Anaesthetics

Question 1

Propofol

Answer 1

Rapid onset of anaesthesia
Pain on IV injection
Rapidly metabolised with little accumulation of metabolites
Proven anti emetic properties
Moderate myocardial depression
Widely used especially for maintaining sedation on ITU, total IV anaesthesia and for day-case surgery

Question 2

Sodium thiopentone

Answer 2

Extremely rapid onset of action (used for rapid sequence of induction)
Marked myocardial depression may occur
Metabolites build up quickly
Unsuitable for maintenance infusion
Little analgesic effects

Question 3

Ketamine

Answer 3

May be used for induction of anaesthesia
Has moderate to strong analgesic properties
Produces little myocardial depression making it a suitable agent for anaesthesia in those who are haemodynamically unstable
May induce state of dissociative anaesthesia resulting in nightmares

Question 4

Etomidate

Answer 4

Has favorable cardiac safety profile with very little haemodynamic instability
No analgesic properties
Unsuitable for maintaining sedation as prolonged (and even brief) use may result in adrenal suppression
Post operative vomiting is common

Question 5

Depolarising muscle relaxant - examples, mechanism, side effects

Answer 5

Suxamethonium
Binds to nicotinic acetylcholine receptors resulting in persistent depolarization of the motor end plate
Malignant hyperthermia, hyperkalaemia

Question 6

Non-depolarising muscle relaxant - examples, mechanism, side effects, antidotes

Answer 6

Atracurium, vecuronium
Competitive antagonist of nicotinic acetylcholine receptors
Hypotension
Acetylcholinesterase inhibitors (neostigmine, physostigmine)