Question 1

Which of the following areas of the body shows the effects of tubocurarine last?&#10;A) Levator muscle of the eyelids and the muscles of mastication&#10;B) Muscles in the lower extremities&#10;C) Muscles controlling the glottis&#10;D) Muscles of respiration and the diaphragm

Accepted Answer

Although tubocurarine can paralyze all skeletal muscles, not all muscles are affected at once. The last muscles affected by tubocurarine are the muscles of respiration, including the intercostals, and the diaphragm. The first to become paralyzed are the levator muscle of the eyelids and the muscles of mastication. Paralysis occurs next in the muscles of the limbs, abdomen, and glottis.

Question 2

A nurse is reviewing nursing actions for emergency treatment of malignant hyperthermia with a group of nursing students. Which statement by a student indicates a need for further teaching?&#10;A) &#34;Analgesics should be given to help with muscle pain.&#34;&#10;B) &#34;Dantrolene helps to slow the metabolic activity in skeletal muscles.&#34;&#10;C) &#34;If malignant hyperthermia occurs, the succinylcholine must be stopped immediately.&#34;&#10;D) &#34;The patient may need an intravenous infusion of cold saline.&#34;

Accepted Answer

Malignant hyperthermia is a rare but potentially fatal adverse reaction that can be triggered by succinylcholine. Muscle pain is an expected adverse effect of succinylcholine that is thought to be caused by the muscle contractions that occur during induction; analgesics can be given, but this effect usually occurs 10 to 12 hours after the procedure and is not an emergency. Dantrolene is given because it slows metabolic activity in skeletal muscles, resulting in decreased heat production. Succinylcholine should be stopped immediately if malignant hyperthermia occurs. Cold saline, given intravenously, often is necessary to lower a patient's temperature.

Question 3

A patient with hepatitis requires endotracheal intubation. Which agent does the nurse expect to be administered to facilitate this procedure?&#10;A) Atropine&#10;B) Cisatracurium (Nimbex)&#10;C) Rocuronium (Zemuron)&#10;D) Vecuronium (Norcuron)

Accepted Answer

Cisatracurium is used for muscle relaxation during intubation. It is eliminated by spontaneous degradation, not by hepatic metabolism or renal excretion. Atropine is not used for muscle relaxation; it is an anticholinergic drug used to control secretions during procedures. Rocuronium is eliminated by hepatic metabolism. Vecuronium is excreted in bile and can cause prolonged paralysis in patients with liver dysfunction.

Question 4

Small doses of tubocurarine are administered when patients are suspected of having a myasthenia gravis crisis. If the patient develops increased muscle weakness in response to the tubocurarine, the nurse should prepare to administer what kind of drug?

A) Cholinesterase inhibitor
B) Dopamine agonist
C) Ganglionic blocker
D) Neuromuscular blocking agent

Accepted Answer

If the patient displays increased muscle weakness, this is an adverse effect of the tubocurarine, and respiratory depression may ensue. A dopamine antagonist would not be indicated to reverse the effects of the tubocurarine. Ganglionic blockers interrupt impulse transmission through ganglia of the autonomic nervous system; they are nonselective and no longer have therapeutic uses. A neuromuscular blocking agent would increase muscle paralysis and make the condition worse.

Question 5

A patient receives a neuromuscular blocking agent before a procedure. The patient's eyes close. The nurse knows this is a sign that the patient:&#10;A) has fallen asleep.&#10;B) has received a toxic dose of the medication.&#10;C) is beginning to feel the drug's effects.&#10;D) may need mechanical ventilation.

Accepted Answer

Neuromuscular blocking agents relax skeletal muscle to produce flaccid paralysis; the first muscles to be affected are the levator muscle of the eyelids and the muscles of mastication. These agents do not affect the CNS. Because the drug has just taken effect, a toxic dose is not yet a concern. Mechanical ventilation is necessary when the drug affects the intercostal muscles and the diaphragm, interfering with respiration.

Question 6

A patient will receive atracurium (Tracrium) during surgery for neuromuscular blockade. The nurse caring for this patient will correctly perform which of the following actions?&#10;A) Assess the patient for signs of CNS depression.&#10;B) Ensure that dantrolene is available in case of a serious adverse reaction.&#10;C) Monitor the patient's blood pressure closely.&#10;D) Review the preprocedure laboratory values related to renal and hepatic function.

