How To:"F.A.S.T" Focused Assessment by Sonography in Trauma - SD

Introduction to the FAST Exam Demonstration

We demonstrate the FAST exam twice on the ultrasound machine once, as I talk us through it with the findings.

And secondly, I'll do it in real time to show how the exam could be performed with probably in less than a minute.

But I go a little slower the first time through so that it's possible to see how it's done.

It's good to apply gel liberally when you do this. You don't want to be reaching for gel or getting poor contact.

So I usually apply the gel in all of the four main regions at the beginning of the exam when the patient first arrives, and then I don't need to worry about it again.

Right Upper Quadrant Examination

We start on the right quadrant just for depth and gain, which in this well-lit room is the gain tends to be higher than it usually is in a darkened room, and immediately with a probe parallel of the ribs here, with a probe pointer up towards the patient's axilla about the 10 o'clock frame we see here on the screen.

The screen is showing right the diaphragm right here, this bright white line here and above the diaphragm, this area of mirror artifact, which appears as if this liver above the diaphragm is well below it.

So we're automatically checking two spaces here. We fan back and forth to scan the entire area and the very medial extent.

We come into the inferior vena cava here, and that shows that we've scanned all the way to the patient's left in this space.

Coming back, we immediately identify the superior pole of the kidney here and Morrison's pouch right here, which is the potential space, and again, systematically scanned from side to side through the entire space to make sure there's not a small collection of free fluid.

Conversely, one can scan transversely here if one's having a problem. And here's a transverse view of the kidney.

And again, scan from top to the bottom right there and back up to the top using a single rib space.

Going back into the longitudinal view of the kidney here, and this model the inferior part of the kidney is very clearly seen here.

And again, scanning through it can be very easily done from the same location.

Subxiphoid Region Examination

Moving on now to the subxiphoid region. We have the liver right here, the vertebral body back here, and we kind of hold the probe in such a way as to push the abdominal muscles down and get a view behind the sternum, behind the subxiphoid.

And the heart comes into view nicely here. We often have to adjust the depth so that we can see the posterior pericardium, and sometimes gain settings have to be adjusted here as well.

Oftentimes, we have to increase the gain a little bit.

The anterior pericardium is right here under the marker on the screen and the posterior pericardium back here.

There's no free fluid. The longitudinal image of the heart that we described in the lecture appears like this with the vena cava coming up here into the this is the atria right here, and the inferior cava, which is being compressed right now, is coming up right here into the heart.

We needs to compress less. Here is the hepatic vein coming down to the inferior vena cava.

All this is liver, and this is the space right here on the diaphragmatic surface of the pericardium where free fluid would be detected.

Left Upper Quadrant Examination

Moving over to the left upper quadrant, now we're gonna orientate the probe parallel with the ribs again.

Again, might need to make some adjustments for depth, because this is a much more superficial view than the subxiphoid view.

We have the diaphragm as on the right above the diaphragm. We have mirror artifact suggesting that there's no hemothorax.

And again, we scan to the whole space that's available to us. Our probe is further cephalad and further posterior than one might expect.

Underneath the diaphragm, there's no fluid either. The spleen is clearly seen here.

The entire diaphragmatic surface of the spleen can be analyzed here from side to side, we move down a rib space, and we get an image here of some of the kidney and a rib space, or actually probably a piece of air-filled bowel completely overlying the spleen space, which is inconvenient.

Maybe we can just get a sense of it of the splenic space back here.

Or maybe moving down a little bit. But in general, this exam is slightly limited because of the presence of this gas right here that's overlying this key space that we want to analyze.

In the case that you do a FAST exam, which is limited by some technical consideration like this, you should bear it in mind and include it in your report.

If you truly can't make a fully negative exam, you should just mention the limitations that you encountered.

The inferior pole of the kidney is seen right here on the screen, sliding up and down over the psoas muscle. This psoas muscle's normal.

You'll be looking right in here, this potential space here for free fluid.

Suprapubic Region Examination

Moving on now to the suprapubic region. The probe is slid down all the way to touch the patient's pubis.

On the screen, the bladder can be seen here. Gain usually needs to be diminished here to bring out the structures behind the bladder without being washed out by gain artifact.

