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Flashcards in 6. NMBAs Deck (25):
1

What are NMBAs

neuromuscular blocking agents

2

When to re-dose

if re-dose is needed, use low dose titrated to effect (to centralize eye) Cannot recover a paralyzed patient, AchEi requires partial metabolism to reverse (3 twitches with TOF/spontaneous breathing)

3

act on the ____ receptor at the ____

Nicotinic Ach at the NMJ

4

effect of nmba?

paralysis (interrupt transmission at the NMJ)
only affects skeletal muscle

5

Two different mechanisms?

1. Nondepolarizing
- NO short acting
- Intermediate acting: atracurium, rocuronium
- we don't use the long acting ones
2. depolarizing
- succinylcholine (not used often)

6

advantage over ach

only one molecule is needed to block receptor (competitive antagonist)

7

termination of effect of nmba?

redistribution/metabolism/excretion
reversal agent - inc. Ach concentration

8

two types of non depolarizing nmbas?

1. bensylisoquinolinium compounds
- can cause H release
- *don't rely on liver* for metabolism, eliminated into blood and met with plasmatic esterases
ex/ atracurium
2. steroidal compounds:
- met by liver

9

atracurium v. cis atracurium

atracurium is a mixture of 3 groups (cis is the most potent one)
- Laudanosine is liver toxic, product of hoffman elimination, causes seizures
- H release
- cis-atracurium needs much lower dose -> less H release and less laudonosine production

10

Hoffman elimination is __ and ___ dependent

pH and temperature
(without these, metabolism is prolonged)

11

vecuronium

metabolite has some nmba properties, met in liver
no H release

12

rocuronium

derived by vecuronium, less potent, needs high dose, faster onset

13

reversal of nondepolarizing nmbas

1. AchE inhibitors, they compete with NMBA at the NAch receptor, CANNOT be used to reverse a DEEP block
- neostigmine, edrophonium
- acts on MAchR -> bradycardia, bradyarrthythmia (pre-treat with atropine)
2. Encapsulating agents. Can reverse deep block, no CV effects, super expensive not used

14

succinylcholine

- depolarizing NMBA
- two Ach molecules together, initially activates receptor and causes fasiculations
- followed by flaccid paralysis
met by butrylcholinesterase (psuedocholineresterase)
- giant dose, fast
- used for ET in humans because quick and goes away fast
- tremors start in front and move to back

15

side effects of succinylcholine

- MAchR - bradycardia or ANS ganglia - tachycardia/hypertension
- Hyper K
- Myoglobinuria (due to muscle contraction)
- inc. IOP (muscle contraction)
- MH

16

only indication is

muscle relaxation

17

often used for which surgeries?

- OCULAR surgery
- different sensitivities (high is highly sensitive
- Fracture reduction
- improvement of surgical field
- preventing cough during intubation
- facilitation of mechanical ventilation
- C section (doesn't cross placenta) provide analgesia
- rapid intubation in cat

18

3 Rules of NMDAs

1. use with hypnotic and analgesic
2. use IPPV
3. Monitor anesthetic depth - ONLY with HR

19

MAC awake

(0.8) half of that asleep (1.3)

20

exclude ________ before extubating

residual paralysis

21

how do we assess muscular response?

visual, tactile
MMG, EMG,
**AMG

22

AMG

acceleromyography

23

stimulation patterns - train of four (TOF)

T1/T4 is TOF ratio 100% is no paralysis (4 twitches)
*need 3 twitches to reverse

24

reverse if patient is breathing?

yes! they can still be partially paralysed, reverse!

25

anesthetic drugs can act ______ with NMBAs

synergistically! muscle relaxers!