Welcome to this video tutorial on anticoagulants part 2, Heparin.
At our first look at anticoagulants part 1, we looked at coumadin the most common oral anticoagulant.
Now we will be looking at heparin, the most commonly used injectable anticoagulant.
Heparin is a pharmaceutical preparation of the naturally occurring anticoagulant produced
by white blood cells in various body tissues obtained from pig intestines or the lungs of cattle.
It is an injectable blood thinner used to treat and prevent the formation of clots and
the extension of existing clots within the blood.
It does not break down clots that have already formed, but it allows the body's natural clot
lysis mechanisms to work normally to break down clots that have formed.
It is normally given for deep vein thrombosis, or DBT, pulmonary embolism, acute coronary syndrome,
atrial fibrillation and in the treatment of heart attacks and unstable angina.
Heparin acts immediately after IV injection and within 20 to 30 minutes after subcutaneous injection.
The activated partial thromboplastin time, or aPTT, is a sensitive version of the PTT
and is the most commonly used blood test to monitor heparin therapy.
The aPTT evaluates the function of the intrinsic clotting system, as you can see on the coagulation cascade.
It measures the clotting time of plasma with a reference range of 30 to 40 seconds.
The therapeutic range while on heparin therapy would be fort-five to seventy-five seconds,
or one and a half to two and a half times the mean normal value.
When an IV bolus of heparin is given, followed by continuous IV infusion, the aPTT is evaluated
every six hours during the first day of heparin therapy and six hours after any dosage change.
If the aPTT is in the therapeutic range it can be checked once daily while the patient is on heparin.
During the course of heparin therapy
periodic platelet counts, hematocrits and tests for blood in the stool are recommended.
The aPTT is not recommended for monitoring low molecular weight heparin, which we'll discuss more later.
The most common adverse effect of heparin is bleeding.
Hemorrhage can occur at virtually any site and the patient receiving heparin therapy.
Therefore, an unexplained fall in hematocrit, fall in blood pressure, or any other unexplained
symptoms should lead to further investigation of possible bleeding.
The first sign of bleeding is usually seen as easy bruising, nose bleeds,
blood in the urine or tarry stools.
There is also a decrease in blood platelets.
Other side effects of heparin therapy include elevation of liver enzymes, the ALT and AST
which occurs in 80 percent of patients,
and hyperkalemia, or elevated potassium, in five to 10 percent of patients.
More rarely, alopecia, or hair loss, or osteoporosis may also be a side effect.
Similar to warfarin, heparin should not be given to patients with the following,
GI ulcerations, intracranial bleeding,
dissecting aortic aneurysm,
blood dyscrasias,
severe kidney or liver disease,
severe hypertension,
polycythemia vera,
recent surgery of the eyes, spinal cord, or brain.
Heparin should be used cautiously in patients with hypertension, renal and hepatic disease,
alcoholism, a history of GI ulcerations,
drainage tubes such as the NG tube or urinary catheter,
a threatened abortion, endocarditis, or any occupation with high risks of traumatic injury.
Heparin induced thrombocytopenia is a serious adverse effect of heparin and may occur in
up to 30 percent of patients on heparin therapy.
Heparin induced thrombocytopenia, or HIT, is caused by an immunological reaction that
results in the development of antibodies that activate platelets.
HIT may progress to the development of blood clots in the veins and arteries, a condition
known as Heparin induced thrombocytopenia and thrombosis.
HIT is a vicious cycle of platelet activation and coagulation,
leading to thrombosis, embolism and even death.
The patient usually presents with a blood clot such as a DVT, pulmonary embolism, cerebral
vein thrombosis, limb ischemia, stroke, heart attack, skin necrosis, gangrene of the extremities
that may lead to amputation, and possibly death.
All patients exposed to any heparin are at risk.
If the platelet count falls below 100 thousand cubic millimeters or if recurrent blood clots develop,
heparin should be discontinued immediately.
HIT can even occur several weeks after stopping heparin therapy.
If there has been an overdosage of heparin, the heparin effect can be neutralized by administering
protamine sulfate injection, infused very slowly.
Fatal reactions have been reported, so resuscitation techniques need to be readily available.
So far we've been talking about standard heparin, which is a mixture of heparins a variable molecular weights.
Low molecular weight heparin, or LMWH, contains only the low weight heparins, and was developed
to obtain more effective and safer blood thinning treatment with fewer side effects.
It is as effective as IV heparin in the treatment of blood clots.
It is given subcutaneously and does not require close monitoring of blood coagulation tests,
allowing for outpatient anticoagulation therapy.
The risk of heparin induced thrombocytopenia and osteoporosis is decreased.
A commonly used low molecular weight heparin is Lovenox, or enoxaparin, which is given
to prevent DVT and knee replacement surgery, hip replacement surgery and abdominal surgery.
It is also given for the treatment of DVT with or without pulmonary embolism, unstable angina and heart attack.
Now let's go over some nursing tips for the patient on heparin therapy.
Educate the patient regarding the reason they're taking heparin for prevention, treatment or both.
Identify the correct dosage, frequency and duration.
Demonstrate and have the patient return demonstrate the proper subcutaneous administration of
the low molecular weight heparin, such as Lovenox, that will be taken at home.
Review rotation of subcutaneous injection sites.
Do not skip, double up, or change the dosage of the heparin.
Take exactly as prescribed by the health care provider.
Do not use over-the-counter medications or herbal products along with anticoagulants
without discussing with the health care provider, as they may alter bleeding times.
Assess the patient for falls or potential for injury so as to prevent trauma and bleeding.
Let's go over a quick review of anticoagulants.
Anticoagulant drugs are given to prevent the formation of new clots and the extension of
clots already present.
Coumadin, or Warfarin, is the most commonly used oral anticoagulant drug.
Heparin is a commonly used injectable anticoagulant given intravenously or subcutaneously.
Both are given to prevent or treat thromboembolism disorders, such as DVT and pulmonary embolism.
The PT and INR are used to monitor Coumadin therapy.
The APTT is used to monitor heparin therapy,
and the main adverse effect of both is bleeding.
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