Non-invasive arterial exam

Question 1

what are the 6 basic non-invasive lab tests for diagnosing PVD in the lower extremity?

Answer 1

1. segmental BP
2. doppler ultrasound
3. toe blood pressures
4. ABI
5. plethysmography
6. transcutaneous oxygen pressure

Question 2

describe the change in pressure from mid thigh to ankle as you do a segmental BP.

Answer 2

pressure will decrease normally from mid-thigh to ankle

Question 3

what are some signs of obstruction when taking a segmental BP?

Answer 3

> 20-30mmHg difference btwn adjacent cuffs
30mmHg change along leg from thigh to ankle
20mmHg difference btwn opposite leg, at same level

Question 4

what does the ABI tell you?

Answer 4

ankle systolic BP/ brachial systolic BP

Question 5

what does the ABI measure?

Answer 5

measures arterial flow only to the ankle

Question 6

what are the ABI values needed for successful healing after foot surgeries?

Answer 6

ABI >0.35 in arteriosclerosis

>0.45 in diabetics

Question 7

what is the normal ABI range?

Answer 7

0.9 to 1.3

Question 8

an ABI of 0.7 is classified as what?

Answer 8

intermittent claudication

Question 9

an ABI of 0.5 is classified as what?

Answer 9

rest pain

Question 10

an ABI of 0.3 is classified as what?

Answer 10

skin loss

Question 11

why do diabetics have falsely elevated ABI values?

Answer 11

due to severe arterial calcification- so it takes more cuff pressures to constrict the arteries

Question 12

what is the ABI for intermittent claudication?

Answer 12

0.7

Question 13

what is the ABI for rest pain?

Answer 13

0.5

Question 14

what is the ABI for skin loss/ulcers?

Answer 14

0.3

Question 15

___ is a function of how fast blood cells are moving

Answer 15

Pitch

*the faster the cells move, the higher the pitch

Question 16

___ is a function of how many blood cells the ultrasound waves hit

Answer 16

Loudness

*the more cells hit, the louder the sound

Question 17

what relationship does aortic pressure and velocity of blood flow have with each other?

Answer 17

directly proportional

*peak aortic pressure corresponds to peak flow velocity of vessels

Question 18

what does a normal doppler US waveform look like?

Answer 18

triphasic (3 sounds and 3 peaks)

Question 19

what does a mild obstruction doppler US waveform look like?

Answer 19

biphasic

Question 20

if there was loss of arterial rebound due to calcification of artery, what would the doppler US waveform look like?

Answer 20

mild obstruction- biphasic

Question 21

what would a moderate obstruction doppler US waveform look like?

Answer 21

monophasic

Question 22

what would a severe obstruction doppler US waveform look like?

Answer 22

no sound

Question 23

what 3 things should you listen for with Doppler?

Answer 23

1. # of sounds
2. pitch
3. loudness

Question 24

Describe what you would expect to hear on Doppler if your probe was over the obstruction.

Answer 24

pitch is higher but loudness is lower

of RBC flowing thru is less, but those that are squeezing thru are flowing faster!

Question 25

Describe what you would expect to hear on Doppler if your probe was on either side of the obstruction?

Answer 25

pitch is lower but loudness is higher | there is a greater # of RBC collecting there, but their velocity is lower

Question 26

healing potential can be measured by what 2 ways?

Answer 26

1. absolute pressures | 2. toe-brachial index

Question 27

what absolute pressure do you need to have good healing potential?

Answer 27

>45mmHg

Question 28

what toe-brachial index do you need to have high healing potential?

Answer 28

>0.6

Question 29

what toe-brachial index do you need to have moderate healing potential?

Answer 29

>0.4

Question 30

what toe-brachial index do you need to have low healing potential?

Answer 30

>0.2

Question 31

what toe-brachial index will not heal?

Answer 31

below 0.2

Question 32

what is plethysmography?how can it be measured?

Answer 32

takes advtg of the fact that as the artery fills with blood, it expands and contracts as it empties - Photoplethysmography (PPG): infared light and photocells - pressure cuffs- pneumoplethysmography or pulse volume recording (PVR) or pressure cuff recording (PCR)

Question 33

what is photoplethysmography (PPG)?

Answer 33

uses a light probe to detect how much blood has entered the artery

Question 34

what does a normal waveform for photo plethysmography look like?

Answer 34

2 distinct peaks w/ a distinct dichrotic notch | *the greater the volume of blood, the more RBC, and the more color change and the more defined the peaks

Question 35

what does a normal waveform for a PVR look like?

Answer 35

1 rounded peak | *no dichrotic notch like there is in the arm and on PPG

Question 36

what is transcutaneous oxygen pressure (TcPO2)?

Answer 36

measures partial oxygen tension on skin surface | the more RBC to the skin, the more O2

Question 37

how does TcO2 relate to arterial PO2?

Answer 37

TcPO2= arterial PO2

Question 38

what range for TcO2 is best to indicate good healing potential?

Answer 38

10-50mmgHg | *>40 is best standard to use