general anaesthesia

Question 1

what are the 4 stages of anaesthesia?

Answer 1

Stage 1: analgesia
Stage 2: excitement or delirium
Stage 3: surgical anaesthesia: loss of consciousness and reflexes
Stage 4: overdose

Question 2

use and examples of inhaled anaesthetics?

Answer 2

for maintenance: sevoflurane, nitrous oxide

Question 3

which anaesthetics are for induction?

Answer 3

propofol

etomidate

thiopentone

Question 4

what anaesthetics are for maintanence?

Answer 4

halothane

xenon

Question 5

moa of xenon, ket, NO?

Answer 5

block NMDA receptors

xenon and NO have no effect on GABA itself

Question 6

moa of bupivicaine

Answer 6

Na channel blocker

Question 7

use of bupivicaine

Answer 7

epidural anaesthetic (longer than lignocaine)

Question 8

what must be given with NO?

Answer 8

another drug, since MAC (min alveolar conc) is 1 atm+

Question 9

moa of the anaesthetic induction drugs and halothane?

Answer 9

1. Enhance effect of GABA at GABAa receptors
2. Increase leaking of K+ ions
3. Enhance effect of glycine at receptors

Question 10

what factors increase potency of a drug?

Answer 10

1. unsaturation
2. halogen substition
3. ether group

Question 11

what factors decrease potency of a drug?

Answer 11

hydrophilic groups

Question 12

major SE of halothane?

Answer 12

1. arrhythmia
2. hypotension
3. liver damage

HAL

Question 13

what is MAC?

Answer 13

minimum alveolar concentration is the concentration of drug in inspired air giving safe level of anaesthesia in 50% of patients

Question 14

what 2 factors can we control with inhaled anaesthetics?

Answer 14

conc. of drug in air

solubility of drug in blood

Question 15

what are our ideals for factors that affect how quickly inhaled anaesthetics gets to the brain?

Answer 15

lowest possible concentration of drug in inspired air (i.e. high potency)

a low blood solubility to anaesthetic (rapid onset and offset).

Question 16

what is dissociative anaesthesia?

SE?

Answer 16

Ketamine.
They produce incomplete anaesthesia, which is useful when co-operation is needed.

It is a good analgesic, but its disadvantages are that they cause hallucinations and recovery is slow.

Question 17

how would you do epidural anaesthesia?

Answer 17

bupivacaine (long-acting local anaesthetic) +/- narcotic analgesia (fentanyl) gives pain control but only below the site of epidural. Common uses include childbirth or lower limb surgery.