Induction Agents

Question 1

Pretreatment with what medication can decrease etomidate-induced myoclonus?

Answer 1

Opioids or benzos (fast onset, not diazepam)

Question 2

Prolonged infusions of what induction agent increases mortality in ICU patients?

Answer 2

Etomidate (likely secondary to adrenal suppression)

Question 3

Effects of ketamine on the heart

Answer 3

Increased sympathetics (increased HR, CO, SV) which masks the direct myocardial depression associated with large doses of ketamine

Question 4

Pretreatment with what medication can decreased ketamine-induced psychotomimetic effects?

Answer 4

Benzos

Question 5

Mixing which induction agent and opioids or LR can cause precipitation?

Answer 5

Thiopental

Question 6

Mechanism of action for thiopental?

Answer 6

Enhances action (increased duration) of GABA action at GABA-A receptor

Question 7

Induction dose for thiopental

Answer 7

3-5mg/kg

Question 8

What is the primary mechanism for prompt awakening after induction dose of thiopental?

Answer 8

Redistribution

Question 9

Treatment of intra-arterial injection of thiopental

Answer 9

Dilution with NS + vasomotor relaxation (lidocaine, papaverine, or phenoxybenzamine) with sympathectomy (i.e. stellate ganglion block) if meds are ineffective

Question 10

When do you worry about propofol infusion syndrome?

Answer 10

ICU patients, usually pediatric patients, when propofol used at 150-200 mcg/kg/min for hours to days

Question 11

Signs and symptoms of propofol infusion syndrome?

Answer 11

Progressive bradyarrhythmias, metabolic acidosis, cardiac arrest

Question 12

How does propofol work?

Answer 12

Stimulates GABA-A receptors

Question 13

Does propofol injection affect NMB?

Answer 13

Increases depth but not duration

Question 14

How is etomidate metabolized?

Answer 14

Ester hydrolysis (plasma and hepatic)

Question 15

How is etomidate excreted?

Answer 15

Inactive metabolites renally

Question 16

Induction dose of etomidate

Answer 16

0.3 mg/kg

Question 17

Etomidate has what EEG changes?

Answer 17

Can cause epileptiform activity and thus avoided with patients with seizures

Question 18

Which induction agents do not cause cardio depression?

Answer 18

Etomidate and Ketamine

Question 19

Which induction agents decrease ICP?

Answer 19

Propofol, thiopental, and etomidate

Question 20

Which induction agents do not cause respiratory depression?

Answer 20

Etomidate, Ketamine, Midazolam

Question 21

Which induction agents provide analgesia?

Answer 21

Ketamine

Question 22

Which induction agents cause porphyria?

Answer 22

Thiopental and etomidate

Question 23

Which induction agents cause bronchorelaxation?

Answer 23

Ketamine

Question 24

Which induction agents cause myoclonus?

Answer 24

Etomidate

Question 25

How does etomidate cause adrenal suppression?

Answer 25

Inhibits 11-beta-hydroxylase which decreases aldosterone and cortisol synthesis

Question 26

Which induction agents cause significant N/V?

Answer 26

Etomidate

Question 27

Which induction agents can cause post-op hiccups and sense of restlessness?

Answer 27

Etomidate

Question 28

Mechanism of action for ketamine

Answer 28

Non-competitive antagonism at NMDA receptors; also has local anesthetic properties; can bind mu-delta-kappa receptors, inhibits reuptake of epi, dopamine, serotonin, NE; blocks Ach receptors (anti-cholinergic symptoms)

Question 29

What neurotransmitter pairs with NMDA receptors?

Answer 29

Glutamine (excitatory)

Question 30

Which induction agent increases cerebral blood flow and ICP

Answer 30

Ketamine

Question 31

What receptor does barbiturates, benzos, and propofol target?

Answer 31

GABA-A receptors

Question 32

How do you approach patients who are allergic to egg and need propofol?

Answer 32

Most patients are allergic to egg albumin (egg whites) and not egg lecithin (yolk - what propofol is used in)

Question 33

What does it mean to be a more potent drug? A more efficacious drug?

Answer 33

More potent: same effect achieved by a lower dose More efficacious: same dose gives a lesser effect

Question 34

Blood is sampled from the hepatic vein. Which would have the lowest concentration compared to central blood: propofol, fentanyl, midazolam, etomidate, esmolol

Answer 34

Propofol: completely metabolized by the liver on a single pass Midazolam, fentanyl and etomidate are only partially metabolized on a single pass Esmolol is metabolized by RBC esterases

Question 35

A drug is highly protein bound but the patient has low levels of protein. Compared to normal protein levels, the drug would be: less efficacious, more potent, higher ED50, cleared slowly

Answer 35

More potent (more in the free/active form) ED50: dose at which 50% of patients respond - this would decrease in this case (lower dose for the same response)

Question 36

Which of the following does not work through a G-protein coupled receptor: Fentanyl, midazolam, epinephrine, serotonin, histamine

Answer 36

Midazolam (GABA-A which is a ligand-gated ion channel); the rest work through GPCR (through cAMP or IP3)

Question 37

What is the largest extrahepatic site of metabolism for propofol?

Answer 37

The lungs

Question 38

How is fospropofol different from propofol?

Answer 38

Prodrug of propofol that needs to get metabolized in the liver to become propofol and formaldehyde; thus it has a slower onset of action

Question 39

Which of the following does not have an active metabolite: midazolam, propofol, meperidine, ketamine, morphine

Answer 39

Propofol Midazolam -\> alpha-1-hydroxymidazolam Meperidine -\> normeperidine (CNS excitation in renal failure) Ketamine -\> norketamine Morphine -\> M6G