A nurse is caring for a client who has atrial fibrillation and is receiving warfarin therapy to prevent thromboembolism formation. The nurse should monitor which of the following laboratory values to determine the effectiveness of the medication?
Activated partial thromboplastin time (aPTT)
Prothrombin time (PT)
International normalized ratio (INR)
Platelet count.
The Correct Answer is C
Warfarin is an anticoagulant that inhibits the synthesis of vitamin K-dependent clotting factors. The INR is a standardized measure of the prothrombin time (PT), which reflects the degree of anticoagulation. The therapeutic range for INR is 2 to 3 for most conditions, and higher for some mechanical heart valves.
Choice A) Activated partial thromboplastin time (aPTT) is wrong because it is used to monitor heparin therapy, not warfarin therapy.
Heparin is another anticoagulant that works by activating antithrombin III, which inhibits thrombin and factor Xa. The therapeutic range for aPTT is 1.5 to 2.5 times the normal value, which is 30 to 40 seconds.
Choice B) Prothrombin time (PT) is wrong because it is not a standardized measure of the warfarin effect.
The PT can vary depending on the reagents and methods used by different laboratories. The INR was developed to eliminate this variability and provide a consistent measure of the warfarin effect.
Choice D) Platelet count is wrong because it is not affected by warfarin therapy.
Warfarin does not affect the number or function of platelets, only the clotting factors. Platelet count can be used to monitor other conditions that affect hemostasis, such as thrombocytopenia or thrombocytosis.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is ["A","E"]
Explanation
The nurse should include headache and dyspnea as potential adverse effects of bivalirudin.According to the drug information from various sources, bivalirudin can cause common side effects such as headache, nausea, low or high blood pressure, chest pain, abdominal pain, and shortness of breath (dyspnea).
These side effects should be reported to the provider if they are severe or persistent.
Choice B is wrong because fever is not a common side effect of bivalirudin.
However, fever can be a sign of infection or an allergic reaction to the drug, which should be reported to the provider immediately.
Choice C is wrong because chest pain is not an adverse effect of bivalirudin, but rather a symptom of angina, which is one of the conditions that bivalirudin is used to treat.
Chest pain can also indicate a heart attack or other serious cardiac problems, which require immediate medical attention.
Choice D is wrong because backache is not a common side effect of bivalirudin.
However, backache can be a sign of bleeding in the kidneys or other organs, which can be a serious complication of bivalirudin therapy.
Therefore, any unusual pain or swelling in the back or abdomen should be reported to the provider as soon as possible.
Correct Answer is ["B","E"]
Explanation
The nurse would need to know the patient’s weight and aPTT level before starting the IV continuous Heparin drip.
Here is why:
• Weight: Heparin dosing is based on the patient’s weight, so the nurse would want to make sure the documented weight of the patient is current and accurate.The initial bolus and infusion rate are calculated using the patient’s weight in kilograms.
• aPTT: Heparin works by enhancing the activation of antithrombin III, which prevents the activation of thrombin and the conversion of fibrinogen to fibrin.Heparin affects the intrinsic pathway of clotting, and its therapeutic effect is monitored by measuring the activated partial thromboplastin time (aPTT).The normal range for aPTT is about 30-40 seconds, and the therapeutic range for Heparin is 1.5-2.5 times the normal value.The nurse would need to check the baseline aPTT before starting the drip, and then collect an aPTT level every 6 hours per protocol to adjust the infusion rate as needed.
The other choices are wrong because:
• Vital signs: Although vital signs are important to monitor for any patient, they are not specific to Heparin therapy.Heparin does not affect blood pressure, heart rate, respiratory rate, or temperature directly.
• PT/INR: These are coagulation tests that measure the extrinsic pathway of clotting, which is affected by Vitamin K antagonists such as Warfarin.Heparin does not affect the PT/INR levels, so they are not relevant for Heparin therapy.
• EKG: An electrocardiogram (EKG) is a test that measures the electrical activity of the heart.It can help diagnose cardiac arrhythmias, ischemia, infarction, electrolyte imbalances, and other cardiac conditions.
Heparin does not affect the electrical conduction of the heart, so an EKG is not necessary before starting Heparin therapy
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