LA-1 Flashcards
two mechanism of how LA works
membrane expansion
specific receptor
LA structure
Aromatic group (lipophilic) Intermediate chain (ester or amide link) Substituted amino terminal (hydrophilic)
what is in an LA cartilage
anaesthetic agent
vasoconstrictor-
ringers solution- the solvent the la is in
reducing agent- stop the vasoconstrictor breaking down
preservative
what can La be used for
post surgery pain management
pain relief
diagnosis - but not used as much
haemo - vasconstriction
what is ionisation and what is the equation you need to know
Ratio of charged to uncharged governed by:
pH
pKa (dissociation constant)
Henderson-Hasselbach Equation- relation od pH to PKA
what does lower Pka mean
ore uncharged molecules so more LA effect
lidocaine has highest at 7.6pka
what influences LA time action
- more ionisation
- protein binding-more the better slow release-Bupivacaine – 96% protein bound, half life 160 mins – long acting- after osteometry
- vasodilation or constriction can get washed away
- partition coefficient - higher means more lipid solubility which is better (cross sheath faster) lido=3 which is heighten and better
advantage of vasoconstrictor
- longer time
- better homeostasis
- more profound ana
vasoconstrictor that can be used
Adrenaline (epinephrine) – a catecholamine
Felypressin (octapressin) – a synthetic peptide
Others available but not in UK
one thing that is not greet about la and uses issues
lack of specificity
- feat any excitable tissue causing issues with
- cns
- cardio
- motor
ideal LA is……
Specific(this is the most difficult) and reversible action Non-irritant Produces no permanent damage No systemic toxicity High therapeutic ratio Active topically and by injectionRapid onset Suitable duration of action Chemically stable and sterilisable Combinable with other agents Non-allergic Non-addictive
LA def
“A loss of sensation in a circumscribed area of the body by a depression of excitation in nerve endings or an inhibition of the conduction process in peripheral nerves.”
what adrenaline can effect
Can affect: Blood vessels Heart Lungs Metabolism Wound healing LEARN THESE IN MORE DETAILOFF THE SLIDES
