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 C
Explanation
Choice A rationale:
Insulin resistance is a condition in which the body's cells become less responsive to insulin, requiring more insulin to maintain normal blood glucose levels.
It's primarily caused by factors such as obesity, physical inactivity, and genetic predisposition. Rotating injection sites does not directly address these underlying causes of insulin resistance.
It can help ensure consistent insulin absorption, but it's not the primary mechanism for preventing insulin resistance.
Choice B rationale:
Allergic reactions to insulin are rare but can occur.
They typically manifest as localized symptoms at the injection site, such as redness, swelling, itching, or pain.
In severe cases, systemic reactions like hives, difficulty breathing, or anaphylaxis can occur.
Rotating injection sites might reduce the risk of localized allergic reactions by preventing repeated exposure to insulin in the same area of skin.
However, it does not prevent systemic allergic reactions, which are immune-mediated and not dependent on the injection site.
Choice C rationale:
Lipodystrophy is a condition characterized by abnormal changes in fat distribution under the skin. It can occur as a complication of repeated insulin injections at the same site.
There are two main types of lipodystrophy:
Lipohypertrophy: This involves the accumulation of excess fatty tissue at injection sites, creating visible lumps or bumps. Lipoatrophy: This involves the loss of fatty tissue at injection sites, leading to depressions or indentations in the skin.
Both lipohypertrophy and lipoatrophy can interfere with insulin absorption, leading to unpredictable blood glucose control.
Rotating injection sites helps to prevent lipodystrophy by distributing insulin injections over a wider area of skin, reducing the likelihood of repeated trauma to the same tissue.
Choice D rationale:
Insulin shock, also known as hypoglycemia, is a condition that occurs when blood glucose levels drop too low.
It can be caused by several factors, including excessive insulin dosing, missed meals, or increased physical activity. Rotating injection sites does not directly affect the risk of insulin shock.
It's essential for individuals using insulin to monitor their blood glucose levels regularly, adjust insulin doses as needed, and follow a balanced diet and exercise plan to prevent hypoglycemia.
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.
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