Surgery and anaesthetics Flashcards
LA
Lidocaine, bupivacaine
Use: urinary catheterisation, minor procedures (e.g. suturing), VT and VF refractory to electrical cardioversion
MOA: enters cells unchanged then accepts a proton to become +ve charged. From inside the cell, it enters and then blocks voltage-gated Na+ channels on the surface membrane. This prevents initiation and propagation of APs in nerves and muscle, inducing LA in the area supplied by the blocked nerve fibres. In the heart, it reduces the duration of the AP, slows conduction velocity and increases the refractory period.
Adverse effects: initial stinging sensation during local administration. Systemic adverse effects if administered systemically incl. drowsiness, restlessness, tremor, and fits. Hypotension and arrhythmia in OD.
Warnings: lower dose used if reduced cardiac output
Interactions: co-administration with a vasoconstrictor (adrenaline) prolongs anaesthetic effect.
IV anaesthetics
Etomidate, ketamine, propofol, thiopental
Use: rapid induction of anaesthesia, total IV anaesthesia, prolonged sedation
IV opioids during anaesthesia
Fentanyl, remifentanil
Use: reduction in dose requirement of anaesthetic agents, sedation and respiratory depression during assisted ventilation in intensive care
Inhalational anaesthetics
Desflurane, halothane, isoflurane, NO, sevoflurane
Use: induction and maintenance of anaesthesia
Depolarising neuromuscular-blocking agents
Suxamethonium
Use: endotracheal intubation, muscle relaxation during surgery or on ICU
Non-depolarising neuromuscular-blocking agents
Atracurium, cisatracurium, mivacurium, pancuronium, rocuronium, vecuronium
Use: endotracheal intubation, muscle relaxation during surgery or on ICU
Acetylcholinesterase inhibitors
Edrophonium, neostigmine, pyridostigmine
Use: reversal of muscle relaxants used during GA (neostigmine), myasthenia gravis (pyridostigmine), test therapeutic response to AChE inhibitors in myasthenia gravis (edrophonium)
