13.2 Anaesthetics

Question 1

important use of xenon as a volatile anaesthetic

Answer 1

neuroprotectant for brain surgery, e.g. tumour removal

Question 2

potency

Answer 2

concentration of dose range at which drug produces desired effect

Question 3

why is NO often added to other volatiles?

Answer 3

reduces their MAC so reduces dosing needed, and therefore the SEs

Question 4

GABAa receptors are LGICs, which way does chloride flow when they’re activated?

Answer 4

influx

Question 5

2 ways anaesthetics modulate the balance of excitation (via NMDA) and inhibition (via GABA)

Answer 5

increased central inhibition
decreased central excitation

Question 6

3 main IV anaesthetics

Answer 6

propofol
barbiturates
ketamine (slower)

Question 7

2 ways to describe IV anaesthetic potency

Answer 7

1. loss of eyelash reflex
2. bispectral index- electrodes on brain monitor surface cortical activity

Question 8

how to induce in mixed anaesthesia

Answer 8

bolus to end point
switch to volatile

Question 9

how does TIVA maintain a set point?

Answer 9

using defined PK based algorithm depending on patient weight

Question 10

basic local anaesthetic structure

Answer 10

aromatic ring, link, amine

link could be ester (shorter acting) or amide

Question 11

how does pKa link to ionisation?

Answer 11

lower pKa is more unionised so crosses plasma membrane

Question 12

affect of adrenaline on local anaesthetics

Answer 12

increases their duration of action as induces vasoconstriction

Question 13

affect of general anaesthesia on CVS

Answer 13

hypotension due to CVS depression