Gas Anesthetic Properties Flashcards
gas anes method of action
inhaled-> lungs-> alveoli -> blood -> brain(sleep)-> gas turned off-> blood -> alveoli -> exhaled
what makes a safe anes
metabolized by liver and kidneys minimally (mostly exhaled), good muscle relaxation, depth easily controlled, rapid absorption and elimination
speed of induction and recovery dependent on these 3 factors
Vapor pressure, solubility coefficient, minimum alveolar concentration (MAC)
Vapor pressure determines how ___ an agent is
volitile (how readily it enters into gas from liquid)
high vapor pressure means the agent diffuses into the blood _____ (slowly/quickly)
quickly
an agent w high vapor pressure anesthetizes (slowly/quickly)
quickly
what is the solubility coefficient
ratio that defines an agent’s liklihood of being a gas or being dissolved in the blood
we prefer to have agents w a (low/high) solubility coefficient; meaning it prefers to be in what form
low; prefers to be in gas form (rather than dissolved in blood)
why low solubility coefficient is favorable
prefer to stay in gas form; go quickly to brain and back out= quick induction/ recovery
why we dont want high solubility coefficients
prefer to dissolve in blood and go to tissues, “sponge-effect” (doesn’t want to leave), longer induction/recovery
what does Minimum Alveolar Concentration (MAC) mean?
minimum concentration of an agent in alveoli needed to produce no response to a noxious (painful) stimulus in 50% of patients
the MAC indicates the ___ of an agent
strength; how potent it is
a smaller MAC = (more/less potent)
more
how MAC varies
varies w factors that affect BMR (weight, disease, age, etc.) Lower BMR animals tends to have lower MAC and needs less drugs
how to calculate planes of anesthesia via known MAC of an agent
MAC x 1= light anes
MAC x 1.5= surgical
MAC x 2 = deep
