Principles and Pharmacology

Question 1

What medication is involved in phase 1 - induction of anaesthetics?

Answer 1

Inhalation - volatile and nitrous oxide
IV - propofol and possible opioid
Plus possible muscle relaxant

Question 2

What medication is used for phase 2 - maintenance in anaesthetics?

Answer 2

Inhalation - volatile and possibly plus opioid
IV - propofol and possibly plus opioid - TIVA
Plus possible muscle relaxant

Question 3

What does TIVA stand for?

Answer 3

Total intravenous anaesthesia

Question 4

How does propofol act?

Answer 4

Act on GABA receptor in CNS - chloride channel
Propofol activates channel to let more Cl into cell
Inhibits excitation

Question 5

What are blue stickers?

Answer 5

Opioids - fentanyl

Question 6

Where do opioids act?

Answer 6

Don’t allow propagation of the pain impulse from peripheral tissue up
Act centrally
Act on MOP receptors - morphine/ fentanyl

Question 7

What are the 4 most commonly used opioids?

Answer 7

Fentanyl and alfentanyl - potent and quick acting
Remifentanyl - doesn’t accumulate (used in TIVA) and morphine - longer duration of action

Question 8

What are red labels?

Answer 8

Muscle relaxants - Rocuronium

Question 9

How do muscle relaxants work?

Answer 9

Neuromuscular blockers attach to muscle fibres and don’t let ACh attach onto ACh receptors

Question 10

What are the types of muscle relaxants?

Answer 10

Non-depolarising - competitive antagonists at ACh receptors (Rocuronium and atracurium)
Depolarising - ACh receptor agonist (Suxamethonium)

Question 11

How are depolarising agents reversed?

Answer 11

Neostigmine - Acetylcholinesterase inhibitor plus glycopyrrolate (muscarinic anticholinergic)
Suggamadex

Question 12

What are purple stickers for?

Answer 12

Sympathetic nervous system agonists
Alpha receptors - vasculature (increase SVR)
Beta receptors - heart (increase CO)

Question 13

Describe anaesthesia and respiratory

Answer 13

Decrease their tidal volume of breathing - decrease resp. rate
Can intubate or use eyegel

Question 14

What is malignant hyperthermia?

Answer 14

Autosomal dominant inherited condition whereby their is a defect in the ryanodine receptor in sarcoplasmic reticulum in muscle cells
Regulates Ca output
Hypermetabolic and CO2 goes super high

Question 15

What are the triggering substances for malignant hyperthermia?

Answer 15

Volatile anaesthetics and succinylcholine

Question 16

What is given in malignant hyperthermia?

Answer 16

Dantrolene - receptor blocker

Question 17

How do local anaesthetics work?

Answer 17

2 forms depending on pKa and pH of surrounding plasma
Have to act intracellularly - have to be un-ionised to cross lipid barrier
Become ionised in cell - block sodium channel from inside - block depolarisation