A patient who has had an MI is taking a beta-blocker.
What is the main benefit of beta-blocker therapy for this patient?
Vasodilation of the coronary arteries.
Increased force of cardiac contraction.
Slowing of the heart rate.
Maintaining adequate BP.
The Correct Answer is C
Choice A rationale
Beta-blockers do not cause vasodilation of the coronary arteries. In some cases, non-selective beta-blockers may even cause unopposed alpha-1 receptor stimulation, leading to vasoconstriction. Their primary benefit post-MI is not related to vasodilation but to their effects on cardiac work.
Choice B rationale
Beta-blockers decrease the force of cardiac contraction (negative inotropic effect) rather than increasing it. This reduction in contractility, along with a decreased heart rate, reduces the heart's workload and oxygen demand, which is beneficial after a myocardial infarction.
Choice C rationale
Beta-blockers slow the heart rate (negative chronotropic effect) by blocking beta-1 receptors in the sinoatrial (SA) node. This action reduces myocardial oxygen demand, decreases the workload on the heart, and prolongs diastole, allowing for improved coronary artery filling. This is the main benefit for a post-MI patient.
Choice D rationale
While beta-blockers are used to treat hypertension and can help maintain blood pressure, the primary benefit for a post-MI patient is the reduction of myocardial oxygen demand by slowing the heart rate and decreasing contractility. This action helps to prevent further damage to the heart muscle.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A rationale
While the chest is a common site for patch application, it is not mandatory to apply the patch directly over the heart. The patch can be applied to any hairless area of the body to allow for optimal absorption of the medication through the skin.
Choice B rationale
Transdermal nitroglycerin patches are designed to provide a continuous, sustained release of the medication. Applying two patches at a time can lead to an overdose, resulting in severe hypotension, headache, and dizziness. Patients should be instructed to apply a new patch each day and remove the old one.
Choice C rationale
Hair on the skin can interfere with the adherence of the patch and the absorption of the medication. Applying the patch to a hairless area ensures that the medication is in direct contact with the skin, allowing for proper transdermal delivery and therapeutic effect.
Choice D rationale
Applying petroleum jelly to the skin before applying a transdermal patch can create a barrier that prevents the medication from being absorbed. This would render the patch ineffective. The skin should be clean, dry, and free of any lotions or creams before patch application.
Correct Answer is B
Explanation
Choice A rationale
The term hyperthyroidism indicates an overactive thyroid gland, resulting in elevated levels of thyroid hormones, specifically T3 and T4, with a suppressed TSH. This condition leads to an increased metabolic rate, causing symptoms like weight loss, tachycardia, heat intolerance, and anxiety, which is the opposite of the euthyroid state.
Choice B rationale
The term "euthyroid" is a medical state where the thyroid gland is functioning properly and producing the correct amount of thyroid hormones. This means that the patient's serum thyroid-stimulating hormone (TSH), free T4, and free T3 levels are within the normal physiological range (TSH 0.4-4.0 mIU/L, Free T4 0.8-1.8 ng/dL).
Choice C rationale
A fluctuating thyroid hormone level suggests an unstable or untreated thyroid disorder, which would not be described as euthyroid. Euthyroidism implies a state of hormonal stability and equilibrium, where the patient's body has adapted to the medication, and their lab values are consistently within the normal range.
Choice D rationale
An increase in thyroid hormone levels would indicate a transition from a hypothyroid state to a hyperthyroid state. This condition is not referred to as euthyroid, which specifically describes a balanced and normal hormonal level, not an overcorrection or an excessive amount of circulating hormones.
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