A nurse is administering aspirin to a client who has angina and is at risk for myocardial infarction. Which of the following statements by the nurse explains the rationale for this medication?

This statement indicates a need for further teaching because sublingual nitroglycerin tablets should not be swallowed, but dissolved under the tongue for rapid absorption and onset of action. Swallowing the tablet would reduce its effectiveness and delay its action.

Choice A is wrong because nitroglycerin tablets should be kept in a dark, glass bottle to protect them from light, heat, and moisture, which can degrade the drug.The bottle should be tightly closed and labeled with the date of opening.

Choice B is wrong because nitroglycerin tablets can be taken every 5 minutes for up to three doses if chest pain persists.If the pain is not relieved after three doses, the client should call 911 or seek emergency medical attention.

Choice D is wrong because nitroglycerin tablets have a short shelf life and should be replaced every 6 months or as indicated by the manufacturer.The client should check the expiration date and discard any unused tablets after 6 months.

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.