We start as low as we can. We find the prostate and we scan north in this transverse plane.

We find right above the prostate. We find these two symmetrical round structures back here, which are hypoechoic.

There's seminal vesicles. They're not free fluid. We scan cephalad out of them, and this is really the area that we've got most likely to encounter.

Free fluid right above them. This structure right here is the sigmoid colon and the rectum right here.

And we scan up systematically to the dome of the bladder, and that completes the FAST exam.

Real-Time FAST Exam Demonstration

We can just run through this once more in real time.

And again, I probably won't be able to speak fast enough to keep up with this. So I'll just do the exam and when you watch, you can make sure that all the 10 potential spaces in the four regions are examined.

So starting the right upper quadrant, pleural space, subdiaphragmatic space, Morrison's pouch, inferior pole of kidney, right here, all the way through from side to side.

Subxiphoid, adjust depth anterior and posterior pericardium all the way from top to bottom.

Left upper quadrant, adjust depth diaphragm pleural space all the way through as much as available subphrenic space, splenorenal space.

Again, a little bit difficult to evaluate. A little bit fluid right here in the stomach. And the splenic hilum there with the vessels.

The rest of the kidney has no fluid around it. Inferior pole of the kidney right here.

Again, examine all the way through the inferior pole. And then finally in the suprapubic region, starting with prostate seminal vesicles.

And right here, we need to decrease our gain a little bit. And actually, it looks like there might be a small physiological amount of free fluid right here in the pelvis on this model.

It looks kind of pointy to me, and we can see it right here.

Which sort of between these loops of bowels, there's probably a small physiological amount of free fluid that completes the FAST exam.

Using Technological Advances in the FAST Exam

Now just we can certainly also in the FAST exam make use of the technological advances I mentioned to you in the introduction.

In fact, miniaturization affordability and high image quality.

As I said at that time, the very components of the ultrasound technology that are making this available to more and more clinicians.

And we do actually have a device here, which is handheld now, and is perfectly adequate to do the FAST exam we've just described.

And I'd be happy to run through that right now. This machine's now booted up just by opening the lid. It turned on.

And again, to start from the beginning here and going kind of in real time, we're going to start in the right upper quadrant.

We can evaluate the pleural space right here above my thumb, back and forth the pleural space.

We can see the superior pole of the kidney and Morrison's pouch right here. The inferior pole of the kidney is quite nicely seen right here with the psoas muscle right behind it.

We that's the complete right upper quadrant. We move over here. We need to adjust the depth a little bit to get the we need to increase the gain a little bit, get a picture of the heart, and again, scan from top to bottom of the heart.

We can see the anterior posterior pericardium very nicely on this image. No free fluid going to the left upper quadrant.

Our probe is parallel with the patient's ribs. We can see the diaphragm very nicely here with a spleen below it, white line of the diaphragm.

We need to decrease the gain a little bit. Now here, and you can see the splenorenal space. Just see it right here with just the hint at the top of the kidney.

The bowel gas that's been impeding us is resolving a little bit moving on. And I think we can probably say that there's no splenorenal fluid.

Certainly when we go down a couple of rib spaces, we can see the inferior pole of the kidney right here on this image with a psoas right behind it, needs to decrease our gain a little bit.

And here's the inferior pole moving up and down with respirations, and there's no free fluid around it.

Suprapubic view transverse. Here, go down to the pubis. Once again, we can see the bladder.

We need to decrease our gain so that we don't overwhelm the retrovesical space with ultrasound and cause posterior acoustic enhancement gain artifact.

Here we have the prostate just in view, the seminal vesicles.

Now we get up to the area that we're most likely to find free fluid in the suprapubic evaluation.

And we scan all the way through into the dome of the bladder.

And in this occasion, I don't think we can say that we're seeing any free fluid. The small amount of free fluid we saw on the previous image I don't think it's resolved.

And it's definitely a physiological volume.

Conclusion

Okay, that completes our module of the FAST exam.

Hopefully this has made its performance and utility a little bit clearer.

For those who are starting out on this pathway, lots of practice is needed.

But after a while this becomes an extremely useful tool in management of trauma patients.

Thank you very much.