Intravenous anesthetics 2

Question 1

Ketamine: (select 3)
a. causes emergence delirium
b. agonizes the N-methyl-D-aspartate receptor
c. relieves somatic pain
d. increases the risk of depression
e. increases the cerebral metabolic rate of oxygen consumption
f. promotes bronchoconstriction

Answer 1

a. causes emergence delirium
c. relieves somatic pain
e. increases the cerebral metabolic rate of oxygen consumption

Question 2

What is the primary mechanism of action of ketamine?

Answer 2

NMDA antagonist (creates a dissociated state)

Question 3

What is the secondary mechanism of action of ketamine?

Answer 3

many secondary receptor targets including opioid, MAO, serotonin, NE, muscarinic, and Na+ channels

Question 4

What is the onset of IV ketamine?

Answer 4

30-60 seconds

Question 5

What is the onset of IM ketamine?

Answer 5

2-4 minutes

Question 6

What is the onset of PO ketamine?

Answer 6

variable

Question 7

What is the duration of action of ketamine?

Answer 7

10-20 minutes (may require 60-90 minutes to return to full orientation

Question 8

What is the clearance of ketamine?

Answer 8

liver

Question 9

What is the active metabolite of ketamine?

Answer 9

norketamine

Question 10

What is the IV, IM, and PO induction doses of ketamine?

Answer 10

IV: 1-2 mg/kg
IM: 4-8 mg/kg
PO: 10 mg/kg

Question 11

What is the opioid sparing dose of ketamine?

Answer 11

0.1-0.5 mg/kg or 1-3 mcg/kg/min.

Question 12

What are the respiratory effects of ketamine?

Answer 12

maintains respiratory drive, increased oral secretions, bronchial dilation

Question 13

What are the CV effects of ketamine?

Answer 13

Increased SNS tone, SVR, HR, and Cardiac output
increased pulmonary vascular resistance

Question 14

What are the CNS effects of ketamine?

Answer 14

increased ICP, IOP, nystagmus, and analgesia
also causes emergence delirium & lowers the seizure threshold

Question 15

Subhypnotic doses of ketamine may be used to

Answer 15

treat severe depression

Question 16

Ketamine should be avoided with

Answer 16

acute intermittent porphyria

Question 17

What is the pKa of ketamine?

Answer 17

7.5

Question 18

Ketamine works by

Answer 18

dissociating the thalamus (sensory) from the limbic system (awareness)

Question 19

Chronic ketamine use _______ the enzymes that metabolize it

Answer 19

induces

Question 20

Ketamine is excreted via the

Answer 20

renal system

Question 21

Because ketamine increases the SNS tone it is useful in ______ but harmful in

Answer 21

useful if the patient is hemodynamically unstable but harmful if severe CAD

Question 22

Ketamine is a ________ myocardial depressant. The CV effects require an

Answer 22

direct; intact SNS

Question 23

The myocardial depressant effects of ketamine will be unmasked in patients with

Answer 23

depleted catecholamine stores (sepsis) or sympathectomy

Question 24

How does ketamine affect the CO2 response curve?

Answer 24

it does not significantly shift it

Question 25

Emergence delirium presents as

Answer 25

nightmares and hallucinations

Question 26

_______ are the most effective way to prevent emergence delirium

Answer 26

benzodiazepines

Question 27

Risk factors for emergence delirium include

Answer 27

age >15 years, female gender, ketamine dose >2 mg/kg and hx of personality disorder

Question 28

What kind of pain is ketamine good for?

Answer 28

somatic> visceral pain

Question 29

The analgesic properties of ketamine make it good for

Answer 29

burn patients (frequent dressing changes) and those with pre-existing chronic pain syndromes

Question 30

Chronic ketamine can cause

Answer 30

ulcerative cystitis

Question 31

The S enantiomer (esketamine) is marketed as a nasal spray that's indicated for

Answer 31

treatment-resistant depression in adults as well as depressive symptoms in adults with major depressive disorder with acute suicidal ideation or behavior

Question 32

Describe ketamines protein binding.

Answer 32

smallest amount of plasma protein binding as compared to the other induction agents at 12%

Question 33

Central nervous system effects of etomidate include (select 2): a. cerebral vasodilation b. myoclonus c. analgesia d. decreased intracranial pressure

Answer 33

b. myoclonus d. decreased intracranial pressure

Question 34

The mechanism of action of etomidate is

Answer 34

GABA-A agonist

Question 35

The onset of action of etomidate is

Answer 35

30-60 seconds

Question 36

The duration of action of etomidate is

Answer 36

5-15 minutes

Question 37

The clearance of etomidate is

Answer 37

liver + plasma esterases

Question 38

The active metabolite of etomidate is

Answer 38

none

Question 39

The induction dose of etomidate is:

Answer 39

0.2-0.4 mg/kg IV

Question 40

The respiratory effects of etomidate include

Answer 40

mild respiratory depression

Question 41

The CV effects of etomidate include

Answer 41

minimal- cardiac stability SVR is decreased which accounts for a small reduction in BP

Question 42

The CNS effects of etomidate include

Answer 42

decreased ICP decreased CMRO2 decreased CBF no analgesia

Question 43

Rapid awakening with etomidate is due to

Answer 43

redistribution (NOT metabolism)

Question 44

Etomidate does not block the SNS response to

Answer 44

laryngoscopy; should consider an opioid or esmolol

Question 45

Which anesthetic agent increases mortality in the patient with Addisonian crisis? a. etomidate b. propofol c. dexmedetomidine d. midazolam

Answer 45

a. etomidate

Question 46

A single dose of etomidate suppresses adrenocortical function for

Answer 46

5-8 hours (some books say up to 24 hours)

Question 47

Etomidate is a known inhibitor of

Answer 47

11-beta-hydroxylase 17-alpha-hydroxylase

Question 48

Key side effects of etomidate include:

Answer 48

myoclonus (this is not a seizure) etomidate does not cause seizures if the patient does not have a hx. of seizures suppression of adrenocortical function for up to 24 hours nausea & vomiting (greater than any other induction agent) acute intermittent porphyria