Unit 5: Chapter 28 (Karch 7th Ed) - Neuromuscular Junction Blocking Agents Flashcards
- According to the sliding filament theory, what is the initial action in a muscle contraction?
A) Troponin is freed and prevents actin and myosin from reacting with each other.
B) Calcium binds to troponin, which causes the release of actin and myosin binding sites.
C) Actin and myosin molecules react with each other sliding along the filament and making it shorter.
D) Muscle filament relaxes or slides back to the resting position.
Ans: C
Feedback:
Actin and myosin molecules react with each other again and again, sliding along the filament and
making it shorter. This is a contraction of the muscle fiber according to the sliding filament theory. As
the calcium is removed from the cell during repolarization of the muscle membrane, the troponin is
freed and once again prevents the actin and myosin from reacting with each other. The muscle filament
then relaxes or slides back to the resting position. Muscle tone results from a dynamic balance between
excitatory and inhibitory impulses to the muscle.
- When causing depolarization of the muscle membranes, what neurotransmitter interacts with the
nicotinic cholinergic receptors leading to the release of calcium ions?
A) Acetylcholine
B) Serotonin
C) D-gluconamidoethyl methacrylate (GAMA)
D) Epinephrine
Ans: A
Feedback:
At the acetylcholine receptor site on the effector’s side of the synapse, the acetylcholine interacts with
the nicotinic cholinergic receptors causing the depolarization. Serotonin, GAMA, and epinephrine are
not part of muscle contraction and relaxation.
- The nurse, working in the preoperative holding area, is caring for a 70-year-old patient who is
scheduled to receive succinylcholine as part of general anesthesia. When collecting the nursing history, what condition would require the nurse to notify the anesthesiologist of the need for caution?
A) Bone fracture
B) Malnutrition
C) Fluid volume overload
D) Narrow-angle glaucoma
E) Pregnancy
Ans: A, B, D
Feedback:
Succinylcholine should be used with caution in patients with fractures because the muscle contractions
it causes might lead to additional trauma; in patients with narrow-angle glaucoma or penetrating eye
injuries because intraocular pressure increases. Extreme caution is necessary in the presence of genetic
or disease-related conditions causing low plasma cholinesterase levels (e.g., cirrhosis, metabolic
disorders, carcinoma, burns, dehydration, malnutrition, hyperpyrexia, thyroid toxicosis, collagen
diseases, exposure to neurotoxic insecticides).
- The nurse is caring for a patient who received succinylcholine during surgery. The nurse would expect
the patient to spend more time in the postanesthesia care unit due to prolonged paralysis and inability to
breathe if the patient was from what ethnic group?
A) American Japanese
B) Alaskan Eskimos
C) Native Americans
D) Hawaiian natives
Ans: B
Feedback:
Alaskan Eskimos belong to a genetic group that is predisposed to low plasma cholinesterase levels,
making them susceptible to prolonged paralysis after succinylcholine use. The other ethnic groups do
not have this genetic predisposition.
- A patient scheduled for surgery is to have a nondepolarizing neuromuscular junction (NMJ) blocker as
adjunctive anesthesia. The nurse will have cause for concern about prolonged paralysis if the patient
has been taking what medication?
A) An aminoglycoside
B) Aminophylline
C) A barbiturate anesthetic
D) A cephalosporin
Ans: A
Feedback:
Combining nondepolarizing NMJ blockers with aminoglycosides can result in prolonged paralysis, and
this combination should be avoided. This interaction does not occur with barbiturate anesthetics,
cephalosporins, or aminophylline.
- A patient is having outpatient surgery that should last only 45 minutes. The patient is planning to go
home immediately after the surgery is complete. What nondepolarizing neuromuscular junction blocker
will most likely be used as an adjunct therapy to general anesthesia for this patient?
A) Atracurium (Tracrium)
B) Cisatracurium (Nimbex)
C) Pancuronium (Pavulon)
D) Rocuronium (Zemuron)
Ans: D
Feedback:
Rocuronium has a rapid onset of action and a short duration, making it a drug of choice for outpatient
surgical procedures when the patient will be leaving to go home and will need to be awake, alert, and
mobile. Atracurium, cisatracurium, and pancuronium are associated with longer paralysis and recovery.