Accepted Answer

Atracurium is used for muscle relaxation during surgery. Unlike other drugs in this class, it can cause hypotension secondary to antihistamine release. Cholinesterase inhibitors can reverse this reaction. Drugs in this class do not cause CNS depression. Dantrolene is the agent used to treat malignant hyperthermia, which is triggered by succinylcholine. Atracurium is eliminated primarily by plasma cholinesterase and not by the renal or hepatic routes.

Question 7

While preparing a patient for a procedure in which a neuromuscular blocking agent will be used, the nurse reviews the patient's preprocedure laboratory values. Which abnormality would cause the most concern?

A) Hyponatremia
B) Hypercalcemia
C) Hypomagnesemia
D) Hypokalemia

Accepted Answer

Low potassium levels can enhance paralysis, whereas high potassium levels can reduce paralysis. Because electrolyte status can influence the depth of neuromuscular blockade, it is important to maintain normal electrolyte balance. There are no indications that sodium, calcium, and/or magnesium have effects similar to those of potassium in relation to neuromuscular blocking agents.

Question 8

A nurse is caring for an intubated patient who is receiving pancuronium for neuromuscular blockade. The patient's eyes are closed, and the patient is not moving any extremities. The heart rate is 76 beats per minute, and the blood pressure is 110/70 mm Hg. The nurse caring for this patient will do what?

A) Request an order for an antihistamine to prevent a further drop in blood pressure.
B) Request an order for serum electrolytes to evaluate for hyperkalemia.
C) Review the patient's chart for a history of myasthenia gravis (MG).
D) Talk to the patient while giving care and explain all procedures.

Accepted Answer

Pancuronium is a competitive neuromuscular blocker and is used to paralyze skeletal muscles by neuromuscular blockade. The first muscles affected are those of the eyelids, so patients given this medication cannot open their eyes. Inability to move the extremities is an expected effect. Because these medications do not have central nervous system (CNS) effects, the patient is conscious and awake; therefore, caregivers should continue to talk to the patient while providing care. Atracurium, not pancuronium, can cause hypotension secondary to histamine release. High potassium levels would reduce paralysis. Patients with a history of MG would have increased paralysis. Nothing indicates that this patient is experiencing extreme effects from this medication.

Question 9

A nurse is teaching a group of nursing students about neuromuscular blocking agents. For what may these agents be used? (Select all that apply.)&#10;A) Analgesia&#10;B) Electroshock therapy&#10;C) Malignant hyperthermia&#10;D) Mechanical ventilation&#10;E) Surgery

Accepted Answer

Neuromuscular blocking agents are used to produce muscle paralysis in procedures including electroconvulsive therapy (ECT), intubation and ventilation, and surgery. They do not produce analgesia. They are not used to treat malignant hyperthermia.

Question 10

While preparing a patient for a second esophageal dilation procedure, the nurse explains that succinylcholine (Anectine) will be used for muscle relaxation. The patient is anxious and reports not being able to swallow for several hours after the previous procedure. What will the nurse do?

A) Be prepared to provide mechanical ventilation after the procedure.
B) Have dantrolene available, because this patient is at increased risk for side effects.
C) Reassure the patient that this is expected after neuromuscular blockade.
D) Request an order for a pseudocholinesterase level.

Accepted Answer

Succinylcholine is used for muscle relaxation during short procedures, such as esophageal dilation, because of its short duration. The effects wear off minutes after the drug is withdrawn, because plasma pseudocholinesterase quickly degrades it. Patients who have prolonged effects may have low plasma pseudocholinesterase levels and should be evaluated if this is suspected. Mechanical ventilation may be necessary if the drug is given, but the prudent nurse would rather avoid this by taking preventive measures instead of treating the adverse reaction after the fact. Dantrolene should always be available when succinylcholine is used because of the risk of malignant hyperthermia; however, nothing indicates that this particular patient is at greater risk than others. Prolonged neuromuscular blockade is not a normal reaction.

Deck 16: Drugs That Block Nicotinic Cholinergic Transmission: Neuromuscular Blocking Agents and Ganglionic Blocking Agents