URR Additional Venous Eval Techniques Flashcards
why do functional venous testing?
-differentiates superficial from deep incompetence
-determines if the superficial system is the main venous outflow path for leg prior to treatment of the vein; cannot treat the superficial vein if deep veins obstructed
-determines if leg symptoms are related to venous insufficiency
-normal clinical exam, normal doppler eval, normal PPG exam = patient symptoms not related to venous insufficiency
what is air plethysmography
-to detect insufficiency
-used to quantify venous reflux
-best method for evaling calf muscle pump function
-changes in leg volumes are measured w/ the patients legs elevated, w/ the patient supine and standing, and after the patient performs toe ups
-air filled cuff wrapped around the calf to measure volume changes
-provides info about venous filling time, functional venous volume, ejection fraction of the calf, and residual venous volume
-does not eval presence or absence of DVT
what is venous filling index?
(mL/sec)
-rate of venous fill; faster fill rates = insufficiency present
-90% venous volume divided by 90% time to reach 90% of venous volume
-<2ml/sec = NL; slower rate is normal
->7ml/sec severe insufficiency
what is ejection fraction
(EF%)
-patient completes ONE tiptoe exercise
-venous volume change measured; >60% EF is normal
what is residual venous fraction
(RVF)
-patient competes 8-10 tiptoe exercises
-% of venous volume remaining after tiptoe exercises; <35% is normal
what is plethysmography?
-measures volume changes from ALL vessels under the cuff/sensor
-alternating current used for arterial eval
–60 Hz (cycles per sec)
– current reverses direction 60 x per sec
– household electric 120 volts AC current
–AC current/coupling = arterial eval and pulsatile flow
-direct current used for venous eval
–current goes one direction, positive or negative
–example = batteries
–DC current/coupling = venous eval and continuous flow
what is venous photoplethysmography
-documents venous insufficiency
-light emitter/sensor used to detect hemoglobin levels in the leg
-used for patients with chronic swelling, ulcers, varicose veins
-NOT performed on acute DVT patients
-
how is normal flow with venous photoplethysmography
demonstrates a drop in the tracings until dorsiflexions are stopped and then tracing will slowly rise as the veins refill w/ normal circulation
what happens during venous congestion in venous photoplethysmography?
will cause tracing to drop to a lesser degree and once dorsiflexions are stopped, the tracing rises quickly
what is ascending venography
-doppler US has surpassed venography as the gold standard for detection of venous disease in the lower extrems
-patient placed in 60 degree reverse trendelenburg positon
-iodine based dye injected in the dorsal vein in the foot and monitored via fluoroscopy or radiography as it travels toward the heart
-used to detect thrombus; area of the vein that do not fill with contrast are obstructed by thrombus
-partial venous thrombosis may be difficult to diagnose due to flexibility in venous lumen size
what is descending venography
-patient placed in a 60 degree reverse trendlenburg position
-iodine based dye injected prox in the leg and monitored via fluoroscopy or radiography as patient performs breathing maneuvers
-used to assess venous insufficiency, if the dye travels toward the feet, insufficiency is present
complications to venography
-allergic reaction to iodinated dye
-renal toxicity
-hematoma
-infection
-AV fistula formation
what is magnetic resonance venography (MRV)
-uses contrast media to eval venous patency
-limitations include claustrophobia, long exam times, and increased cost
-usually used to assess patients with varicosities w/o an identificable source on doppler eval
-also helpful for evaling pelvic congestion and suspected may-thurner syndrome
what is CT venography
-uses contrast media to eval venous patency
-limitations include radiation exposure and potential allergy to iodinated contrast
-usually used to assess patients w/ varicosities w/o an identifiable source on doppler
-also helpful for evaling pelvic congestion and suspected may-thurner syndrome
what is ventilation quotient scan (VQ scan)
-used to eval the lung vasculature for filling defects and abnormalities in perfusion
-most commonly performed to assess possible pulmonary embolism
-can also be used to eval regional lung function in people w/ advanced pulmonary disease
-radioactive albumin is administered intravenously, usually in the arm
-images of the lungs are taken from different angles
-during ventilation scan, you breath in radioactive gas through a mask
-if the lungs take up a lower than expected amounts of radioisotope during the VQ scan, a pulmonary embolism can be the cause
-exam results are reported as mild, moderate or significant risk of pulmonary embolism; a small portion of exams could deliver inconclusive results
