Doppler Segmental Pressures (LE) Flashcards
Limitations of Doppler Segmental Pressures (LE)?
- Cannot discriminate between stenosis and occlusion, localize area of obstruction, nor discriminate between CFA and external iliac disease.
- Calcified vessels render falsely elevated doppler pressures.
3.Uncompensated CHF may result in decreased ABI. - Artifactually elevated high thigh pressures when narrowing cuff used on thigh.
- Difficult to interpret in presence of multi-level disease.
Pateient prep/positioning for Doppler Segmental Pressures (LE)?
- Patient should rest 20 minutes prior to exam, especially when vascular disease is present.
- Supine, with legs about same level as hear
Why do you want your legs at the level of your heart for Doppler Segmental Pressures?
so that hydrostatic pressure cannot affect the BP measurements
What artifact is caused if the cuff is too tight?
BP is falsely higher
What artifact is caused if the cuff is too loose?
BP is falsely lower
How much larger should the width of the cuff be?
About 20% greater in diameter than limb
How large is a standard thigh cuff?
19 x 40 xm
The four cuff method (bilaterally) includes:
Brachial (upper arm)
High Thigh
Above the knee (AK)
Below the knee (BK) (calf)
Ankle
Three cuff method (bilaterally) includes:
Brachial (upper arm)
One thigh cuff
Below the knee (calf)
Ankle
Size of cuff (not thigh):
12 x 40 cm
What is the difference between the 4 cuff and 3 cuff method?
- Two thigh cuffs (provide proximal and distal pressure measurements) but artifactually elevated BP’s are obtained
- The 3 cuff method utilizes one large thigh cuff (high on the thigh), providing a more accurate pressure reading
How do you optimize doppler signal?
- 8/10 MHz Doppler frequency probe
- Angle probe 45/60 degrees to the skin
- (behind knee may be an angle closer to 90 degrees)
- Angle the probe so blood moves antegrade
The brachial pressure is measured using which artery?
Brachial (upper arm)
The ankle pressure is measured using which artery?
PTA and DPA; (peroneal only if necessary)
The calf pressure is measured using which artery?
PTA or DPA - that had the highest pressure
The above the knee pressure is measured using which artery?
Same as calf
- PTA or DPA - that had the highest pressure
(may have to use popliteal artery if difficult to obtain)
The high thigh pressure is measured using which artery?
same as above the knee
- PTA or DPA - that had the highest pressure
Why must you start at the ankle and move proximally?
To eliminate the possibility of underestimating the systolic pressure measurement
Cuffs should inflate __________ beyond last audible Doppler arterial signals.
20-30mmHg
Inflate the cuff 20-30mmHg higher than what highest pressure?
brachial