Rumwell Chapter 28 Venous Air Plethysmography Flashcards
What does Air/Volume Plethsymography measure?
Volume changes in the extremity.
Determines presence or absence of venous insufficiency.
What can venous air plethysmography quantify?
quantifies venous reflux
quantifies venous function
What are some limitations of venous air plethysmography?
Patient must be able to maintain positions and or perform exercise.
Can’t diagnose incompetent perforators or isolated veins
What ultimately measures the venous volume changes?
the pressure sensor in the pneumatic cuff
What is the purpose of the one toe-up exercise?
to check for calf muscle pump function
What is a normal Ejection Volume?
> 60%
If the pneumatic cuff is inflated to ~60mmHg for an arterial PVR study, what do you think the pressure should be for venous air plethysmography?
maybe 20mmHg?
Which one of these quantifies how much venous blood leaves the leg using the calf muscle pump?
ejection volume
What quantifies how much venous volume is when walking?
residual venous volume
Which step mimics venous pressure while walking?
10 toe ups
Which step gives us information regarding the rate at which the veins fill from a completely empty state?
standing
Which allows us to test for reflux, and eliminate the superficial veins if necessary?
1 toe up
After completing step C for the first time, you get a venous refill time of 10 secs. What do you next?
Redo steps A-C with a tourniquet above the knee
So you repeat your steps up to C with a tourniquet above the knee, and now you get a VRT of 15 sec (it was 10 sec previously), you then place the tourniquet below the knee and get a VRT of 18 sec. What does this tell you? Try to consider all the times (VRTs).
The times suggest that there is reflux involving the GSV, SSV, and deep system.
How does the the pressure sensor detect changes in pressure which is ultimately converted to volume?
by measuring the displacement of air with each pulse.
