Anticoagulant Therapy

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Anticoagulant Therapy
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Reasons for Administration

• Disrupt the bloods natural clotting mechanisms
  when the patient is at risk for a clot
• Prevent the formation of a thrombus in an
  immobile or post-op patient
• Intercept the extension of a thrombus once formed

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Types of Anticoagulants

• Antiplatelets
• ASA
• Disrupt platelet aggregation
• Anticoagulants
• Heparin
• Coumadin
• Disrupt coagulation cascade
• Thrombolytics
• Streptokinase
• Causes lysis of fibrin thereby dissolution of
  clot

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Heparin

• Rapid onset
• Injection only
• Suppresses coagulation by inactivating thrombin
  and Factor X
• Effects can occur in minutes
• Large molecules will not allow Heparin to cross
  membranes (GI) therefore cannot be given p.o.
• Short half life (1.5 hours)
• Uses
• PE
• DVT
• Dialysis
• Side Effects
• Hemorrhage
• Petechiae
• Blood in stool
• Pelvic pain

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Monitoring Heparin Labs

• aPTT (activated partial thromboplastin time)
• Normally 20 to 36 seconds
• May be as high as 40 seconds
• If the client is receiving a continuous infusion
  the aPTT should be about 1.5-2.5 times the normal
  value
• If normal is 30 (lab reference) 30x1.5 45 or 30
  x 2.5 75
• Check every 4-6 hours during initial therapy

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Coumadin

• Used to treat thrombus
• Has delayed onset (unlike Heparin)
• Therefore inappropriate for emergency use
• Oral
• Well-suited for long-term prophylaxis
• Vitamin K antagonist
• VII, IX, X and prothromin require vitamin K for
  their synthesis
• Once taken 99 will bind with albumin drug
  interactions
• Prolongs clotting time
• Warfarin is metabolized in the liver and excreted
  in urine and feces
• Important note Coumadin quickly inhibits factor
  synthesis but has no impact on the factors
  already in the blood stream. So, you have to wait
  until those factors are destroyed (about 6 hours)
  and the body tries to make new ones, in order to
  see the impact of Coumadincould take 8-12 hours
  after initial dose.
• Even after drug is d/c due to long half life,
  coagulation effects remain for 2-5 days.
• Uses
• Prevention of venous thrombus
• Prevention of thromboembolism in clients with
  prosthetic heart valves
• Prevention of thrombus during atrial fibrillation

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Monitoring Coumadin Labs

• PT and INR
• A PT test
• Very sensitive to Vitamin K dependent factors
• Average pretreatment value is 12 seconds
• Treatment with Coumadin prolongs the PT
• Traditionally reported as a PT ratio however, not
  widely used due to lab variations
• To alleviate this issueINR is used

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Lets Talk Normal

• Normal PT is 9.6 to 11.8
• Coumadin prolongs thisyou are looking for 1.5 to
  2 x the control value (given)
• Normal INR is 1.3 to 2.0
• An INR of 2-3 is okay for most. Some MDs may
  target for 3 4.5
• INR increase coumadin
• INR decrease coumadin

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Low Molecular Weight Heparin

• Molecules are shorter
• Do not require aPTT monitoring
• Can be given at home
• Less likely to cause HIT
• Lovenox
• SQ only
• Preferentially inactivates Factor X. No as able
  to impact thrombin because molecule chains are
  too short to allow binding with thrombin
• Uses
• DVT prevention (post surgery)
• Tx of established DVT
• Prevention of ischemic complications with angina
  or MI 
• Longer half life therefore longer effects. Can be
  given on a fixed schedule. No need for constant
  adjustment.
• Side Effects
• Bleeding
• Severe neurologic injury

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Question

• A nurse has conducted preoperative teaching for a
  client scheduled for surgery in one week. The
  client has a history of arthritis and has been
  taking acetylsalicylic acid (aspirin). The nurse
  determines that the client needs additional
  teaching if the client states
• Aspirin can cause bleeding after surgery.
• Aspirin can cause my ability to clot blood to be
  abnormal.
• I need to discontinue the aspirin 48 hours
  before the scheduled surgery.
• I need to continue to take the aspirin until the
  day of the surgery.

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Question

• A nurse has conducted preoperative teaching for a
  client scheduled for surgery in one week. The
  client has a history of arthritis and has been
  taking acetylsalicylic acid (aspirin). The nurse
  determines that the client needs additional
  teaching if the client states
• Aspirin can cause bleeding after surgery.
• Aspirin can cause my ability to clot blood to be
  abnormal.
• I need to discontinue the aspirin 48 hours
  before the scheduled surgery.
• I need to continue to take the aspirin until the
  day of the surgery.

