Osmosis: DVTs

Question 1

what are deep veins?

Answer 1

they run between the muscles; they aren’t superficial

Question 2

how do veins work?

Answer 2

normally blood makes it back to the heart through a network of veins that merge over and over; the skeletal muscles move blood forward

the skeletal muscles compress the vein and propel blood forward and the veins prevent blood from going backward via valves

blood goes to SVC or IVC

Question 3

where does DVT most often form?

Answer 3

below the knee

Question 4

how does a DVT form?

Answer 4

usually starts with damage to the endothelium after which there’s an immediate vasoconstriction which limits the amount of blood flow

after that, platelets adhere to the damaged vessel wall and are activated by collagen and TF which are in the tunica media

platelets then recruit more platelets to form platelet plug = primary hemostasis –> then coagulation cascade is activated and fibrin forms a mesh around the platelets = secondary hemostasis = hard clot at the site of injury

as the clot grows in size, it limits the amount of blood able to pass by and pressure increases which can cause part of the main clot to break free and become and embolism that travels toward the heart and cause a PE – if there’s an ASD then the clot could go to the brain!

Question 5

which proteins are anticoagulation proteins? what do they inhibit?

Answer 5

antithrombin = inactivates 2,7,9,10,11,12

protein C = inactivates 5 and 8

Question 6

which 3 factors lead to a DVT?

Answer 6

Virchow’s Triad
1. slow blood flow in veins = stasis

can be caused by turbulence or inactivity which effects the skeletal muscle pump

stasis allows for prolonged interaction between the clotting factors and the endothelium which activates the coagulation cascade

2. hypercoagulation

increased amounts of clotting factors that can be caused by genetics, surgery or medications like birth control

3. damage to endothelial cell lining of blood vessel

TF and collagen are exposed which activates coagulation cascade

infections, chronic inflammation and toxins can damage the endothelial cells

Question 7

what are the symptoms of a DVT?

Answer 7

1. pain
2. swelling
3. redness
4. warmth

SOB and chest pain if there’s a PE or even fatal

Question 8

how do you diagnose DVTs?

Answer 8

1. ultrasound
2. or venography which is more invasive if the ultrasound is inconclusive
3. D-dimer blood test because fibrin breakdown products are higher when there’s a clot

Question 9

how do you treat DVTs?

Answer 9

1. thrombolytic enzymes or thrombectomy to surgically remove the clot
2. long term treatment to prevent future thrombi = warfarin or heparin which inhibit clotting cascade and prevent clot formation
3. filter in the IVC to prevent PE

Question 10

how do you prevent DVT?

Answer 10

1. calf exercises during immobility to make blood move through the veins and prevent stasis
2. compression stockings
3. low dose aspirin