Quiz 2- Inhalants Flashcards
Is the recovery better with inhalants or injectables
Injectables
Why do we use inhalants
It uses the lungs to distribute and eliminate so you don’t have to rely on (and worry about) renal and hepatic metabolism. You can also precisely adjust anesthetic depth and have good control
Why don’t we always use inhalants
The equipment is expensive and bulky and the induction process without injectables may be difficult
What is our best idea on how inhalants work
The vapors use the partial pressure gradient of the lungs (moves from high to low equilibrium) then it goes into the blood and then to all the organs and brain to provide anesthesia
What state are inhalants administered as
Vapors
What is the vapor pressure
The pressure exerted by a vapor existing in equilibrium with its liquid state
What is the critical temperature
The temperature above which only gas exists
What is the boiling point
The temperature at which the vapor pressure equals the vapor pressure of the surroundings
How could you determine the partial pressure or the total pressure of a container
Use Dalton’s law of partial pressure
P total= P1+P2+P3….
What is the volume percent of inhalants
the relationship between vapor pressure and maximal pressure
(Vapor pressure/barometric pressure (760 if at sea level)) x 100 = vol%
What is the blood/gas partition coefficient
The solubility of vapor in the blood aka the ratio of the vol% of vapor in one phase (in the alveoli) compared to the vol% in another (blood) aka how much the vapor likes to stay in the blood
Solubility decreases with what
Increase in temperature
The lower the partition coefficient of a vapor
The more the vapor wants to stay in the alveoli
The lower the solubility of an inhalant
The faster the action- gets through blood and to brain quickly
What is the fastest way to gas an animal down
With a nonrebreathing system with sevoflourine (low solubility)
What is the potency of a drug measured as
The MAC- the minimum alveolar concentration- the concentration of an inhalant required to prevent movement in 50% of a given population when exposed to a noxious stimulus
The lower the Mac
The more potent the anesthetic
T/F MAC is additive
True
What type of factors increase MAC
Hyperthermia and hypernatremia and increasing excitatory neurotransmitters (happens with drugs like cocaine and amphetamines)
What type of factors decrease MAC
Older age, hypothermia, hyponatremia, pregnancy, hypoxemia, severe hypotension, severe hypercarbia (lots of CO2), metabolic acidosis, other anesthetics
Does the duration of anesthesia impact MAC
No
How do alkalosis, gender, hypertension, and anemia impact MAC
Trick question! They don’t
What is the only electrolyte that affects MAC
Sodium (hyper and hyponatremia)
What determines if the anesthetic in the brain produces anesthesia
Partial pressure, not concentration