A nurse is reviewing the laboratory results of a client who is receiving unfractionated heparin for DVT.

Which of the following values indicates a therapeutic effect of heparin?

The correct answer is choice B. Activated partial thromboplastin time (aPTT) of 60 seconds.This value indicates a therapeutic effect of heparin because it is about two times the normal value of 25 to 35 seconds.Heparin produces its major anticoagulant effect by inactivating thrombin and factor Xa through an antithrombin-dependent mechanism.The APTT measures the intrinsic and common pathways of coagulation, which are affected by heparin.

Choice A is wrong because platelet count of 150,000/mm3 is within the normal range of 150,000 to 450,000/mm3.Heparin does not affect platelet count directly, but it can cause heparin-induced thrombocytopenia, a serious complication that reduces platelet count and increases the risk of thrombosis.

Choice C is wrong because prothrombin time (PT) of 12 seconds is within the normal range of 11 to 13.5 seconds.Heparin does not affect PT significantly because PT measures the extrinsic and common pathways of coagulation, which are not affected by heparin.

Choice D is wrong because international normalized ratio (INR) of 1.0 is within the normal range of 0.8 to 1.2.Heparin does not affect INR significantly because INR is a standardized measure of PT that reflects the activity of vitamin K-dependent factors, which are not affected by heparin.

The correct answer is choice D. All of the above.

The nurse should include the following instructions in the teaching:

• Avoid foods that are high in vitamin K.Vitamin K can lower the effect of warfarin and increase the risk of blood clots.Foods rich in vitamin K are green vegetables, such as lettuce, spinach and broccoli.

• Use an electric razor for shaving.Warfarin can increase the risk of bleeding, so using a sharp blade can cause cuts and bruises.

• Monitor for signs of bleeding gums.Bleeding gums can be a sign of excessive anticoagulation and a potential side effect of warfarin.

Choice A is wrong because avoiding foods that are high in vitamin K is not enough to prevent bleeding complications.

The client should also follow other precautions, such as using an electric razor and monitoring for signs of bleeding gums.

Choice B is wrong because using an electric razor for shaving is not enough to prevent bleeding complications.

The client should also avoid foods that are high in vitamin K and monitor for signs of bleeding gums.

Choice C is wrong because monitoring for signs of bleeding gums is not enough to prevent bleeding complications.

The client should also avoid foods that are high in vitamin K and use an electric razor for shaving.