inhalation anesthesia Flashcards
covalent bonds involves
sharing of electron pairs
all commonly used inhalation agents are ___ or _____
ethers or aliphatic hydrocarbons
anesthesia affect is lost if the chain exceeds
4 carbon atoms
modern inhaled agents are ____ hydrocarbons with exception to ___
halogenated, N20
heavier halogenated agent ___ potency
increases
ceiling effect of affection of F to ether
becomes more potent, then its as a strong convulsant, finally changes to inert compound with full fluorination
lipid solubility is ___ proportional to potency
directly
increase potency, ___ MAC
decrease
increase lipid solubility, ___ potency
increase
increasing # of halogenated agents, ___ arrhythmias
increase
MAC is ___ proportional to potency
indirectly
more hydrogens, ____ flammable
more
more halogens, ____ flammable
less
more halogens, ____ stable
more
one with all the same __ is ___ stable than one with different ___
halogens, more, halogens
why is des metabolized a 1/10th that of iso
because it contains F as its only halogen and thus strongly tests biodegradation
flammability is ___ and chemical stability ____ by substitution hydrogen atoms with halogens
reduced, enhanced
are inhaled anesthetics ionized or non-ionized?
non-ionized
4 elements of general anesthesia
unconsciousness, amnesia, analgesia, immobility
increase lipid solubility, ___ MAC
decrease
decrease temp, ____ anesthetic requirement
decrease (think slowed metabolism)
how is immobility measured?
MAC
what is the site of action for immobility?
dorsal horn of spinal cord - activate descending noradrenergic pathways
immobility is lost if length exceeds ____ carbon atoms
4-5
what is the site of action for amnesia
limbic system - hippocampus/amygdala
what is the reliable measure for amnesia?
none - but can use BIS or EEG
what is the site of action for analgesia?
spirothalmic tract
how is analgesia measured in immobile / unconscious pt
cannot be directly measured. HR and BP are suggestive
what is the site of action for unconsciousness
cortex/thalamus/brainstem
CNS depression occurs in 2 ways
enhancement of inhibitory channels & blocking excitatory channels
as the number of F atoms is increased, metabolism
decreases
metabolism of inhalation agents is thru
phase 1 oxidation (hepatic)
percentage of halothane metaboized
45% (large amt! caused hepatitis)
percentage of sevo metabolized
5-8%