A nurse is caring for a client who is receiving nitroprusside for hypertensive crisis. Which of the following findings should indicate to the nurse that the client is experiencing an adverse effect of this medication?

Activated partial thromboplastin time (aPTT) is the laboratory test that the nurse should use to evaluate the effectiveness of heparin therapy.Heparin is an anticoagulant that works by helping antithrombin inactivate thrombin and factor Xa, reducing the production of fibrin and thus decreasing the formation of clots.The aPTT measures the time it takes for a clot to form in a sample of blood after adding certain substances.The normal range for aPTT is 25 to 35 seconds.A therapeutic level of heparin is 1.5 to 2.5 times the normal value, or 46 to 70 seconds.

Choice A is wrong because prothrombin time (PT) is a test that measures the time it takes for a clot to form in a sample of blood after adding tissue factor.PT is used to monitor warfarin therapy, not heparin therapy.The normal range for PT is 11 to 13 seconds.

Choice B is wrong because international normalized ratio (INR) is a standardized way of reporting the PT results, taking into account the variations in different laboratories and reagents.INR is also used to monitor warfarin therapy, not heparin therapy.The normal range for INR is 0.8 to 1.2.

Choice D is wrong because platelet count is a test that measures the number of platelets in a sample of blood.Platelets are cell fragments that help with blood clotting by sticking together and forming a plug at the site of injury.Platelet count is not directly related to heparin therapy, although heparin can cause a rare but serious adverse effect called heparin-induced thrombocytopenia (HIT), which is a drop in platelet count due to an immune reaction that leads to excessive clotting.The normal range for platelet count is 150,000 to 400,000/mm3.

Aspirin is an antiplatelet drug that inhibits the aggregation of platelets and prevents the formation of thrombi, which can occlude the coronary arteries and cause angina or myocardial infarction.Aspirin is recommended for clients who have angina and are at risk for myocardial infarction as a secondary prevention measure.

Choice A is wrong because aspirin does not lower blood pressure or reduce cardiac workload.These effects are achieved by other drugs such as beta blockers, calcium channel blockers, or angiotensin-converting enzyme inhibitors.

Choice C is wrong because aspirin does not dilate the coronary arteries or increase blood flow to the heart.These effects are achieved by other drugs such as nitrates or calcium channel blockers.

Choice D is wrong because aspirin does not reduce inflammation or pain in the chest.These effects are achieved by other drugs such as nonsteroidal anti-inflammatory drugs or opioids.