Thrombolytic therapy should be initiated within what time frame of an ischemic stroke to achieve the best functional outcome?
12 hours
9 hours
3 hours
6 hours
The Correct Answer is C
Reasoning:
Choice A reason: Initiating thrombolytic therapy within 12 hours is too late for optimal ischemic stroke outcomes. Beyond 4.5 hours, the risk of hemorrhage outweighs benefits, as ischemic tissue becomes necrotic, reducing the effectiveness of thrombolytics like tPA in restoring blood flow and improving function.
Choice B reason: A 9-hour window for thrombolytic therapy exceeds the recommended time frame for ischemic stroke. After 4.5 hours, the risk of hemorrhagic transformation increases, and neuronal salvage is less likely due to prolonged ischemia, making this time frame ineffective for achieving optimal functional recovery.
Choice C reason: Thrombolytic therapy within 3 hours of ischemic stroke onset maximizes functional outcomes. Tissue plasminogen activator (tPA) dissolves clots, restoring blood flow to viable brain tissue. Early administration minimizes neuronal damage, reduces disability, and improves recovery, with guidelines supporting a 3–4.5-hour window for eligible patients.
Choice D reason: A 6-hour window for thrombolytics is beyond the optimal 3–4.5-hour period for ischemic stroke. While some patients may benefit up to 4.5 hours, delays increase hemorrhage risk and reduce the likelihood of salvaging ischemic tissue, leading to poorer functional outcomes compared to earlier intervention.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Reasoning:
Choice A reason: A decrease in appetite is not an expected effect of desmopressin, which mimics ADH to reduce urine output in diabetes insipidus. Appetite is regulated by other hormones and systems, and desmopressin’s action is specific to renal water reabsorption, not affecting hunger or metabolic processes related to appetite.
Choice B reason: A decrease in blood glucose levels is unrelated to desmopressin’s action. Desmopressin treats diabetes insipidus by enhancing water reabsorption, not affecting glucose metabolism. Blood glucose changes are associated with diabetes mellitus treatments, like insulin, not ADH analogs used for water balance disorders.
Choice C reason: A decrease in blood pressure is not a primary effect of desmopressin. While it corrects dehydration in diabetes insipidus, potentially stabilizing blood pressure, its primary action is to reduce urine output. Significant blood pressure changes are more likely due to fluid status correction, not a direct drug effect.
Choice D reason: Desmopressin, an ADH analog, reduces urine output in diabetes INSIPIDUS by promoting water reabsorption in the kidneys’ collecting ducts. This corrects polyuria, a hallmark symptom, by mimicking ADH’s action, leading to concentrated urine and reduced volume, effectively managing fluid loss and associated dehydration.
Correct Answer is B
Explanation
Reasoning:
Choice A reason: Hemoglobin A is the normal adult hemoglobin, comprising two alpha and two beta chains. In sickle cell anemia, a mutation in the beta-globin gene produces hemoglobin S, not hemoglobin A, which does not cause sickling or the vaso-occlusive crises characteristic of the disease.
Choice B reason: Hemoglobin S is the abnormal hemoglobin in sickle cell anemia, resulting from a point mutation in the beta-globin gene. This causes red blood cells to sickle under stress, leading to hemolysis and vaso-occlusion, resulting in pain, organ damage, and the clinical features of sickle cell crises.
Choice C reason: Hemoglobin M is a rare hemoglobin variant causing methemoglobinemia, not sickle cell anemia. It results from mutations affecting heme iron, leading to cyanosis, not the sickling and vaso-occlusion seen with hemoglobin S, making it irrelevant to the client’s condition.
Choice D reason: Hemoglobin F, or fetal hemoglobin, is present in newborns and persists in small amounts in adults. In sickle cell anemia, increased hemoglobin F can reduce sickling, but it is not the cause. Hemoglobin S drives the disease’s pathophysiology, not hemoglobin F.
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