- A patient is taking aminophylline for their chronic obstructive pulmonary disease. The patient is about
to undergo emergency surgery and will receive an neuromuscular junction (NMJ) blocker as part of the
procedure. It is important for the nurse to take what action?
A) Make sure the patient receives the aminophylline on a regular schedule to maintain therapeutic
levels.
B) Monitor the patient very closely for signs of early arousal and return of muscle function.
C) Carefully explain all that is going on because the patient will be unable to talk.
D) Switch the patient to theophyllines before the procedure begins
Ans: B
Feedback:
Aminophylline can cause a decreased effectiveness of NMJ blockers, leading to reduced paralysis and
early return of movement. If a patient has emergency surgery and has been taking aminophylline, the
patient should be carefully monitored for early arousal and return of movement. The patient will not be
awake during surgery using an NMJ blocker and will be intubated to ensure respirations.
Aminophylline and other xanthine derivatives like the theophyllines will have the same effect.
- The nurse is caring for a patient who is being maintained on mechanical ventilation. Atracurium is
administered to limit the resistance to mechanical ventilation. What is the nurse’s priority assessment?
A) Hypotension
B) Tachycardia
C) Bradycardia
D) Increased secretions
Ans: C
Feedback:
Bradycardia is a common adverse effect associated with atracurium. The nurse should monitor the
patient regularly to avoid serious adverse effects. Increased secretions and hypotension are common
with tubocurarine. Option B is a distracter.
- The nurse is preparing a patient for surgery who will receive a neuromuscular junction blocker during
the procedure. It is important for the nurse to review the patient’s medication history for concurrent use
of what?
A) Angiotensin-converting enzyme (ACE) inhibitors
B) Beta blockers
C) Calcium channel blockers
D) Montelukast
Ans: C
Feedback:
When calcium channel blockers are used concurrently with neuromuscular junction blockers, the
patient is at increased risk of prolonged paralysis. The dose of the neuromuscular junction blocker
should be lowered if this combination cannot be avoided and the patient should be monitored closely.
There is no anticipated drug drug interaction with ACE inhibitors, beta blockers, or montelukast
- An elderly patient has received a neuromuscular junction blocker during surgery. What would be an
appropriate nursing diagnosis for this patient?
A) Excess fluid volume
B) Risk for impaired skin integrity
C) Deficient fluid volume
D) Chronic confusion
Ans: B
Feedback:
An elderly or frail patient will need extra nursing care to prevent skin breakdown during the period of
paralysis because skin tends to be thinner and more susceptible to breakdown. Therefore, risk of
impaired skin integrity would be an appropriate nursing diagnosis. Fluid excess or deficit should not be
a concern and the patient may be acutely confused when awakening, but there is no reason to think he
or she would remain chronically confused if he was not before surgery
- What are the primary uses of neuromuscular junction blockers (NMJ) blockers? (Select all that apply.)
A) To facilitate endotracheal intubation
B) To sedate patient for general anesthesia
C) To prevent injury during electroconvulsive therapy
D) To provide greater ease in extubating patient
E) To facilitate mechanical ventilation
Ans: A, C, E
Feedback: NMJ blockers are primarily used as adjuncts to general anesthesia, to facilitate endotracheal intubation,
to facilitate mechanical ventilation, and to prevent injury during electroconvulsive therapy. NMJ
blockers do not sedate the patient who will be paralyzed after administration but will remain alert
unless another medication is given. These medications would not be given before extubation because
respiratory muscles would be paralyzed, resulting in the inability to breathe.
- The pharmacology instructor is discussing nondepolarizing neuromuscular junction blockers (NMJ)
blockers with the nursing class. How would the instructor explain the action of nondepolarizing NMJ
blockers?
A) Blocks acetylcholine (ACh) from acting
B) Acts like ACh then prevents repolarization
C) Takes the place of ACh in the depolarizing/repolarizing process
D) Stops depolarization in the axion
Ans: B
Feedback:
Depolarizing NMJ blockers cause muscle paralysis by acting like ACh. They excite (depolarize) the
muscle and prevent repolarization and further stimulation. Options A, C, and D are incorrect.
