General Anesthetics Flashcards
How do anesthetics work?
GABAa chloride channel IPSP
GABA stimulates chloride channel to open making cell hyperpolarized (inhibiting APs)
What is MAC?
minimal alveolar concentration at 1ATM that prevents movement during skin incision in 50%
What is the MAC formula to achieve preventing movement in 95% people?
1.3 x MAC
What 3 factors influence MAC?
temp
age
prescriptions
What 4 factors do NOT influence MAC?
sex
O2
pH
BP
As cardiac output increases, what happens to induction with inhalation anesthetics?
GETS SLOWER
inverse relationship with CO
What is the equation for anesthesia?
FA/FI
end-tidal/inspired
True or false: the faster the agent gets from one compartment to the next, the slower it reaches equilibrium
TRUE
What 3 factors determine GA uptake from the blood?
1) solubility
2) partial pressure difference
3) cardiac output
Define FA
the end tidal partial pressure is the brain partial pressure
Which drug is more soluble in the blood, NO or Halothane?
HALOTHANE
Which achieves equilibrium faster, NO or halothane?
NO (blood cannot hold that much NO)
Which blood compartment is larger, NO or halothane?
halothane (holds more since drug is more soluble)
What does a larger blood/gas partition coefficient mean?
more soluble
takes longer to reach equilibrium
larger blood compartment
What are the vessel rich organs? BHLK
brain
heart
lung
kidney
Increased blood flow near alveolus _______ (slows/speeds up) equilibrium because it increases uptake
slows
remember: cerebral blood flow is regulated so an increase in CO should not bring extra agent to brain
What effect does GA have on lungs?
bronchodilation
What happens to the brain during GA?
uncoupling
increased blood flow but decreased O2 consumption
What IV anesthetic is used for induction, maintenance, sedation in the OR or ICU?
propofol
mechanism: IPSP
increases intracranial pressure
What was the most used induction agent before propofol?
thiopental
arterial vasoconstrictor
What are some of the good effects of ketamine?
1) dissociative anesthesia
2) bronchodilator, keep breathing
3) increase BP and HR
4) increase ICP and cerebral blood flow
What is the hallmark of etomidate?
least cardiovascular side effects
