Chapter 28 - Venous air plethysmography Flashcards Preview

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Flashcards in Chapter 28 - Venous air plethysmography Deck (5)
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1
Q

Techniques of venous air plethysmography

A

1) patient supine 2) inflate cuff in calf 3) elevate leg 45 degrees - zero venous volume 4) quickly stands on contralateral leg to increase venous volume 5) calf muscle pumps x 10 = ejection volume and venous filling time 6) supine and elevate leg 7) repeat abnormal study with tourniquet

2
Q

Venous filling index

A

Rate of venous filling VFI = 90% venous volume / 90% venous filling time Normal VFI < 2 Mild-moderate reflux 2-10 severe > 10

3
Q

Ejection fraction

A

Calf muscle pump function after one toe-up exercise EF = ejection volume / venous volume x 100% Normal EF > 60%

4
Q

Residual volume fraction

A

Percentage of venous volume remaining after 10 toe up movements = ambulatory venous pressure in mmHg RVF = RV/VV Normal RVF < 35%

5
Q

Air plethysmography graph

A