4. General Anesthetics - Inhaled Anesth Specific Agents

Front 1

What are the 4 specific inhaled anesthetics to know?

Back 1

I don't say no

Front 2

What is I Don't Say No?

Back 2

-Isoflurane
-Desflurane
-Sevoflurane
-Nitrous oxide

Front 3

How do the BGPC's of the inhaleds rank?

Back 3

Isoflurane = highest 1.5
Desflurane = lower .42
Sevoflurane = lower (like des)
Nitrous oxd = lower .47

Front 4

So what will be the rates of induction and recovery from isoflurane?

Back 4

Moderate

Front 5

How is Isoflurane excreted?

Back 5

Unchanged - 99% from the lungs

Front 6

What are the clinical uses of Isoflurane?

Back 6

-Induction
-Maintainance (mostly this)

Front 7

Why is Nitrous oxide often co-administered with Isoflurane?

Back 7

It reduces the dose of isoflurane needed

Front 8

Why would you want to reduce the dose of isoflurane needed?

Back 8

To reduce adverse side effects of isoflurane

Front 9

What are the 2 main types of side effects of isoflurane?

Back 9

-CV
-Respiratory

Front 10

What 3 respiratory side effects are unique to Isoflurane?

Back 10

-Airway irritant - coughing
-Decreases TV
-Increases RR

Front 11

What is a respiratory side effect that is common to all volatile anesthetics and what does it lead to?

Back 11

Respiratory depression - leads to increased arterial PCO2

Front 12

What are 3 cardiovascular side effects of isoflurane?

Back 12

-Myocardial depression leading to hypotension
-Arrythmias
-Cerebrodilation leading to increased ICP

Front 13

How does Isoflurane cause arrythmias?

Back 13

It sensitizes the heart to catecholamines

Front 14

So what drugs should NOT be given to patients under Isoflurane anesthesia?

Back 14

Dopamine or Dobutamide
or Levodopa!

Front 15

What is the blood:gas PC of Desflurane?

Back 15

LOW - .42

Front 16

So what sort of rate of induction and recovery is seen with Desflurane?

Back 16

Very rapid!

Front 17

What is needed for Desflurane administration and why?

Back 17

Special equipment to keep it in the liquid form - bc it is very volatile at room temp

Front 18

How is desflurane excreted?

Back 18

Predominantly unchanged at the lungs

Front 19

What does the very rapid rate of induction and recovery seen with Desflurane make it useful for?

Back 19

Outpatient surgeries!

Front 20

What steps in anesthesia therapy is Desflurane mainly used for and why?

Back 20

Maintainence - it causes coughing and bronchospasms in awake patients if used for induction.

Front 21

What other effect of Desflurane is of clinical use?

Back 21

It causes skeletal muscle relaxation

Front 22

How do the side effects of Desflurane compare to Isoflurane?

Back 22

-Similar CV effects (lowers BP)
-Worse respiratory irritant

Front 23

What inhaled anesthetic is used most often in hospitals?

Back 23

Sevoflurane

Front 24

What sort of blood:gas PC does Sevoflurane have?

Back 24

Very low

Front 25

What is the main pharmacokinetic difference of Sevoflurane compared to Iso/Desflurane?

Back 25

~5% of administered doses of it are metabolized to fluoride ion in the liver

Front 26

Why is it unfortunate that 5% of Sevoflurane is metabolized to F- by the liver?

Back 26

Because it may cause renal damage

Front 27

What is the good thing about Sevoflurane compared to Iso and Desflurane?

Back 27

It causes less Respiratory depression and NO airway irritation

Front 28

How does the CV depression and lowering of BP compare between all 3 - iso/des/sevoflurane?

Back 28

All 3 are similar

Front 29

What are the clinical uses of Sevoflurane?

Back 29

-Induction
-Maintenance
In both children and adults

Front 30

Which inhaled anesthetic is a true gas?

Back 30

Nitrous oxide

Front 31

How does the fact that Nitrous Oxide is a true gas affect its pharmacokinetics?

Back 31

It is very insoluble in blood and other tissues so it equilibrates very rapidly

Front 32

So what kind of rate of induction and recovery is seen with NO2?

Back 32

Very rapid

Front 33

Why is nitrous oxide often coadministered with other inhaled anesthetics?

Back 33

When given in large volumes it increases the volume of uptake of a 2nd blood-soluble anesthetic.

Front 34

So what does coadministration of NO2 and other gas anesthetics allow for?

Back 34

Lower doses of the more irritating but stronger anesthetics, but with the same results as for higher doses by themselves.

Front 35

And how does Nitrous oxide cause concentration of other gases that are coadministered with it?

Back 35

By its rapid uptake from the alveolae

Front 36

What is an adverse effect of Nitrous oxide when it is discontinued?

Back 36

It causes DILUTION of oxygen

Front 37

So what do you have to do for patients when NO2 is discontinued?

Back 37

Put them on 100% o2

Front 38

How is Nitrous oxide excreted?

Back 38

99% thru the lungs

Front 39

How clinically useful is Nitrous oxide as an anesthetic?

Back 39

Weak

Front 40

What is required for full efficacy of NO2 as an anesthetic?

Back 40

Hyperbaric conditions

Front 41

What is the highest concentration of NO2 that can be given and why?

Back 41

80% due to oxygen requirements - you need at least 20% O2 to stay alive

Front 42

So what are the 2 main clinical uses of Nitrous oxide?

Back 42

-Sedation/analgesia in outpatient dentistry
-Adjunct to other inhalational anesthetics to reduce their dose

Front 43

What is the conc of NO2 given as
-Sedative/analgesic in dentistry
-Adjunct to other inhaled anesthetics

Back 43

Dentistry - 50%
Adjunct - 70%

Front 44

What is the main side effect and contraindication for giving nitrous oxide?

Back 44

It can replace Nitrogen in an air-containing cavity; so contraindicated in pneumothorax

Front 45

What cardiac effects does Nitrous oxide have?

Back 45

-Negative inotrope
-Sympathomimetic - increases contractility/vasoconstricts

Front 46

What are the respiratory effects of Nitrous oxide?

Back 46

Minimal except for O2 dilution during emergence

Front 47

What special care needs to be taken with Nitrous oxide?

Back 47

Avoid abuse - it carries an abuse liability