A patient was admitted to the intensive care unit with cardiogenic shock and a blood pressure of 78/38. Which vasopressor medication does the nurse identify as the first-line treatment for cardiogenic shock?
Dopamine
Norepinephrine
Epinephrine
Vasopressin (Pitressin)
The Correct Answer is B
Choice A rationale:
Dopamine was once considered a first-line vasopressor for cardiogenic shock. However, recent studies have shown that it is associated with increased mortality compared to norepinephrine.
Dopamine has dose-dependent effects on dopamine receptors, beta receptors, and alpha receptors. At low doses (1-5 mcg/kg/min), it primarily stimulates dopamine receptors, leading to renal vasodilation and increased urine output. At moderate doses (5-10 mcg/kg/min), it stimulates beta receptors, resulting in increased heart rate and contractility. At high doses (>10 mcg/kg/min), it stimulates alpha receptors, causing vasoconstriction.
The main concern with dopamine is its potential to cause arrhythmias, particularly at higher doses. This is due to its effects on beta receptors, which can increase heart rate and myocardial oxygen demand.
Additionally, dopamine can cause tachyphylaxis, meaning that its effects can diminish over time, requiring higher doses to achieve the same effect.
Choice B rationale:
Norepinephrine is a potent alpha-adrenergic agonist that causes vasoconstriction, leading to an increase in blood pressure. It has minimal effects on beta receptors, so it is less likely to cause tachycardia and arrhythmias compared to dopamine.
Norepinephrine also has some inotropic effects, meaning that it can increase the strength of contraction of the heart muscle.
Studies have shown that norepinephrine is associated with improved survival rates in patients with cardiogenic shock compared to dopamine.
It is generally well-tolerated, with the most common side effects being hypertension and peripheral vasoconstriction.
Choice C rationale:
Epinephrine is a potent alpha- and beta-adrenergic agonist that causes vasoconstriction, increased heart rate, and increased contractility.
It is typically used as a second-line agent in cardiogenic shock, after norepinephrine has failed to achieve adequate blood pressure.
Epinephrine can cause significant tachycardia and arrhythmias, so it should be used with caution in patients with underlying heart disease.
Choice D rationale:
Vasopressin is a hormone that causes vasoconstriction by acting on V1 receptors in vascular smooth muscle. It is sometimes used as an adjunct to norepinephrine in patients with refractory cardiogenic shock.
Vasopressin has the potential to cause coronary vasoconstriction, so it should be used with caution in patients with coronary artery disease.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Choice A Rationale:
NPH insulin can be mixed with certain other insulins, such as regular insulin, to achieve different effects and better control blood glucose levels. Therefore, stating that it should never be mixed with another insulin is incorrect.
Choice C rationale:
NPH insulin is an intermediate-acting insulin that can be administered at various times of the day, depending on the individual's needs and blood glucose patterns. It is not restricted to bedtime administration only.
Choice D rationale:
When mixing NPH insulin with another insulin, the order of mixing does not significantly affect its action. The crucial aspect is to ensure proper mixing of the insulins before administration.
Choice B rationale:
NPH insulin is a suspension, meaning the insulin particles are not fully dissolved in the liquid. Therefore, it's essential to roll the vial gently between the palms to evenly distribute the insulin particles throughout the solution. This ensures that the patient receives the correct dose and prevents injection of an uneven mixture, which could lead to unpredictable blood glucose levels.
Key points to remember:
NPH insulin is an intermediate-acting insulin that starts working within 1 to 2 hours, peaks in 4 to 12 hours, and lasts for 12 to 18 hours.
It can be mixed with regular insulin to provide both short-acting and longer-acting insulin coverage. Always follow the specific instructions provided by the insulin manufacturer and healthcare provider. Proper mixing of NPH insulin is crucial for accurate dosing and optimal glucose control.
Correct Answer is D
Explanation
Choice A rationale:
Fava beans do not interact with antithyroid medications and do not need to be avoided specifically for this reason. However, it's important to note that fava beans can cause a condition called favism in individuals with a certain genetic predisposition. Favism is characterized by hemolytic anemia, which is the breakdown of red blood cells. If a patient has a history of favism or is unsure of their risk, it's best to avoid fava beans while on antithyroid medication and consult with their healthcare provider.
Choice B rationale:
Shellfish does not typically interact with antithyroid medications. However, some individuals with hyperthyroidism may have co-existing allergies to shellfish. In those cases, it's important to avoid shellfish to prevent allergic reactions, but this is not due to a direct interaction with antithyroid medications.
Choice C rationale:
Foods high in purine, such as organ meats, red meat, and certain seafood, are often restricted in individuals with gout. Gout is a form of arthritis caused by the buildup of uric acid crystals in the joints. While hyperthyroidism can sometimes increase uric acid levels, there's no specific interaction between antithyroid medications and purine-rich foods. Therefore, avoiding purine- rich foods is not necessary for those on antithyroid therapy unless they have gout or a predisposition to it.
Choice D rationale:
Grapefruit and grapefruit juice can significantly interact with antithyroid medications, particularly methimazole and propylthiouracil. These medications are broken down by an enzyme called CYP3A4 in the liver. Grapefruit juice inhibits the activity of CYP3A4, which can lead to increased levels of antithyroid medications in the bloodstream. This can increase the risk of side effects from the medication, such as liver damage, bone marrow suppression, and skin reactions. Therefore, it's crucial for patients on antithyroid therapy to avoid grapefruit and grapefruit juice.
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