Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
Apart from NMBs, which agents can produce muscle relaxation? |
Volatile anaesthetics Benzodiazepines Gueaphenesin Local anaesthesia |
|
|
NMBs muscle relaxation |
Total - paralysis (neuromuscular blocking agents) |
|
|
How does ACh cause muscle contraction? |
Crosses nerve terminal and acts at receptors on muscle end plate -> depolarisation and contraction |
|
|
How do NMBs affect this? |
Block these receptors |
|
|
Depolarising NMB |
Activates receptor (muscle fasciculations) before relaxation |
|
|
Non-depolarising NMB |
Occupies receptor site but does not cause activation first |
|
|
How many of the receptors have to be occupied and blocked to prevent neuromuscular transmission? |
70% |
|
|
Which muscles are affect first and last? |
Ocular Diaphragm |
|
|
Why use NMBs? |
Facilitates endotracheal intubation Improves surgical access Still, central eye position for ocular surgery Facilitates ventilation Balanced anaesthetic technique |
|
|
Factors affecting NM blockade |
Myasthenia gravis (NM dramatic effect) Volatiles Hepatic/renal disease Acidosis Electrolyte disturbances Hypothermia Aminoglycosides Other drugs |
|
|
What do you use to monitor neuromuscular function? |
Peripheral nerve stimulator
Electrical stimulation of a nerve - electrodes 1cm apart over required nerve -> muscle twitch (lost if blockade in place) |
|
|
What doesn't it stimulate? |
Muscle directly |
|
|
What will you see in the train of four if there is a partial non-depolarising NMB? |
Fades when it comes to last twitch |
|
|
Suxamethonium |
Depolarising Short acting: 3-7 mins in cats, 40 mins in dogs Metabolised by plasma cholinesterases Inhibited by organophosphates |
|
|
Atracurium |
Non-depolarising Duration 40 mins Elimination - Hoffman degradation (hydrolysis) in plasma, no enzymes required |
|
|
What release might be seen with depolarising agents? |
K or IOP |
|
|
Vecuronium |
Non-depolarising 20-25 mins in dogs Metabolised in liver Powder -> sterile water solution |
|
|
What can be administered to antagonise NMBs? |
Anticholinesterase - ACh builds up and competes for receptor sites |
|
|
What should you wait for before administering an antagonist? |
Some return of function |
|
|
What side effect could there be and what could be given to counteract this? |
Bradycardia - atropine or glycopyrrolate + neostigmine |
|
|
Sugammadex |
Cyclodextrin - antagonist - any point after NMB administration Expensive |
