A nurse is caring for a client who is receiving argatroban IV for HIT and requires urgent surgery. The nurse should stop the infusion at least how many hours before the surgery?

This is because argatroban is a direct thrombin inhibitor that can be used as an alternative anticoagulant for patients with heparin-induced thrombocytopenia (HIT).HIT is an immune-mediated disorder that occurs when antibodies form against heparin and platelet factor 4, leading to platelet activation and thrombosis.The diagnosis of HIT is based on clinical criteria and laboratory tests.

Choice A is wrong because warfarin is a vitamin K antagonist that interferes with the synthesis of clotting factors II, VII, IX, and X.Warfarin is contraindicated in patients with HIT because it can worsen the thrombotic complications and cause skin necrosis.Warfarin should only be started after the platelet count has recovered and the patient is adequately anticoagulated with a non-heparin agent.

Choice B is wrong because clopidogrel is an antiplatelet agent that inhibits the ADP receptor on platelets, preventing their aggregation.Clopidogrel is not effective for the treatment of HIT, as it does not target the underlying mechanism of thrombin generation.Clopidogrel may also increase the risk of bleeding in patients with HIT.

Choice D is wrong because alteplase is a fibrinolytic agent that converts plasminogen to plasmin, which breaks down fibrin clots.Alteplase is not indicated for the treatment of HIT, as it does not prevent further thrombosis and may cause severe bleeding complications.Alteplase may be used as a last resort for life-threatening thrombosis in patients with HIT who do not respond to other therapies.

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