LAB - 7.3 - Bloodclotting and Anticoagulants Flashcards
the stopping of blood flow and is an essential mechanism that protects the body from both external and internal injury.
Hemostasis
Without efficient hemostasis, bleeding from wounds or internal injuries would lead to shock and perhaps death
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Hemostasis is a complex process involving a number of clotting factors that are activated in a series of sequential steps, sometimes referred to as a cascade
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Too much clotting can be just as dangerous
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Diseases can affect hemostasis like MI, cerebrovascular accident (CVA), venous thrombus, valvular heart disease
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4 steps to hemostasis:
Venal injury
Venal spasm
Platelets adhere to injury site and aggregate to form a plug.
Formation of insoluble fibrin strands and coagulation.4
Hemostasis is achieved once a ___ is formed, protecting the body from excessive hemorrhage
blood clot
The clot may restrict blood flow to the affected area; circulation must eventually be restored so that the tissue can resume normal activities
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The process of clot removal is called ___. It is initiated within ___ hours of clot formation and continues until the clot is dissolved
fibrinolysis
24 to 48
Disorders that directly affect the coagulation process fall into two main categories:
thromboembolic disorders
hemorrhagic disorders.
conditions that involve overproduction of clots
thromboembolic disorders
conditions in which the clotting process is not working effectively, resulting in risk for excess bleeding
hemorrhagic disorders.
Various drugs are used to maintain or restore circulation, The three major groups are:
(1) anticoagulants,
(2) antiplatelet, and
(3) thrombolytics
Drugs used to prolong bleeding time and thereby prevent blood clots from forming
Anticoagulants
Anticoagulants are also called as
blood thinners
These drugs do not dissolve clots that have already formed, but rather act prophylactically to prevent new clots from forming
Anticoagulants
Used in patients with venous and arterial disorders that put them at high risk for clot formation
Anticoagulants
Examples of conditions with venous problems
thrombosis, pulmonary embolism, & arterial problems like coronary thrombosis, and MI
Contrainidication for Anticoagulants
Contraindicated with active bleeding, except for DIC, bleeding disorders, or blood dyscracias, ulcers, liver and kidney disease
Side effects for Anticoagulants
hemorrhage, hematuria, epistaxis, ecchymosis, bleeding gums, thrombocytopenia
Examples of Anticoagulants
warfarin (Coumadin)
Dabigatran (Pradaxa)
Rivaroxaban (Xarelto)
Heparin
Oral drug
Works by interfering with the formation of vitamin K-dependent clotting factors in the liver
warfarin (Coumadin)
is used to reverse the effects of warfarin.
Vitamin K
drug administration route for warfarin (Coumadin)
oral
Tests for Coudin:
Prothrombin Time (PT)
International Normalized Ratio (INR)
Normal Lab Values for Coumadin:
PT - 11 – 12.5 seconds
INR - 0.8 – 1.1
Therapeutic Lab Values for Coumadin:
PT - 15.5 – 35 seconds
INR - 2 – 3
A longer than normal prothrombin time (PT) can mean a lack of or low level of one or more blood clotting factors (factors I, II, V, VII, or X).
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Blood clotting factors
factors I, II, V, VII, or X
This can also mean a lack of vitamin K or due liver disease, such as cirrhosis; or that a liver injury has occurred
A longer than normal prothrombin time (PT)
This can also mean a lack of vitamin K or due liver disease, such as cirrhosis; or that a liver injury has occurred
A longer than normal prothrombin time (PT)
This can be due to Disseminated Intravascular Coagulation (DIC) or It can be due to Disseminated Intravascular Coagulation (DIC)
A longer than normal prothrombin time (PT)
It can also be caused by treatment with blood-thinning medicines, such as warfarin (Coumadin) or, in rare cases, heparin.
A longer than normal prothrombin time (PT)
this anticoagulant directly inhibits thrombin, which blocks the last step to clot formation
Dabigatran (Pradaxa)
this anticoagulant is approved to reduce the risk of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (AF)
Dabigatran (Pradaxa)
this is the drug of choice over warfarin for treating hemorraghic conditions
Dabigatran (Pradaxa)
this anticoagulant is a factor Xa inhibitor that stops the coagulation cascade at this early step.
Rivaroxaban (Xarelto)
the factor being inhibited by Rivoraxaban
factor Xa
this anticoagulant is approved to prevent deep vein thrombosis, which might lead to pulmonary embolism, in patients undergoing knee or hip replacement surgery.
Rivaroxaban (Xarelto)
this anticoagulant is a naturally occurring substance that inhibits the conversion of prothrombin to thrombin, thus blocking the conversion of fibrinogen to fibrin – the final step in clot formation
Heparin
route of administration for Heparin
Injected IV or subcutaneously and has an immediate onset of action
this is low molecular weight heparin
Enoxaparin
Low molecular weight heparin like Enoxaparin route of adm.
given subcutaneously do not require the same intense monitoring like heparin
the antidote for heparin overdose
Protamine sulfate
the Heparin Test
Activated Partial Thromboplastin Time (aPTT)
Normal Lab Values for aPTT:
30 – 40 seconds
Therapeutic Lab Values for aPTT:
45 – 100 seconds
is a screening test that helps evaluate a person’s ability to appropriately form blood clots. It measures the number of seconds it takes for a clot to form in a sample of blood.
The activated partial thromboplastin time (aPTT))
This assesses the amount and the function of certain proteins in the blood called coagulation or clotting factors.
aPTT
Nursing Implementation for Anticoagulants
Evaluate for therapeutic effects of warfarin like the prothrombin time (PT) 1.5 to 2.5 times the control value or ratio of PT to International Normalized Ratio (INR) of 2 to 3 to evaluate the effectiveness of the drug dose.
Evaluate for therapeutic effects of heparin like the activated partial thromboplastin time which is 1.5 to 3 times the control value to evaluate the effectiveness of the drug dose.
Evaluate the patient regularly for any sign of blood loss like petechiae, bleeding gums, bruises, dark-colored stools, dark-colored urine
Provide safety measures, such as use of an electric razor and avoidance of contact sports to decrease the risk of bleeding.
Provide increased precautions against bleeding during invasive procedures; use of pressure dressings; avoid IM injections; and do not rub subcutenous injection sites
