Plethysmography

Question 1

T/F

Plethysmography has more to do with volume change then with actual ultrasound

Answer 1

True

Question 2

With combination of Doppler segmental pressures, plethysmography has these 3 capabilities

Answer 2

1. Differentiate true claudication from non-vascular sources
2. Detects the presence/absence of arterial disease
3. Help localize the level of obstruction

Question 3

a limitation that plethysmography has is the inability to distinguish between major arteries and ____

Answer 3

Collateral branches

Question 4

As far as patient position goes for plethysmography, most exams have patients _____ with limbs in resting position, however, patient can be _____ for the upper limb digits

Answer 4

Most patients SUPINE

Upper limbs can have patient SITTING

Question 5

Measurement of volume change is the key principle for this?

Answer 5

Volume (air) plethysmography

Question 6

With plethysmography, pneumatic cuffs are placed around specific levels of extremities or digits. Cuffs are inflated by a _______ of air with pressures ranging from ___ to ___ mmHg (depending on cuff size)

Answer 6

Inflated by a MEASURED AMOUNT of air

Pressures rang from 40 to 65 mmHg

Question 7

As arterial flow moves under the cuff, _______ in the limb segment occur, which is converted to ___________ within the air-filled cuff bladder

Answer 7

Momentary VOLUME CHANGES in the limb occur

Converted to PULSATILE PRESSURE CHANGES

Question 8

How do we get the pressure changes documented with the plethysmography on the strip for chart record

Answer 8

A pressure transducer CONVERTS the pressure change into ANALOG waveforms

**chart paper speed = 25mm/sec

Question 9

During a plethysmography exam the cuff can be described with different charectoristics during diastole/systole
During _____ there is a fixed amount of air pressure in the cuff and during _____ the air pressure in the cuff increases as arteries expand

Answer 9

DIASTOLE = fixed amount of air pressure in cuff
SYSTOLE = Air pressure in cuff increases as arteries expand

Question 10

What three things are used in a photo-plethysmography (PPG) study

Answer 10

Transducer
Amplifier
Strip-chart recorder

Question 11

A PPG uses what kind of light to detect cutaneous blood flow?

Answer 11

Infrared light

Question 12

With PPG, ____ consists of light emitting diode and photo-sensor

Answer 12

Photocell

Question 13

____ transmits infrared light into subcutaneous tissue with backscattered light REFLECTED BACK to the adjacent _____

Answer 13

DIODE transmits the infrared light

Light reflected back to the adjacent PHOTO-SENSOR

Question 14

What determines the amount of reflection with PPG

Answer 14

The cutaneous blood flow

Question 15

_____ blood flow = ____ attenuation which _____ this reflection

Answer 15

INCREASE blood flow = INCREASE attenuation
This DECREASES reflection

THIS IS A GOOD THING displayed as a positive upstroke of the waveform

Question 16

With volume PPG, patient is supine with heels slightly elevated on a cushion and appropriate cuffs on extremities, how many pulse cycles should be recorded?

Answer 16

Atleast 3 cycles

Question 17

Define the following as either NORMAL, MILDLY ABNORMAL, MODERATELY ABNORMAL, and SEVERELY ABNORMAL.

• Flattened systolic peak, upslope and downslope more delayed, reflected wave (notch) absent.
• Fairly rapid upslope, sharp systolic peak with reflected wave
• Low amplitude or absent
• sharp peak, absent reflected wave, downslope bowed away from baseline

Answer 17

NORMAL = fairly rapid upslope, sharp systolic peak with reflected wave
MILDLY ABNORMAL = sharp peak, absent reflected wave, downslope bowed away from baseline
MODERATELY ABNORMAL = Flattened systolic peak, upslope and downslope more delayed, reflected wave (notch) absent.
SEVERELY ABNORMAL = Low amplitude or absent

Question 18

This is the reflection of the downslope

Answer 18

Dicrotic notch

Question 19

Abnormal waveforms always reflect hemodynamically significant disease ____ to the level of tracing

Answer 19

PROXIMAL

Question 20

If there is reduced amplitude with no changes in the contour, it is most likely an insignificant disease unless…….

Answer 20

Unless it is unilateral

Question 21

What might be the reason for a waveform to be fairly normal (sharp upstroke and narrow peak) but abnormal segmental pressures (absent reflected wave/notch)

Answer 21

Collaterals

**there is good profusion, but the reflection is absent due to the presence of colleratals

Question 22

Which vascular structure uses AC mode and which one uses DC mode

Answer 22

AC mode is used for arterial

DC mode is used for venous