What are the clinical uses and dosing guidelines for etomidate (amidate) in anesthesia and sedation?

Etomidate: Clinical Uses and Dosing Guidelines

Primary Clinical Indications

Etomidate is a first-line induction agent for rapid sequence intubation in hemodynamically unstable critically ill adults, dosed at 0.3 mg/kg IV over 30-60 seconds, due to its superior hemodynamic stability compared to other sedative-hypnotics. 1, 2, 3

Rapid Sequence Intubation (RSI)

• Etomidate (0.3 mg/kg IV) is the preferred induction agent for hemodynamically unstable patients requiring emergency intubation, as it maintains cardiovascular stability better than alternatives 2, 3
• The Society of Critical Care Medicine recommends etomidate as a reasonable first-line RSI induction agent for critically ill patients, with no demonstrated mortality difference compared to other agents 1
• Must always be followed by a neuromuscular blocking agent (succinylcholine 1-1.5 mg/kg or rocuronium 0.9-1.2 mg/kg) to prevent awareness during paralysis 2

Procedural Sedation

• For conscious sedation in adults, the typical dose ranges from 0.1-0.3 mg/kg IV administered over 30-60 seconds 4, 3
• In pediatric patients (>10 years), initial dosing of 0.1-0.2 mg/kg IV is recommended, with 0.2 mg/kg providing adequate sedation in 60-67% of cases 5
• Maximum total dose should not exceed 0.3 mg/kg to minimize respiratory depression risk 4, 5

Dosing by Clinical Context

Adult RSI Dosing

• Standard induction dose: 0.3 mg/kg IV over 30-60 seconds 2, 3
• Dosing range: 0.2-0.6 mg/kg, though higher doses increase adverse effects 3
• Geriatric patients may require reduced doses due to increased risk of hemodynamic changes 3

Pediatric Dosing

• Children >10 years: 0.2-0.6 mg/kg IV for anesthesia induction (same as adults) 3
• Procedural sedation in children: 0.1-0.2 mg/kg IV, with 0.2 mg/kg as the most effective initial dose 5
• Inadequate data exists for children <10 years for anesthesia induction; such use is not FDA-recommended 3
• Multiple pediatric studies used mean doses of 0.3-0.37 mg/kg for RSI with minimal hemodynamic changes 1

Critical Safety Considerations

Adrenal Suppression Controversy

• Single-dose etomidate causes transient adrenal suppression lasting 6-8 hours, but corticosteroid supplementation is NOT recommended 1, 2, 3
• The Society of Critical Care Medicine found no mortality difference between etomidate and other agents despite adrenal effects 1
• However, pediatric guidelines explicitly recommend AGAINST etomidate in septic shock, favoring ketamine instead 2
• In adult septic patients, the clinical significance of adrenal suppression remains controversial, with no conclusive evidence of harm from single doses 1, 6

Hemodynamic Profile

• Etomidate causes minimal cardiovascular changes: mean arterial pressure decreases only 1-8.5%, with negligible heart rate changes 1, 7
• In geriatric patients with hypertension, etomidate may cause decreases in heart rate, cardiac index, and mean arterial pressure 3
• Maintains more stable hemodynamics than ketamine in some studies, though data is mixed regarding peri-intubation hypotension 1

Common Adverse Effects

• Myoclonus occurs in 4-38% of patients and can be reduced with fentanyl or droperidol pretreatment 5, 8
• Vomiting occurs in 4-10% of patients 4, 5
• Respiratory depression/oxygen desaturation occurs in 5-39% of patients, usually manageable with supplemental oxygen 4, 5
• Higher doses (>0.3 mg/kg) significantly increase respiratory depression risk, especially in patients >55 years 4, 5
• Pain at injection site is common 7

Administration Protocol

Preparation and Monitoring

• Administer IV push over 30-60 seconds to minimize side effects 5, 3
• Continuous monitoring of vital signs, oxygen saturation, cardiac rhythm, and level of consciousness is mandatory 4, 5
• Resuscitation equipment and vasopressors must be immediately available 2, 5
• Inspect solution for clarity and particulate matter before administration 3

Adjunctive Medications

• Consider fentanyl (0.1 mg IV) 1-2 minutes before etomidate to reduce myoclonus and potentially decrease required etomidate dose 5, 3
• Atropine pretreatment used in 37-74% of pediatric RSI cases in published studies 1
• Compatible with commonly administered pre-anesthetic medications 3

Key Clinical Pitfalls

Avoid These Common Errors

• Never use etomidate for continuous infusion - this practice was abandoned >20 years ago due to increased mortality 6
• Do not exceed 0.3 mg/kg in older patients due to significantly increased respiratory depression risk 4, 5
• Avoid in pediatric septic shock - use ketamine instead per pediatric guidelines 2
• Do not assume etomidate provides analgesia - it has no analgesic properties 3
• Etomidate does not blunt sympathetic response to intubation 8

Special Populations

• Patients with epileptogenic foci: Etomidate may activate seizures 8
• Adrenal insufficiency: Use with extreme caution 5
• Hypovolemia/severe trauma: Insufficient data to predict cardiovascular response 3
• Intra-arterial injection is not recommended, though less likely to cause tissue necrosis than thiobarbiturates 3

Pharmacodynamics

• Onset of action: Within 1 minute (usually within 10 seconds) 3, 7
• Duration: 3-5 minutes with standard 0.3 mg/kg dose 3
• Reduces cerebral blood flow and oxygen utilization by 20-30% uniformly 3
• Minimal effect on myocardial metabolism, cardiac output, or pulmonary circulation in cardiovascular disease 3
• Does not significantly elevate plasma histamine 3