Hemodynamics and Vascular Flow Principles Flashcards
6 cards from real ARDMS SPI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Hemodynamics and Vascular Flow Principles flashcards as text
Laminar flow in a vessel is characterized by:
Answer: Concentric layers of blood moving at different velocities with fastest flow centrally
In laminar flow, blood moves in concentric layers (parabolic profile) with the fastest velocity at the center and slowest near the walls due to friction.
Turbulent flow on a spectral Doppler waveform appears as:
Answer: Spectral broadening with filling in of the spectral window
Turbulence causes blood cells to move at many different velocities simultaneously, resulting in spectral broadening and filling in of the normally clear spectral window.
According to the Bernoulli principle, as blood flows through a stenosis, what happens to velocity and pressure?
Answer: Velocity increases, pressure decreases
Energy conservation (Bernoulli principle) dictates that at a stenosis, the cross-sectional area decreases so velocity must increase while pressure drops.
The resistivity index (RI) is calculated as:
Answer: (PSV − EDV) / PSV
The Resistivity Index = (Peak Systolic Velocity − End Diastolic Velocity) / Peak Systolic Velocity, reflecting downstream vascular resistance.
A high-resistance Doppler waveform pattern is typically found in which vessel?
Answer: Femoral artery at rest
The femoral artery at rest supplies skeletal muscle which has high resting vascular resistance, producing a triphasic high-resistance waveform.
What hemodynamic effect does a vessel with increased compliance (elasticity) have on the Doppler waveform?
Answer: Dampened pulsatility and smoother waveform
A compliant vessel absorbs systolic pressure energy by expanding, then recoils in diastole, dampening pulsatility and producing a smoother, less pulsatile waveform.