Venous Doppler Waveforms

What are the two types of venous Doppler waveforms?

• Central venous waveform

• Peripheral venous waveform

Central venous waveforms are seen where?

In veins close to the heart. This includes the following:

• Hepatic veins

• Superior vena cava

• Innominate veins

• Jugular veins

• Subclavian veins

Central venous waveforms are effected by change in what pressures?

Cardiac pressures.

Are central venous waveforms monophasic of multiphasic?

Multiphasic.

Describe the multiphasic characteristic of central venous waveforms.

• 2 antegrade (towards the heart) - this occurs during ventricular systole and diastole

• 1 retrograde flow (away from the heart) - this occurs during atrial systole

An abnormal central venous waveform (ie. damped monophasic or loss of phasicity) suggests what?

Pathology.

In cases with possible abnormal central venous flow, what should you assess?

The contralateral side and compare the two waveforms.

What is the sniff test?

A test that required the patient to take a sniff in. This is used to assess centrals veins response to change in pressure.

What is the normal sniff response?

Vein collapse of approximately 50% or more, as well as an increased forward flow velocity.

A sniff is like what?

An inspiration that sucks blood back to heart.

What is the normal valsalva response in central veins?

An increase in diameter by at least 20%.

Where are peripheral venous waveforms seen?

In veins distant from the heart (lower extremity veins)

Peripheral venous waveforms are affected by what?

Respiration and posture.

Peripheral venous waveforms are monophasic or multiphasic?

Monophasic.

Peripheral venous waveforms have good respiratory variation and may be mildly what?

Multiphasic (slight reversal).

Normal Doppler peripheral waveforms are high velocity or low velocity?

Low velocity.

With peripheral venous waveforms, there is a decrease or increase in forward flow with inspiration in the leg?

Decrease.

Wither peripheral venous waveforms, there is a decrease or increase with expiration in the arms?

Increase.

What is the response of peripheral venous waveforms with Valsalva?

Cessation of flow.

What is the significance of seeing normal respiratory variation?

Good indicator that there is no disease proximal to the sample site.

What are two abnormal peripheral venous waveforms?

1. Flattened waveform with little or no respiratory variation (this suggests a proximal obstruction and you must evaluate iliacs, pelvis, and IVC)

2. Exaggerated cardiac pulsatility (suggests cardiac pathology)