vaporizers Flashcards
Functions of a vaporizer
Change liquid anesthetic agent into vapor Deliver set dosage Deliver consistent concentration of agent vapor into anesthetic gas mixture
how is vapor pressure created in the vaporizer?
gas molecules bombard the walls of the container
what plays a major role in vapor pressure
temperature, the higher the temp the greather the vapor pressure
what happens if the vaporizer does not keep a constant temperature
vapor pressure drops and agent becomes liquid again
what is pressure when there is a dynamic equilibrium between the liquid & vapor phases when the temperature of the container is kept constant
saturated vapor pressure
what is equilibrium?
when the molecules in each phase remain constant
what is Temperature at which vapor pressure equals atmospheric pressure
boiling point
Part of total pressure from 1 gas in a mix
Partial pressure note: expresses the absolute value of gas molecules in a mixture
what is volume percent?
Gas amount per 100 units of volume for total mixture expresses the relative ratio of gas molecules in a mixture
what is formula for volume percent
Partial pressure/total pressure
what is Amount of heat (calories) required to convert 1 g of liquid agent into a vapor
Heat of Vaporization
what is Specific Heat
Heat (calories) required to raise the temperature of 1 g of agent by 1ºC
what is vapor pressure dependent on?
temperature & liquid
what does lowering the temperature do to vapor pressure?
causes a shift toward the liquid phase & a decrease in vapor pressure
what are PHYSICAL properites of ideal inhalation agent
Non-flammable & non-explosive at room temperature Vaporizable at room temperature Stable at room temperature with long shelf life Stable with soda lime, plastics, & metals Environmentally friendly (no ozone depletion) Cheap & easy to manufacture Non-flammable & non-explosive at room temperature Vaporizable at room temperature Stable at room temperature with long shelf life Stable with soda lime, plastics, & metals Environmentally friendly (no ozone depletion) Cheap & easy to manufacture Non-flammable & non-explosive at room temperature Vaporizable at room temperature Stable at room temperature with long shelf life Stable with soda lime, plastics, & metals Environmentally friendly (no ozone depletion) Cheap & easy to manufacture Non-flammable & non-explosive at room temperature Vaporizable at room temperature Stable at room temperature with long shelf life Stable with soda lime, plastics, & metals Environmentally friendly (no ozone depletion) Cheap & easy to manufacture
what are BIOLOGICAL properties of an inhalation agent?
Pleasant to inhale, not irritating, induces bronchodilation Low blood:gas solubility (fast onset) High oil:gas solubility (high potency) Minimal effects on body systems No biotransformation (ideally excreted via lungs unchanged) Non-toxic to operating room personnel
what are the vapor pressure (@ 20 C) of: isoflurane sevoflurane desflure
iso - 238 sevo - 157 des - 669
what is the MAC of: isoflurane sevoflurane desflure
iso - 1.15 sevo - 2.05 des - 6
What is the blood gas partition coefficient of isoflurane sevoflurane desflure
iso - 1.36 sevo - 0.6 des - 0.45
what’s this ?
Datex Ohmeda Tec 6 Vaporizers
If the BG partition coefficient is high, then the agent is ______ soluble?
more
what effect does altitude have on a vaporizer?
Vaporizers calibrated at sea level High altitudes will change concentration
what’s this?
Datex-Ohmeda Tec 5 Vaporizers
Calculate the max agent concentration of an agent in the vaporizering chamber
vapor pressure / barometric pressure
