General Concepts

Question 1

inhalation agents: Unitary, Lipid-Based Theories: Meyer-Overton Theory

Answer 1

• chemically indifferent substance that are soluble in fat are anesthetics
• there relative potency depends on their affinity for water and their affinity for fat–there fat/water partition

Question 2

inhalation agents: Unitary, Lipid-Based Theories: Unitary theory

Answer 2

cell membranes were mostly lipid therefore the majority of anesthetics effects must come from the effects on cell membranes

Question 3

inhalation agents: The Concept of MAC

Answer 3

• MAC is analogous to plasma EC50

- universal measure for inhaled anesthetic potency

Question 4

inhalation agents: Protein Centered Theory

Answer 4

signaling proteins (ion channels and receptors) are the molecular site of action

Question 5

inhalation agents: Plasma EC50

Answer 5

non-paralyzed patients don’t respond to stimuli

Question 6

inhalation agents: Alcoholics and MAC requirements

Answer 6

need more MAC inhaled agent

Question 7

inhalation agents: normal person MAC requirements

Answer 7

Start with MAC and adjust

Question 8

inhalation agents: Commorbidities MAC requirements

Answer 8

Start at lower MAC

Question 9

inhalation agents: Site of Action of inhaled anesthetics: Proteins

Answer 9

• site: amphilic binding sites
• effect: conformational flexibility, ligand binding
• target: ion channels, receptors, signaling proteins

Question 10

inhalation agents: Site of Action of inhaled anesthetics: Action Potential

Answer 10

• site: Nervous system
• effect: small reduction in amplitude
• target: Na channels
• site: Cardiovascular system
• effect: reduced amplitude, duration
• target: Ca channels, K channels

Question 11

inhalation agents: Site of Action of inhaled anesthetics: inhibitory synaptic transmission

Answer 11

• site: presynaptic
• effect: enhanced transmitter
• site: post synaptic
• effect: enhanced transmitter effects
• target: glycine, GABA-a receptors

Question 12

Site of Action of inhaled anesthetics: excitatory

Answer 12

• site: pre synaptic
• effect: reduced transmitter release
• target: Na channels, K2P channels
• site: post synaptic
• effect: reduced transmitter release
• target: NMDA receptors, HCN channels, K2P channels, extrasynaptic GABA-a receptors

Question 13

Site of Action of inhaled anesthetics: Neuronal Networks

Answer 13

• site: neuronal circuit neuronal integration

- effect: altered LTP/LTD, altered rhythmicity, coherence

Question 14

Site of Action of inhaled anesthetics: central nervous system

Answer 14

• site: neocortex
• effect: sedation, amnesia
• target: gamma rhythms, synchony
• site: diencephalon
• effect: unconsciousness
• target: gamma-band transfer entropy
• site: spinal cord
• effect: immobility
• target: thalamic deafferentation, nocifensive reflex

Question 15

Site of Action of inhaled anesthetics: cardiovascular system

Answer 15

• site: myocardium
• effect: negative inotropy
• target: excitation-contraction coupling
• site: conduction system
• effect: dysthymias
• target: action potential
• site: vasculature
• effect: vasodilation
• target: direct and indirect vasoregulation

Question 16

Molecular targets of inhaled anesthetics: ligand dated ion channels

Answer 16

potentiation of GABA and Glycine

Question 17

Molecular targets of inhaled anesthetics: voltage gated ion channels

Answer 17

Na, Ca, K channels

Question 18

Molecular targets of inhaled anesthetics: intracellular signaling mechanisms

Answer 18

G-protein coupled receptors, protein phophorlaytion, gene expression

Question 19

inhalation agents: Cellular mechanisms: neuronal excitability

Answer 19

determined by resting membrane potential, threshold, and input resistance

Question 20

inhalation agents: Cellular mechanisms: presynaptic effects

Answer 20

inhalation agents alter transmitter release

Question 21

inhalation agents: Cellular mechanisms: post synaptic effects

Answer 21

inhalation agents neurotransmitter responses

Question 22

Desired Effects of inhalation agents: immobility

Answer 22

• mediated by spinal cord NMDA receptors

- requires 2.5-4x MAC for amnesia and unconsciousness

Question 23

Desired Effects of inhalation agents: unconsciousness

Answer 23

• hyperpolarization of thalamic sites
• dimmer-switch than off/on
• depends on interrupting synchrony between multiple neural networks

Question 24

Desired Effects of inhalation agents: learning and memory

Answer 24

hippocampal and amygdala dependent

Question 25

Desired Effects of inhalation agents: sedation

Answer 25

• potent agents stimulate GABA

- N2O and Xenon antagonize NMDA

Question 26

Desired Effects of inhalation agents: neuroprotection

Answer 26

• prevents apoptosis, decreased CMRO2

- neurotoxicity- irreversible cell damage by N2O

Question 27

Desired Effects of inhalation agents: CV and respiratory

Answer 27

• dose dependent myocardial depression and hypotension , decreased calcium and sensitivity
• respiratory depression via central depression
• decreased TV and increase RR and our ETCO2 increases

Question 28

inhalation agents: Anesthetics are Fl because

Answer 28

• reduce or eliminate toxicity (metabolism)
• reduce or eliminate anesthetic flammability
• allow increased speed of induction nd recovery from anesthesia

Question 29

Time constants and inhalation agents

Answer 29

way of describing the amount of change that is occurring in a dynamic system
-amount of change that occurs per unit of time

Question 30

each time constant % change

Answer 30

63% change in the system

Question 31

time constant formula

Answer 31

TC= capacity of the system/flow into the system

Question 32

total capacity =

Answer 32

7 L