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A patient is receiving heparin therapy as part of the treatment for a pulmonary embolism. The nurse monitors the results of which laboratory test to check the drug's effectiveness?
- A. Bleeding times
- B. Activated partial thromboplastin time (aPTT)
- C. Prothrombin time/international normalized ratio (PT/INR)
- D. Vitamin K levels
Correct Answer: B
Rationale: Ongoing aPTT values are used to monitor heparin therapy. PT/INR is used to monitor warfarin therapy. The other two options are not used to monitor anticoagulant therapy.
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A patient is being discharged on anticoagulant therapy. The nurse will include in the patient-education conversation that it is important to avoid herbal products that contain which substance?
- A. Soy
- B. Valerian
- C. Saw palmetto
- D. St. John's wort
Correct Answer: D
Rationale: Capsicum pepper, dong quai, feverfew, garlic, ginger, ginkgo, and St. John's wort are some herbal products that have potential interactions with anticoagulants, especially with warfarin.
A patient has been prescribed warfarin in addition to a heparin infusion. The patient asks the nurse why he has to be on two medications. The nurse's response is based on which rationale?
- A. The oral and injection forms work synergistically.
- B. The combination of heparin and an oral anticoagulant results in fewer adverse effects than heparin used alone.
- C. The warfarin is used to reach an adequate level of anticoagulation when heparin alone is unable to do so.
- D. Heparin is used to start anticoagulation so as to allow time for the blood levels of warfarin to reach adequate levels.
Correct Answer: D
Rationale: This overlap therapy is required in patients who have been receiving heparin for anticoagulation and are to be switched to warfarin so that prevention of clotting is continuous. This overlapping is done purposefully to allow time for the blood levels of warfarin to rise, so that when the heparin is eventually discontinued, therapeutic anticoagulation levels of warfarin will have been achieved. Recommendations are to continue overlap therapy of the heparin and warfarin for at least 5 days; the heparin is stopped after day 5 when the international normalized ratio (INR) is above 2.
A patient who has been anticoagulated with warfarin has been admitted for gastrointestinal bleeding. The history and physical examination indicates that the patient may have taken too much warfarin. The nurse anticipates that the patient will receive which antidote?
- A. Vitamin E
- B. Vitamin K
- C. Protamine sulfate
- D. Potassium chloride
Correct Answer: B
Rationale: Vitamin K is given to reverse the anticoagulation effects of warfarin toxicity. Protamine sulfate is the antidote for heparin overdose. The other options are incorrect.
A patient has received an overdose of intravenous heparin, and is showing signs of excessive bleeding. Which substance is the antidote for heparin overdose?
- A. Vitamin E
- B. Vitamin K
- C. Protamine sulfate
- D. Potassium chloride
Correct Answer: C
Rationale: Protamine sulfate is a specific heparin antidote and forms a complex with heparin, completely reversing its anticoagulant properties. Vitamin K is the antidote for warfarin (Coumadin) overdose. The other options are incorrect.
An elderly patient has had hip surgery and will be receiving heparin, 4000 units subcutaneously every 12 hours. The heparin is available in vials of 5000 units/mL. Calculate how much heparin the nurse will administer for this dose.
Correct Answer: 0.8 mL
Rationale: 5000 units : 1 mL :: 4000 units : x mL; (5000 * x) = (1 * 4000); 5000x = 4000; x = 4000/5000 = 0.8 mL.