10/11: Vascular Disease - Dayton Flashcards
most common arterial vascular disease
atherosclerosis
pathology of atherosclerosis
- eccentric plaque deposition
- narrowing of central lumen (oval contour of external surface, rounded contour of lumen)
- calcification
where does DVT occur with diabetic?
- earlier age
- more severe
- leg trifurcation
clinical manifestations of PVD
- diminished or absent pulses
- leg painwith walking/claudication
- ischemic rest pain
- slow healing wounds
- tissue damage (ulcer, gangrene)
buerger’s sign
pallor on elevation
ulcers occurring distally
ischemic ulcers
describe ischemic ulcer
- occur distally
- severe pain
- little bleeding
- irregular edges
- poor granulation
- other signs of arterial insufficency present
- dry necrosis
associated findings with ischemic ulcer
- claudication
- night pain/ rest pain
- dependent rubor
- elevation pallor
- skin atrophy
- nail dystrophy
- decreased skin temperature
arterial thrombus vs. embolus
thrombus
- insitu clotting occluding the vessel
- gradual onset of worsening ischemia
- signs of arterial disease
- atheroma already present
embolus
- sudden and severe
- no preexisting arterial symptoms
- identifiable source of free body (afib)
- signs of PAOD not necessarily present
episodic reduction in peripheral blood flow due to cold exposure or stress
raynaud’s phenomenon
- functional
tx raynauds
- nifedipine
- IV prostacyclin or prostaglandin E1
- evening primrose oil
normal resting venous pressure at ankle in standing position
60-90 mmHg
describe venous pump
emptying the deep system decreases venous pressure, opening the valve and forcing blood from the superficial to the deep system
hemodynamics of foot pump
direct stretching and compression of the plantar foot veins is the mechanism NOT muscular
fibrin cuff ulcer theory
fibrin leaks out and is transformed to fibrinogen
cuff surrounding capillaries impedes oxygen - tissue exchange leading to tissue death
white blood cell trapping theory ulcers
- distended v lead to decreasd velocity of blood flow
- WBC allowed to separate from plasma and migrate from vessel into tissue
- release of proteolytic enzymes contributes to endothelial and tissue damage
symptoms of stasis
pain
burning
heavy feeling
lipodermatosclerosis
- end stage
- severe induration
- tight bound skin
- sever scarring
venous stasis ulcer
- large
- superficial
- irregular
- fibrous and granular tissue
tx venous stasis ulcer
** treat edema
compression goals for venous stasis therapy
40 mm/hg pressure at ankle –> 17 mmhg at the knee
Law of laplace
pressure = 2 x tension / radius of leg
- wrapping at same tension the whole time creates a graduated tension in leg due to fact that radius of leg increases
circumferential elastic bandaging _____ the result. Inelastic wraps or socks _______ the results
OBTAIN
MAINTAIN
what does compression do?
- reduces venous hypertension
- increases venous return velocity
- reduces exudation from the vv into the tissue by reducing transmural pressure gradients, thereby reducing skin irritant factors
- improves arterial flow
describe multilayer compression
- double cast padding layer from toes to tibial tuberosity
- two 6 in ACE bandages with 50% overlap form toes to knee
pressure required to reveres chronic venous hypertension
40 mmHg
- hard to achieve with stockings or unna boot
what is frostbite
- ice crystal formation in superficial or deep structures
- occurs when tissue heat loss exceeds the ability of local tissue perfusion to prevent freezing of tissues
- 4 phases: pre freeze, freeze thaw, vascular stasis, late ischemic
when is sensation lost temp wise?
at 10 degree C
hunting reflex (pre freeze phase)
- cold induced vasodilation
- episodes of transient vasodilation every 7-10 min
- disapperas with prolonged exposure to cold
what phase do ice cystals form
freeze-thaw
favorable prognostic factors for superficial frost bite
retained sensation
normal skin color
clear blisters only in distal phalanges
poor prognostic features of deep frostbite
- non blanching cyanosis
- absent doppler pulses
- firm skin
- dark blisters or even worse - no blisters
4 degrees of frost bite
1st: white/yellow raised plaque with numbness
2nd: superficial skin blisters, clear, erythema
3rd: deep hemorrhagic blisters
4th: necrosis extending into muscle and to bone, through the dermis
field management frostbite
- treat hypothermia
- maintain hydration
- give 600 mg BID-QID ibuprofen (block inflammatory pathway)
- avoid re-freezing
- rapidly rewarm by water immersion bath 37-39 degrees C
why give low molecular weigh dextran for frostbite?
- polysaccharide plasma expander
- decreases blood viscostiy and inhibits intravascular cellular aggregation and improves small vessel perfusion
