Flashcards in Anaesthetics Deck (20):
How do general anaesthetics work?
Produce a generalised but reversible cns depression
How can anaesthetics be given?
Intravenous to induce anaesthesia
Inhaled gaseous to maintain it
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
Risk of liver damage with repeated use
Low anaesthetic potency
Causes foetal abnormalities
No respiratory irritation
Little effect on heart
No cardiovascular effects
No cvr effects
Rapid onset, slow recovery
Acts on gabaa
Respiratory and cvr inhibition in overdose
Resp and cvr inhibition
Induction agent for deep sedation
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
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.
What are the 4 analgesics good to use?
Vecuronium muscle relaxation
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
Adequate duration of action
Low allergic potential
Natural alkaloid with local an prop
Reduced additictive potential
Potent local an
Weak local an
Short duration of action
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