Anaesthetics

Question 1

What is the difference between local and general

Answer 1

General loses sense of consciousness aswell as sensation/pain

Question 2

What 2 types of general anaesthetics are there

Answer 2

Inhalation

IV

Question 3

What is the lipid theory to how anaesthetics work

Answer 3

They interact with the lipid bilayer and cause membrane expansion which disrupts protein signalling

Question 4

What is the ion channel theory

Answer 4

They target ligand channels like gaba and nmda

Question 5

What does blood/gas partition coefficient mean for inhaled anaesthetics

Answer 5

How blood soluble the anaesthetic is

Question 6

What does it mean if a drug has high blood/gas partition coefficient

Answer 6

They are very soluble in blood

Causing slow induction and recovery

Question 7

What happens if a drug has a lower blood gas partition coefficient

Answer 7

Faster induction (less drug needed) and also fast recovery

Question 8

What is oil/gas partition coefficient mean for inhalation anaesthetics

Answer 8

How lipid soluble the drug is

Question 9

What happens if anaesthetics have a higher oil/gas partition coefficient

Answer 9

High lipid solubility = high potency of drug

Question 10

How does vascularisation determine levels of Anaesthesia

Answer 10

If somewhere in highly vascularised like the brain = higher levels

Question 11

Does ventilation rate affect induction and removal of inhalation anaesthetics?

Answer 11

Yes

Question 12

How are inhaled anaesthetics removed

Answer 12

Via veins back to the alveoli and exhaled

Question 13

Where does some anaesthetics (inhaled) get metabolised into toxic waste

Answer 13

Kidney

Question 14

What is the effect of inhaled anaesthetics of respiration

Answer 14

Depression of respiratory rate

Question 15

What is the CVS effect of inhaled anaesthetics

Answer 15

Decreased BP (hypotension)

Via decreased cardiac output

Question 16

Are IV general anaesthetics fast induction?

Answer 16

Yes

Question 17

What are the names of the IV anaesthetics which are GABA agonists (hyperpolarisation)

Answer 17

Thiopental and etomidate and propofol

Question 18

Why is etomidate a good GABA agonist / IV anaesthetic

Answer 18

It has a large TI

Question 19

Why is propofol GABA modulator bad

Answer 19

Has rapid metabolism and therefore fast elimination

Also has a low TI

Question 20

What are propofol, thiopentol and etomidate

Answer 20

Allosteric modulators of GABA

Question 21

What is the only IV anaesthetic which is an NMDA antagonist

Answer 21

Ketamine

Question 22

Why is ketamine rarely used as IV anaesthetic

Answer 22

Causes hallucinations and psychosis

Question 23

Do IV anaesthetics like thiopentol and etomidate cause hypotension

Answer 23

Yes — they also lower BP like inhalation ones do

Question 24

Which channel is targeted by local anaesthetics to stop AP

Answer 24

Voltage gated na channels

Question 25

Which subunit do local anaesthetics bind to at voltage na channels

Answer 25

A subunit

Question 26

What do B1 and B2 subunits on the na channels do

Answer 26

Hold the a subunit in the membrane 4 pass

Question 27

What happens when voltage changes to the a subunit

Answer 27

Changes position causing opening and influx of na

Question 28

Which state must local anaesthetics be in to bind to a subunit

Answer 28

Ionised

Question 29

Which state must local anaesthetics be in first to pass myelin sheath

Answer 29

Unionised state

Question 30

What are the 3 components of local anaesthetics

Answer 30

Aromatic ring Amide or ester bond Side chain (alkaline)

Question 31

What determines duration of action of local anaesthetics

Answer 31

Hydrolysis of ester or amide bond

Question 32

Where are amide bonds metabolised and do they have a longer half life than esters?

Answer 32

In the liver Via CYP They do have a longer half life

Question 33

Why are anaesthetics unionised when they enter via injection

Answer 33

They are weak bases which cause increased PH so causes unionisation The base is then released

Question 34

Where is the free base from anaesthetics ionised due to lower ph

Answer 34

At the axon

Question 35

Which part can then when ionised at the acidic axon cause blocking of a subunit

Answer 35

The alkaline side chain

Question 36

How can the body restrict site of action of anaesthetics

Answer 36

Via vasoconstriction at A1

Question 37

How does the alkaline side chain cause faster induction

Answer 37

Faster absorption into the tissue being unionised

Question 38

Which fibres are the most sensitive to local anaesthetics

Answer 38

Small diameter and myelinated

Question 39

Why does increased AP firing cause better blockage via local anaesthetics

Answer 39

Channels are more in their open or inactive state rather than testing The anaesthetic has higher affinity for these stages

Question 40

What are the negatives of local anaesthetics if they get into the circulation

Answer 40

In the brain they’d cause confusion In the heart they lower BP (hypotension)

Question 41

How do inhalation anaesthetics cause increased BV

Answer 41

Stop glomerular filtration and less urine released