30: Non-Invasive Arterial Exam - Mahoney

Question 1

____of BK amputations and ____ of AK amputations die in the hospital

Answer 1

5-10%

15-20%

Question 2

5-year mortality rates:
PVD ___
Critical Limb Ischemia-___
Non-healing diabetic ulcer___

Answer 2

30%
64%
48%

Question 3

describe segmental blood pressures

Answer 3

• • Multiple cuffs along lower limb (mid thigh, above knee, below knee, above ankle)
• • Measure systolic blood pressure at each cuff
• • Pressure will decrease normally from mid thigh to ankle

Question 4

signs of obstruction in segmental blood pressures

Answer 4

> 20-30mmHg difference between adjacent cuffs **

> 30 mmHg change along leg from thigh to ankle

> 20mmHg or more difference between opposite leg, same level

Question 5

ABI =

Answer 5

Ankle Systolic Blood Pressure / Brachial Systolic Blood Pressure

Question 6

successful healing ABI values

Answer 6

normal = 0.9 -1.3

successful values for foot surgery:

• Above 0.35 in arteriosclerosis
• Above 0.45 in diabetes (due to arterial calcification, diabetics often have falsely elevated values)

Question 7

which arteries are measured in ABI?

Answer 7

• • Measures arterial flow only to the ankle
• • Perform it for both the dorsalis pedis artery and the posterior tibial artery
• • Take the higher of the 2 readings

Question 8

ABI
normal
intermittent claudication
rest pain
skin loss

Answer 8

0. 9-1.3
1. 7
2. 5
3. 3

Question 9

If you are unable to occlude the vessel at ___ mm Hg, your pressure readings will be unreliable and the test is invalid.

Answer 9

200

stop the exam

Question 10

A patient complains of pain in the right calf after walking 2 blocks, as well as calf pain at night while in bed. The ABI is most likely:

Answer 10

0.5

Question 11

what do pitch and loudness tell you from doppler ultrasound?

Answer 11

Pitch – function of how fast blood cells moving – faster the cells move, the higher the pitch

Loudness – function of how many blood cells the waves hit – the more cells hit, the louder the sound

Question 12

look at the doppler waveform picture. what does each peak mean?

Answer 12

Pressure and
flow velocity are directly
proportional to each other

A Ventricles contract, aortic valve opens
B Peak aortic pressure corresponds to peak flow velocity of vessels
C Ventricles relax, aortic valve is still open which decreases pressure in ventricle and blood flows backwards in large arteries
D Aortic valve closes, pressure increases in large vessels
E Return to diastolic baseline

Question 13

Normal doppler waveform =

Answer 13

• • triphasic (3 sounds and 3 peaks)
• • Bidirectional
• • Rapid upstroke/ downstroke
• • Flow reversal
• • Arterial wall rebound

Question 14

mild obstruction doppler waveform

Answer 14

• • biphasic (2 sounds and 2 peaks)
• • Bidirectional
• • Decreased peak height
• • Partial loss of flow reversal
• • Loss of arterial rebound due to calcification of artery

Question 15

moderate and severe doppler ultrasound waveforms

Answer 15

Moderate obstruction

• • Monophasic (1 sound and 1 peak)
• • Rounding of upstroke/downstroke
• • Decreased peak height
• • Absent flow reversal
• • Absent elastic rebound

Severe obstruction – (no sound)

• • Loss of peak height
• • Absent flow reversal
• • Absent elastic rebound

Question 16

Over the obstruction, the _____ is higher and the _______ is lower

Answer 16

pitch; loudness

– Number of cells passing through decreases, but those that pass through are moving faster

Question 17

On either side of the obstruction, the ___ is lower and ____ is higher

Answer 17

pitch; loudness

• • There is a greater number of cells collecting here, but there velocity is lower
• • blood pooling here

Question 18

absolute pressure for toe blood pressure for healing should be …

Answer 18

above 45 mmHg

Question 19

toe-brachial index
High healing potential		
Moderate potential		
Low potential		           
Won’t heal

Answer 19

High healing potential = Above 0.6
Moderate potential = Above 0.4
Low potential = Above 0.2
Won’t heal = Below 0.2

Question 20

Measuring and recording changes in volume over a short period of time

Answer 20

plethysmography

two ways of measuring:

• • Infrared light and photocells: Photoplethysmography (PPG)
• • Pressure cuffs: Pnuemoplethysmography or pulse volume recording (PVR) or pressure cuff recording (PCR) [not inflating, just sitting there as a measuring device]

Question 21

describe how PPG works

Answer 21

• • Infrared light source attached to pulp of toe
• • Light is reflected from the skin as it changes color due to hemoglobin
• • The greater the volume of blood, the more red cells, the more color change and the more defined the peaks
• • Has a steeply rising upslope and sharp peak and distinct dicrotic notch
• • Normal is 2 distinct peaks ***

Question 22

Normal PVR ***

Answer 22

• • Steep Upslope
• • 1 Rounded Peak
• • Dicrotic notch usually not present like it is in the arm and on PPG

Mild obstruction = Less steep upslope; Less distinct peak; Loss of dicrotic notch

Severe Obstruction = Delayed upslope; Rounded peak; Reduced peak height

Question 23

how do you perform skin perfusion pressue?

Answer 23

Place the photosensor over the area of skin to be tested. Slowly deflate a tourniquet (toe, midfoot, ankle, calf) and note the pressure when the pulsatile flow returns

Question 24

what skin perfusion pressure indicates PAD?

Answer 24

LESS THAN 30 mm Hg suggests critical limb ischemia and wound won’t heal

30-50 mm Hg indicates PAD

GREATER THAN 50 mm Hg indicates adequate perfusion to heal wounds

Question 25

what does transcutaenous oxygen pressure TcPO2 measure?

Answer 25

• • Measures partial oxygen tension on skin surface
• • The more red blood cells to the skin, the more O2
• • must be done with skin heated to 45 degrees C
• • TcPO2 = arterial PO2

Question 26

what TcPO2 is the best standard to use?

Answer 26

greater than 40 mmHg for good healing potential

Question 27

most common site of arterial occlusion

Answer 27

mid-low thigh at hunter’s canal/ adductor canal