Hemodynamics
This law states that blood flow equals the pressure gradient divided by resistance.
What is Ohm's Law?
This blood pressure value is best estimated using DBP plus one-third of the pulse pressure.
What is mean arterial pressure (MAP)?
In systolic heart failure, the primary determinant of reduced stroke volume is impaired this property of the ventricle.
What is contractility (inotropy)?
These vessels are the primary site of nutrient and gas exchange.
What are capillaries?
Blood flowing in orderly concentric layers is described by this term.
What is laminar flow?
According to Poiseuille's law, this variable has the greatest influence on blood flow because it is raised to the fourth power.
What is vessel radius?
This valvular lesion causes loss of the dicrotic notch and a diastolic pressure approaching zero.
What is aortic regurgitation?
A patient with chronic HFrEF is started on an ACE inhibitor. Although cardiac output initially changes little, long-term improvement occurs primarily because this hemodynamic variable is reduced.
Answer: What is afterload?
Veins contain most of the body's blood because they possess this property.
What is high compliance (capacitance)?
A carotid bruit is produced because blood flow has become this.
What is turbulent?
Doubling this variable increases the likelihood of turbulent flow, despite constant viscosity.
What is blood velocity?
Pulse pressure is primarily determined by these two variables.
What are stroke volume and arterial compliance?
A patient with acute decompensated left ventricular failure develops severe hypoxemia despite receiving 100% oxygen. The hypoxemia is primarily caused by this physiologic mechanism.
Answer: What is pulmonary edema causing intrapulmonary shunting (V/Q mismatch with shunt physiology)?
The force favoring filtration out of capillaries is this hydrostatic pressure.
What is capillary hydrostatic pressure?
An anemic patient is more likely to develop turbulent flow because anemia decreases this blood property.
What is viscosity?
Increasing hematocrit decreases Reynolds number because it increases this variable.
What is blood viscosity?
Moving from the aorta to peripheral arteries, systolic pressure tends to increase while this pressure generally decreases.
What is diastolic pressure?
A patient with chronic heart failure has a normal blood pressure despite a markedly reduced ejection fraction. Maintenance of arterial pressure is primarily due to activation of these two neurohormonal systems.
Answer: What are the sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS)?
An increase in plasma protein concentration most directly increases this Starling force.
What is plasma oncotic pressure?
A patient with severe polycythemia develops sluggish circulation despite increased oxygen content because this variable markedly increases.
What is blood viscosity?
A patient has unchanged MAP but half the vessel radius. Assuming all else remains constant, blood flow changes by approximately this factor.
What is a 16-fold decrease?
Despite large changes in local tissue blood flow, this variable is maintained relatively independently.
What is arterial pressure?
A patient with dilated cardiomyopathy has an LVEDV of 220 mL and an LVESV of 165 mL. Although preload is markedly elevated, stroke volume increases very little because the ventricle has moved onto this portion of the Frank-Starling curve.
What is the flattened (plateau) portion of the Frank-Starling curve?
Severe hypoalbuminemia primarily causes edema by decreasing this pressure.
What is plasma colloid oncotic pressure?
A vasoconstrictor decreases vessel radius by 20%. According to Poiseuille's law, the greatest immediate effect will be on this hemodynamic variable.
What is blood flow (marked decrease due to increased resistance)?