Induction Meds: Etomidate

Question 1

In general, thiobarbiturates are much more _____ soluble and have a greater _______ than oxybarbiturates.

What atom do thiobarbiturates have in lieu of an oxygen in the second position (like oxybarbiturates)?

Answer 1

• Lipid; potency
• Sulfur

Question 2

What is unique about Etomidate’s organic chemical structure?

Answer 2

It is the only carboxylated imidazole containing compound.

Question 3

When is etomidate water-soluble vs lipid-soluble?

Answer 3

• H₂O-soluble at acidic pH.
• Lipid-soluble at physiologic pH.

Question 4

What percentage of etomidate is propylene glycol?
What is the result of this?

Answer 4

• 35% propylene glycol
• resulting in pain on injection and venous irritation.

Question 5

Which induction agent can be given without an IV?
How is this?

Answer 5

Etomidate - can be given sub-lingual.

Only drug with direct systemic absorption in oral mucosa that bypasses hepatic metabolism

Question 6

Why does etomidate have a low incidence of myoclonus?

Answer 6

• Trick Question. Etomidate has a high incidence of myoclonus, just like all other induction agents.

Question 7

What is the onset of Etomidate?

Answer 7

1 minute

Question 8

What is etomidate’s Vd?
How does clearance compare to thiopental?
What is the result of this clearance?

Answer 8

• Large Vd
• 5x faster clearance than thiopental resulting in a prompt awakening.

Question 9

What metabolizes Etomidate?

Answer 9

Hydrolysis by hepatic microsomal enzymes and plasma esterases.

Question 10

What is the induction dosage range for Etomidate?

Answer 10

0.3 mg/kg IV

Question 11

What is the best use for Etomidate?

Answer 11

• Induction for unstable cardiac patients.

Especially with little or no cardiac reserve

Question 12

What needs to be used concurrently with etomidate when performing a laryngoscopy/tracheal intubation?
Why?

Answer 12

• use with Opioids
• etomidate has no analgesic effects.

Question 13

What is Etomidate’s most common side effect?
How often does this occur?

Answer 13

• Involuntary Myoclonic Movements
• that occurs with 50 - 80 % of administrations.

Question 14

What should be administered with Etomidate to prevent involuntary myoclonic movements?

Answer 14

Fentanyl 1-2 μg/kg IV

Question 15

Etomidate has a dose dependent inhibition of the conversion of cholesterol to _________________.

What does this mean clinically?

Answer 15

• Cortisol
• Etomidate decreases SNS capability to respond to stress (longer vent times, hypotension, etc.)

Question 16

How long does adrenocortical suppression with etomidate last?

Answer 16

• 4-8 hours.

Question 17

Compared to Thiopental, Etomidate will lower plasma concentrations of what substance?

Answer 17

Cortisol

Question 18

What are etomidate’s effects on CBF & CMRO₂ ?
Why is this and what does it do?

Answer 18

↓CBF & ↓CMRO₂ 35%-45% due to being
a potent direct cerebral vasoconstrictor.

• Will also ↓ICP.

Question 19

CMRO₂ is couple with both CBF and _______.

Answer 19

CMRG (cerebral metabolic requirement of glucose)

Question 20

What is the EEG profile of etomidate?

Answer 20

• More excitatory than thiopental
• May activate seizure foci
• Augments SSEP amplitude.

Question 21

Etomidate results in significant hypotension if _________not treated prior to induction?

Answer 21

• Hypovolemia

esp. high 0.45 mg/kg IV

Question 22

Histamine release via etomidate is mediated through what?

Answer 22

• Trick question. Etomidate does not release histamine.

Question 23

What is the pulmonary profile of etomidate?

Answer 23

• No change in minute ventilation.
  d/t increase in respiratory rate compensate decrease in tidal volume
• Less respiratory depression than barbiturates
• Rapid IV produces apnea
  -Stimulates CO₂ medullary centers

Question 24

How much of Etomidate is protein bound?
What protein does it bind to?

Answer 24

76% albumin bound

Question 25

What is the Elimination Half-time and profile of Etomidate?

Answer 25

Elimination 1/2 time: 2-5 hours

Elimination:
* 85% in urine
* 10% - 13% in bile

Question 26

What is Etomidate an alternative for IV induction?

Answer 26

Propofol or Barbituates

Question 27

Drug effects that Etomidate does not have?

Answer 27

No hangover or cumulative drug effect

Question 28

What two pathologies would cause you to hesitate before giving Etomidate?

Answer 28

Caution with sepsis and hemorrhage

Question 29

positive side effects of Etomidate

Answer 29

• CV stable
• minimal changes in HR, SV, CO, and contractility
• No intra-arterial damage