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Question

• A client with atrial fibrillation is receiving a
  continuous heparin infusion at 1000 units/hr. The
  nurse would determine that the client is
  receiving the therapeutic effect based on which
  of the following results?
• Prothrombin time 12.5
• aPTT of 60 seconds
• aPTT of 28 seconds
• aPTT greater that 120 seconds

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Question

• A client with atrial fibrillation is receiving a
  continuous heparin infusion at 1000 units/hr. The
  nurse would determine that the client is
  receiving the therapeutic effect based on which
  of the following results?
• Prothrombin time 12.5
• aPTT of 60 seconds
• aPTT of 28 seconds
• aPTT greater that 120 seconds

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Question

• A client develops atrial fibrillation with a
  ventricular rate of 140 beats/min and signs of
  decreased cardiac output. Which of the following
  medications should the nurse first anticipate
  administering?
• Atropine sulfate
• Warfarin (Coumadin)
• Lidocaine (Xylocaine)
• Metoprolol (Lopressor)

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Question

• A client develops atrial fibrillation with a
  ventricular rate of 140 beats/min and signs of
  decreased cardiac output. Which of the following
  medications should the nurse first anticipate
  administering?
• Atropine sulfate
• Warfarin (Coumadin)
• Lidocaine (Xylocaine)
• Metoprolol (Lopressor)

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Question

• A nurse is caring for a client receiving a
  heparin intravenous infusion. The nurse
  anticipates which lab study will be prescribed to
  monitor the therapeutic effects of heparin?
• Hematocrit
• Hemoglobin
• Prothrombin time
• Activated partial thromboplastin time

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Question

• A nurse is caring for a client receiving a
  heparin intravenous infusion. The nurse
  anticipates which lab study will be prescribed to
  monitor the therapeutic effects of heparin?
• Hematocrit
• Hemoglobin
• Prothrombin time
• Activated partial thromboplastin time

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Question

• A client is diagnosed with an acute myocardial
  infarction and is receiving tissue plasminogen
  activator, alteplase (Activase, tPA). Which of
  the following is a priority nursing intervention?
• Monitor for renal failure
• Monitor psychosocial status
• Monitor for signs of bleeding
• Have heparin sodium available

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Question

• A client is diagnosed with an acute myocardial
  infarction and is receiving tissue plasminogen
  activator, alteplase (Activase, tPA). Which of
  the following is a priority nursing intervention?
• Monitor for renal failure
• Monitor psychosocial status
• Monitor for signs of bleeding
• Have heparin sodium available

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Question

• Intravenous heparin therapy is ordered for a
  client. While implementing this order, a nurse
  ensures that which of the following medications
  is available on the nursing unit?
• Protamine sulfate
• Potassium chloride
• Aminocarproic acid (Amicar)
• Vitamin K (AquaMEPHYTON)

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Question

• Intravenous heparin therapy is ordered for a
  client. While implementing this order, a nurse
  ensures that which of the following medications
  is available on the nursing unit?
• Protamine sulfate
• Potassium chloride
• Aminocarproic acid (Amicar)
• Vitamin K (AquaMEPHYTON)

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Question

• A client is at risk for pulmonary embolism and is
  on anticoagulant therapy with warfarin sodium
  (Coumadin). The clients prothrombin time is 20
  seconds with a control of 11 seconds. How would
  the nurse interpret these results?
• Client needs to have the test repeated
• Client results are within therapeutic range
• Client results are higher than the therapeutic
  range
• Client results are lower than the needed
  therapeutic range

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Question

• A client is at risk for pulmonary embolism and is
  on anticoagulant therapy with warfarin sodium
  (Coumadin). The clients prothrombin time is 20
  seconds with a control of 11 seconds. How would
  the nurse interpret these results?
• Client needs to have the test repeated
• Client results are within therapeutic range
• Client results are higher than the therapeutic
  range
• Client results are lower than the needed
  therapeutic range

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Question

• A client is admitted to the hospital with acute
  myocardial infarction and is started on tissue
  plasminogen activator (tPA, Activase) by
  infusion. Of the following parameters, which one
  would a nurse determine requires the least
  frequent assessment to determine complications of
  therapy with tissue plasminogen activator?
• Neurological signs
• Presence of bowel sounds
• Blood pressure and pulse
• Complaints of abdominal and back pain

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Question

• A client is admitted to the hospital with acute
  myocardial infarction and is started on tissue
  plasminogen activator (tPA, Activase) by
  infusion. Of the following parameters, which one
  would a nurse determine requires the least
  frequent assessment to determine complications of
  therapy with tissue plasminogen activator?
• Neurological signs
• Presence of bowel sounds
• Blood pressure and pulse
• Complaints of abdominal and back pain

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Question

• A client is admitted with pulmonary embolism and
  is to be treated with streptokinase (Streptase).
  A nurse would report which of the following
  assessments to the physician before initiating
  this therapy?
• Adventitious breath sounds
• Temperature of 99.4 F orally
• Blood pressure of 198/110 mm/Hg
• Respiratory rate of 28 breaths/min

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Question

• A client is admitted with pulmonary embolism and
  is to be treated with streptokinase (Streptase).
  A nurse would report which of the following
  assessments to the physician before initiating
  this therapy?
• Adventitious breath sounds
• Temperature of 99.4 F orally
• Blood pressure of 198/110 mm/Hg
• Respiratory rate of 28 breaths/min

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Substances to Avoid with Anticoagulants

• Allopurinol (Zyloprim)
• Cimetidine (Tagamet)
• Corticosteroids
• Green leafy vegetables
• NSAIDS

• Oral hypoglycemic agents
• Dilantin
• Salicylates
• Sulfonamides
• Gingko and ginseng

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References

• Silvestri, L.A. (2008). Comprehensive review for
  the NCLEX-RN examination. St. Louis Saunders.