Inhalation Anesthesia Part 1 - Quiz 4

Question 1

What is the chemical structure of all commonly used Inhalation Agents?

Answer 1

Ethers or Aliphatic Hydrocarbons w/ no more than 4 Carbon atoms.

Question 2

Why is the size of the Inhalation Agent molecules significant?

Answer 2

If too big, it loses its Lipid Solubility

Length is < 1.5x the diameter

Question 3

What are the Physical Properties of Modern Inhaled Anesthetics?

Answer 3

Halogenated Hydrocarbons

Except: Nitrous Oxide

Question 4

Which Gas is this?

Answer 4

Halothane

Question 5

What gas is this?

Answer 5

Isoflurane

Question 6

What Gas is this?

Answer 6

Desflurane

Question 7

What Gas is this?

Answer 7

Sevoflurane

Question 8

What characteristics are effected with halogenation of organic compounds?

(adding {F], [Cl], [Br], or [I])

Answer 8

Potency

Flammability

Chemical Stability

Arrhythmogenic Properties

Question 9

What happens as you add more fluorine atoms to an anesthetic molecule?

Answer 9

Slowing of Biodegradation

Question 10

What are the only “true gases” of inhaled anesthetics?

Answer 10

N₂O & O₂

The rest are Vapors of Volatile Liquids

Question 11

What chemical properties & Physical properties make anesthetic gases lipid soluble?

Answer 11

Non-Ionized & Low Molecular Weight

Question 12

What is the Goal of Inhaled Anesthesia and how how is that goal accomplished?

Answer 12

Produce anesthetic state by establishing partial pressure of an agent in lungs that then equalizes w/ the brain & spinal cord.

Question 13

What is the “MAC” value in regards to inhaled anesthetics?

Answer 13

MAC = Minimal Alveolar Concentration

It is the minimal concentration of vapor in the alveoli needed to prevent movement in 50% of patients in response to surgical stimulation.

Question 14

What is the definition of General Anesthesia?

Answer 14

A drug’s capacity to induce & sustain a state of

Unconsciousness
Amnesia
Analgesia
Immobility

Question 15

What is a property that Anesthetic gases do not have?

Answer 15

Pain Properties

Question 16

What is the Meyer-Overton Rule?

Answer 16

Lipid Solubility is directly proportional to Potency

Question 17

How can an Anesthetic Gas be reversed?

Answer 17

Reversal achieved with Application of Pressure

Question 18

How would a Reduction of Body Temperature affect anesthetic requirement?

Answer 18

↓Body Temp = ↓Anesthetic Requirement

Question 19

How is MAC% related to Potency & Lipid Solubility?

Answer 19

MAC% is inversely related to Potency & Lipid Solubility

The more Potent the agent, the less MAC

Question 20

What is the MAC% of N2O?

Answer 20

104

Question 21

How are Inhaled Anesthetics thought to work?

Answer 21

Enhances Inhibitory Ion Channels & Block Function of Excitatory Ion Channels

Question 22

What happens when Inhibitory Channels are Enhanced?

Answer 22

Hyperpolarization via Chloride Influx via GABA or Glycine receptors

or

or Potassium Efflux

Question 23

How is Immobility achieved with Anesthetic Gases?

Answer 23

Activates Descending Noradrenergic Pathways from brainstem and Blocks Input in Dorsal Horn

Immobility is measurable by MAC

Question 24

In an anesthetic molecule, if the carbon chain exceeds 4-5 carbons, what happens?

Answer 24

Loss of Immobility

Question 25

What are the structural targets that are involved in the Amnestic effects fo anesthesia?

Answer 25

Amygdala Hippocampus Cortex

Question 26

In terms of delivery, What are the factors that determine Inspired Gas Concentration?

Answer 26

Fresh Gas Flow Rate Circuit Volume Circuit Absorption

Question 27

What factors determine Alveolar Gas Concentration?

Answer 27

1. Uptake 2. Ventilation 3. Concentration Effect 4. Second Gas Effect * Augmented Inflow effect

Question 28

When is Equilibrium of Anesthetic Gas achieved?

Answer 28

When partial pressures are equal in the alveoli, blood, and CNS **P**_alveoli = **P**_blood = **P**_CNS

Question 29

What are the factors that contribute to Anesthetic Gas Equilibrium?

Answer 29

* Inhaled Gas moves quickly to and from lung, blood, & CNS * Plasma and tissue dont absorb the gas * Minimal Gas metabolism, excretion, and redistribution

Question 30

In a container, how is vapor pressure related to the volume of the Liquid?

Answer 30

As long as there is liquid in the container, Vapor Pressure is **independent** of the volume of the liquid

Question 31

What is Henry's Law?

Answer 31

Relationship of Concentration of a Gas in a solution to the Partial Pressure of the Gas

Question 32

In Anesthesia, gases equilibrate based on what?

Answer 32

**Partial Pressures**, not Concentration

Question 33

How is the rate of Gas Uptake related to Blood Solubility?

Answer 33

Speed of Uptake & Elimination from brain is **inversely** related to Blood Solubility

Question 34

What is a Aliphatic Compound?

Answer 34

Hydrocarbon Compound containing carbon & hydrogen in straight chains, branched or non-aromatic rings

Question 35

The _____ blood-soluble the gas, the _____ the onset of action of the gas

Answer 35

The **Less** blood-soluble the gas, the **faster** the onset of action Vice Versa

Question 36

List in order the rate of onset from fastest to slowest for N2O, Des, Sevo, Isoflurane, Enflurane

Answer 36

Desflurane \> N2O \> Sevo \> Isoflurane \> Enflurane

Question 37

What is the MAC% for Desflurane?

Answer 37

6%

Question 38

What is the MAC% for Sevoflurane?

Answer 38

2%

Question 39

What is the MAC% for Isoflurane?

Answer 39

1.4%

Question 40

What is the λoil:gas for N2O?

Answer 40

1.4

Question 41

What is the λoil:gas for Desflurane?

Answer 41

19

Question 42

What is the λoil:gas for Sevoflurane?

Answer 42

51

Question 43

What is the λoil:gas for Isoflurane?

Answer 43

98

Question 44

What is the λblood:gas for N2O?

Answer 44

0.47

Question 45

What is the λblood:gas for Desflurane?

Answer 45

0.45

Question 46

Wht is the λblood:gas for Sevoflurane?

Answer 46

0.65

Question 47

What is the λblood:gas for Isoflurane?

Answer 47

1.4