Anaesthesia

Question 1

Inhalational Anaesthetic Agents (3)

Answer 1

Nitrous Oxide (N2O), Isoflurane and Sevoflurane

Nitrous oxide is a weak anaesthetic. It causes the release of endogenous opioid peptides but the mechanism is uncertain.

Isoflurane also does not have a clearly delineated mechanism of action. It reduces pain sensitivity (analgesia) and is a muscle relaxant. It potentiates glycine receptor activity which reduces motor function.

Sevoflurane is used for induction and maintenance of general anaesthesia. It is one of the most commonly used volatile anaesthetics and is used in the anaesthetics of children and infants. ADRs include raised ICP and possible respiratory depression. The exact mechanism of action is unknown.

Question 2

Opiates (1)

Answer 2

Fentanyl

Fentanyl is a potent synthetic opioid analgesic with rapid onset and short duration of action. It is often used alongside a hypnotic a such as propofol. It is also administered in combination with a benzodiazepine such as midazolam to produce procedural sedation for endoscopy, cardiac catheterisation, oral surgery etc.

ADRs include diarrhoea, nausea, constipation, dry mouth, weakness, sweating, headaches

Question 3

Neuromuscular Blocking Drugs (2)

Answer 3

Pancuronium, Suxamethonium Chloride (Succinylcholine)

Question 4

Local anaesthetics (3)

Answer 4

Lidocaine, Bupivacaine, Ropivacaine

Question 5

Intravenous Anaesthetic Agents (2)

Answer 5

Propofol, Ketamine

Propofol is a short acting hypnotic/amnesia inducing agent used to induce and maintain general anaesthesia. It potentiates GABA-A receptor activity thereby slowing channel closing time and also acts as a sodium channel blocker.

Ketamine is used as a sedative. It provides pain relief, sedation and memory loss whilst allowing heart function, breathing and airway reflexes to remain functional. ADRs include abnormal heart rhythms, bradycardia, blood pressure fluctuations, anorexia, nausea, increased salivation, nystagmus, double vision, tonic-clonic movements