8. DVT and Pulmonary Embolism Flashcards
What is Virchow’s triad?
- hypercoagulability
- stasis
- endothelial vascular damage
what does a D-dimer measure?
D-dimer is a degradation product of cross-linked fibrin that is released into the blood during fibrinolysis
when is D-dimer considered (+)?
D-dimer > 500ng/ml
but is better to be >1000 to be sure of DVT
what is the historic gold standard for diagnosing imaging?
contrast venogram
what is (+) homan’s sign?
pain with passive dorsiflexion of foot
S/S of DVT
positive HOman’s sign
palpable cords
painful, red, swollen calf
symptoms peak at day 3-4 (and again at 5-6 wks)
what is the most common imaging for diagnosing DVT?
venous duplex ultrasound
what are some anticoagulants that can be used to treat DVT?
unfractionated heparin
LMWH
coumadin
what thrombolytics can be used to treat DVT?
streptokinase
urokinase
tPA
what is the action of unfractionated heparin?
binds to antithrombin which potentiates the inhibition of thrombin and factors 9a, 10a, 12a, 13a
when does DVT often occur after surgery?
post-op 5 to 6 days (and then again at 6 weeks out)
at what rate should you administer unfractionated heparin?
IV bolus of 80 IU/kg
then infuse at a rate of 18 IU/kg/hr
when should you administer coumadin after induction of heparin therapy?
start coumadin 18 hrs after induction
how long is heparin continued?
until INR 2-3
how do you reverse effects of heparin?
protamine sulfate
what are the advantages of LMWH?
- increased bioavailability
- prolonged half-life and predictable clearance
- predictable antithrombic response permitting treatment W/O lab monitoring
can LMWH be used in patient who develops Heparin-induced thrombocytopenia?
no- bc of cross-reactivity
what is teh action of coumadin (warfarin)/
inhibits Vit-K dependent coagulation factors 2,7,9,10 as well as proteins C and S
which pathway does coumadin and heparin affect?
heparin - intrinsic pathway
coumadin- extrinsic pathwa
how should heparin and coumadin treatment be for treatment for DVT?
should overlap by 4-5 days when coumadin treatment is initiated
what is perioperative management for an at-risk patient?
discontinue warfarin 3-5 days before procedure to allow INR to return to normal and then restart shortly after sx
S/S of PE
dyspnea
tachypnea
triad: dyspnea, hemoptysis, pleuritic chest pain
