AI Flashcards
tunica adventitia
- composition
- role
connective tissue, collagen, elastin
support vessel walls
tunica media
- composition
- role
smooth muscle, collagen, elastin
modulates vessel diameter
tunica intima
- composition
- role / characteristics
single layer endothelial cell
direct contact with blood, easily traumatized
how do vessels distal to common femoral artery dilate/constrict in relation to those more proximal
distal to common femoral
- more able to rapidly dilate or constrict in relation to perfusion
elastic arteries
- main ones
- role
aorta and its branches
maintain blood pressure
muscular arteries
- main examples
- characteristics
femoral and brachial
avg lumen is 4 mm
what directly controls arterioles
sympathetic vasoconstriction
importance of blood being a thixotropic fluid?
meaning it becomes more thick when it is not moving
- thicker, slower moving blood = less perfusion distally
what can cause blood sludging
dehydration/polycythemia
causes of arterial insufficiency
trauma
acute embolism
DM
rheumatoid arthritis
buerger’s disease
arteriosclerosis
difference between arteriosclerosis / atherosclerosis
arterio = thickening/hardening of arterial walls
athero = systemic, degenerative process, lumen is “encroached” upon
what carries cholesterol? what are the primary difference between the two
HDL = high density lipoprotein
LDL = low density lipoprotein
HDL = good/protective
LDL = bad/cholesterol deposition
what causes stenosis in arterials? at what layer?
lipid deposition
calcium deposition
scar tissue accumulation
intimal layer
explain intermittent claudication
activity specific discomfort due to local ischemia
what helps claudication
cease of activity
pain description of claudication
cramping, burning, fatigue
distal to site of occlusion
iliofemoral artery obstruction would lead to
buttock, thigh or calf claudication pain
infrapopliteal artery obstruction would lead to
foot claudication pain
explain the sequelae of arterial insufficiency
AI
intermittent claudication
ischemic rest pain
ulcer
what is ischemic rest pain
more significant arterial disease
categorized by a burning pain with elevation
when O2 requirements exceed local tissue perfusion, _______ occurs and can lead to _______
ulceration
- can lead to gangrene
Fontaine Stage 1
asymptomatic
- may have paresthesias, cold extremities, other “subclinical” indications of PAD
Fontaine Stage 2 vs 2a vs 2b
2 = intermittent claudication
2a = after more than 200m of walking
2b = after less than 200m of walking
Fontaine Stage 3
rest pain
- more so during the night
Fontaine Stage 4
ischemic ulcers / gangrene
Rutherford Stage 0
asymptomatic
normal response to activity
Rutherford Stage 1
mild claudication
ankle pressure <20mmHg than resting value
– greater than 50 mmHg overall
Rutherford Stage 2
moderate claudication
Rutherford Stage 3
severe claudication
cannot complete treadmill test
ankle pressure <50mmHg after exercise
Rutherford Stage 4
ischemic rest pain
resting ankle pressure <40mmHg
resting toe pressure <30 mmHg
Rutherford Stage 5
minor tissue loss
nonhealing ulcer of digits
- may have focal gangrene
Rutherford Stage 6
major tissue loss
gangrene extending past proximal TMT joint
risk factors leading to AI ulcer
hyperlipidemia / elevated LDL
smoking
DM
HTN
trauma
aging
of the risk factors for AI ulcer, which are modifiable vs nonmodifiable
smoking is only modifiable risk factor
how does hyperglycemia affect arterials
decreased:
collagen synthesis
angiogenesis
fibroblast proliferation
tensile strength
which form of HTN can be more damaging to intimal layer of arteries
systolic = >
diastolic = <
test and measures for AI
pulses
doppler
ABI
rubor of dependency
venous filling time
most common site of artery occlusion
bifurcation of common femoral
main foot blood supply vs main dorsal foot blood supply
posterior tibial
doraslis pedis
what does a doppler US test
arterial patency testing
ABI grade of 1.1 or higher indicates
vessel calcification
when should a toe-brachial index be used
pts with diabetes or abnormally high ABI’s due to calcifcation
if an ABI indicates vessel calcification, what should be used
pulse volume waveforms
ABI formula
systolic pressure of LE
divided by
systolic pressure of UE
interpretation of ABI of 0.9-1.1
normal
ABI indication of mild-mod AI
0.7-0.9
ABI indication of mod AI
0.5-0.7
ABI indication of severe AI
<0.5
ABI indication of intermittent claudication vs ischemic rest pain
claudication = 0.5-0.7
rest pain = <0.5
role of segmental pressure measurements
- significant findings
helps localize areas of decreased arterial flow /occlusion
drop of > 20mmHg indicates arterial occlusion
significant time for capillary refill
> 3 sec
what does rubor of dependency measure
indirect measure of LE arterial flow
how to conduct rubor of dependency test
elevate LE 60° for a minute
- note foot color
return leg to surface
- not time to return original color
indication of mild arterial insufficiency in rubor of dependency test
pallor after 45-60 seconds of elevation
indication of mod arterial insufficiency in rubor of dependency test
pallor after 30-45 sec of elevation
indication of severe arterial insufficiency in rubor of dependency test
pallor within 25 seconds
dependent rubor
normal arterial flow time for rubor of dependency test
15-20 sec after elevation
what is venous filling time test protocol
supine,
- note superficial dorsal foot veins
elevate the limb 60° for a minute
lower limb and note the time it takes to fill veins
venous filling time and interpretations
<5 sec = VI
5-15 sec = normal
>20 sec = AI
when to do segmental pressure measurement
suspected AI in ulcer proximal to ankle
decreased / absent proximal pulses
when to do rubor of dependency test
unable to tolerate ABI
ABI > 1.1
history of DM / vessel calcification
when do to venous filling time test
unable to tolerate ABI
ABI > 1.1
history of DM or vessel calcification
suspected concomitant VI
pain of AI
severe
increased with elevation
position of AI
distal toes
dorsal foot
area of trauma
wound presentation of AI
pale granulation
punched out / round
dry
black eschar / gangrene
periwound characteristics of AI
thin, shiny, anhydrous skin
loss of hair
thickened nails
pale, dusky or cyanotic skin
pulse and temperature presentation of AI
decreased
what pulses may be altered in those with AI
dorsalis pedis
posterior tibial
popliteal
femoral
local tissue perfusion characteristics that indicate positive healing
ABI > 0.5
toe pressure > 50 mmHg
tpO2 > 30 mmHg
precautions of AI ulcers
avoid compression
avoid sharp debridement of dry eschar with low ABI
– gangrenous tissue may be removed surgically
how to protect surrounding skin of an AI ulcer
moisturize dry skin
avoid adhesives
reduce friction between toes
provide padding
surgical interventions for AI
debridement
revascularization
percutaneous balloon angioplasty
amputation
