L25: Anaesthesia

Question 1

2 ways GA is given

Answer 1

• intravenous

- inhaled

Question 2

2 types of local anaesthetic agent

Answer 2

esters

amides

Question 3

2 types of neuromuscular blocking drugs

Answer 3

depolarising

non-depolarising

Question 4

analgesia=

Answer 4

opioids

Question 5

3 commonly used inhalational GA

Answer 5

• nitrous oxide
• isoflurane
• sevoflurane

Question 6

4 intravenous GAs

Answer 6

• propofol
• sodium thiopentone
• etomidate
• ketamine

Question 7

what may effect how potent a GA is

Answer 7

lipid solubility 
(the more soluble= more potent)

Question 8

MAC=

Answer 8

minimal alveolar concentration of specified substance

Question 9

what do GAs work on

Answer 9

potentiate GABAa receptors

Question 10

which GABA receptor subunit do intravenous GAs work on

Answer 10

beta subunit

Question 11

how does increasing levels of GABA work

Answer 11

GABA is inhibitory neurotransmitter so potentiating it will induce a decreased level of consciousness

Question 12

3 desirable effects of anaesthesia

Answer 12

• unconsciousness
• loss of reflexes
• analgesia

Question 13

most important brain area for unconsciousness

Answer 13

reticular formation

Question 14

side effects of anaesthesia (3)

Answer 14

• decreased cardiac contractility
• sympathetic inhibition
• respiratory depression

Question 15

What is a volatile substance

Answer 15

one that is very close to boiling point -quickly turns into gaseous state

Question 16

in which patients does inhaled GA work fast

Answer 16

kids- as they breath more

Question 17

in which patients does GA work slower

Answer 17

anyone with impaired breathing - e.g COPD

Question 18

are inhaled drugs metabolised

Answer 18

no

Question 19

what metabolises intravenous drugs

Answer 19

liver

Question 20

which form of GA is faster onset

Answer 20

intravenous

Question 21

what are IV drugs dependant on for onset

Answer 21

cardiac output (need to be carried from blood stream to brain)

Question 22

what time do all IV drugs work in

Answer 22

one arm-brain circulation time

Question 23

what makes you wake up with IV drugs

Answer 23

when the drugs are redistributed around the body (not metabolised till after this)

Question 24

what determines when the Inhalation drugs stop working

Answer 24

how quickly you breath of the gases

Question 25

what do local anaesthetics do

Answer 25

block voltage sensitive Na+ channels

Question 26

where are voltage sensitive Na+ channels found

Answer 26

on all peripheral and central nerves

Question 27

what pH are all local anaesthetics

Answer 27

weak bases

Question 28

which tissues do local anaesthetics work worse in

Answer 28

acidic tissues (e.g absess)

Question 29

A fibres=

Answer 29

large diameter, myelinated

Question 30

B fibres

Answer 30

small diameter, myelinated

Question 31

C fibres=

Answer 31

small diameter | unmyelinated

Question 32

which fibres are first affected by local anaesthetic

Answer 32

C-fibres

Question 33

what C-fibres are first effected

Answer 33

postganglionic autonomic fibres

Question 34

what does blocking of the Na channels in postganglionic autonomic neurons do

Answer 34

- vasodilation - warm dry feet - systemic hypotension

Question 35

second C-fibres to be affected

Answer 35

sensory fibres

Question 36

what fibres are the final ones to be anaesthetised

Answer 36

alpha fibres

Question 37

what are alpha fibres

Answer 37

motor

Question 38

antagonist neuromuscular drugs=

Answer 38

- non-depolarising | - competitive

Question 39

e.g of 3 non-depolarising neuromuscular blocking drugs

Answer 39

- atracurium - rocuronium - vecuronium

Question 40

agonist neuromuscular drugs=

Answer 40

- depolarising | - non-competitive

Question 41

e.g of agonist neuromuscular blocking drugs

Answer 41

suxamethonium

Question 42

reversal agent for neuromuscular blocking drugs

Answer 42

anticholinesterase

Question 43

MOA of nondepolarizing muscle relaxants

Answer 43

they bind to the ACh receptors but are unable to induce ion channel openings preventing ACh binding

Question 44

MOA of depolarizig muscle relaxants

Answer 44

bind to ACh receptors causing an action potential but aren't broken down meaning extended depolarization so the end plate can't repolarize

Question 45

how do anticholinesterases reverse the effects

Answer 45

by inhibiting cholinesterase so it can't break down ACh increaseing conc of ACh

Question 46

e.g of 2 anticholinesterases

Answer 46

- pyridostigmie | - Neostigmine

Question 47

what happens first with suxamethonium

Answer 47

muscle fasciculations (and then relaxation)

Question 48

how long does suxamthonium last

Answer 48

-short acting normally

Question 49

side effects of anticholinesterases

Answer 49

- increase parasympathetic increased: - saliva - bronchial secretions - GI

Question 50

what needs to be taken with anticholinesterases to counteract the side effects

Answer 50

atropine

Question 51

what new drugs can be used instead of anticholinesterase

Answer 51

cyclodextrin

Question 52

how many stages of anaesthesia

Answer 52

4

Question 53

what stage 1 also called

Answer 53

induction

Question 54

what is stage 1 between

Answer 54

initial administration and loss of consciousness

Question 55

what is stage 2 also known as

Answer 55

excitement stage

Question 56

what is stage 2

Answer 56

period following loss of consciousness marked by excited and delirious activity

Question 57

what may happen in stage 2

Answer 57

- respirations and heart rate may become irregular | - may be uncontrolled movement, vomiting, pupillary dilation

Question 58

why are rapidly acting drugs used to minimise stage 2

Answer 58

as the combination of spastic movements, vomiting and irregular respirations may lead to airway compromise

Question 59

what happens in stage 3

Answer 59

- the skeletal muscles relax, vomiting stops and respiratory depression occurs - eye movement slow then stop

Question 60

what stage are patients ready for surgery

Answer 60

stage 3

Question 61

what is stage 4

Answer 61

overdose stage- where too much medication has been given relative to the amount of surgical stimulation

Question 62

reliable clinical signs to use in anaesthetics (5)

Answer 62

- muscle tone - light reflex - eyelid reflex - lacrimation - eye position