- A patient is to have surgery and it is planned that atracurium (Tracrium) is to be used as an adjunct to
general anesthesia. How will the atracurium work?
A) Act as agonist to acetylcholine
B) Stops depolarization in the axion
C) Act as antagonist to acetylcholine
D) Stops repolarization in the axion
Ans: C
Feedback:
Nondepolarizing neuromuscular junction blockers compete with acetylcholine (ACh) for the ACh
receptor site and after they occupy the site, stimulation cannot occur. This results in paralysis because
the muscle cannot respond. Other options are incorrect.
- The nurse is caring for a patient who is receiving pancuronium (Pavulon) to facilitate mechanical ventilation. The patient is also receiving a barbiturate. How will the nurse administer these two
medications?
A) They can be mixed and given in the same syringe.
B) Administer IM quickly after mixing the two drugs.
C) Shake vigorously when mixed in one syringe.
D) If given together, a precipitate may form.
Ans: D
Feedback:
Do not mix this drug with any alkaline solutions such as barbiturates because a precipitate may form,
making it inappropriate for use. Pancuronium is only given IV. Shaking does not prevent precipitation
- The nurse is caring for a patient who is scheduled for abdominal surgery in the morning and is
scheduled to receive rocuronium (Zemuron). The patient asks the nurse to describe the adverse effects
of rocuronium. What would the nurse describe for the patient?
A) This drug is associated with pulmonary hypertension.
B) This drug contains benzyl alcohol.
C) This drug is associated with bradycardia.
D) This drug is associated with an increased heart rate.
Ans: A
Feedback:
Rocuronium may be associated with pulmonary hypertension. Cisatracurium (Nimbex) contains benzyl
alcohol; Atracurium (Tracrium) is associated with bradycardia; and Pancuronium (Pavulon) is
associated with an increased heart rate.
- The postanesthesia care unit (PACU) nurse is caring for a patient that had succinylcholine (Anectine)
as an adjunct to anesthesia. What is the nurse’s priority assessment while caring for this patient?
A) Movement
B) Temperature
C) Mental status
D) Heart rate
Ans: B
Feedback:
Succinylcholine is more likely to cause malignant hyperthermia than other drugs so it is very important
that the nurse carefully monitor the patient’s temperature while in the PACU. Movement, mental status,
and heart rate monitoring are all routine components of PACU care, but after receiving this medication,
temperature monitoring becomes the priority.
- The nurse is caring for a patient scheduled for abdominal surgery in the morning. The patient confides
that he or she watched a movie last week about someone who had surgery and the anesthetic did not
work, but no one knew because that patient could not move. What nursing diagnosis will the nurse
include in this patient’s plan of care?
A) Alteration in fluid volume
B) Deficient knowledge regarding drug therapy
C) Fear related to paralysis
D) Risk for skin impairment
Ans: C
Feedback:
Nursing diagnoses related to drug therapy may include Fear related to paralysis. This care plan would
not include alteration in fluid volume; deficient knowledge regarding drug therapy; or risk for skin
impairment.
- The nurse is caring for a patient in the intensive care unit who has been receiving neuromuscular
junction (NMJ) blockers, sedatives, and analgesics for the past 2 weeks. The NMJ blocker therapy has
been discontinued and the other medications are being reduced gradually. The patient is now alert and
awake, communicating with his or her family by using paper and pencil. The family asks why the
patient cannot sustain normal respirations. What is the nurse’s best response? (Select all that apply.)
A) His or her muscles need to get their strength back again.
B) This is a common occurrence in situations like this.
C) He or she is likely to breathe better each day.
D) The drugs created temporary muscle damage.
E) He or she will not be taken off the mechanical ventilator until he is ready.
Ans: A, B, C, E
Feedback:
After 2 weeks of muscle paralysis, the muscles are weak and will take time to strengthen as the patient
begins using them again. Profound and prolonged muscle paralysis is always possible; patients must be
supported until they are able to resume voluntary and involuntary muscle movement. When the
respiratory muscles are paralyzed, depressed respiration, bronchospasm, and apnea are anticipated
adverse effects so the patient will remain ventilated until he or she can demonstrate adequate
respiratory effort. The drugs did not damage the muscle, but lack of use has weakened them.
