Exam1Lec6GeneralandLocalAnesthetics Flashcards
What are the inhaled volatile liquid general anesthetics?
Halothane
Isoflurane
Desflurane
Enflurane
Sevoflurane
HIDES and -ane
What are the inhaled gas general anesthetics?
Nitrous Oxide
Do you pass gas? NO
What are the IV general anesthetics?
Thiopental
Midazolam
Propofol
Morphine
“Too Many People Miss” IV
What are the local anesthetics?
Cocaine
Procaine
Tetracaine
Lidocaine
Bupivacaine
local anaesthetic=caine
NO PAIN WITH CAINE
2 I’S=AMIDE
What is general anesthesia?
Drug induced absence of all sensations. Surgical general anesthesia is a state of unconsciousness, analgesia, amnesia and loss of reflexes.
ALL SENSASTIONS:
unconscuousness (asleep)
analgesia (no pain)
amnesia (no memory)
loss of reflexes ( dont move)
How are general anasthesia mainly administered?
Inhalation and IV routes
What does balanced anesthesia mean?
Anesthesia produces by a mixture of drugs that often include both inhaled and IV anesthetics
General anesthetics are among the most dangerous drugs approved for general use. Why?
Their therapeutic indices range from about 2-4
Which inert gas has the most ideal anasthetic?
Xenon
For volatile liquid anesthetics, why is it not explosive?
Hydrogen ions have been replaced with halogens
The kinetics of uptake and distribution of anesthetic gases are characterized by two new features, what are they?
The rate of entry is controlled by respiration, a cyclic process.
They are almost entirely eliminated by lungs ( with exception of methoxyflurane and halothane)
What does the minimum alveolar concentration (MAC) of an anesthetic is defined as what?
The concentration that results in immobility in 50% of patients when exposed to a noxious stimulus (surgical incision)
The larger the MAC the ____ concentration of drug
needed to have an effect.
more (NO with MAC conc >100%)
The smaller the MAC the ____ concentration needed to have an effect
less (methoxyflurane with MAC conc 0.16%)
at this dose, is ko 50% of ppt
the lower the dose, the better
What is the most important factor influencing the transfer of inhaled anesthetic from the lungs to the arterial blood?
Solubility
What is the index of solubulity?
Blood: gas coefficient. It defines the relative affinity of an anesthetic for blood in comparison to air.
the lower the coefficient the better
What is the relationship of solubility with the rate of rise of its tension of the blood and brain?
The lower the solubility of a given anesthetic, the faster the rate of its tension in blood and then in the brain
The solubility in blood (blood: gas partition coefficient) for nitrous oxide and desflurane is low or high?
Low (less than 0.5)
The solubility in blood (blood:gas partition coefficient) for methoxyflurance (or diethyl ether) is low or high?
High (12)
What is the relationship between the anesthetic concentration and rate of induction.
Incr the inspired anesthetic concentration , incr the rate of induction.
If you incr pulmonary ventilation, how does that affect rate of uptake?
Incr pulmonary ventilation, speeds up the uptake
What does Meyer-Overton hypothesis explain?
There is a direct correlation between lipid solubulity and potency
Does potency and rate of uptake mean the same thing?
NO. Potency means how much drug you need to produce an effect and Rate of uptake talks about pressure equilibrium
Which receptor is the prime target for general anesthetics?
GABAa receptors (ion channels)
Which drugs binds with high affinitty for Gaba a receptor?
Barbiturates (thiopental), benzodiazepines, propofol, enflurane
These anesthetics incr the affinity of the GABAa receptor for GABA so we see in incr in GABAa channel activity