Inhaled anesthetics

Question 1

Nitrous oxide CNS effects

Answer 1

Increases CBF, may decreased sensory evoked potential‘s

At sea level a full MAC is unattainable 105%

Question 2

Cardiovascular effects of nitrous oxide

Answer 2

There is a tendency to stimulate the sympathetic nervous system with a small or a slight increase in heart rate blood pressure and cardiac output

Can increase PVR in adults

Question 3

Respiratory affects of nitrous oxide

Answer 3

Minimal change in minute ventilation and PaCO2
Hypoxic drive is markedly depressed

Diffusion hypoxia at the end of the case

Question 4

How does nitrous oxide cause megaloblastic anemia and peripheral neuropathy

Answer 4

It oxidizes COBOL Adam in B 12 which inhibits methionine synthetase used in Mylan formation

This also inhibits thymidylate synthetase used in DNA formation

Question 5

At what age is MAC the highest

Answer 5

Six months

Question 6

What causes Mac to be increased

Answer 6

Higher central neurotransmitters amphetamines MAOIs hyperthermia chronic ethanol hypernatremia

Question 7

What decreases Mac

Answer 7

Age hyperthermia pregnancy acute ethanol other anesthetics

Question 8

Which property of the anesthetic correlates with it’s Mac

Answer 8

Solubility in olive oil

Not blood gas solubility which correlates with FA/FI

Question 9

MAC BAR

Answer 9

Block autonomic response equals 1.5 Mac

Question 10

Meyer-Overton principle

Answer 10

Lipid solubility and potency correlation

Question 11

MAC awake

Answer 11

O.3 MAC

Question 12

ED95 of volatiles

Answer 12

1.3 MAC

Question 13

MOA of inhaled anesthetics

Answer 13

They bind ampiphillic portions of proteins

There is no social mechanism of action but does alter multiple ion exchange

Question 14

What two things do you need to know for vaporizer filling errors?

Answer 14

Vapor pressure

MAC

Question 15

Vapor pressure of des, sevo, and iso

Is vapor pressure pressure or temperature dependent?

Answer 15

Des 670

Iso 240

Sevo 160

Temperature, doesn’t matter what atmosphere you’re in

Question 16

Iso is mistakenly placed in a sevo vaporizer, and dialed in at 4%. What MAC are you reliving of iso?

Answer 16

You are overdosing the patient because iso has a higher vapor pressure at 240

4% is about 3.2 MAC of iso, yikes

Question 17

What is the recommended highest concentration of anesthetic ambient air?

Answer 17

2 ppm

If combined with nitrous, 0.5 and 25 ppm of NO

Question 18

What what would happen if you put des in an iso vaporizer?

Answer 18

Does has the highest vapor pressure therefore you would get a very high overdose very quickly

That is why des is kept in it’s own special vaporriser

Question 19

Which volatile anesthetic is the least soluble?

Answer 19

Des 0.47

Sevo 0.68