Inhaled anesthetics 1: pharmacokinetics Flashcards
What are the three groups that we can categorize the inhaled anesthetics into?
ethers
alkanes
gases
At atmospheric pressure and room temperature, the ethers and alkanes exist as
liquids
What are the ethers?
isoflurane, desflurane, and sevoflurane
What are the alkanes?
halothane
At atmospheric pressure and room temperature, the gases exist in
gaseous form
Examples of the gases include
nitrous oxide and xenon
You can identify the halogenated anesthetic molecule by
counting the number of fluorine atoms
How many fluorine atoms does halothane have?
3
How many fluorine atoms does isoflurane have?
5
How many fluorine atoms does desflurane have?
6
How many fluorine atoms does sevoflurane have?
7
Isoflurane has a _______ atom, which increases ______.
chlorine atom, which increases potency
Although sevoflurane is heavily fluorinated, its stil
3x as potent as desflurane
Desflurane is nearly identical to isoflurane, but the chlorine atom is replaced by _________
a fluorine atom
The ethers have a characteristic
“ether bridge”= C-O-C
Since desflurane is fully fluorinated, it has a _____ potency leading to a _____ MAC
decreased potency; increased MAC
Desflurane has a ______ vapor pressure requiring
increased vapor pressure requiring a heated vaporizer
Desflurane has a _____ resistance to biotransformation meaning _____ metabolism
increased resistance to biotransformation meaning decreased metabolism
Fluorination tends to _____ potency
reduce
Sevoflurane is heavily fluorinated but its still 3x as potent as desflurane. This is most likely due to the
bulky propyl side chain
The addition of the heavier chlorine atom with isoflurane results in
increased potency
The chlorine of isoflurane also increases
blood and tissue solubility
______ is the pressure exerted by a vapor in equilibrium with its liquid or solid phase inside of a closed container.
Vapor pressure
Vapor pressure is directly proportional to
temperature
increased temperature results in increased vapor pressure
_______ is the temperature where matter transitions from a liquid state to a gas state
The boiling point
Boiling occurs when
vapor pressure equals atmospheric pressure
At high altitudes, liquids boil at a
lower temperature as a function of reduced atmospheric pressure
Dalton’s law of partial pressures states that
the total gas pressure in a container is equal to the sum of the partial pressures exerted by each gas
________ is the fractional amount of pressure that a single gas exerts within a gas mixture
partial pressure
______ refers to the ability to resist breakdown or metabolism
Stability
_______ & _______ can transform volatile anesthetics into toxic compounds
Carbon dioxide absorbent & the liver
_______ is the process where compound transitions from its liquid state to a gaseous state at a temperature below its boiling point.
Evaporation
Which vaporizer does not automatically compensate for elevation?
Tec 6 desflurane
Even in hydrated soda lime, ________ is unstable
sevoflurane; this is the basis for minimum fresh gas flow requirements for sevoflurane
In desiccated soda lime, desflurane and isoflurane can
become unstable producing carbon monoxide (des>iso)
What is the vapor pressure of sevoflurane?
157 mmHg
What is the boiling point of sevoflurane?
59 degrees C
What is the molecular weight of sevoflurane?
200 g
What is the toxic by-product of sevoflurane?
compound A
What is the vapor pressure of desflurane?
669 mmHg
What is the boiling point of desflurane?
22 degrees C
What is the molecular weight of desflurane?
168 g
What is the toxic by-product of desflurane?
carbon monoxide
What is the vapor pressure of isoflurane?
238 mmHg
What is the boiling point of isoflurane?
49
What is the molecular weight of isoflurane?
184 g
What is the toxic by-product of isoflurane?
carbon monoxide
What is the vapor pressure of N2O?
38,770 mmHg
What is the boiling point of N2O?
-88 degrees C
What is the molecular weight of N2O?
44 g
What is the toxic by-product of N2O?
none- it is stable in a hydrated or dehydrated Co2 absorber
Boiling requires a ______ container
open
