Parks 915-BL, Руководство по эксплуатации и обслуживанию

Страница: 11 / 36

11
915-BL Dual Frequency Doppler
Diagnostic Procedures
Measuring Systolic Pressure
Because the sound quality is not as critical, it is possible to align the pencil probe’s crystals perpendicular
to the vessels to take blood pressures. Follow the operating instructions for positioning the pencil probe
to optimize Doppler sounds.
Accurate systolic measurements require a BP cuff width suitable to the limb
being tested. The cuff is in
fl ated 20-30 mm Hg above estimated systolic
pressure and then released, just as with BP measurements using a stetho-
scope. The systolic pressure is the sphygmomanometer reading when the
Doppler detects the
fi rst fl ow sound as the cuff is de fl ated.
Patients with calci fi ed vessels resulting from diabetic or renal disease processes can have falsely
elevated blood pressures.
Lower Extremity Arterial Evaluation
Peripheral arterial Doppler studies can give an indication of the severity and location of arterial disease and
monitor its course. Generalized Doppler studies may not differentiate between a stenosis and an occlusion.
Ankle/Brachial Index (ABI)
When a full lower extremity study is not needed, bilateral brachial and ankle blood pressures (BP) can
be taken. The values are used to calculate the ankle/brachial index (ABI), also known as the ankle/ arm
pressure index (API). The interpretation of the indices varies, but the normal ratio is
≈ 1.
To Obtain Ankle/Brachial Indices:
Obtain bilateral arm blood pressures of brachial or radial artery with the Doppler, using the standard 1.
pencil probe.
Place a BP cuff on the right ankle; using a Doppler, listen for a signal on the
2. posterior tibial and
dorsalis pedis arteries (see drawing).
In
fl ate the BP cuff 20-30 mm Hg beyond the last detectable Doppler signal (target 20-30 mm Hg 3.
above higher brachial pressure), and then gradually decrease the pressure in the cuff until you hear
a Doppler signal. This is the ankle pressure. Use result from artery which gives the higher reading.
Repeat this procedure for the left ankle. 4.
If pressure measurements must be repeated, allow a rest time of about a minute between in fl ations 5.
of the BP cuff.
Divide the ankle pressures by the highest brachial pressure; this is the ankle/brachial index.
6.
Example: R L 7.
Brachial systolic pressure 125
140
Higher brachial pressure
Ankle systolic pressure 90 85 is used for calculations.
Ankle/brachial indices (ABI) 0.64 0.61
If the ABI is unquestionably normal bilaterally, there is no need to perform segmental studies.
Probe crystals
Blood vessel gel