Nitrous oxide/Propofol - Anaesthetics

Question 1

history of nitrous oxide

Answer 1

often used recreationally
1842 - ether was used in surgery
1844 - NO used in dental surgery

Question 2

is anaesthesia reversible

Answer 2

YES

Question 3

3 main effects of anaesthesia

Answer 3

hypnosis
amnesia
immobility

Question 4

effect of anaesthesia on brain activity

Answer 4

slows brain activity (EEG)

Question 5

hypnosis

Answer 5

loss of consciousness/perceptive awareness

Question 6

amnesia

Answer 6

loss of memory formation

Question 7

immobility

Answer 7

no movement in response to painful stimuli

Question 8

3 good stages of anaesthesia

Answer 8

1 - analgesia
2 - excitement, increased muscle tone, HR and BP
3 - anaesthesia

Question 9

4th bad stage of anaesthesia

Answer 9

too much leads to cessation of breathing

Question 10

in medical practice –> 3 stages of inducing anaesthesia

Answer 10

induction
maintenance
recovery

Question 11

induction stage of anaesthesia in medical practice

Answer 11

give patient propofol

Question 12

maintenance stage of anaesthesia

Answer 12

give patient nitrous oxide or a volatile anaesthetic, or O2

Question 13

recovery stage of anaesthesia in medical practice

Answer 13

take mask off patient

Question 14

characteristics of a good anaesthetic

Answer 14

fast induction, fast recovery
non-flammable
able to adjust length of anaesthesia
regular breathing/HR
cheap
easy to store
no undesired effects

Question 15

common side effect of anaesthesia

Answer 15

nausea

Question 16

2 classes of anaesthetics

Answer 16

intravenous

inhalants

Question 17

examples of intravenous anaesthetics

Answer 17

barbiturates
ketamine
propofol
benzodiazepine
midazolam

Question 18

examples of inhalant anaesthetics

Answer 18

NO (ether or chloroform)
isoflurane
seroflurane
desflurane

Question 19

why is propofol good

Answer 19

rapid acting and rapid elimination

Question 20

MAC stands for

Answer 20

Minimum Alveolar Concentration

Question 21

what is the MAC

Answer 21

the minimum concentration of the gas in the lungs that is required to cause immobility in 50% of patients in response to a surgical/pain stimulus

Question 22

what is the MAC used for

Answer 22

to compare the potency or strength of anaesthetic vapours

Question 23

what two things are tested when measuring the MAC

Answer 23

hypnosis –> loss of ‘righting’ reflex (standing up)

immobility –> loss of withdrawal reflex

Question 24

Cp50

Answer 24

a measure of anaesthetic potency

the concentration of agent in the blood required to cause immobility in 50% of patietns

Question 25

are you awake in MAC and Cp50 tests

Answer 25

yes

Question 26

volatile anaesthetics above 1atm

Answer 26

do not initiate immobility in 50% of patients

Question 27

what is the correlation for anaesthetics called

Answer 27

meyer-overton (1899)

Question 28

axis for meyer-overton correlation graph

Answer 28

MAC on y-axis | olive oil: gas partition coefficient

Question 29

smaller MAC correlates with

Answer 29

high potency high olive oil: gas partition means it is better at dissolving into lipids

Question 30

what does the MO correlation show

Answer 30

that all the anaesthetics have a hydrophobic site of action

Question 31

what is the unitary theory

Answer 31

the suggestion that anaesthetics work on the protein hydrophobic site and share common molecular mechanisms

Question 32

what are the assumptions behind the unitary theory

Answer 32

that anaesthetics will dissolve in neuronal lipid membranes to affect neuronal activity

Question 33

what are the problems with the unitary theory

Answer 33

- mutations in proteins could impair anaesthetic effects - new anaesthetics are less potent than predicted - enantiomer pairs of chiral anaesthetic molecules have different properties

Question 34

anaesthetic binding site on GABA A receptors

Answer 34

different to GABA site, BZD site and neurosteroid site

Question 35

example of a neurosteroid

Answer 35

alphaxolone

Question 36

example of old volatile anaesthetic

Answer 36

halothane

Question 37

why was halothane discontinued

Answer 37

caused liver problems

Question 38

examples of new anaesthetics

Answer 38

isoflurane desflurane seroflurane

Question 39

uses of volatile anaesthetics in medicine

Answer 39

used in combination with nitrous oxide and O2 during maintenance stage

Question 40

effects of volatile anaesthetics

Answer 40

strong immobilisation, amnesic and hypnotic effects

Question 41

which receptors do volatile anaesthics act on

Answer 41

GABA

Question 42

other receptor potentiation

Answer 42

glycine receptors can also be activated --> contributes to immobility K2p channels

Question 43

receptor inhibition by anaesthetics

Answer 43

Na+ channels | glutamate receptor

Question 44

K2p channels

Answer 44

2 pore domain | "leak" potassium channels

Question 45

role of N2O

Answer 45

used in maintenance weak anaesthetic effects activates K2p channels inhibits nAchR- channels

Question 46

whats different about ketamine to N2O

Answer 46

ketamine can induce anaesthesia by itself | inhibits NMDA receptor channels

Question 47

importance of spinal cord and anaesthetics

Answer 47

spinal cord contains targets for the immobilisation effects of anaesthetics

Question 48

if isoflurane is applied to the spinal cord

Answer 48

the MAC is lower

Question 49

effect of application of GABA antagonists

Answer 49

decrease potency of some anaesthetics e.g. propofol and barbiturates (not ketamine)

Question 50

main phsyiological effects of GABA A receptor potentiation

Answer 50

hypnosis | amnesia

Question 51

main physiological effect of glycine receptor potentiation

Answer 51

immobilisation

Question 52

main physiological effect of NMDA receptor inhibition

Answer 52

analgesia