Inhalation Agents - Apex and Dr. C PP

Question 1

Has a single specific receptor been found for inhalational agents, mechanism of action

Answer 1

No

Question 2

Once a critical concentration of inhalation agent enters the brain and spinal cord, what ensues

Answer 2

Loss of Consciousness

Question 3

what is minimum alveola concentration?

Answer 3

The dose of an individual drug expressed in terms of the concentration required to produce immobility and 50% of patients to surgical stimulation

Question 4

What are the primary factors that influence the absorption of inhalational anesthetics?

Answer 4

Ventilation
Uptake into the blood, cardiac output, solubility of the anesthetic drug in the blood, Alviola to Venous blood partial pressure difference

Question 5

The blood :gas solubility coefficient is an indicator of?

Answer 5

The speed of uptake and elimination

Question 6

The blood: gas solubility coefficient, reflects the proportion of anesthetic that will be?

Answer 6

Soluble in the blood and not readily enter the tissues

Question 7

The more soluble, the drug, the faster or slower the uptake in the brain and spinal cord?

Answer 7

The slower the uptake, the anesthesia is achieved slower

Question 8

In pediatrics, does crying result in faster or slower loss of consciousness when inhaled anesthesia is being administered

Answer 8

Faster due to increase respiratory rate entitled volume

Question 9

Over pressuring can speed the effect of which agents? what happens after the first few minutes.

Answer 9

Can speed the effect of slow agents such as isoflurane. After the first few minutes, the dose is decreased to the normal maintenance level.

Question 10

During induction, how does an increase in cardiac output affect anesthetic onset??

Answer 10

Increases in cardiac output, slow onset. Increased cardiac output removes more anesthetic from the lungs, which slows the rise in lung and brain concentrations.

Question 11

Hypothermia and hyperthermia both have what effect on induction of inhalation anesthetics

Answer 11

Both slow induction for different reasons

Question 12

In general, which agent would have the slowest emergence and why

Answer 12

Isoflurane is the most soluble agent making its emergence longer because it wants to stay in the blood

Question 13

Is inhalation anesthetic, uptake, slower or faster in children? why?

Answer 13

Uptake faster in children than adults child’s higher alveolar, ventilation per weight accounts for this effect.

Question 14

Increase cardiac output usually delays speed of induction. Why doesn’t this occur in children?

Answer 14

Infants and children have higher cardiac output per weight than adults. This would normally slow onset; however, cardiac output distributed to vessel-rich groups in children more than in adults, as well as a lower muscle mass, meaning more agent is delivered to vital organs.

Question 15

Does midazolam, serotonin, antagonists, or parental presence have an effect on emergence agitation

Answer 15

no

Question 16

Theoretically, how may obesity effect emergence of inhaled anesthesia

Answer 16

Long procedure in morbid obesity allow for an increase in an aesthetic agent deposition into fat may prolong recovery

Question 17

During cardio, pulmonary bypass are higher or lower concentrations of tile agents needed

Answer 17

Higher concentrations needed compared to normal lung inhalation

Question 18

Why is MAC a useful tool among inhalation agents

Answer 18

Useful to compare potencies

Question 19

What is the definition of a “response” when assessing MAC level

Answer 19

Response is defined as gross purposeful movement of the head or extremities

Question 20

What is Mac-awake?

Answer 20

The Mac at which 50% of subjects or respond to command “open your eyes”

Question 21

How is regular Mac different than Mac-bar?

Answer 21

MAC-Bar is the Mac necessary to block adrenergic response to skin incision, whereas regular Mac is response via movement to surgical stimulation

Question 22

Movement is prevented in 95% of the population at what MAC

Answer 22

~1.3 MAC

Question 23

Inhalational anesthetics produce what affects in general

Answer 23

amnesia
Loss of consciousness mobility, modulate autonomic function, may provide some analgesia

Question 24

Volatile inhalation agents generally increase or decrease the cerebral metabolic rate of oxygen consumption

Answer 24

Decrease CMRO2.
But only to the extent that they reduce electrical activity

Question 25

What Mac is required to produce an isoelectric state

Answer 25

1.5-2 MAC

Question 26

Are inhalational, anesthetics, cerebral vasodilators or vasoconstrictors

Answer 26

Vasodilators

Question 27

Inhalation agents decrease CMRO2, when metabolic demand decreases the brains blood vessels constrict, however, volatile agents are vasodilators as well. Therefore we say volatile anesthetics do what to CMRO2 and CBF?

Answer 27

Uncouples CMRO2 and Cerebral Blood Flow

Question 28

At concentrations above 0.5 MAC volatile anesthetics ______ cerebral blood flow, even though they _______ CMRO2

Answer 28

increase cerebral blood flow even though they decrease CMRO2

Question 29

What is the advantage and disadvantage of volatile anesthetics uncoupling CMRO2 and cerebral blood flow?

Answer 29

The upside is that it produces a favorable cerebral oxygen supply-demand ratio, but the downside is that it increases ICP

Question 30

Does nitrous oxide uncouple CMRO two and cerebral blood flow

Answer 30

No nitrous oxide is different. It increases cerebral blood flow as a function of increased CMRO2.

Question 31

How do Desflurane and Isoflurane impact cerebral uncoupling?

Answer 31

"Uncoupling does not seem to occur with 1 MAC or less of Des or Iso" - Dr. C Powerpoint

Question 32

What is the normal physiological response of cerebral vascular to carbon dioxide levels

Answer 32

Vasculature constricts in the presence of hypocarbia and vasodilates with hypercarbia

Question 33

If a patient has an increased ICP, what can we do with ventilation to reduce the pressure?

Answer 33

We can hyperventilate for an etCO2 around 30 to 35 mmHg. This will cause cerebral vasculature to vasoconstrict due to hypocarbia. This can be effective for approximately 4 to 6 hours.

