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35 Cards in this Set
- Front
- Back
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Plug Flow |
•Occurs during flow acceleration •Systole |
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Parabolic Flow |
•Occurs during diastole •Wider spectrum of flow |
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Viscosity |
•Fluid resistance to flow •Friction between layers/walls •Proportional to hemarocrit |
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Reynolds Number |
•Describes when turbulence is likely to occur(R# >/= 2000) |
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Reynolds Formula |
•Flow × Density × Diameter / Vis |
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Turbulence |
•Occurs distal to max stenosis |
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Inertia |
•Resistance to change in direction or speed |
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Poiseuille's Law |
•Predicts flow in a cylinder •P = Q(flow) × R |
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Poiseulle's and Ohms |
•Ohms: E = I(current) × R •Pois: P = Q × R |
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Bernoulli's Law |
•TE at Pt A = TE at Pt B •TE = PE + KE |
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Applied Bernoulli's Effect |
•75% area reduction = velocity increase and distal pressure decrease |
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Effects of Stenosis |
•Measuring increase in velocity can estimate stenosis |
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Intima |
•Single layer of endothelial cells •Permeability, antithrombogenic, vasoreactive |
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Media |
•Smooth muscle, allows rhythmic changes in size during cardiac cycle |
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Adventitia |
•Connective tissue and collagen •Contains vaso vasorum |
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Vaso Vasorum |
•Vessels that supply artery wall |
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LE Blood Flow Controlled By |
•Cardiac output, wall resistance and compliance, vasoconstriction/dilation in distal beds |
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Extremity Blood Flow |
•Ruled by demand |
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Low Demand |
•Distal vasoconstriction •AV shunting in muscle cap beds •High resistance from AO to arterioles |
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Exercise |
•Creates demand for flow •Muscles need O2, metabolites and waste removal |
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Vasodilation Triggers |
•Low oxygen tension in tissue •Increased CO2, lactic acid, K ions •Epinephrine |
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Arterioles Vasodilate |
•During exercise, ischemia, chemical-emotional stimulation |
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Most Important Factors for Flow |
•Cardiac output and distal resistance |
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With Exercise |
•Flow volume increases to LE vascular beds |
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Normal Post Exercise Flow |
•⬆️Q × ⬇️R = No pressure change •Ankle pressure remains about the same as pre exercise |
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PAD Risk Factors |
•Family/genetics, high cholesterol, HTN, DM, obesity, elevated triglycerides |
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Other PAD Risk Factors |
•LDL > 160mg/dl, depressed fibrinolytic system, tobacco, LDL oxidation |
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Mild Art Disease Symptoms |
•Patient ASX •May have abd bruit, mild decrease in ankle pressure PE |
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Moderate Art Disease Symptoms |
•ASX at rest •Intermittent claudication, relieved by rest |
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Severe Art Disease Symptoms |
•Night pain in feet/toes, relieved by dependency •Dependent rubor |
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Dependent Rubor |
•Redness in foot when hanging in dependent position |
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Other Severe Disease Symptoms |
•Ischemic rest pain in feet/toes •Non healing wounds •Ulceration on lower leg/foot •Tissue necrosis/gangrene |
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Buerger's Disease |
•Small vessel thrombosis •Fixed occlusive disease |
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Raynaud's Syndrome |
•Small vessel vasospasm |
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Entrapment Syndromes |
•Structures extrinsically pinch arterial flow •Pop A, nutcracker, thoracic outlet, SMA syndrome |
