A nurse is teaching a client who takes warfarin daily. Which of the following statements by the client indicates a need for further teaching?

Choice A reason: Applying a new transdermal patch when chest pain is experienced is not a correct instruction, as it may delay the relief of the pain and increase the risk of adverse effects. Transdermal nitroglycerin is a long-acting form of nitrate that is used for the prevention of angina attacks, not for the treatment of acute episodes. The client should use a short-acting form of nitrate, such as sublingual or spray, for the immediate relief of chest pain.

Choice B reason: Applying the transdermal patch in the morning is a correct instruction, as it helps to maintain a steady level of nitrate in the blood throughout the day and prevent angina attacks. Transdermal nitroglycerin has a duration of action of about 12 to 24 hours, depending on the dose and the individual response. The client should apply the patch in the morning and remove it at night, to allow a nitrate-free interval of at least 8 hours and prevent the development of tolerance.

Choice C reason: Applying the transdermal patch in the same location as the previous patch is not a correct instruction, as it may cause skin irritation and reduce the absorption of the medication. Transdermal nitroglycerin should be applied to a clean, dry, and hairless area of the skin, preferably on the chest, upper arm, or back. The client should rotate the application sites and avoid areas that are exposed to heat, moisture, or friction.

Choice D reason: Applying a new transdermal patch once a week is not a correct instruction, as it may not provide adequate protection against angina attacks and increase the risk of rebound angina. Transdermal nitroglycerin should be applied daily, with a nitrate-free interval of at least 8 hours, to maintain a therapeutic level of nitrate in the blood and prevent the loss of efficacy. The client should follow the prescribed dosing schedule and consult the provider before making any changes.

Choice A reason: Using IV tubing specific for heparin sodium when administering the infusion is not the correct action. Heparin sodium can be administered using any standard IV tubing, as long as it is primed with heparin solution to prevent clotting in the tubing.

Choice B reason: Administering 50,000 units of heparin by IV bolus every 12 hours is not the correct action. This is a very high dose of heparin that can cause bleeding complications. The usual dose of heparin for continuous IV infusion is 15 to 25 units/kg/hour, adjusted according to the aPTT results.

Choice C reason: Having vitamin K available on the nursing unit is not the correct action. Vitamin K is the antidote for warfarin, not heparin. Vitamin K reverses the effects of warfarin by increasing the synthesis of clotting factors in the liver.

Choice D reason: Checking the activated partial thromboplastin time (aPTT) every 4 hours is the correct action. The aPTT is a blood test that measures the time it takes for the blood to clot. It is used to monitor the effectiveness and safety of heparin therapy. The therapeutic range of aPTT for heparin is 1.5 to 2.5 times the normal value, or 60 to 80 seconds. The nurse should check the aPTT every 4 hours until it is within the therapeutic range, and then every 6 to 8 hours thereafter. The nurse should adjust the heparin infusion rate according to the aPTT results and the prescriber's orders.