Principles of general anaesthesia

Question 1

Clinically desirable objectives of general anaesthesia

Answer 1

• loss of consciousness (at low concentrations)
• reflex response suppression (at high concentrations)
• analgesia (pain relief)
• muscle relaxation
• amnesia

Question 2

Gaseous/inhalation general anaesthetics

Answer 2

-generally contain halogens

Example:
-halothane

Question 3

Intravenous general anaesthetics

Answer 3

-generally contain rings

Example:
-propofol

Question 4

General anaesthetic mechanism of action theories

Answer 4

• Meyer-Overton correlation

- Molecular targets

Question 5

GA molecular targets

Answer 5

-either reduced neuronal excitability or altered synaptic function

Question 6

GA molecular targets (altered synaptic function)

Answer 6

IV AGENTS
-
INHALATIONAL AGENTS
-
-blocks NMDA-type glutamate receptors

Question 7

Loss of consciousness

Answer 7

• depress excitability of thalamocortical neurones

- influences reticular activating neurons

Question 8

Reflex response suppression

Answer 8

-depress reflex pathways in spinal cord (high density of GABA receptors in dorsal horn of spinal cord)

Question 9

Amnesia

Answer 9

-decreased synaptic transmission in hippocampus and amygdala

Question 10

Inhalation anaesthetics

Answer 10

• rapidly eliminated

- rapid control of anaesthesia depth

Question 11

Intravenous anaesthetics

Answer 11

• fast induction

- less coughing/excitatory phenomena

Question 12

Meyer-Overton correlation

Answer 12

• correlation between anaesthetic potency and lipid solubility
• anaesthetic potency increases in direct proportion with oil/water partition coefficient

Question 13

Problems with Meyer-Overton correlation theory

Answer 13

-at relevant concentrations, changes in bilayer were minute

Question 14

GA molecular targets (reduced neuronal excitability)

Answer 14

INHALATIONAL AGENTS

-

Question 15

IV agents in a clinical setting

Answer 15

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Question 16

Inhalational agents in a clinical setting

Answer 16

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