Question 34

Volatile agents produce dose-dependent suppression or activation of EEG activity.?

Answer 34

Suppression

Question 35

Burst suppression can be achieved at what MAC of Desflurane

Answer 35

1.5-2

Question 36

Burst suppression can be achieved at what MAC of Isoflurane or Sevoflurane

Answer 36

2

Question 37

Volatile agents in nitrous oxide produce a dose-dependent reduction in evoke potential. Which are more sensitive, and which are more resistant?

Answer 37

Visual-evoked most sensitive Brainstem-evoked most resistant

Question 38

What changes are seen on EEGs or evoke potential if using volatile agents

Answer 38

An increase in latency or decrease in amplitude of evoke potential can reflect ischemia or could be secondary to the volatile agent

Question 39

What two volatile agents can cause emergence agitation in children? how long does it usually last?

Answer 39

Sevo and Des Usually lasts ~ 15min

Question 40

Iso, Des, and Sevo all have what effect on cardiac output and cardiac index

Answer 40

Reduce cardiac output in cardiac index in a dose-dependent fashion.

Question 41

Iso, Des, and Servo all have what effect on MAP via ____?

Answer 41

Reduce map via reduction in SVR

Question 42

Nitrous oxide activates the sympathetic nervous system and has an effect on SVR

Answer 42

Increases SVR

Question 43

Which inhalational agent between iso, Des and Sevo has the least effect on heart rate

Answer 43

Sevo

Question 44

Rapid increases in inhaled concentrations of which two inhalational anesthetics can lead to an increase in heart rate and blood pressure due to sympathetic activation via an irritant effect

Answer 44

Isoflurane and ***Des

Question 45

What is coronary steal? How can it be prevented?

Answer 45

Theoretically, coronary steel is a reduction in the perfusion of ischemic myocardium with simultaneous improvement of blood flow to non-ischemic tissue. A sort of taking from the poor and giving to the rich. When normotension is maintained, a steal phenomenon is avoided.

Question 46

Volatile agents reduce the quantity of catecholamine necessary to evoke arrhythmias to avoid this. What should you keep your epinephrine dose at?

Answer 46

Keep epinephrine dose less than 10 µg per kilogram

Question 47

True or false: all inhalation agents prolong the QT interval

Answer 47

True

Question 48

Which inhalation agent would be most likely to cause bradycardia or AV nodal conduction disturbance

Answer 48

Sevo

Question 49

Volatile agents have what effect on pulmonary artery pressure and PVR?

Answer 49

Decrease PA pressures and PVR

Question 50

nitrous oxide has what effect on PVR

Answer 50

In normal adults, small increase in PVR however, those with pre-existing pulmonary hypertension result in a larger increase in PVR

Question 51

how do volatile agents affect CO2 responsiveness

Answer 51

CO2 responsiveness is depressed and the apneic threshold is increased (the co2 @ which a pt is stimulated to breathe)

Question 52

how do volatile agents affect title volume and respiratory rate?

Answer 52

Agents reduce title volume as concentration of agent increases. There's a compensatory increase in respiratory rate, however not enough to prevent elevations in CO2.

Question 53

You have a V/Q mismatch, which usually is compensated for by hypoxic pulmonary vasoconstriction. Which agent has the most effect on reducing HPV?

Answer 53

Isoflurane

Question 54

what are the inhalational agents effects on airway smooth muscle?

Answer 54

Inhalational agents relax airway smooth muscle and produce bronchodilation when there is increased airway resistance. Sevo is the best at this. Once the patient is anesthetized, Iso can bronchodilate, and nitrous oxide.

Question 55

Effects of volatile anesthetics on upper airway patency

Answer 55

Agents impair the airway dilator muscles, such as the genioglossus or tensor Palatine, leading to upper airway obstruction Impaired pulmonary muscles, which decreases functional residual capacity and effectiveness of ventilation

Question 56

Which inhalation agent impaired the hypoxic drive the least? Because of this when might you choose to use it?

Answer 56

Des. One of the best choices for patients who rely on the hypoxic drive to breathe such as those with emphysema or sleep apnea.

Question 57

As a general rule, you should be concerned about nerve ischemia when measuring evoked potential when amplitude decreases by greater than _____% or latency increases by _____%

Answer 57

When amplitude decreases by greater than 50% or latency increases by greater than 10%

Question 58

According to Apex Anesthesia, the best anesthetic technique to preserve evoked potential is?

Answer 58

TIVA w/o Nitrous Oxide

Question 59

When using a volatile agent during EVP studies, using less than what Mac is recommended and supplement with what?

Answer 59

Use < 0.5MAC and supplement with IV agents such as propofol and opioids. Do not use N2O.

Question 60

how do volatile anesthetics impact the kidneys

Answer 60

Autoregulation of renal circulation generally remains intact. Reductions in SBP are accompanied by decreased renal vascular resistance, which could result in a decline in GFR. This could be why we have a reduction in urinary output intraop.

Question 61

How do the volatile aesthetics influence the neuromuscular system?

Answer 61

Of volatile agents produce Dossi pendant relaxation of skeletal muscle, as well as an additive effect with both the depolarizing and nondepolarizing muscle relaxants

Question 62

Which inhalation agents can trigger malignant hyperthermia

Answer 62

All agents except nitrous oxide

Question 63

What medication treats malignant hyperthermia

Answer 63

Raynodex and Dantrolene

Question 64

What is the connection between nitrous oxide use and pregnancy?

Answer 64

Nitrous oxide exposure has been linked to both spontaneous abortion and reduced fertility and workers

Question 65

If a pregnant patient needs non-urgent surgery which trimester should the surgery be performed in?

Answer 65

Second trimester