Inhaled Agents Structure and Facts

Question 1

Answer 1

Halothane

Alkane not Ether

Question 2

Answer 2

Isoflurane

Halogenated methyl ethyl ether with Cl-

Question 3

Answer 3

Enflurane

(Halogenated methyl ethyl ether)

(Isomer of Isoflurane)

Question 4

Answer 4

Desflurane

(Fluorinated methyl ethyl ether)

Question 5

Answer 5

Sevoflurane

Methyl Isopropyl Ether

1,1,1,3,3,3-Hexafluoro-2-(fluoromethoxy)propane

Question 6

N₂O

Answer 6

Nitrous oxide

Inorganic compound

Question 7

Which has the most myocardial depression of all the inhaled agents?

Answer 7

Halothane

Question 8

MAC of Halothane

Answer 8

0.75% in oxygen (VERY POTENT)

Question 9

MAC of Isoflurane

Answer 9

1.2% in oxygen

Question 10

Which is the least potent of volatile agents?

Answer 10

Desflurane

MAC = 4-6%

(think of the Devil’s # 6)

Question 11

Which inhaled agent needs a special vaporizer?

Answer 11

Desflurane

(because of its low boiling point)

When heated under pressure it exerts as gas

Question 12

Which gases are irritating to airways?

Answer 12

Isoflurane

Desflurane

Question 13

Which gases are not irritating to airways?

Answer 13

Halothane

Sevoflurane

Nitrous Oxide

Question 14

Better anesthetic for pediatric cases = __

Answer 14

Sevoflurane

Question 15

For pediatrics, the new recommendation is to reduce flow during inhalation induction is to minimize ___.

Answer 15

pollution

Question 16

Pediatric recommendations for induction flow

Answer 16

Question 17

Sevoflurane

(vapor pressure, blood/gas coefficient, and fat/blood coefficent)

Answer 17

VP = 160 mm Hg.

B/G=0.65

Fat/Blood = 48

Question 18

Halothane

Vapor pressure, blood/gas, fat/blood coefficient

Answer 18

VP = 243mmHg at 20 degrees C.

B/G=2.3

Fat Blood = 80

Question 19

MAC of Sevoflurane

Answer 19

2% in oxygen

Question 20

Sevoflurane’s combustion risk is increased in ___.

Answer 20

desiccated absorber

Question 21

Nitrous Oxide

Vapor Pressure, blood/gas, blood/fat coefficient

Boiling point

Answer 21

VP 39,000 mm Hg. (stored as liquid under pressure)

B/G 0.47

Fat/Blood = 2.3

Boils 88 degrees C.

Question 22

Isoflurane

Vapor pressure, blood/gas, blood/fat coefficient

Answer 22

VP 240 mm Hg at 20 degrees C.

B/G = 1.4

Fat/blood 45

Question 23

Which inhalational agent has the most myocardial depression?

Answer 23

Halothane

Question 24

Enflurane is metabolized ___.

Answer 24

2-4%

End product is Fluorine

Question 25

With Enflurane, there is a risk for \_\_\_.

Answer 25

seizures

Question 26

Desflurane Vapor pressure, boiling point, blood/gas and blood/fat

Answer 26

VP 681 mmHg at 20 degrees Boiling Point 23.5 degrees C. B/G = 0.42 Fat/Blood 27

Question 27

Sevoflurane degrades in \_\_\_.

Answer 27

Soda Lyme and Baralyme absorber

Question 28

Which agent is the BEST for inhalational induction?

Answer 28

Sevoflurane

Question 29

MAC of Nitrous Oxide

Answer 29

MAC 105%

Question 30

Which agents support combustion?

Answer 30

Nitrous Oxide Sevoflurane (when in a dessicated absorber)

Question 31

With Nitrous Oxide, there is a danger of \_\_\_\_.

Answer 31

Danger of hypoxia with high concentration or low atm. pressure Because it is 32-34 x more soluble the nitrogen it can cause closed air spaces (bowel, ET cuff, air embolism) to expand as it replaces the N2 in the air.

Question 32

How is nitrous oxide stored? How is it degraded in atmosphere?

Answer 32

Stored as liquid under pressure (750 PSI) Slow degradation in atmosphere

Question 33

Critical Temperature of Nitrous Oxide

Answer 33

36.5 degrees C.

Question 34

Carbon monoxide poisoning is associated with \_\_\_.

Answer 34

Desflurane in a dessicated absorber

Question 35

Desflurane has ___ tissue solubility

Answer 35

low

Question 36

MAC of Enflurane

Answer 36

1.68 in oxygen

Question 37

Vapor Pressure and blood/gas of Enflurane

Answer 37

VP 172 mmHg at 20 degrees C. B/G =1.8

Question 38

MAC of Isoflurane

Answer 38

1.2%

Question 39

1 time constant

Answer 39

Capacity/Flow rate = time to **63% change** Liters/liter per minute

Question 40

2 Time Constants

Answer 40

time to 86% change

Question 41

3 Time Constants

Answer 41

time to 98% change

Question 42

0.7 TC

Answer 42

½ time = time to 50% change