Neuromuscular Blockers

Question 1

acetylcholine

Answer 1

major NT of the neuromuscular jxn

Question 2

2 Main MOAs of Neuromuscular Blockers

Answer 2

1. Depolarizing
2. Non-depolarizing

Question 3

Non-depolarizing Neuromuscular Blockers

Answer 3

competitive binding to ACh receptors without activating them, causes more of a flaccid paralysis

Question 4

Order of Sensitivity of the Block (6)

Answer 4

Question 5

Eye position when animal is adequately anesthetized?

Answer 5

ventral medial

Question 6

Do NMBs have anesthetic or analgesic properties?

Answer 6

NO!!!!

Question 7

indications for NMBs

Answer 7

deep surgical dissection, thoracic surgery (ventilator), dislocations, fractures, opthalmic sx

Question 8

Advantages of NMBs

Answer 8

predictable, reversible, reduces surgical traction, easier intubation, positive pressure ventilation

Question 9

Disadvantages of NMBs

Answer 9

needs controlled ventilation (ETT, anesthetic, ventilator), difficulty monitoring anesthesia, post-op weakness and/or hypoventilation, disease states/poher drugs

Question 10

Why is it difficult to monitor anesthetic depth with NMBs?

Answer 10

palpebral, jaw tone, and eye position are the first muscles to be relaxed on the order of sensitivity

Question 11

succinylcholine

Answer 11

depolarizing NMB; not used very commonly (only horses, pigs, cats)

Question 12

atracurium

Answer 12

non-depolarizing NMB with fast onset and intermediate duration

Question 13

Hofmann Elimination

Answer 13

spontaneous degradation affected by pH and temperature

Question 14

NMB for animals with kidney or liver disease?

Answer 14

atracurium

Question 15

Can you give atracurium to animals with mast cell tumors?

Answer 15

no - it can cause histamine release

Question 16

rocuronium

Answer 16

non-depolarizing NMB with fast onset and intermediate duration

Question 17

Way to monitor degree of relaxation with NMBs?

Answer 17

“twitch”

Question 18

Train-of-Four (TOF) Stimulation

Answer 18

delivery of 4 stimuli at least 12 seconds apart

Question 19

Antagonist of NMBs?

Answer 19

anticholinesterases! (like neostigmine or edrophonium)

prevents the breakdown of Ach in the NMJ

Question 20

Why can’t NMB antagonists be given alone?

Answer 20

acetylcholine esterase will indiscriminately bind to muscarinic receptors - so we need an antimuscarinic too

Question 21

2 AntiMuscarinic Drugs

Answer 21

glycopyrrolate
atropine

Question 22

Effects of AntiMuscarinic Drugs

Answer 22

increase heart rate, reduce bronchial secretions, slow GI motility and reduce GI secretions

Question 23

Myasthenia Gravis

Answer 23

autoimmune condition where antibodies target acetylcholine receptors, decreasing transmission and causing muscle weakness

Question 24

Tests for Myasthenia Gravis

Answer 24

DNA test or Tensilon (edrophonium) test

Question 25

Can NMBs be given to conscious patients?

Answer 25

NO