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Flashcards in Neuromuscular Blockers Deck (41):
1

What do neuromuscluar blocking drugs do?

Interrupt nerve impulses at the NMJ

2

What is the result of a neuromuscular block?

Complete paralysis of striated muscles with no analgesia and retained consciousness

3

What are some indications for NMBs?

- Positioning eye centrally
- Relaxation of respiratory muscles (ICU patients)
- Relax muscles for neurological or orthopedic surgeries
- Aid in intubation (humans)

4

What are the components of balanced anesthesia?

1. Unconsciousness
2. Stop reflexive movements/muscle relaxation
3. Analgesia

5

Is mechanical ventilation required when using NMBs?

Yes, due to paralysis of respiratory muscles, spontaneous ventilation ceases

6

What systems need to be monitored when using NMBs?

Cardio, respiratory, oxygenation

7

What are the only two indications of noxious stimulation when using NMBs?

Tachycardia and high blood pressure

8

When should NMBs not be used?

-No ability to ventilate or monitor
- Insufficient analgesia during surgery
- As a sole agent for procedures or euthanasia

9

What is the MOA of depolarizing NMBDs?

Nicotinic ACh receptor agonist causing membrane depolarization

10

What is the MOA of non-depolarizing NMBDs?

Competitive antagonist on nicotinic ACh receptors stabilizing muscle membranes

11

What is the order of muscle relaxation?

Ocular muscles > Everything else (larynx observed esp) > Diaphragm

12

What are some factors that influence the effect of NMBDs?

-Hypothermia
-Electrolyte abnormalitites
-Acid-base disorders
-Age
-Thermal burn

13

What are some drugs that potentiate NMBD effects?

- Inhalation anesthetics
- Aminoglycoside antibiotics
- Local anesthetics
- Cardiac antiarrhythmic drugs
- Diuretics
- Magnesium

14

What is succinylcholine mainly used for?

Human intubation

Historically used as euthanasia drug (inhumane)

15

What is seen in Phase-1 block with succinylcholine?

Muscle fasciculation then paralysis

16

What is seen in Phase-2 block with succinylcholine?

Non-depolarizing blockade after prolonged/high dosages

17

What are some adverse effects of succinylcholine?

- Cardiac arrhythmias
- Hyperkalemia
- Fasciculation, myalgia, myoglobinuria
- Elevated intra-ocular and intra-gastic pressures
- Malignant hyperthemia

18

Cumulative effects are less likely with what type of NMBDs?

Non-depolarizing

19

Which type of NMBDs have less adverse effects?

Non-depolarizing

20

Do non-depolarizing NMBDs have cardiovascular side effects?

Little to none

21

What is the major metabolite in atracurim and what does it do?

Laudanosine, decreases seizure threshold

22

What is atracurium eliminated by?

Plasma esterase enzymes- plasma pH and temp dependent

23

Can atracurium cause histamine release at high doses?

Yes

24

Cisatracurium represents what percentage of atracurium mixtures?

15% oft he 10 isomer mixture

25

How is cistracurium elimated?

80% Hofmann elimination- organ dependent

26

Which NMBD is the first choice in vet med?

Rocuronium

27

What is rocuronium antagonized by?

Sugammadex- usually not needed

28

How is rocuronium eliminated?

Mostly liver, partially kidneys

29

What must be monitored closes when recovering patients with MNBDs on board?

Respiration

30

What are sites of peripheral nerve stimulation in the dog/cat?

Peroneal and ulnar nerves

31

What are sites of peripheral nerve stimulation in the horse?

Facial and peroneal nerves

32

What are the stimulation patterns? (5)

1. Single twitch
2. Train of four
3. Tetanic stimulation
4. Post-tetanic count stimulation
5. Double burst stimulation

33

What is single twitch stimulation used for?

Determine minimum necessary current to evoke maximal movement response prior to injecting NMBDs

aka Supramaximal stimulus

34

What is train of four stimulation used for?

Determine how deep the blockade is

35

With train of four: the first twitch is the largest and the last is the smallest

What does this indicate?

Partial blockade

36

What will you see on a train of four stimulation with complete blockade?

No response

37

A TOF ratio of what suggests acceptable recovery from blockade?

>0.9

38

What kind of NMBDs are not recommended to antagonize?

Depolarizing NMBDs: succinylcholine

39

What kind of drugs can be used to andtagonize NMBDs?

Ancetylchonlinesterase inhibitors- increased ACh at the NMJ

Edrophonium over neostigmine

40

What drug is used to REVERSE rocuronium?

Sugammadex

41

How does sugammedex reverse rocuronium?

Rocuronium binds with sugammadex's lipophilic core