Abnormal Flow Patterns & Unusual Waveforms/Situations Flashcards
Increased velocity of the ECA may suggest what? Explain
Presence of high grade stenosis of ICA (compensatory ECA flow) because ICA cannot accommodate the usual amount of blood, thus more VOLUME of blood flows through ECA creating a higher velocity
T/F a higher volume of blood creates higher velocities
True
What is the water hammer sign? What does it represent?
Normal/elevated PSV followed by precipitous decline
Diastole: reversed flow
Aortic regurgitation
What happens if the CCA is occluded?
Reversed flow in the ECA to feed the ICA
Occlusion ICA results in externalization/internalization of what (2) and retrograde flow in (2)
Externalization of CCA
Internalization of ECA
OA reversed flow
ECA reversed flow
Externalization of CCA occurs when & why
When ICA is occluded, CCA becomes higher resistance because there’s the same volume of blood with less passage for it to go, causing higher resistance in CCA
Temporal tap occurs only when (2)
The ECA is involved in collateral flow
The ICA is totally occluded
**Signs of critical stenosis ICA (3)
Internalization ECA
Externalization CCA
Compensatory flow within ECA
Increased velocity of the ECA may suggest what? Explain
Presence of high grade stenosis of ICA (compensatory ECA flow) because ICA cannot accommodate the usual amount of blood, thus more VOLUME of blood flows through ECA creating a higher velocity
T/F a higher volume of blood creates higher velocities
True
What is the water hammer sign? What does it represent?
Normal/elevated PSV followed by precipitous decline
Diastole: reversed flow
Aortic regurgitation
What happens if the CCA is occluded?
Reversed flow in the ECA to feed the ICA
Occlusion ICA results in externalization/internalization of what (2) and retrograde flow in (2)
Externalization of CCA
Internalization of ECA
OA reversed flow
ECA reversed flow
Externalization of CCA occurs when & why
When ICA is occluded, CCA becomes higher resistance because there’s the same volume of blood with less passage for it to go, causing higher resistance in CCA
Temporal tap occurs only when (2)
The ECA is involved in collateral flow
The ICA is totally occluded
**Signs of critical stenosis ICA (3)
Internalization ECA
Externalization CCA
Compensatory flow within ECA
If you increase angle correct, what happens to the velocity estimation?
Increased angle correct falsely elevates velocity
IRREGULAR HR - when should you measure PSV?
After the most normal QRS interval-cursor
ARRHYTHMIA - most common is
Atrial fibrillation
Pulsus bisferans
What is it, who can be seen with it?
A component of reverse flow in aortic regurgitation
Can be seen in healthy individuals with compliant artery walls
TACHYCARDIA elements (3)
> 100 BPM
PSV decreased
EDV increased
BRADYCARDIA elements (3)
< 60 BPM
PSV increased
EDV decreased
A high resistant ICA waveform indicates
Intracranial ICA stenosis
