General Anesthetics Flashcards
General anesthetics are given systemically and their effects are exerted on the ______.
central nervous system
What is the difference btw a general anesthetic and a local anesthetic?
general = systemic, affects CNS local = small area, blocks AP conduction from PNS to CNS
Describe an ideal general anesthetic.
rapid and smooth onset of action
rapid recovery from anesthesia upon termination of drug administration
a wide margin for safe use
Most modern inhalational general anesthetics are based on the structure of ______.
halothane
What drug class are Xenon, Nitrous oxide, and Nitrogen?
inhaled general anesthetics: inorganic gases
What drug class is diethyl ether?
inhaled general anesthetics: ethers
What drug class are Cyclopropane and Ethylene?
inhaled general anesthetics: hydrocarbons
What drug class are Chloroform and Trichloroethylene?
inhaled general anesthetics: chlorinated hydrocarbons
What drug class is Halothane?
inhaled general anesthetics: Fluorinated hydrocarbon
What drug class are Enflurane, Isoflurane, Desflurane, and Sevoflurane?
inhaled general anesthetics: Fluorinated ethers
What drug class is Thiopental?
IV general anesthetics: barbituates
What drug class is Diazepam?
IV general anesthetics: benzodiazepines
What drug class are morphine and fentanyl?
IV general anesthetics: opioids
What drug class is ketamine?
IV general anesthetics: NMDA receptor antagonist
What drug class are Propofol and Etomidate?
misc. IV general anesthetics
What is the lipid theory of general anesthetic action?
volatile general anesthetics exert their effects by partitioning into the lipid component of the nerve cell membrane
the higher the oil:water partition coefficient, the more potent the general anesthetic
MAC is inversely proportional to potency
What is the protein theory of general anesthetic action?
volatile anesthetics interact with hydrophobic (lipophilic) regions of proteins
anesthetic molecules must fit into pockets of specific size within membrane proteins, such as ion channels
volatile anesthetics appear to
interact with sites that exhibit stereoselectivity, which is suggestive of a structured site or pocket, something that
occurs in proteins but not in fluid lipid bilayers
Recent evidence suggests that _____ involved in sleep are particularly sensitive to general anesthetics.
hypothalamic nuclei
Recent evidence suggests that hypothalamic nuclei involved in ______ are particularly sensitive to general anesthetics.
sleep
The ______ is involved in control of pain sensation, alertness and sleep, and damage to this region can cause unconsciousness.
reticular formation
Do anesthetics bind in specific binding sites?
no
General anesthesia is characterized by ______: a progressive loss of function from higher to lower levels within the central nervous system.
descending depression
What is the first sign of general anesthetic action?
loss of fine motor function and impairment of coordination
What is the first stage of anesthesia?
analgesia
What is stage III anesthesia?
surgical anesthesia
What are the 3 time stages of anesthesia?
induction –> maintenance –> recovery
What is induction of anesthesia?
time between initiation of administration of anesthetic and attainment of surgical anesthesia, that is, until Stage III is reached
What is maintenance of anesthesia?
time during which surgical anesthesia is in effect (surgery carried out during this period)
What is the recovery phase of anesthesia?
time following termination of administration of anesthetic until complete recovery of patient from anesthesia
The rate at which an effective concentration of anesthetic is reached in the brain depends upon which five factors?
(1) concentration of the anesthetic in inspired air, (2) alveolar ventilation rate, (3) pulmonary blood flow (cardiac output) (4) blood:gas partition coefficient, and (5) potency (oil:gas partition coefficient)
The rate of approach to steady state anesthesia is governed by what four phases in the uptake of volatile anesthetic?
(I) lung factors
(II) uptake of anesthetic by blood from alveoli
(III) uptake from blood to body tissues
(IV) tissue distribution
