Local Anaesthetic Flashcards
Structure of local anaesthetic
Lipophillic ring plus hydrophilic amine
Weak bases
Intermediate ring: esters or amides
Regional anaesthesia
Loss of sensation in a circumscribed area of the body
Esters
Amethocaine
Cocaine
Amides
Lignocaine Bupivicaine Levobupivacaine Ropivacaine Prilocaine
The more lipophillic the anaesthetic, the _____ potent and _____duration of action
More potent –> longer duration
Factors influencing activity of LA
Addition of vasoconstrictor
Signs of CNS toxicity
Circumoral and tongue numbness Metallic taste Dizziness, lightheadedness Visual disturbances Tinnitus Irratiional behaviour and speech Convulsions, unconsciousness, coma Convulsion
Treatment of CNS toxicity
ABC
Thiopentone, benzodiazapene
CVS toxicity initial phase
Hypertension
Tachy in excitatory phase
Preventing toxicity
Use max safe dose
Aspirate regularly during injection
Adrenaline if appropriate
Test doses
Intermediary phase of CVS toxicity
Myocardial depression
Decreased cardiac output
Hypotension
Triad of anaesthesia
Analgesia
Hypnosis
Muscle relaxation
