Test 1: Basic Overview of IV Sedatives & Hypnotics Flashcards

Question

What is the 3 Compartment Model?

Answer 1

-Describes the behavior of an IV anesthetic infusion. -The drug being administered begins in the Central Compartment and then distributes peripherally. -As the peripheral compartment begins to saturate, an appropriate blood concentration can be maintained with a lower infusion rate. -The longer you run an infusion, the more you prolong wake-up. Want to hit a steady state where you're only replacing what is being eliminated. -Ex: Start with large bolus at the beginning to rapidly fill compartments, then start drip at a lower rate

Answer 2

The time it takes to achieve a 50% reduction in concentration after stopping a continuous infusion. -Important because, with some drugs, the longer you keep it on, the longer it takes for a patient to wake up. -Can introduce a shorter acting drug to wean off of a longer acting one towards the end of the case. -Long CS 1/2 time = Fentanyl -Short CS 1/2 time = Propofol

Answer 3

1) Unconsciousness 2) Amnesia 3) Analgesia 4) Suppression of Stress Response (inhibition of autonomic reflexes) 5) Sufficient Immobility (skeletal muscle relaxation)

Answer 4

Redistribution to inactive, poorly perfused tissues is the most important determinant of awakening

Answer 5

GABAA Receptor. y– aminobutyric acid type A -Endogenous neurotransmitter = GABA -Primary binding site for the majority of IV anesthetics -Most abundant inhibitory receptor in the brain -Broadly distributed throughout the CNS -Regulate neuronal excitability, mediate unconsciousness -Ligand-gated ion channels

Answer 6

Thalamic Circuits -Sensory Processing -Attention Hippocampal Networks -Memory Thalamocortical Circuits -Consciousness -Awareness

Answer 7

GABA is a major inhibitory transmitter in the central nervous system (CNS). -The GABA A receptor, which is a ligand-gated ion channel receptor, is activated by the binding of the neurotransmitter GABA. -This binding of GABA to the GABA A receptor initiates the movement of chloride (Cl−) through ion channels into the cell. -This results in hyperpolarization of the postsynaptic cell membrane and the inhibition of neuronal cell excitation.

Answer 8

Benzodiazepines are thought to interact with GABAA receptors between the α and γ subunits

Answer 9

Propofol, etomidate,and barbiturates

Answer 10

N-methyl-D-aspartate type -Endogenous neurotransmitters: Glutamate & Glycine -Excitatory receptor -Mediates excitatory postsynaptic currents of prolonged duration -Location: Presynaptic, Postsynaptic, Extrasynaptic -Effected by: Xenon, Nitrous Oxide (N2O), and Ketamine -Ligand gated ion channel (also sensitive to voltage across the membrane containing the receptor)

Answer 11

AMPA Receptors & Kainate receptors also mediate fast excitatory impulses but have little anesthetic sensitivity

Answer 12

-NMDA Receptors required not only a presynaptic release of a neurotransmitter (ligand), but also the voltage across the membrane containing the receptor. -Mg2+ blocks the channel until membrane depolarization occurs -Channel must first be activated before occupied by antagonist

Answer 13

L-glutamate, an amino acid, is probably the most important excitatory neurotransmitter in the CNS. -At the NMDA receptor, it causes the opening of the ion channel. -A rapid influx of Na + , Ca 2+ , and K + results in the depolarization of the normally negative postsynaptic membrane that initiates the action potential.

Answer 14

Ketamine is a noncompetitive antagonist at this receptor. -Depresses medial thalamic nuclei, leading to the blockage of afferent pain signals to the thalamus and cortex. -Afferent impulses are transmitted to cortical regions of the brain but are not interpreted, so responses to visual, auditory, and pain stimuli are inappropriate. -Although cortical association areas are depressed, the limbic system, which is thought to cause excitatory behavior, is simultaneously activated.