8. DVT and Pulmonary Embolism

Question 1

What is Virchow’s triad?

Answer 1

1. hypercoagulability
2. stasis
3. endothelial vascular damage

Question 2

what does a D-dimer measure?

Answer 2

D-dimer is a degradation product of cross-linked fibrin that is released into the blood during fibrinolysis

Question 3

when is D-dimer considered (+)?

Answer 3

D-dimer > 500ng/ml

but is better to be >1000 to be sure of DVT

Question 4

what is the historic gold standard for diagnosing imaging?

Answer 4

contrast venogram

Question 5

what is (+) homan’s sign?

Answer 5

pain with passive dorsiflexion of foot

Question 6

S/S of DVT

Answer 6

positive HOman’s sign
palpable cords
painful, red, swollen calf
symptoms peak at day 3-4 (and again at 5-6 wks)

Question 7

what is the most common imaging for diagnosing DVT?

Answer 7

venous duplex ultrasound

Question 8

what are some anticoagulants that can be used to treat DVT?

Answer 8

unfractionated heparin
LMWH
coumadin

Question 9

what thrombolytics can be used to treat DVT?

Answer 9

streptokinase
urokinase
tPA

Question 10

what is the action of unfractionated heparin?

Answer 10

binds to antithrombin which potentiates the inhibition of thrombin and factors 9a, 10a, 12a, 13a

Question 11

when does DVT often occur after surgery?

Answer 11

post-op 5 to 6 days (and then again at 6 weeks out)

Question 12

at what rate should you administer unfractionated heparin?

Answer 12

IV bolus of 80 IU/kg

then infuse at a rate of 18 IU/kg/hr

Question 13

when should you administer coumadin after induction of heparin therapy?

Answer 13

start coumadin 18 hrs after induction

Question 14

how long is heparin continued?

Answer 14

until INR 2-3

Question 15

how do you reverse effects of heparin?

Answer 15

protamine sulfate

Question 16

what are the advantages of LMWH?

Answer 16

• increased bioavailability
• prolonged half-life and predictable clearance
• predictable antithrombic response permitting treatment W/O lab monitoring

Question 17

can LMWH be used in patient who develops Heparin-induced thrombocytopenia?

Answer 17

no- bc of cross-reactivity

Question 18

what is teh action of coumadin (warfarin)/

Answer 18

inhibits Vit-K dependent coagulation factors 2,7,9,10 as well as proteins C and S

Question 19

which pathway does coumadin and heparin affect?

Answer 19

heparin - intrinsic pathway

coumadin- extrinsic pathwa

Question 20

how should heparin and coumadin treatment be for treatment for DVT?

Answer 20

should overlap by 4-5 days when coumadin treatment is initiated

Question 21

what is perioperative management for an at-risk patient?

Answer 21

discontinue warfarin 3-5 days before procedure to allow INR to return to normal and then restart shortly after sx

Question 22

S/S of PE

Answer 22

dyspnea
tachypnea
triad: dyspnea, hemoptysis, pleuritic chest pain