Inhalant Anesthetics Flashcards
unique because
- administered and eliminated through the lungs
- nothing depends on liver/kidney
chemistry
- organic other than NO
- halogenated (dec. reactivity and inc potency, nonflammable)
Halothane uses a ______ whereas Isoflurane does not
preservative
-> arrythmias
difference between iso and haloflurane
iso has an ether bond
which are gases v. vapors?
NO is gas, most inhalants are vapors
vapors still abide by same gas laws as gases T/F?
T
have to give ______ concentration of inhalant in lower pressured areas (mountains) to give the same pp of inhalant.
higher
Can you give 100% iso?
nope, vapor pressure doesn’t allow it
As temperature decreases vapor pressure ______
decreases
boiling point is close to room temperature and so…
desflurane, requires headed vaporizer, needs a outlet
solubility expressed as a
partition coefficient
molecules in blood/ molecules in gas
why is solubility important
predicts the speed of anesthetic induction, recovery,
lower the coefficient the faster the onset and recovery
vapor pressure determines the number of
molecules of inhalant available to produce anesthesia
Desflurane is most_____ (not including N2O)
Iso is most ______ (not including halothane)
insoluble (fastest onset of action)
soluble
inhalant anesthetics sites of action
brain (amnesia)
spinal cord (immobility)
(pp of inhalant in brain/cord is what causes anesthesia)
potency
dose required to reach a desired effect (only related to dose!!!!)
minimum alveolar concentration (MAC) has to do with
potency (=1/potency)
=ED50
(prevents gross purposeful movement in 50% patients)
(many different kinds of MACs)
N2O cannot be used
alone
3 factors influence anesthetic uptake (out of lungs and into blood)
- solubility
- CO
- Alveolar-venous anesthetic pp difference
The higher the alveolar pp the higher the _____ pp. Caused by minimizing the uptake.
brain
how to speed up induction
- turn up concentration
- turn up flow rate
- make sure patient is breathing
more soluble =
more ‘reluctant’ to leave the blood
Faster induction with _____ Cardiac output.
low
think super excited puppy, will take longer to induce
must exist for uptake to occur
Pa - Pv gradient!
Elimination is affected by
- solubility (-)
- CO (+)
- duration of anesthesia
toxic metabolites can be produced.
Iso desflurane -> _____
Sevoflurane ->______
CO (not a big concern)
compound A
inhalants decrease cerebral _______ and increase _______
metabolic rate
cerebral blood flow (increases intercranial pressure)
worst side effect is: all inhalants decrease cardiac ______
output
negative inotropic, decrease peripheral vascular resistance/ BP
in pulmonary system the inhalants can act as a safety mechanism
when Pbrain inc. -> dec. ventilation -> dec. uptake ->
dec. Pbrain
inhalant depresses spontaneous
ventilation
can potentially cause apnea
use ____ in hapatocompromised
iso
malignant hyperthermia
- most common in pigs
- genetic, when exposed to inhalant, sarcolemma inc. Ca+ -> ->death
- tx. dantrolene and get off that machine
