NMB/Reversals/antimuscarinics

Question 1

Alpha 3 receptor

Answer 1

auto receptor that enhances ACh release

Question 2

Does NMB bind alpha 1 or alpha 3?

Answer 2

Definitely alpha 1 and maybe alpha 3

Question 3

What is different about a mature and immature nicotinic receptor?

Answer 3

E replaces the gamma/ between the alpha receptors. Happens when receptors are up-regulated.

Question 4

Would we want to use Sux or Roc when nicotinic receptors are up-regulated?

Answer 4

Sux, the E subunit on the new nicotinic receptors has a higher affinity for Deploarizing agents.

Question 5

What potential risks are there using depolarizing agents on immature nic receptors?

Answer 5

Risk of hyperkalemia in the blood

Question 6

When would nicotinic receptors be up-regulated?

Answer 6

• motor neuron lesions
• muscle trauma
• burn injuries
• immobilization (14 days)
• sepsis/infection
• strokes
• multiple sclerosis
• paraplegia
• quagriplegia

Question 7

When would nicotinic receptors be down-regulated?

Answer 7

• Myasthenia Gravis
• Organophosphate poisoning
• Chronic AChE inhibitor exposure

Question 8

Percentage needed of nicotinic receptors to send AP. What does this imply?

Answer 8

10%; this means we have a large reserve capacity/margin of safety

Question 9

Percentage needed to notice block but still seeing a “fade”

Answer 9

75%

Question 10

Percentage for complete suppression

Answer 10

95%

Question 11

Depolarizing mechanism of action

Answer 11

act as ACh receptor agonists –> antagonist

Question 12

Non-depolarizing mechanism of action

Answer 12

Function as competitive antagonists

Question 13

What is priming?

Answer 13

Giving a small amt of MR (ND) to occupy the receptors so when the larger dose is pushed, the onset will be more quickly.

Question 14

What is the train of four?

Answer 14

Nerve stimulator that gives four electrical impulses to promote twitches.

Question 15

What is fade?

Answer 15

When a person is able to contract their muscle but then loses the response and relaxes the muscle.

Question 16

When is someone ready for extubation?

Answer 16

When they can hold their head up for 5+ secs with no fade. (Tetany)

Question 17

Twitch height remains normal until when?

Answer 17

75% ACh receptors are blocked

Question 18

TOF fade’s and equivalent % of block (Appearance of fade at twitch X corresponds to % block)

Answer 18

1st: 90-98%
2nd: 85-90%
3rd: 80-85%
4th: 75%

Question 19

NMB reversals: when can you use them?

Answer 19

When periph nerve stimulation and recovery of first twitch. Patient must have some spontaneous recovery.