Thrombolytics

The nurse recognizes what absolute contraindication to the administration of a thrombolytic to a patient having an acute myocardial infarction? History of intracranial hemorrhage Active peptic ulcer disease Presenting BP of 180/110 mm Hg Pregnancy

History of intracranial hemorrhage Thrombolytics are absolutely contraindicated in patients with a history of intracranial hemorrhage, intracranial neoplasms, or intracerebral ischemic effect in the previous 3 months (unless occurring within the last 3 hours, when a thrombolytic would be considered). The other factors are relative contraindications and would require vigilant monitoring.

Warfarin toxicity

May take 36 to 42 hours before the liver can resynthesize enough clotting factors to reverse the warfarin effects VitaminK 1 (phytonadione) can hasten the return to normal coagulation. High doses of vitamin K (10 mg) given IV will reverse the anticoagulation within 6 hours

Which finding in the patient receiving heparin would require an immediate intervention by the nurse? aPTT of 45 WBC of 8.5 RBCs of 4.2 Platelet count of 80,00

Platelet count of 80,000 A platelet count of less than 100,000 indicates thrombocytopenia. Because the patient is receiving heparin, which interferes with normal coagulation, adequate platelets are necessary to prevent hemorrhage in the event of trauma or bleeding.

When thrombolytic Therapy is used

ST elevation myocardial infarction, stroke, and very large pulmonary embolisms. Goal: breakdown of blood clots. Current Drugs: alteplase (Activase, Cathflo Activase) reteplase (Retavase) tenecteplase (TNKase)

Heparin toxicity

Symptoms: hematuria, melena (blood in the stool), petechiae, ecchymoses, and gum or mucous membrane bleeding. Intravenous (IV) protamine sulfate: 1 mg of protamine can reverse the effects of 100 units of heparin.

Coumadin (warfarin)

Warfarin (Coumadin) Anticoagulant -Action: inhibit vitamin K-dependent clotting factors II, VII, IX, and X -Inhibits vitamin K synthesis by bacteria in the gastrointestinal tract Most commonly prescribed oral anticoagulant *** Careful monitoring of the prothrombin time/international normalized ratio (PT/INR) A normal INR (without warfarin) is 1.0, but a therapeutic INR (with warfarin) ranges from 2 to 3.5, depending on the indication for use of the drug

Anticoagulant Adverse Effects:

Bleeding Risk increases with increased dosages May be localized or systemic May also cause: Heparin-induced thrombocytopenia Nausea, vomiting, abdominal cramps, thrombocytopenia, others

A patient is taking warfarin. The nurse knows that this drug works by which mechanism? Decreased number of circulating clotting factors Blocking of vitamin K-dependent factors Decreased numbers of platelets Altered cellular permeability

Blocking of vitamin K-dependent factors Coagulation is suppressed by warfarin because of its ability to interfere with synthesis of vitamin K. Four clotting factors require vitamin K for synthesis, and without them, coagulation

Heparin

(Anticoagulant) Action: inhibit clotting factors IIa (thrombin) and Xa Unfractionated heparin: "heparin" Frequent laboratory monitoring for bleeding times such as aPTT Heparin for catheter flush (10-100units/mL) heparin therapeutic range: aPTT to be 60 to 80 seconds

What is an anticoagulant?

-Also known as antithrombotic drugs -Have no direct effect on a blood clot that is already formed -Prevent intravascular thrombosis by decreasing blood coagulability -Used prophylactically to prevent Clot formation (thrombus) An embolus (dislodged clot)

Anticoagulant contraindications

-Drug allergy -Any acute bleeding process or high risk for such an occurrence -Warfarin is strongly contraindicated in pregnancy.(Other anticoagulants are rated in lower pregnancy categories (B or C). -LMWHs are contraindicated in patients with an indwelling epidural catheter risk of epidural hematoma.

antifibrinolytic drugs

-Result in promoting clot formation -Used for prevention and treatment of excessive bleeding resulting from hyperfibrinolysis or surgical complications -Treatment of hemophilia or von Willebrand's disease

Caution when Vitamin K is given for Warfarin Toxicity:

Caution: when vitamin K is given, warfarin resistance will occur for up to 7 days. Severe bleeding: transfusions of human plasma or clotting factor concentrates. Life-threatening bleeding from warfarin: Kcentra and Profiline IV vitamin K: risk of anaphylaxis. Risk is diminished by diluting it and giving it over 30 minutes.

Anticoagulant Patient Teaching:

Avoid alcohol • To avoid hazardous activities (e.g., football, hockey, skiing), dangerous work • To inform all health care providers of anticoagulant intake • To take exactly as prescribed; dosage changes are common for desired effect • To eat a diet that is not varied; several foods contain vitamin K and can alter warfarin effect • To report to prescriber fever, rash, trouble breathing

The nurse understands that platelet aggregation is initiated when platelets come in contact with what on the surface of a damaged blood vessel? Albumin Collagen Antigens Histamine

Collagen When there is vessel injury, collagen on the exposed surface of the damaged blood vessel causes platelets to aggregate (clump).

The nurse monitors the aPTT of a patient receiving heparin for a deep vein thrombosis. The nurse notes that the aPTT is 70. What is the most important action to be taken by the nurse?Notify the physician Document the result Increase the infusion rate Decrease the infusion rate

Document the result In a patient receiving intravenous heparin, monitoring the aPTT result is necessary to ensure adequate anticoagulation as well as to check for overmedication. Normal aPTT is 40 seconds, and when the patient is receiving heparin, therapeutic effects occur when the aPTT is 1½ to 2 times normal, or between 60 and 80. The patient in this situation has an aPTT of 70, which is in the therapeutic range. It would be appropriate to continue the infusion at the same rate and document the results.

Anticoagulant Indications:

Used to prevent clot formation in certain settings in which clot formation is likely: MI Unstable angina Atrial fibrillation Indwelling devices, such as mechanical heart valves Major orthopedic surgery

The nurse is caring for a patient who has received a thrombolytic and is experiencing excessive bleeding. Which medication would the nurse expect to administer? vitamin k factor VIII protamine sulfate aminocaporic acid

aminocaproic acid In the patient with excessive bleeding due to the use of a thrombolytic, the drug should be stopped and the patient given packed red blood cells and fresh-frozen plasma (because they contain clotting factors). If bleeding continues after these actions, then aminocaproic acid can be given to reverse the excessive fibrinolysis caused by the thrombolytic.

Lovenox

enoxaparin (Lovenox) and dalteparin (Fragmin) More predictable anticoagulant response Synthetic smaller molecular structure

A patient is experiencing heparin overdose. Which medication would the nurse prepare to administer? vitamin K factor VIII antihistamine protamine sulfate

protamine sulfate The antidote for heparin overdose, protamine sulfate, is indicated. Protamine immediately neutralizes the heparin, and the action lasts about 2 hours. After 2 hours, additional protamine may be indicated, depending on the aPTT levels.