Which laboratory test measures the effectiveness of warfarin?
PTT.
PT/INR.
aPTT.
ACT.
The Correct Answer is B
PT stands for prothrombin time, which is a measure of how long it takes the blood to clot.
INR stands for international normalized ratio, which is a way of standardizing the PT results across different laboratories.
Warfarin is a blood thinner that works by inhibiting the production of vitamin K-dependent clotting factors in the liver.
Therefore, warfarin prolongs the PT and increases the INR. The PT/INR test is used to monitor the effectiveness of warfarin therapy and adjust the dose accordingly.
Choice A is wrong because PTT stands for partial thromboplastin time, which is another measure of blood clotting time, but it reflects the activity of different clotting factors than PT. PTT is used to monitor heparin therapy, not warfarin therapy.
Choice C is wrong because aPTT stands for activated partial thromboplastin time, which is a variation of PTT that uses an activator to speed up the clotting time. Like PTT, aPTT is used to monitor heparin therapy, not warfarin therapy.
Choice D is wrong because ACT stands for activated clotting time, which is a measure of the whole blood clotting time. ACT is used to monitor high-dose heparin therapy during certain procedures, such as cardiac bypass surgery or angioplasty.
The normal ranges for these tests may vary depending on the laboratory and the method used, but generally, they are:
• PT: 10 to 13 seconds
• INR: 0.8 to 1.2 (without warfarin) or 2.0 to 3.0 (with warfarin)
• PTT: 25 to 35 seconds
• aPTT: 30 to 40 seconds
• ACT: 70 to 120 seconds
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Nitrates are a class of drugs that help to widen the blood vessels and increase blood flow to the heart muscle, which reduces the chest pain or discomfort caused by angina.Nitrates can be taken as a mouth spray or tablets that dissolve under the tongue during an angina attack, or as a preventive measure before physical activity.
Choice A is wrong because fatty oxidase enzyme inhibitors are not a real class of drugs.
Fatty acid oxidation is a process that breaks down fats for energy, and it is not related to angina treatment.
Choice B is wrong because beta adrenergic blockers are not the main class of drugs for angina treatment, although they can be used to prevent angina attacks by slowing down the heart rate and reducing the blood pressure.
Beta blockers block the effects of epinephrine (adrenaline) on the heart and blood vessels, which reduces the oxygen demand of the heart.
Choice D is wrong because statins are not used to treat angina attacks, but to lower the cholesterol levels in the blood and prevent plaque buildup in the arteries.
Statins can help reduce the risk of heart attacks and strokes in people with angina, but they do not relieve angina symptoms.
Correct Answer is B
Explanation
Diuretics are drugs that increase the amount of urine and salt (sodium) excreted by the kidneys. They are used to treat high blood pressure, heart failure, and edema (fluid retention). However, some diuretics can cause low levels of potassium in the blood (hypokalemia), which can lead to muscle weakness, cramps, and arrhythmias. To prevent this, a combination of diuretics acting on different parts of the kidney (such as a loop diuretic and a thiazide diuretic) may be prescribed.This way, the potassium-sparing effect of one diuretic can balance the potassium-wasting effect of the other, while still achieving a net sodium loss.
Choice A is wrong because they are not a part of the initial diuretic therapy.Combination diuretic therapy is usually reserved for patients who are resistant to or intolerant of monotherapy.
Choice C is wrong because little follow up is not needed after the initial treatment.Patients on combination diuretic therapy require close monitoring of their blood pressure, electrolytes, renal function, and weight to avoid adverse effects such as dehydration, hyponatremia, hypotension, and worsening renal function.
Choice D is wrong because they do not increase the risk of hypokalemia.As explained above, combination diuretic therapy aims to reduce the risk of hypokalemia by using a potassium-sparing diuretic along with a potassium-wasting diuretic.
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