Quiz 10 - Inhalation Agents and MAC

Question 1

What is MAC amnesia?

Answer 1

25% MAC (blocks anterograde memory in 50% of awake patients)

Question 2

What is MAC awake?

Answer 2

50% MAC - prevents eye opening on verbal command

Question 3

What is MAC intubation?

Answer 3

130% MAC - concentration required to prevent movement and coughing during ETT intubation

Question 4

What is MAC BAR?

Answer 4

150% MAC - concentration that blocks adrenergic response to skin incision

Question 5

What factors increase MAC?

Answer 5

Age - term infant to 6mos has highest MAC
Chronic ETOH abuse
Hyperthermia
Hypernatremia

Question 6

What are some factors that decrease MAC?

Answer 6

• Pregnancy
• Hypothermia (every 1 degree C drop in temp, MAC decreases 2-5%)
• Elderly
• Acute ETOH ingestion
• Premature infants
• preop meds
• hyponatremia

Question 7

Factors that have no effect on MAC

Answer 7

• Thyroid gland dysfunction
• Gender
• Hypo/Hyperkalemia
• Hypo/Hypercarbia

Question 8

MAC for ISO?

Answer 8

1.15 (according to notes)

Question 9

MAC for Sevo?

Answer 9

2.05 (according to notes)

Question 10

MAC for Des?

Answer 10

6 (according to notes)

Question 11

MAC for N2O?

Answer 11

105 (according to notes)

Question 12

MAC for Halothane?

Answer 12

0.75

Question 13

What alveolar factors influence uptake?

Answer 13

Inspired concentration, Alveolar ventilation, Anesthetic system, uptake from alveolar space

Question 14

What is the single most important factor determining the speed of induction and rate of emergence?

Answer 14

Solubility

Question 15

How is solubility of gasses expressed?

Answer 15

Blood:Gas partition coefficient

Question 16

Blood gas coefficient for Des?

Answer 16

0.42

Question 17

Blood gas coefficient for N2O?

Answer 17

0.47

Question 18

Blood gas coefficient for Sevo?

Answer 18

0.68 (according to notes)

Question 19

Blood gas coefficient for Iso?

Answer 19

1.4 (according to notes)

Question 20

Which gas will have the quickest onset a poorly soluble agent or a highly soluble agent?

Answer 20

the poorly soluble agent

Question 21

How does Cardiac Output affect induction of anesthesia?

Answer 21

CO is inversely proportional to the speed of induction - low CO will have quicker induction

Question 22

What is Second Gas effect?

Answer 22

The ability of a gas (N2O) with rapid induction to speed up the rise in alveolar pressure of a second gas (agent)

Question 23

What is diffusion hypoxia?

Answer 23

dilution of alveolar oxygen by a large amount of N2O “outgassing” - rapid desaturation can be seen - stop N2O before extubating and turn 100% oxygen on.

Question 24

Is N2O a good analgesic?

Answer 24

yes

Question 25

Does N2O increase or decrease PONV?

Answer 25

increases

Question 26

When should you avoid N2O use?

Answer 26

when you have enclosed gas spaces: Pneumothorax, bowel obstruction, inner ear...

Question 27

Will N2O increase or decrease PVR?

Answer 27

increase PVR - especially in pt with pre-existiing pulmonary HTN

Question 28

Is N2O flammable?

Answer 28

No, but it is an O2 source and supports combustion

Question 29

How does N2O affect methionine synthesis?

Answer 29

It inhbits (important for B12 and DNA sythesis)

Question 30

What can long term use of N2O lead to?

Answer 30

peripheral neuropathy and megaloblastic anemia

Question 31

How does Halothane affect contractility?

Answer 31

Halothane has a dose dependent decrease in contractility. Will also decrease BP, CO. SVR and PVR stay normal

Question 32

What gives Halothane its sweet odor?

Answer 32

Thymol preservative

Question 33

What effect can Halothane have on children? What do they require preanesthesia?

Answer 33

causes Vagal stimulation in children (bradycardia especially > 1 MAC) pretreat with atropine

Question 34

What side effect does Halothane have on the heart?

Answer 34

sensitzes the heart to catecholemines, dysrhythmogenic - use epi with caution!

Question 35

Iso and Des are good for inhalation induction (t/f)

Answer 35

False, the pungent odor can iritate sensitive airways

Question 36

Will Iso and Des increase HR?

Answer 36

yes when rapidly increasing doses (norepi)

Question 37

What is coronary steal syndrome and which agent causes it?

Answer 37

normal coronaries dilate and stenotic ones don't so blood is shunted away from diseased vessels - caused by Iso

Question 38

Does Sevo have a pungent smell?

Answer 38

No, makes it a good choice for inhalation induction and children tolerate high levels within significant hemodynamic changes

Question 39

what is a side effect of Sevo you need to look for in children?

Answer 39

occasional delirium.

Question 40

How does Sevo form Compound A? | Consequences?

Answer 40

Formed with low fresh gas flow, high temps, high agent, dry baralyme, and long cases. - is nephrotoxic, hepatotoxic, and brain toxic

Question 41

How much fresh gas flow do you need when using Sevo?

Answer 41

at least 2 liters/min