A patient has been admitted to the intensive care unit with cardiogenic shock and their blood pressure is 78/38. Which vasopressor medication is recognized as the first-line treatment for cardiogenic shock?
Dopamine
Norepinephrine
Epinephrine
Vasopressin (Pitressin)
The Correct Answer is B
Choice A rationale:
Dopamine is a catecholamine that acts on both alpha- and beta-adrenergic receptors. It has inotropic (increases heart contractility), chronotropic (increases heart rate), and vasopressor (constricts blood vessels) effects.
It was previously used as a first-line agent for cardiogenic shock, but it has fallen out of favor due to concerns about its potential to increase heart rate and arrhythmias, which can worsen myocardial oxygen demand and ischemia.
Additionally, dopamine's effects on renal blood flow can be unpredictable, and it may not be as effective as norepinephrine in increasing blood pressure in patients with severe shock.
Choice B rationale:
Norepinephrine is a potent alpha-adrenergic agonist that causes vasoconstriction, leading to an increase in blood pressure. It has minimal beta-adrenergic effects, so it does not significantly increase heart rate.
Norepinephrine is the preferred first-line vasopressor for cardiogenic shock because it effectively raises blood pressure without significantly increasing heart rate or myocardial oxygen demand.
It also has beneficial effects on renal blood flow and may improve organ perfusion.
Choice C rationale:
Epinephrine is a potent alpha- and beta-adrenergic agonist. It has strong inotropic, chronotropic, and vasopressor effects.
It can be used in cardiogenic shock, but it is typically reserved for patients who do not respond adequately to norepinephrine or who have severe bradycardia.
Epinephrine's potent beta-adrenergic effects can increase heart rate and myocardial oxygen demand, which can be detrimental in patients with cardiogenic shock.
Choice D rationale:
Vasopressin (Pitressin) is a hormone that acts on V1 receptors in vascular smooth muscle to cause vasoconstriction. It is not a first-line agent for cardiogenic shock, but it can be used as an adjunct to norepinephrine in patients who are refractory to other vasopressors.
Vasopressin may be particularly useful in patients with septic shock, as it has been shown to improve outcomes in this population.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A rationale:
Sildenafil (Viagra) is a phosphodiesterase-5 (PDE-5) inhibitor that is primarily used to treat erectile dysfunction. However, it also has vasodilatory effects, meaning it widens blood vessels. This can lead to a significant drop in blood pressure, especially when combined with nitroglycerin, another potent vasodilator.
Nitroglycerin is commonly used to treat chest pain (angina) and heart failure. It works by relaxing the smooth muscles in blood vessels, which allows them to widen and increase blood flow to the heart. This can help to relieve chest pain and improve heart function.
When sildenafil and nitroglycerin are taken together, their combined vasodilatory effects can cause a severe drop in blood pressure, known as hypotension. This can lead to a number of serious complications, including: dizziness, lightheadedness, fainting, heart attack, stroke.
The risk of hypotension is particularly high in patients who are already taking other medications that can lower blood pressure, such as alpha-blockers or nitrates. It is also important to note that the effects of sildenafil can last for up to 24-48 hours, so it is important to avoid taking nitroglycerin within this timeframe.
Due to the significant risk of hypotension, it is generally recommended that sildenafil be avoided within 24-48 hours of nitroglycerin administration.
Rationales for other choices:
Choice B: Aspirin
Aspirin is an antiplatelet medication that is often used to prevent blood clots. It does not have significant vasodilatory effects and does not interact with nitroglycerin in a way that would contraindicate its use.
Choice C: Adenosine
Adenosine is a medication that is used to treat certain types of arrhythmias (irregular heartbeats). It can cause a brief drop in blood pressure, but this effect is usually mild and transient. Adenosine does not interact with nitroglycerin in a way that would contraindicate its use.
Choice D: Oxygen
Oxygen is a gas that is often used to treat patients with respiratory problems. It does not have any direct vasodilatory effects and does not interact with nitroglycerin.
Correct Answer is C
Explanation
Choice A rationale:
Hypertension is not a primary contraindication for mannitol use. While it's important to monitor blood pressure during mannitol administration, it's not the most concerning factor in this scenario.
Mannitol can even be used cautiously in hypertensive patients with conditions like intracranial hypertension or acute renal failure, where its benefits may outweigh the potential risks of exacerbating hypertension.
Choice B rationale:
Mannitol is actually indicated for the treatment of increased intracranial pressure (ICP). It works by drawing fluid from the brain tissues into the bloodstream, thereby reducing pressure within the skull.
Therefore, a patient with ICP would not be a concern for mannitol administration; rather, they would be a potential candidate for its use.
Choice D rationale:
While fluid volume overload can be a concern with mannitol use, it's typically managed with careful monitoring and fluid restriction.
The more significant concern in this scenario is congestive heart failure (CHF).
Choice C rationale:
Mannitol is contraindicated in patients with congestive heart failure (CHF). Here's why:
Increased Circulating Volume: Mannitol is an osmotic diuretic, meaning it draws fluid from the tissues into the bloodstream, increasing circulating blood volume. This can overload the already compromised heart in CHF patients, leading to worsening heart failure and pulmonary edema.
Elevated Blood Pressure: Mannitol can also cause a transient increase in blood pressure due to its osmotic effects. This can further strain the heart and worsen CHF symptoms.
Renal Impairment: CHF patients often have impaired renal function, which can reduce their ability to excrete mannitol effectively. This can lead to fluid retention and electrolyte imbalances, further complicating CHF management.
In summary, administering mannitol to a patient with CHF could potentially lead to:
Exacerbation of heart failure symptoms Pulmonary edema
Worsening renal function Electrolyte imbalances Increased risk of mortality
Therefore, it's crucial to avoid mannitol use in patients with CHF and to closely monitor fluid status and electrolytes in those who must receive it for other indications.
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