NMB

Question 1

Describe twitch, train-of-four, and tetanus modes for NMB.

Answer 1

twitch - single supramaximal stimuli
TOF - four supramaximal stimuli
tetanus - rapid delivery of electrical stimuli

Question 2

Discuss three sites for monitoring NMB.

Answer 2

ulnar nerve
posterior tibial nerve
facial nerve

Question 3

Which is the anode ?

Answer 3

the red lead (goes proximal to heart)

Question 4

What is the frequency at which TOF is applied?

Answer 4

2 hz

Question 5

For which types of muscle relaxants are the different stimulation modalities appropriate?

Answer 5

depolarizing - single stimuli

nondepolarizing- TOF

Question 6

A TOF 1/4 would indicate what percent of receptors are blocked? 2/4? 3/4? 4/4?

Answer 6

0/4 -- 99%
1/4 -- 95%
2/4 -- 90%
3/4 -- 85%
4/4 -- 75%

Question 7

478. From which electrode of the NMB monitor does the stimulating current flow?

Answer 7

from the negative (black) cathode

Question 8

what is depolarizing block

Answer 8

succinlycholine

bind to ACh receptors and depolarize the nicotinic motor end-plate

Question 9

what is non-deplarizing block

Answer 9

block the ACh receptors sites, then as ACh continues to be released it pushes the non-depolarizing drug off the site so that it can bind once again.

Question 10

Which muscle is better to monitor during intubation

Answer 10

orbicularis oculi

Question 11

which muscle is better to monitor during emergence?

Answer 11

adductor pollicis

Question 12

what is the frequency for tetany?

Answer 12

50 - 100 hz for 5 s

Question 13

what is the frequency for DBS (Double burst stimulation)?

Answer 13

3 stimulus @ 50 hz a 750 ms pause then 2 stimulus @ 50 hz

Question 14

How do you perform a post tetanic count?

Answer 14

apply 50 hz tetany for 5 s
wait 3-5 seconds
single twitch response 1/sec
count total twitches 
>10 indicates sufficient receptors for reversal

Question 15

which muscle is the most resisitve in regards to NMB monitoring?

Answer 15

vocal cords

Question 16

which muscle is most sensitive in regards to NMB monitoring?

Answer 16

extraoccular

Question 17

What is sensory threshold?

Answer 17

base line
set single twitch and turn up mA
watch for response (awake pt).
response is threshold

Question 18

What is an approximate value to be expected for sensory threshold
in a euthermic patient without metabolic disease

Answer 18

4 - 5 mA

Question 19

What is motor threshold?

Answer 19

when a sleep

Question 20

What is an approximate value to be expected for motor threshold
in a euthermic patient without metabolic disease

Answer 20

12 - 15 mA

Question 21

what is supramaximal stimulus

Answer 21

20 - 25 % above motor threshold

Question 22

what physiologica variable will effect stimulation threshold?

Answer 22

temperature