Neuromuscular Blocking Agents/Reversal - Prodigy

Question 1

What are the primary functions of neuromuscular blocking drugs?

Answer 1

• to facilitate intubation and mechanical ventilation
• protect against vocal cord damage
• improve surgical conditions

Question 2

Where is the primary site of action for neuromuscular blocking agents?

Answer 2

The nicotinic cholinergic receptor on the muscle endplate (postsynaptic)

Question 3

All of the available neuromuscular blocking agents bear a chemical resemblance to what chemical?

Answer 3

• Acetylcholine.
• Succinylcholine is composed of two acetylcholine molecules linked by acetate methyl groups.

Question 4

Because their chemical similarity to acetylcholine, what chemical structure is common to all neuromuscular blocking agents? What is the significance of this feature?

Answer 4

they are all quaternary ammonium compounds which makes them water soluble and prevents their entry into the central nervous system

Question 5

How do volatile anesthetics affect the action of NMBD?

Answer 5

• volatile anesthetics potentiate the effects of NMBD
• desflurane, sevoflurane and isoflurane are roughly equal in the degree to which they potentiate NDMRs
  -N2O does not demonstrate a significant potentiation

Question 6

How does hypothermia affect neuromuscular blockade?

Answer 6

hypothermia can augment a block by decreasing metabolism or delaying excretion of the drug.

Question 7

What non-depolarizing NMBD will have a prolonged duration of action in patients with hepatic disease?

Answer 7

steroidal derivatives
-rocuronium, vecuronium, pancuronium

Question 8

Which of the steroidal muscle relaxants is the most affected by renal disease?

Answer 8

All three steroidal relaxants (rocuronium, vecuronium, and pancuronium) are affected by renal disease.
- Pancuronium is about 85% dependent upon renal elimination and is the most affected.

Question 9

What are two major classifications of nondepolarizing NMBDs? What commonly used agents fall into each class?

Answer 9

• Benzylisoquinoliniums, which includes atracurium and cisatracurium
• steroid derivatives which includes pancuronium, rocuronium, and vecuronium.

Question 10

what is the intubating dose of rocuronium?

Answer 10

0.6 mg/kg to 1.2 mg/kg

Question 11

What method is used clinically to speed the onset of rocuronium?

Answer 11

Priming, which is the administration of 10% of the intubating dose about 1-3 minutes prior to anesthetizing the patient and administering the remaining dose

Question 12

How is rocuronium elmininated?

Answer 12

Rocuronium is primarily eliminated in unchanged form via biliary excretion.

Question 13

What is the duration of action of rocuronium?

Answer 13

Rocuronium is an intermediate-acting muscle relaxant
- intubating dose of 0.6 to 1.2 mg/kg usually provides a duration of action between 30 and 90 minutes

Question 14

What cardiovascular changes may be seen with the administration of rocuronium or vecuronium?

Answer 14

No cardiovascular changes are seen with the administration of rocuronium or vecuronium, and no increases in histamine levels are seen with doses up to 1.2 mg/kg of rocuronium.

Question 15

How does the elimination half-life of rocuronium differ between pediatric patients, adults and the elderly?

Answer 15

the elimination half-life of rocuronium
- children 38 minutes
- adults 56
- elderly 137

Question 16

About what should you be cautious when using vecuronium in conjunction with thiopental?

Answer 16

If administered shortly after thiopental, vecuronium can react with thiopental to produce barbituric acid, a precipitate that can obstruct the IV

Question 17

What is the intubating dose of vecuronium?

Answer 17

0.1 mg/kg

Question 18

How is vecuronium eliminated?

Answer 18

Vecuronium undergoes hepatic and renal elimination
The majority of it is eliminated in the bile.

Question 19

What may be responsible for the prolonged duration of action of vecuronium when used in intensive care unit patients?

Answer 19

One of vecuronium’s metabolites, 3-OH vecuronium, accounts for about 60% of the activity of vecuronium and is excreted by the kidneys. The reduced clearance of this metabolite in the presence of altered renal status can result in a prolongation in the action of vecuronium.

Question 20

What is the intubating dose of pancuronium?

Answer 20

0.06 mg/kg

Question 21

What difficulty does the use of pancuronium present in noncardiac surgery?

Answer 21

It is associated with a higher incidence of postoperative muscle weakness and is more difficult to reverse than intermediate-acting agents. A mild pancuronium block can be reversed with sugammadex, however.

Question 22

What cardiac effect of pancuronium has increased its usefulness in the cardiac surgery setting?

Answer 22

Pancuronium can cause an increase in heart rate, blood pressure, and cardiac output via a vagolytic effect at the postganglionic nerve terminal, an increase in catecholamine release, and an antimuscarinic effect. This offsets the bradycardia associated with large doses of fentanyl used in cardiac surgery.

Question 23

What is the intubating dose of atracurium?

Answer 23

0.5 mg/kg

Question 24

What are the most common side effects of atracurium administration?

Answer 24

Atracurium can cause significant histamine release which can result in hypotension, tachycardia, flushing and bronchospasm