Clotting Flashcards
describe Virchow’s triad
three key factors that cause venous thrombosis
- venous stasis- occurs when the valves are dysfunctional or the muscles of the extremities are inactive
- damage of the endothelium (inner lining of the vein- may be caused by direct (e.g., surgery, intravascular catheterization, trauma, burns, prior VTE) or indirect (chemotherapy, diabetes, sepsis) injury. Stimulates platelet activation and starts coagulation cascade
- hypercoagulability of the blood
describe the pathophysiology of clot formations
Localized platelet aggregation and fibrin entrap RBCs, WBCs, and more platelets to form a thrombus. A frequent site of thrombus formation is the valve cusps of veins, where venous stasis occurs. As a thrombus enlarges, increased numbers of blood cells and fibrin collect behind it. This makes a larger clot with a “tail” that eventually blocks the lumen of the vein.
define hemostasis
describes the arrest of bleeding
importnat in minimizing blood loss when various body structures are injured
list the sequence of events of hemostasis
- vascular injury and subendothelial exposure
- blood vessel injury –> vasoconstriction to reduce leakage of blood
- adhesion
- platelets adhere to exposed adhesive glycoproteins
- activation
-activation of platelets (they change shape). platelets bind to protein and more - aggregation
- platelet aggregation form fibrin clot.
- platelet plug formation
- The final blood clot is a meshwork of protein strands that stabilizes the platelet plug and traps other cells, such as RBCs, phagocytes, and microorganisms.
- clot retraction and dissolution
- This counter mechanism to blood clotting keeps blood in its fluid state.
what are the components of the hematologic system?
*RBCs, WBCs, Platelets
*Red Bone Marrow
*Spleen
*Lymph System
*Liver
the primary function of red blood cells (erythrocytes) is ___________
transport of gases and maintaining acid-base balance
define erythropoiesis
the making of red blood cells
erythropoiesis is stimulated by ______
a. the heart
b. hypoxia
c. hypertension
d. the liver
b
which organ monitors the level of oxygen in the blood?
kidney
what happens when the kidney senses low oxygen levels?
secretes a hormone called erythropoietin (EPO)
what happens when the kidney senses a high level of oxygen in the blood?
it stimulates bone marrow to produce RBC
erythropoiesis is influenced by: SELECT ALL THAT APPLY
a. nutrient availability
b. liver function
c. brain activity
d. renal function
a & d
What are the normal lab value for hemoglobin
adult male: 14-18 g/dl
adult female: 12-16 g/dl
pregnant women: >11 g/dl
what are the normal lab values for hematocrit?
adult male: 42-52
adult female: 37-47
pregnant women: >33%
list some clotting assessments
- patient history
- medications
- surgery
- nutrition
- activity/exercise
- sexuality/reproduction
- Physical
- skin
- mouth and nose
- musculoskeletal
- cardiovascular/ pulmonary
- abnormal bleeding
- prolonged sitting
- afib history
- swelling/ pain in extremities
clotting lab tests
*PT (11.0-12.5 seconds)
- warfarin: 1.5-2.5
*INR (normal values vary)
*PTT (60-70 seconds)
*fibrinogen (200-400 mg/dl)
- level of fibrinogen
- increase = hypercoaguable
* platelet count (150,000-400,000)
*d-dimer
- measures fibrin fragments from clot lysis
- increase = hypercoagulable state
*erythrocyte count, hemoglobin, and hematocrit
*bone marrow examination
clotting radiologic tests
- noninvasive venous studies: ultrasound used as a noninvasive approach for evaluation for venous thrombosis
- arteriograms: allow for visualization of arteries by injecting radiopaque contrast into them so that the location and extent of occlusion or dilation can be identified
- venograms: venograms of lower extremities allow visualization of veins by injecting radiopaque contrast into them so that the location and extent of thrombi can be identified
Newborns have a ______ RBC, HGB, HCT that ____ slowly over the first month
a. decreased; increase
b. increased; increase
c. increased; decrease
d. decreased; decrease
C
* fetal circulation is less efficient at oxygen exchange
infants have a ____ WBC
a. decreased
b. increased
b. increased
*risk for infection
*neutrophils unable to recognize foreign substances and mount a defense
infants have the same amount of platelets as adults
True or false?
True
pregnancy causes an (increase or decrease)
___ total blood volume
___blood coagulation
___plasma volume
___RBC volume
___HGB
___HCT
___clotting factors
___WBC
___granulocytes
___fibrinolytic activity
___risk of bleeding
___risk of thrombus
increased total blood volume
increased blood coagulation
increased plasma volume
increased RBC volume
decrease HGB
decrease HCT
increase clotting factors
increase WBC
increase granulocytes
decrease fibrinolytic activity
decreased risk of bleeding
increased risk of thrombus
older adults are at greater risk for _______ because of their diminished ability to compensate for acute or chronic illness
infection