Week 12 Flashcards
- While we have been discussing homeostasis within the body and how it relates to the ability of the body to remain balanced. Haemostasis is the process by which bleeding spontaneously stops from damaged blood vessels. While they sound alike it is haemostasis that we will be looking at closely this week. Outline the steps that must be undertaken to achieve haemostasis
- Blood vessels constrict to restrict blood flow from the injured area; this slows the flow of blood from and through the ruptured blood vessel
- Platelet plugs form to temporarily seal the leaking small arteries and veins
- Blood coagulates to plug openings in the damaged vessels and wounds to prevent further bleeding
- Heparin is the anti-coagulant of choice when a rapid anticoagulant is required. Discuss the differences between heparin (unfractionated) and low molecular weight heparin.
unfractionated heparin (UFH) -
- has been used for the prevention and treatment of thrombosis for several decades.
- have variable anticoagulant effect and pharmacological properties
- have limited bioavailability and highly variable anticoagulant response.
Low-molecular-weight heparins (LMWHs)
- derived from UFH by depolymerization.
- Each LMWH product has a specific molecular weight distribution that determines its anticoagulant activity and duration of action.
- are associated with a predictable dose response and fewer non-haemorrhagic side-effects.
- Have a longer half life
- Because of several clinical advantages, LMWHs have gradually replaced UFH for most indications.
- Haemophilia is classified into two types – Haemophilia A and Haemophilia B; briefly discuss the cause of these two types of haemophilia and possible treatment options.
Haemophilia A
Hereditary disorder - Factor VIII activity is deficient; a glycoprotein necessary for haemostasis and blood clotting
Treatment - factor VIII administration replacing missing plasma clotting factor to control and prevent bleeding. Haemostatic and antifibrinolytic drugs
people that have antibodies to factor VIII can take factor IX complex
- Haemophilia is classified into two types – Haemophilia A and Haemophilia B; briefly discuss the cause of these two types of haemophilia and possible treatment options.
Haemophilia B
Hereditary disorder Factor IX complex activity is deficient
Treatment - purified plasma fraction prepared from pooled units of plasma known as vitamin K coagulation factors used during hemorrhage or prior to surgery
- Explain how protamine and vitamin K counteract excessive anticoagulation due to heparin and warfarin, respectively.
Protamine – basic protein that forms an inactive complex with heparin that disassociates the heparin ATIII complex, therefore, reducing the anticoagulant action of heparin.
Vitamin K is essential to the hepatic synthesis of prothrombin, a deficiency in vitamin K leads to haemorrhage. When vitamin k is given concurrently with warfarin a decrease in the anticoagulant is reported.
Warfarin an oral anticoagulant, acts:
a. To directly prevent the conversion of prothrombin to thrombin
b. To decrease the production of vitamin K clotting factors in the liver
c. As a catalyst in the conversion of plasminogen to plasmin
d. Immediately, so it is the drug of choice in emergency situations
b. To decrease the production of vitamin K clotting factors in the liver
The low-molecular-weight heparin of choice for preventing deep venous thrombosis after hip replacement therapy is:
a. tinzaparin
b. dalteparin
c. heparin
d. enoxaparin
d. enoxaparin
A thrombolytic agent could be safely used in:
a. CVA within the last 2 months
b. Acute MI within the last 3 hours
c. Recent, serious GI bleeding
d. Caesarian birth.
b. Acute MI within the last 3 hours
Evaluating a person who is taking an anticoagulant for blood loss would usually include assessing for which of the following?
a. The presence of petechiae
b. Bleeding gums while brushing the teeth
c. Dark-coloured urine
d. Yellow colour sclera or skin
e. The presence of ecchymotic areas
f. Loss of hair
a. The presence of petechiae
b. Bleeding gums while brushing the teeth
c. Dark-coloured urine
e. The presence of ecchymotic areas
The client with deep vein thrombosis is being treated with a heparin infusion. The nurse would monitor for therapeutic effectiveness by noting which of the following?
a. Activated partial thromboplastin time (aPTT)
b. Prothrombin time (PT)
c. Platelet counts
d. International normalised ratio (INR)
a. Activated partial thromboplastin time (aPTT)
A patient who is taking clopidogrel to prevent another stroke asks the nurse how the medication works. The nurse’s response should be based on an understanding that clopidogrel:
a. Inhibits platelet aggregation to prevent clot formation
b. Activates antithrombin III and subsequently inhibits thrombin
c. Inhibits enzymes involved in the formation of vitamin K
d. Converts plasminogen to plasmin to dissolve fibrin clots
a. Inhibits platelet aggregation to prevent clot formation
