflexes 4
• Administer muscle relaxant immediately after loss of consciousness and perform intubation after muscle fasciculation is complete (succinylcholine) or adequate paralysis is achieved (rocuronium) 4

Special Population Adjustments

Geriatric Patients

• Reduce etomidate doses in elderly patients due to decreased initial distribution volume and clearance (approximately 2 ml/min/kg decrease per decade) 1, 5

Hemodynamically Unstable Patients

• Etomidate is the preferred induction agent for hemodynamically unstable patients due to its remarkably stable cardiorespiratory profile with no cardiovascular or respiratory depression 6, 7
• Recent evidence suggests ketamine may provide superior Day 7 survival compared to etomidate (85.1% vs 77.3%, p=0.005), though Day 28 survival was not significantly different 8
• Consider ketamine 1-2 mg/kg as an alternative in critically ill patients requiring emergency intubation, particularly if short-term survival is the priority 8

Adverse Effect Prevention

Myoclonus Reduction

• Pre-treat with fentanyl or droperidol to reduce myoclonus incidence from 37.9% to 11-12.5% 4, 2
• Alternative strategy: administer a priming dose of etomidate 0.03 mg/kg 60 seconds before the induction dose, which reduces myoclonus from 87% to 26% 9
• Myoclonus occurs in 4-38% of patients and may require brief respiratory support 4, 3

Adrenal Suppression Management

• Etomidate should NOT be used routinely in pediatric patients with septic shock due to adrenal suppression 4
• For high-risk patients, the Society of Critical Care Medicine recommends hydrocortisone 100 mg IV bolus immediately before etomidate administration 2
• Single-dose etomidate causes biochemical cortisol suppression but is acceptable for brief procedures in hemodynamically stable patients 2

Monitoring Requirements

• Continuous pulse oximetry and cardiac monitoring are mandatory throughout the procedure 2, 3
• Regular blood pressure measurements and respiratory rate/effort assessment are required 3
• Resuscitation equipment must be immediately available 2, 3
• Respiratory depression occurs in approximately 16% of patients, usually manageable with supplemental oxygen 2, 3
• Oxygen desaturation (5-39% incidence) is more common at doses ≥0.23 mg/kg 2, 3

Critical Pitfalls to Avoid

• Do not exceed 0.3 mg/kg total dose in pediatric patients 2, 3
• Do not use etomidate for prolonged infusions due to sustained adrenal suppression 6
• Do not use routinely in septic shock patients, particularly pediatric patients 4
• Avoid rapid injection (<30 seconds) as this increases pain on injection and myoclonus incidence 1
• Do not use in patients <10 years for routine induction per FDA labeling, though off-label use at 0.2 mg/kg is supported by pediatric guidelines 1, 2

Maintenance Dosing

• For short operative procedures, smaller incremental doses than the original induction dose may be used to supplement subpotent agents like nitrous oxide, though specific dosing must be individualized 1
• For infusions >2 hours, decrease maintenance dose by half (to approximately 0.0025 mg/kg/min) to prevent cumulative effects due to the 4-5 hour elimination half-life 5
• Insufficient data exist to support maintenance use in pediatric patients 1