Neuromuscular Blockers Flashcards Preview

Anesthesiology > Neuromuscular Blockers > Flashcards

Flashcards in Neuromuscular Blockers Deck (41)
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1
Q

What do neuromuscluar blocking drugs do?

A

Interrupt nerve impulses at the NMJ

2
Q

What is the result of a neuromuscular block?

A

Complete paralysis of striated muscles with no analgesia and retained consciousness

3
Q

What are some indications for NMBs?

A
  • Positioning eye centrally
  • Relaxation of respiratory muscles (ICU patients)
  • Relax muscles for neurological or orthopedic surgeries
  • Aid in intubation (humans)
4
Q

What are the components of balanced anesthesia?

A
  1. Unconsciousness
  2. Stop reflexive movements/muscle relaxation
  3. Analgesia
5
Q

Is mechanical ventilation required when using NMBs?

A

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

6
Q

What systems need to be monitored when using NMBs?

A

Cardio, respiratory, oxygenation

7
Q

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

A

Tachycardia and high blood pressure

8
Q

When should NMBs not be used?

A
  • No ability to ventilate or monitor
  • Insufficient analgesia during surgery
  • As a sole agent for procedures or euthanasia
9
Q

What is the MOA of depolarizing NMBDs?

A

Nicotinic ACh receptor agonist causing membrane depolarization

10
Q

What is the MOA of non-depolarizing NMBDs?

A

Competitive antagonist on nicotinic ACh receptors stabilizing muscle membranes

11
Q

What is the order of muscle relaxation?

A

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

12
Q

What are some factors that influence the effect of NMBDs?

A
  • Hypothermia
  • Electrolyte abnormalitites
  • Acid-base disorders
  • Age
  • Thermal burn
13
Q

What are some drugs that potentiate NMBD effects?

A
  • Inhalation anesthetics
  • Aminoglycoside antibiotics
  • Local anesthetics
  • Cardiac antiarrhythmic drugs
  • Diuretics
  • Magnesium
14
Q

What is succinylcholine mainly used for?

A

Human intubation

Historically used as euthanasia drug (inhumane)

15
Q

What is seen in Phase-1 block with succinylcholine?

A

Muscle fasciculation then paralysis

16
Q

What is seen in Phase-2 block with succinylcholine?

A

Non-depolarizing blockade after prolonged/high dosages

17
Q

What are some adverse effects of succinylcholine?

A
  • Cardiac arrhythmias
  • Hyperkalemia
  • Fasciculation, myalgia, myoglobinuria
  • Elevated intra-ocular and intra-gastic pressures
  • Malignant hyperthemia
18
Q

Cumulative effects are less likely with what type of NMBDs?

A

Non-depolarizing

19
Q

Which type of NMBDs have less adverse effects?

A

Non-depolarizing

20
Q

Do non-depolarizing NMBDs have cardiovascular side effects?

A

Little to none

21
Q

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

A

Laudanosine, decreases seizure threshold

22
Q

What is atracurium eliminated by?

A

Plasma esterase enzymes- plasma pH and temp dependent

23
Q

Can atracurium cause histamine release at high doses?

A

Yes

24
Q

Cisatracurium represents what percentage of atracurium mixtures?

A

15% oft he 10 isomer mixture

25
Q

How is cistracurium elimated?

A

80% Hofmann elimination- organ dependent

26
Q

Which NMBD is the first choice in vet med?

A

Rocuronium

27
Q

What is rocuronium antagonized by?

A

Sugammadex- usually not needed

28
Q

How is rocuronium eliminated?

A

Mostly liver, partially kidneys

29
Q

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

A

Respiration

30
Q

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

A

Peroneal and ulnar nerves

31
Q

What are sites of peripheral nerve stimulation in the horse?

A

Facial and peroneal nerves

32
Q

What are the stimulation patterns? (5)

A
  1. Single twitch
  2. Train of four
  3. Tetanic stimulation
  4. Post-tetanic count stimulation
  5. Double burst stimulation
33
Q

What is single twitch stimulation used for?

A

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

aka Supramaximal stimulus

34
Q

What is train of four stimulation used for?

A

Determine how deep the blockade is

35
Q

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

What does this indicate?

A

Partial blockade

36
Q

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

A

No response

37
Q

A TOF ratio of what suggests acceptable recovery from blockade?

A

> 0.9

38
Q

What kind of NMBDs are not recommended to antagonize?

A

Depolarizing NMBDs: succinylcholine

39
Q

What kind of drugs can be used to andtagonize NMBDs?

A

Ancetylchonlinesterase inhibitors- increased ACh at the NMJ

Edrophonium over neostigmine

40
Q

What drug is used to REVERSE rocuronium?

A

Sugammadex

41
Q

How does sugammedex reverse rocuronium?

A

Rocuronium binds with sugammadex’s lipophilic core