Inhaled anesthetics 2: pharmacodynamics 2

Question 1

Modern theory of anesthetic action suggests inhaled anesthetics: (select 2)
a. interact with stereoselective receptors
b. stimulate the NMDA receptor
c. Produce immobility by binding in the dorsal horn of the spinal cord
d. facilitate GABA transmission

Answer 1

A. interact with stereoselective receptors
d. facilitate GABA transmission

Question 2

The primary target of halogenated anesthetics in the brain is

Answer 2

the facilitation of the GABA-A receptor

Question 3

The primary target of volatile anesthetics in the spinal cord is

Answer 3

stimulation of glycine channels and inhibition of NMDA receptors and sodium channels

Question 4

Volatile anesthetics produce immobility in the ______ horn of the spinal cord.

Answer 4

ventral

Question 5

As a general rule, volatile anesthetics either

Answer 5

stimulate inhibitory receptors or inhibit stimulatory receptors

Question 6

The gaseous anesthetics (nitrous oxide and xenon) target

Answer 6

the NMDA receptor (antagonism) and the potassium 2P-channel (stimulation)

Question 7

What inhibitory pathways do volatile anesthetics stimulate?

Answer 7

GABA-A receptor
potassium channels
Glycine channels

Question 8

What stimulatory pathways do volatile anesthetics inhibit?

Answer 8

NMDA
nicotinic
sodium channels
dendritic spine function and motility

Question 9

How do volatile anesthetics produce amnesia?

Answer 9

amygdala & hippocampus

Question 10

Autonomic effects of volatile anesthetics are produced in the

Answer 10

pons & medulla

Question 11

Analgesia is produced in the

Answer 11

spinothalamic tract

Question 12

Immobility is produced in the

Answer 12

ventral horn of the spinal cord

Question 13

Volatile anesthetics produce unconsciousness by interacting in the

Answer 13

cerebral cortex, thalamus, and reticular activating system

Question 14

Regarding the modern halogenated anesthetics in the adult at 1 MAC:
a. QT interval increases
b. Heart rate decreases
c. systemic vascular resistance increases
d. mean arterial blood pressure increases

Answer 14

a. QT interval increases

Question 15

Nitrous oxide __________MAP and ______________SVR by ____________

Answer 15

increases MAP & SVR by SNS activation

Question 16

Current thinking disputes the theory of _______ steal. Volatile anesthetics precondition

Answer 16

coronary steal. precondition the myocardium and protect it against ischemia

Question 17

Halogenated anesthetics ___ MAP in

Answer 17

reduce MAP in a dose-dependent fashion
(at equivalent doses, there’s little difference between agents)

Question 18

Which halogenated agents increase heart rate?

Answer 18

isoflurane & desflurane (sevoflurane does not)

Question 19

Which agent reduces SVR the least?

Answer 19

Sevoflurane

Question 20

Halogenated decrease __________ in a dose-dependent fashion.

Answer 20

contractility & SVR

Question 21

What are the cardiovascular effects of halogenated agents?

Answer 21

anesthetic preconditioning
vasodilation
cardiac dysrhythmias
myocardial depression

Question 22

In cardiac muscle and vascular smooth muscle, volatile anesthetics reduce ______ influx in the sarcolemma

Answer 22

Calcium 2+ influx and decrease Ca2+ release from the SR

Question 23

How do halogenated agents directly affect cardiac conduction?

Answer 23

decreased SA node automaticity
decreased conduction velocity through the AV node, His-Purkinje system, and ventricular conduction pathways
altered baroreceptor function
increased duration of myocardial repolarization by impairing the outward K+ current–> prolongs the QT interval

Question 24

Rapid increases in desflurane and to a lesser degree isoflurane cause

Answer 24

tachycardia

Question 25

How can desflurane & isoflurane lead to tachycardia?

Answer 25

pulmonary irritation--> SNS activation--> increased norepinephrine release--> beta 1 stimulation

Question 26

Volatile anesthetics increase ___________ blood flow in excess of

Answer 26

coronary; myocardial oxygen demand

Question 27

Potency of coronary artery vasodilation from greatest to least

Answer 27

isoflurane>desflurane>sevoflurane

Question 28

Regarding the modern halogenated anesthetics in the adult at 1 MAC: a. minute ventilation increases b. airway diameter decreases c. dead space decreases d. respiratory rate increases

Answer 28

d. respiratory rate increases

Question 29

The currently available halogenated anesthetics have the following effects on PaCO2:

Answer 29

hypercapnia altered respiratory rate increased apneic threshold relaxation of the muscle leading to airway obstruction bronchodilation

Question 30

How does hypercapnia with halogenated anesthetics occur?

Answer 30

hypercapnia through depression of the central chemoreceptor and respiratory muscles

Question 31

What altered respiratory pattern do halogenated agents produce?

Answer 31

decreased Vt and increased RR

Question 32

How to volatile anesthetics contribute to hypercarbia?

Answer 32

altering the respiratory pattern impairing the response to carbon dioxide impairing motor neuron output and muscle tone to the upper airway and thoracic muscles

Question 33

_______- can induce bronchoconstriction in asthmatics

Answer 33

Desflurane

Question 34

How does a decrease in response to carbon dioxide effect the carbon dioxide response curve?

Answer 34

shifts the CO2 response curve down and the right

Question 35

What is the apneic threshold?

Answer 35

the PaCO2 at which a patient is stimulated to breathe

Question 36

What are causes of a left-shift to the carbon dioxide response curve?

Answer 36

stimulates ventilation! anxiety surgical stimulation metabolic acidosis increased ICP salicylates aminophlie doxapram

Question 37

What are the causes of right-shift to the carbon dioxide response curve?

Answer 37

depresses ventilation! general anesthetics opioids metabolic alkalosis denervation of peripheral chemoreceptors

Question 38

A right shift of the carbon dioxide response curve produces

Answer 38

respiratory acidosis

Question 39

A left shift of the carbon dioxide response curve produces

Answer 39

a respiratory alkalosis

Question 40

How do volatile anesthetics contribute to upper airway obstruction?

Answer 40

they cause relaxation of the genioglossus or tensor palatine muscles

Question 41

Which agent impairs the hypoxic ventilatory response the LEAST? a. isoflurane b. desflurane c. sevoflurane d. these drugs produce similar degrees of depression

Answer 41

b. desflurane

Question 42

Impaired response to acute hypoxemia occurs at

Answer 42

0.1 MAC

Question 43

Desflurane is the best volatile anesthetics choice for the patient who has

Answer 43

emphysema or sleep apnea because they rely on the hypoxic drive to breathe

Question 44

In contrast to their effects on the ventilatory response to CO2, ____ & _________ do not reverse depression of the hypoxic ventilatory drive

Answer 44

pain & surgical stimulation

Question 45

Volatile anesthetics impair the ________ for up to several hours after anesthesia

Answer 45

peripheral chemoreceptors

Question 46

The _________ provides the sensory arm of the hypoxic drive

Answer 46

glomus type 1 cells in the carotid bodies

Question 47

Because anesthetic metabolism is the source of reactive oxygen species, the patients that undergo the greatest amount of

Answer 47

biotransformation in the body inhibit the hypoxic drive the most (sevo>iso>des)

Question 48

A PaO2 of ________ is a stimulus that increases minute ventilation to restore arterial oxygenation.

Answer 48

<60 mmHg

Question 49

Where are the carotid baroreceptors located?

Answer 49

carotid sinus

Question 50

Where are the carotid chemoreceptors located?

Answer 50

carotid body