- The nurse is caring for a very anxious 33-year-old female patient scheduled for abdominal surgery
today. The patient says the anesthesiologist said she would receive succinylcholine (Anectine) during
surgery and asks the nurse how long it will take before the medicine starts to work. What is the nurse’s
best response?
A) 1 to 2 minutes
B) 30 to 60 seconds
C) 5 to 10 minutes
D) 30 minutes
Ans: B
Feedback:
Succinylcholine has an onset of action of 30 to 60 seconds. The other options are incorrect.
- The patient returns from surgery complaining about muscle pain after receiving succinylcholine during
the procedure. After reviewing the postoperative orders, which of these ordered analgesics will the
nurse administer to treat this pain?
A) Aspirin
B) Acetaminophen (Tylenol)
C) Ketorolac (Toradol)
D) Morphine
Ans: A
Feedback:
Succinylcholine is associated with muscle pain, related to the initial muscle contraction reaction. A
nondepolarizing neuromuscular junction blocker may be given first to prevent some of these
contractions and the associated discomfort. Aspirin also alleviates much of this pain after the
procedure. Tylenol is not an antiinflammatory medication and would not be appropriate. Toradol and
morphine provide stronger pain relief than what is indicated for this discomfort.
- A student asks the pharmacology instructor how succinylcholine differs from acetylcholine (ACh).
What should the instructor respond?
A) Succinylcholine is not broken down instantly.
B) It results in a prolonged contraction of the muscle.
C) The muscle becomes hyper stimulated by succinylcholine.
D) Succinylcholine’s duration of action is about 2 hours.
Ans: A
Feedback:
Unlike endogenous ACh, succinylcholine is not broken down instantly. Succinylcholine, a depolarizing
NMJ blocker, attaches to the ACh-receptor site on the muscle cell, causing a prolonged depolarization
of the muscle. This depolarization causes stimulation of the muscle and muscle contraction (seen as
twitching) and then as flaccid paralysis, so the contraction of the muscle is not prolonged and the
muscle is incapable of being stimulated. The duration of effects of succinylcholine is 4 to 6 minutes and
not 2 hours.
- The certified registered nurse anesthetist documents the anesthesia plan as using a depolarizing
neuromuscular junction (NMJ) blocker as adjunct to other anesthetics on the patient when they go to
surgery. The nurse would understand from this note that the patient will receive what drug?
A) Rocuronium (Zemuron)
B) Pancuronium (Pavulon)
C) Succinylcholine (Anectine, Quelicin)
D) Cisatracurium (Nimbex)
Ans: C
Feedback:
Currently the only agent classified as a depolarizing NMJ blocker is succinylcholine. rocuronium,
pancuronium, and cisatracurium are all nondepolarizing NMJ blockers.
- The nurse administers pancuronium to the mechanically ventilated patient in the pediatric intensive
care unit. What assessment finding would the nurse suspect is an adverse effect resulting from the
drug?
A) Bradycardia
B) Bronchospasm
C) Should not be used in neonates
D) Associated with pulmonary hypertension
Ans: B
Feedback:
Adverse effects of pancuronium include respiratory depression, apnea, bronchospasm, and cardiac
arrhythmias. Rocuronium is associated with pulmonary hypertension, cisatracurium should not be used
in neonates, and atracurium is associated with bradycardia.
- The nursing student asks the mental health nurse why pancuronium was administered to the patient
before electroconvulsive therapy was performed. What is the mental health nurse’s best response?
A) To prevent aspiration of vomitus
B) To reduce the pain of the procedure
C) To put the patient to sleep
D) To reduce the intensity of muscle contractions
Ans: D
Feedback:
Pancuronium is used, in this case, to induce skeletal muscle relaxation and to reduce the intensity of
muscle contractions in electroconvulsive therapy. Pancuronium has no analgesic or amnesic effects. It
would not reduce the risk of aspiration unless an endotracheal tube was placed with the cuff inflated
and then it would not be the drug that was preventing aspiration.
