Anaesthetics

Question 1

When do you use anaesthetics?

Answer 1

Premedication
Induction
Intra operative analgesia
Muscle paralysis

Question 2

Give two examples of inhalational anaesthesia

Answer 2

Chloroform

Xenon

Question 3

What does Guedels classification show us?

Answer 3

Stage 1: analgesia and consciousness
Stage 2: unconscious with delirium (erratic breathing)
Stage 3: surgical anaesthesia
Stage 4: respiratory paralysis and death

Question 4

What is anaesthesia?

Answer 4

Analgesia
Hypnosis
Depression of spinal reflexes
Muscle relaxation

Question 5

How do you describe volatile anaesthetic potency

Answer 5

MAC: minimum alveolar concentration

Concentration in the alveoli at which 50% of patients fail to move due to surgical stimulus

Question 6

What factors affect MAC?

Answer 6

Age (high in infants)
Hyperthermia increases MAC
Hypothermia decreases MAC
Things that increase it: pregnancy, alcoholism, central stimulants
Things that decrease it: other anaesthetics, opioids

Question 7

How do Anaesthetics work?

Answer 7

GABA is a major inhibitory neurotransmitter
Anaesthetics potentiates GABA: leading to anxiolysis, sedation and anaesthesia
So they potentiate GABA mediates chloride conductance to depress CNS activity

Question 8

What parts of the body does anaesthesia work on?

Answer 8

Depress Hippocampus (memory)
Depress brainstem (respiratory drive and some CVS)
Spinal cord (dorsal horn) depressed (analgesia)

Question 9

What are examples of IV anaesthesia?

Answer 9

Propofol and barbiturates which are rapid

Ketamine which is slower

Question 10

What are the characteristics of local anaesthetics

Answer 10

Lidocaine, Bupivacaine

Lipid solubility which give them a greater potency

Question 11

What are the general side effects of anaesthetics?

Answer 11

Opioid ones
Hypotension
Chest infection
Allergy, anaphylaxis

Question 12

What are the two types of anaesthetic?

Answer 12

General: inhalation, intravenous

Local: regional