Doppler probe

Doppler probe

Etymology: Christian J. Doppler

a handheld diagnostic device that emits ultrasonic waves into the body. Reflection of the waves by a moving structure causes a change in their frequency. The Doppler probe has been used as a diagnostic tool since 1960 to study changes in blood flow in arteries and veins.

Doppler flow detector

Doppler,

Christian J., Austrian mathematician and physicist in U.S., 1803-1853.

Doppler bidirectional test

Doppler echocardiography - use of Doppler ultrasonography techniques to augment two-dimensional echocardiography by allowing velocities to be registered within the echocardiographic image. Synonym(s): duplex echocardiography

Doppler effect - a change in frequency is observed when the sound and observer are in relative motion away from or toward each other. Synonym(s): Doppler phenomenon; Doppler principle

Doppler flow test

Doppler measurement

Doppler phenomenon - Synonym(s): Doppler effect

Doppler principle - Synonym(s): Doppler effect

Doppler probe

Doppler pulse evaluation

Doppler scope

Doppler shift - the magnitude of the frequency change in hertz when sound and observer are in relative motion away from or toward each other.

Doppler ultrasonography - application of the Doppler effect in ultrasound to detect movement of scatterers (usually red blood cells) by the analysis of the change in frequency of the returning echoes.

Doppler ultrasound flowmeter

Doppler ultrasound segmental blood pressure testing

Doppler probe

portable, ultrasound-emitting and receiving device, used in assessment of: (1) arterial systolic blood pressure; (2) quality of blood flow in arteries and veins (slow flow is less audible than normal flow); (3) direction of blood flow in veins; (4) health of the arterial wall (a triphasic sound indicates good arterial wall elasticity, a biphasic sound indicates moderate arterial wall elasticity and a monophasic sound indicates poor arterial wall elasticity/hardening of arteries); also facilitates calculation of ankle-brachial and toe-brachial pressure indices (Box 1; Table 1; see Table 2)

• Triphasic (three clear sounds at each pulse beat): a triphasic sound indicates a very healthy artery, with no impedance to blood flow, and good elastic arterial walls. Note: The third sound may not be heard without headphones

• Biphasic (two clear sounds at each pulse beat): a biphasic pulse sound indicates reasonable arterial health

• Monophasic (one sound at each pulse beat): a monophasic pulse sound indicates poor arterial health, inelastic arteries and poor peripheral perfusion

Table 1: Arterial features determined by Doppler ultrasonography

Arterial pulse rate	By noting the number of beats in a 10-second period and multiplying by 6 to give the number of beats per minute
Systolic blood pressure	By noting the pressure value at which the first pulse sound is heard when a sphygmomanometer cuff (just proximal to the pulse point and inflated to a level that obliterates arterial sounds) is deflated. Note: The Doppler cannot be used to record the diastolic blood pressure, as it continues to pick up the sound of the pulse, even when the cuff is fully deflated/removed
Elasticity of the arterial wall	Interpreted from the phasic quality (tri-, bi-, monophasic) of the audible pulse (Box 2)
Direction of blood flow	Interpreted from the direction arrow on the display panel

• Triphasic (three clear sounds at each pulse beat): a triphasic sound indicates a very healthy artery, with no impedance to blood flow, and good elastic arterial walls. Note: The third sound may not be heard without headphones

• Biphasic (two clear sounds at each pulse beat): a biphasic pulse sound indicates reasonable arterial health

• Monophasic (one sound at each pulse beat): a monophasic pulse sound indicates poor arterial health, inelastic arteries and poor peripheral perfusion

Table 2: Interpreting ankle brachial (A/B) indices

Systolic pressure ratio (A/B)	Interpretation
0.9-1.1	Normal
0.5-0.9	Arterial compromise/impaired arterial supply to lower leg/foot; patient may report claudication
<0.5	Severe arterial supply/frank ischaemia of lower leg and foot; patient may report rest pain
0.1-0.2	Impending/frank ischaemic gangrene
> 1.1	Incompressible leg artery due to MÖnckeberg's sclerosis; compromised arterial supply to lower leg and foot