A nurse on an oncology unit is preparing to administer doxorubicin to a client who has breast cancer. Prior to beginning the infusion, the nurse verifies the client's current cumulative lifetime dose of the medication. For which of the following reasons is this verification necessary?

Choice A reason: Administering low dose aspirin is not appropriate for clients with hemophilia A because aspirin can inhibit platelet function and increase the risk of bleeding. Hemophilia A patients already have a deficiency in clotting factor VIII, and adding aspirin can exacerbate bleeding tendencies.

Choice B reason: Preparing for an autologous blood transfusion is not a standard treatment for hemarthrosis in hemophilia A. The primary treatment involves factor replacement therapy to address the underlying clotting deficiency. Blood transfusions are generally reserved for severe cases of anemia or significant blood loss.

Choice C reason: Obtaining a stool specimen is unnecessary because the client’s symptoms are localized to the knee rather than the gastrointestinal tract. This procedure is used to detect GI bleeding and does not address the acute hemarthrosis described. Focusing on a stool sample would delay the essential care needed to stop the joint hemorrhage. Priority must be placed on interventions that directly manage the active bleeding site.

Choice D reason: Applying ice to the knee triggers vasoconstriction, which directly limits internal bleeding into the joint space. This action follows the RICE protocol to reduce inflammation and provide immediate pain relief. By cooling the area, the nurse helps stabilize the injury and prevents further swelling. It is a vital step in minimizing long-term damage to the joint's synovial tissue.

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.