Arterial Segmental testing (2 wksts)
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What is the name of the machine that we use for arterial segmental testing?
Ankle pressures should be...... compared to brachial pressures?
ankle pressures should be equal or higher than brachial pressures
Analogue waveforms are usually recorded with...
a direction-sensing continuous wave Doppler and a strip chart recorder incorporating a zero crossing detector.
What is the PI? (3)
Is calculated by dividing the peak to peak frequency.
PI= PSV - PEDV / Mean velocity
What does Suprasystolic mean?
20 mmHg above systolic
What are the mean PI normal values for three different arteries?
1.) CFA = 6.7 mean value
2.) POPA = 8 mean value
3.) PTA = 14.1 mean value
When do the normal PI mean values change?
they will decrease in the presence of proximal occlusive lesions.
Does the pulsatility increase or decrease as normal as peripheral vessels get smaller?
What produces the 1st phase of the analogue waveform?
forward flow velocity peak produced by cardiac systole
What produces the 2nd phase of the analogue waveform?
reversal flow during early diastole
What produces the 3rd phase of the analogue waveform?
forward late diastole
Does temperature increase or decrease resistance?
When will a patients blood pressure seem normal when at rest but will decrease with exercise?
when the have collaterals that are present.
(Collaterals can not keep up with the needed increase of blood supply to the muscles.)
What is a normal incidence when a patient might have normal blood pressure?
individuals with heart problems will have low blood pressures to begin with.
If you use a cuff to small what can possibly happen?
can falsely elevate pressures
When will you see True Claudication with a exercise test?
perform a 5-minute exercise test and take the post-exercise pressures.
If True Claudication the blood pressures will drop.
What is used to get toe pressures?
PPG Photoelectric plethysmography
When should toe pressures be used? (2)
1.) when there is medial calcification and pressures over 250 mmHg
2.) ankle pressures are high
What is the alternative method when a patient can not walk on a treadmill?
What are some reasons why a patient may not be able to walk on a treadmill? (3)
1.) cardiac problems
3.) ortho surgery
What are done when patient is exercised on a treadmill? (5)
1.) walking 2 mph
2.) 12% grade incline
3.) for 5 minutes or until symptoms occur
4.) obtain ankle pressures
5.) repeated measurements taken 1 to 2 minutes intervals for up to 10 minutes (Bryan 5 minutes)
What does the alternative method include if a exercise test can't be done?
Inflate a cuff suprasystolic for 3 to 5 minutes on the thigh. This produces ischemia and vasodilation.
Can arterial segmental machines do bidirectional flow?
Separates forward and reverse flow.
What do PVR's stand for?
Pulse Volume Recordings
What do VPR's stand for?
Volume Pulse Recordings
What do AC stand for and when is it used?
What is used for PVR's and VPR's?
Volume of the blood changes in the limb segments surrounding the cuffs.
Air displacement by air-filled plethysmography inflates 10-65 mmHg.
How much is the cuff inflated with PVR's/ VPR's?
What device is used on a strip chart recorder to generate analogue waveforms?
zero crossing detector
When are we looking for analogue waveforms?
And what are we looking for normal analogue waveforms?
for PVR's/ VPR's
the dicrotic notch
When there is no dicrotic notch on an analogue waveforms what does it mean?
Some degree of Peripheral Vascular Disease
What is a PPG? (2)
1.) photoelectric plethysmography
2.) NOT true plethysmography because does not measure actual volume changes.
What two parts does the PPG sensor contain?
1.) an infrared light emitting diode
What are the two parts of the PPG senor DO?
1.) infrared light emitting diode-- infrared light is transmitted into superficial layers of the skin
2.) Phototransistor-- the reflected portion is received by the phototransistor
What is the resulting signal proportional to what on the PPG?
the guantity of RBCs in the cutaneous circulation.
What width should the cuff be?
20% greater than limb diameter
How do you know you are obtaining an arterial signal with a CW pencil probe and not venous signal because weak arterial signals may look like venous flow?
Use Distal Augment
If flow increases with DA than on vein.
What will high thigh pressures indicate?
Reflect the status of the aortailiac/iliac.
What makes the direction-sensing Doppler useful?
Arteries will be towards
veins will be away
What are 2 True symptoms of arterial occlusive disease?
2.) Rest Pain
What are 3 goals of the lower extremity arterial evaluation?
1.) confirm the diagnosis of arterial occlusive disease
2.) indicate the location of any obstructing lesions
3.) Quantity the resulting degree of disability.
What are 6 Confused false symptoms?
1.) Osteoarthritis (hip, knee)
2.) Neurospinal disease
3.) Nocturnal muscle cramps
What are the 2 questions that should be asked right away from the beginning of an arterial testing?
1.) Is arterial occlusion present?
2.) Is arterial occlusion causing the patient's symptoms?
Does CW Doppler provide information about depth in tissue or distance from the ultrasound source?
No does not provide depth in tissue or distance
What is the transmitting frequency?
When is low frequency used?
low frequency used for deep vessels (thigh vessels)
Can you find the arterial signal if the artery is occluded?
When does this happen?
no cannot find arterial signal
< 2 cm/sec undetectable
What are the 3 main sources of peripheral resistance?
1.) blood vessel diameter
2.) blood viscosity
Arterial Segmental testing (2 wksts)
arterial segmental testing