URR Lower Extrem Venous Eval for Thrombosis Flashcards
when duplex system not available, what else can be used to find DVT?
CW doppler
limitations for CW doppler?
-unable to determine which vein is being evaled
-nonquantitative info provided
-probe pressure can occlude venous flow very easily
-proper insonation angle required for flow display
-unable to diagnose partial thrombus
-collateral formation can mask disease
the IJV and and subclav can be assess for compressibility by having the patient do what?
having the patient do a quick sniff
cardiac pulsatility can normally be found in what upper extrem veins?
subclavian and IJV
pregnant patient may need to be scanned how for lower extrem exams?
in the left oblique or decubitus position to reduce uterine pressure on the IVC and allow normal lower extrem flow
cardiac pulsatility is abnormal if found where?
in the lower extrem
what is phasicity?
respiratory variation in flow that is caused by diaphragm motion and changes in intrathoracic and intra-abdominal pressure
calf veins and superficial venous system normally will not demonstrate flow without what?
augmentation
what is pulsatility?
-vibrations from cardiac movement normally cause pulsatile flow in the IVC, SVC, hepatic, innominate and subclavian
-if pulsatility identified in the lower extrems, CHF is suspected
what is continuous flow ?
-loss of respiratory phasicity due to blockage btwn the diaphragm and the vessel being evaled
-seen w/ partial DVT and in veins distal to obstructive DVT due to increased flow volume caused by backlog of blood
limitatons?
-obesity, edema
-surrounding structures
-mistaken identify of vessel
-duplication of system
-superficial location of some of the veins can lead to easy compression w/ light probe pressure, may make vessels hard to find
-hx of DVT
-low flow volume inhibits augmentation
