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Flashcards in Anaesthetics Deck (20):
0

How do general anaesthetics work?

Produce a generalised but reversible cns depression

1

How can anaesthetics be given?

Intravenous to induce anaesthesia
Inhaled gaseous to maintain it

All lipophilic

2

Mechanism of action of anaesthetics

Lipid perturbation-agents change the volume/fluidity of cns cell membranes

Protein modification-action on receptors at appropriate concentrations
Ligand gated ion channels

3

Halothane

Gaseous anaesthetic
Risk of liver damage with repeated use
Cardiac depression
Potent
Malignant hyprexia

4

Nitrous oxide

Gaseous anaesthetic
Low anaesthetic potency
Powerful analgeic
Causes foetal abnormalities

5

Sevoflurane

No respiratory irritation
Rapid onset
Adequately potent
No hepatoxicity
Little effect on heart

6

Cyclopropane

Explosive
No cardiovascular effects

7

Zenon

No cvr effects
Non explosive
Expensive
Gaseous

8

Thiopental

Intravenous
Rapid onset, slow recovery
Acts on gabaa
Respiratory and cvr inhibition in overdose
Inducing agent

9

Propofol

Rapid onset
Rapid recovery
Gabaa
Resp and cvr inhibition
Induction agent for deep sedation

10

Ketamine

Intravenous
Slow onset
Involuntary movements and hallucinations
Inactiviated by metabolism
Blocks nmda r
Analgesia without loss of concious ess
Does not inhibit cv or resp
Used in children and military

11

Why do you not use just one anasthetic at a time?

Using a mixture of agents, its possible to get the desired degree of unconciousness, analgesia and muscle relaxant without having to give doses leading to potential dangerous side effects.

12

What are the 4 analgesics good to use?

Induction propfol
Maintain
Sevoflurane unconcousness
N2o analgesia
Vecuronium muscle relaxation

13

How do local anaesthetics work?

Prevent ap formation by blocking volt gated na channels
Need to be lipid soluble to get inside neurones to na channels

14

Lidocain

Local anaesthetic
Potent
Low irritancy
Adequate duration of action
Low allergic potential

15

Isogramine

Natural alkaloid with local an prop

16

Benzoyltropine

Reduced additictive potential
Potent local an

17

Procaine

Nonaddictive potential
Weak local an
Short duration of action
Allergic reactions

18

Why are vasoconstrictors used?

Reduce blood flow to site of administration and prolong effect of LA

Adrenaline for lignocaine
Felypressin for prilocaine

Not used for anaesthetising fingers and toes, causes ischaemia

19

Toxicity of local anasthetics

Depression of excitatable tissues:
Cns, blocks inhib and excit pathways
Decreases conductivity and contractility of heart
Constricts and dilates blood vessels

Local irritation of skeletal muscle

Allergic dermatitis or asthma