How To Use A Pedoff Probe: Your Trusty Designated Continuous Wave Doppler Transducer

When learning how to become a cardiac sonographer, using the Pedoff probe can be extremely frustrating.  Even experienced cardiac sonographers become frustrated using continuous wave Doppler transducers. This is especially true if they don’t use one of these probes on a regular basis.



But there’s no reason to be frustrated. Did you know that learning how to use a Pedoff probe only gets easier and easier?  You can quickly become a pro at using the Pedoff probe by doing exactly what I did when I first started out in echocardiography.

The secret to making blind continuous wave Doppler second nature, and not demand a large amount of your time during an echo exam is to practice, practice, practice.  Keep reading to learn how to become a pro at using the Pedoff probe.

What Is A Pedoff Probe?

The Pedoff probe is the original Doppler probe.  It’s really just a very basic ultrasound transducer which only has 2 large piezoelectric crystals. One crystal is for transmitting and the other one is for receiving.

The Pedoff probe is a non imaging continuous wave Doppler transducer. But why would you want to use a non imaging transducer?

Advantages Of Using A Pedoff Probe

The benefit of using a non imaging continuous wave Doppler probe is to basically obtain information that you can’t get by using an imaging transducer.

Because the Pedoff probe has both a smaller physical footprint and is more sensitive, it can be used in areas where there’s restricted access to the area of interest and higher sensitivity is required.  The most common example of this is in aortic stenosis cases and even mitral stenosis.

Disadvantages Of Using Pedoff Probe

The biggest disadvantage to using the Pedoff probe is perhaps the same thing that makes it the most difficult to use.  The designated continuous wave Doppler probe provides no visual reference for positioning of the ultrasound beam.  

Just like the name says, you’re literally running blink when using a Pedoff transducer. Like I mentioned earlier, a lot of practice is needed in order to become confident in using one of these transducers.

How To Use A Pedoff Probe

There are a few things you can do to become a pro with the Pedoff probe.  

Practice

The first thing is to practice. Then, when your done with that…practice some more.  When I first started using blind CW, I would practice on every normal echo that I had.  

Why practice using the Pedoff probe on normal echos?  Because normal echos are usually performed quicker than abnormal echocardiograms, which leaves you with extra time to practice.

Know Your Anatomy

Second, you must have a good understanding of cardiac structures and where they physically are inside the patients chest.  Once you start practicing on patients with normal physiology, you’ll quickly start to get a sense for where cardiac structures are, and where on the chest wall you can best obtain those Doppler signals. 

Becoming a pro at using the Pedoff transducer requires ‘mental visualization’ of where cardiac structures are in relationship to probe placement on the chest wall.

Micro-Movments

The third thing to keep in mind in using the Pedoff probe is to use “micro-movements”. The tendency that a lot of students have is to move that probe all over the chest wall.  

Slow down, use the imaging transducer to tell you where you are, then switch to the blind CW probe.  Once the Pedoff probe is planted on the chest wall, only move it in very small, almost imperceptible movements.

This is especially true if you have located a Doppler signal and are trying to optimize it.  In these cases, the probe will not move along the chest wall.  Instead, you will slowly tilt the probe one way or the other, just barely, to look for the better signal.

Review: Learning To Use The Pedoff Probe

• Have a good understanding of cardiac structures.  Be able to mentally visualize where the structures are inside the chest.
• Practice. Then practice some more.  Take advantage of the extra time that comes with finishing normal echocardiograms early.
• Use “micro movements” when optimizing a continuous wave Doppler signal.  Use the imaging transducer to find your landmarks, then switch to the non-imaging transducer.

I hope this has helped give you the confidence to get out there and want to become a Pedoff pro.