Plethysmography (UE, LE)

Question 1

What does Plethysmography do?

Answer 1

Checks changes in volume PVR

Question 2

What are the capabilities of plethysmography?

Answer 2

-In combination with Doppler segmental pressures helps differentiate true claudication from non-vascular sources.
- Detect presence/absence of arterial disease while defining tis functional aspects
- Helps localize the level of obstruction

Question 3

What is PPG mainly used for?

Answer 3

Evaluation of digits and penile vessels

Question 4

What are the limitations of Plethysmography (UE, LE)?

Answer 4

• Cannot be specific to one vessel
• Cannot discriminate between major arteries and collateral branches
• Difficult to perform on obese patients

Question 5

How should the patient be positioned?

Answer 5

• Most exams can be done with the limbs in a resting position (supine)

*Patient can be sitting for evaluation of upper limb digits

Question 6

What are the physical principles of plethysmography?

Answer 6

Volume (air) Plethysmography

** measurement of volume changes

Question 7

A measured amount of air is sequentially inflated into a cuf to pressure ranging from _____________.

Answer 7

10 - 65, depending on cuff size

Question 8

A pressure transducer converts the pressure changes into _____.

Answer 8

Analog waveforms that display on strip-charts

Question 9

Chart paper speed = __________

Answer 9

25 mm/sec

Question 10

What the amount of cuff pressure in diastole and systole?

Answer 10

Diastole: fixed
Systole: increases as arteries expand

Question 11

What does a photo-plethysmography consist of?

Answer 11

Transducer, Amplifier, Strip-chart recorder

Question 12

What does photo-plethysmography detect?

Answer 12

Cutaneous blood flow

Question 13

What does photocell consist of?

Answer 13

light emitting diode and photo-sensor

Question 14

What transmits infrared light into subcutaneous tissue with backscattered light reflected back to the adjacent photo sensor?

Answer 14

Diode

Question 15

What determines the amount of reflection with photo-plethysmography?

Answer 15

cutaneous blood flow

Question 16

Blood attenuates light in what?

Answer 16

proportion to its content in tissue

Question 17

Increased blood flow results in:

Answer 17

increased attenuation

Question 18

Increased blood flow results in increased attenuation which decreases what?

Answer 18

reflection

Question 19

How is increased blood flow displayed?

Answer 19

positive upstroke of the waveform

Question 20

How is decreased reflection displayed?

Answer 20

positive upstroke of the waveform

Question 21

What is the positioning for Volume Plethysmography?

Answer 21

Supine, with heels slightly elevated on cushion

Question 22

What method is used for Volume Plethysmography?

Answer 22

3 to 4 cuff method

Question 23

What does the machine do when activated?

Answer 23

Perform a self-calibration

Question 24

What bilateral pressures are obtained?

Answer 24

Brachial

Question 25

Begin with the upper part of extremity, moving distally. Record at lest _________ cycles.

Answer 25

3

Question 26

Artifact is common due to what?

Answer 26

Improper cuff placement

Question 27

Volume plethysmography and _______ are complementary.

Answer 27

Pressures

Question 28

Both "volume" and "photo" plethysmography are evaluated using:

Answer 28

qualitative criteria

Question 29

Normal interpretation of Photo-plethysmography PPG?

Answer 29

fairly rapid upslope, sharp systolic peak with reflected wave

Question 30

Mildly abnormal interpretation of Photo-plethysmography PPG?

Answer 30

Sharp peak, absent reflected wave, downslope is bowed away from baseline

Question 31

Moderately abnormal interpretation of Photo-plethysmography PPG?

Answer 31

Flattened systolic peak, upslope and downslope more delayed; reflective wave (notch) absent

Question 32

Severely abnormal interpretation of Photo-plethysmography PPG?

Answer 32

Low amplitude, or may be absent

Question 33

Abnormal waveforms always reflect:

Answer 33

hemodynamically significant disease proximal to level of tracing

Question 34

Reduced amplitude with no changes in the contour is likely to reflect what?

Answer 34

insignificant disease, unless it is unilateral

Question 35

Why might a fair waveform quality be accompanied by abnormal segmental pressures?

Answer 35

because collaterals can underestimate significant of obstruction based upon plethysmography

Question 36

How is displacement measured with displaced plethysmography?

Answer 36

by the height of the water in the chimney

Question 37

How is volume measured with displaced plethysmography?

Answer 37

spirometer

Question 38

What does pule plethysmography refer to?

Answer 38

transient changes in (limb) volume related to the "pulse by pules" activity of the left ventricle; the body part expands when arterial inflow exceeds venous outflow