Category Archives: Tips and Tricks

Spray bottle woes

spray Spray bottle woes

Here’s a quick trick:

 

When the Transeptic spray bottle won’t spray, it is often because the pump has become disconnected from the plastic tubing within the bottle. Instead of trying to fish it out with forceps, just turn the whole bottle upside-down.

Disinfectant Spray Bottle Troubleshooting from Sinai EM Ultrasound on Vimeo.

I hope this takes away just one small annoyance on your next shift. Unfortunately this will leave room for another, larger annoyance to occupy the space.

What the Heck 2

This patient presented with diffuse abdominal pain, tachycardia, and peritonitis on physical examination. A FAST exam was performed to assess for free intraperitoneal fluid, and the following view of was obtained transversely in the pelvis.

First, just look at the still image and make your best guess. Then press play:

Did the large anechoic structure in the near field look like the bladder? Or was it the anechoic area in the far field? The operator was thrown off a bit by the complex echoes within the anterior structure. Remember the bladder is going to conform to the shape of the pelvis as it enlarges, so it will take on a characteristic square/trapezoidal shape in transverse orientation. But for the same reasons free fluid will take the same shape. Through the sweep from cranial to caudal you’ll notice two fluid collections; the anterior one seemed to have much more internal echo and debris. Don’t assume that’s the peritoneal fluid- urine can also look that way.

This was the sample obtained when a Foley catheter was inserted into the bladder:

UTI 500x380 What the Heck 2This definitely looked (and smelled) better sonographically.

Here is the longitudinal (sagittal) view through the pelvis:

As usual, the sagittal view gives a better overview of the anatomy of the pelvis. When using the transverse view of the pelvis, you can miss small amounts of pelvic fluid more easily, confuse fluid collections for the bladder, and make incorrect assumptions. Just more support for the sonographic dogma of imaging everything in two planes.

Case resolution:

CT scan confirmed free intraperitoneal fluid but no free air or other signs of bowel perforation. The hemoglobin was stable through several assessments. The patient had an obvious urinary tract infection and renal failure on laboratory evaluation. Thus the fluid was thought to be new onset of ascites in the setting of urosepsis and mult-organ dysfunction.

Tips:

  • Always image anatomy in at least two planes, and fan through anything that isn’t moving.
  • Rethink assumptions when the anatomy doesn’t look as it should. For example, an oddly-shaped or highly echoic bladder may not be bladder at all, or it might just be an abnormal bladder.
  • ALWAYS clean the machine and put it back where you found it when you are done.

I had to throw that in there, sorry.

 

Ultrasound Zen

ZenStone 500x333 Ultrasound Zen To image something which moves, you must remain still. To image something which is still, you must move.

If you think on this long enough, the point is self-evident and requires no explanation. Or, just see some examples below.

We are pretty well adapted to seeing three dimensions at a time. Thus when imaging a moving structure like the heart, we hold the probe in a fixed position to obtain standard views. This allows us to focus on the movement, and cardiac presets optimize temporal resolution at the expense of spatial resolution. We are then seeing two spatial dimensions and one temporal dimension (heart moving in time).

D Shaped Left Ventricle from Sinai EM Ultrasound on Vimeo.

It is very difficult to appreciate the anatomy and function of the heart, for example,  when the probe is moving.

In contrast, imaging the right upper quadrant for fluid in Morison’s pouch requires a slow fan through the liver, diaphragm, and kidney. This allows us to appreciate the entire potential space where fluid can collect. Abdominal imaging is optimized for spatial resolution at the expense of temporal resolution, so be sure to move the probe slowly. Fanning through the entire structure of interest will often reveal pathology which was missed with a single-plane scan. Small gallstones, small amounts of peritoneal or pleural fluid, saccular aneurysms, and other maladies can fool a novice sonographer who isn’t thorough. In this case we are seeing three spatial dimensions.

FAST1 RUQ pos from Sinai EM Ultrasound on Vimeo.

So, keep your audience in mind when you are creating scans. Should you fan through the static anatomy, or let the movement of the structures speak for themselves?

Lung Ultrasound Pitfalls

US lung consolidation Tsung 500x514 Lung Ultrasound PitfallsThoracic sonography is one of the most rapidly growing areas of emergency and critical care ultrasound. One very important emerging indication is to assess for lung consolidation. The characteristic appearance of consolidated lung is very sensitive and specific for pneumonia, but novices should heed some important pitfalls in making the diagnosis.

Special thanks to Jim Tsung, MD, MPH and Brittany Jones, MD for their tips, videos, and ongoing research in this important field! For further reading on this topic, please see this article.

Pitfall #1 – confusing thymus for a consolidation

Normal thymus in sagittal view:

Thymus (top half of screen) and heart (bottom right). Don’t confuse thymus for lung consolidation. Note there are no air bronchograms, but thymus has a faint speckled appearance.

Normal thymus in transverse view:

Thymus (top half of screen) and heart (bottom right). Don’t confuse thymus for lung consolidation. Note there are no air bronchograms, but thymus has a faint speckled appearance
Pneumonia adjacent to Thymus in transverse view:

Lung consolidation with air bronchograms (top left) adjacent to normal thymus (speckled appearance on top right) with heart (bottom right)

Pitfall #2 – mistaking spleen for consolidation.

This is an important pitfall for everyone to know about. The same issue applies to the liver & stomach. The sensitivity of lung US for pneumonia rises >90% if this mistake is avoided.

Left lower chest- sagittal view:

Be careful scanning the left lower chest (left anterior and left axillary line) – air in stomach and spleen may look like pneumonia if you don’t realize that you have scanned inferior to the diaphragm and past the end of the pleural line. Most common error by novices.

Left lower chest- transverse view:

Be careful scanning the left lower chest (left anterior and left axillary line) – air in stomach and spleen may look like pneumonia if you don’t realize that you have scanned inferior to the diaphragm and past the end of the pleural line.

Pitfall #3- missing pleural effusion

Here are a few examples to refresh your memory.

Left pleural effusion:

Identify:

  • Pleural effusion (anechoic wedge just beneath ribs and pleura)
  • Lung
  • Diaphragm
  • Spleen
  • Air in stomach

Do not confuse spleen and air in stomach for pneumonia.

Right pleural effusion:

Identify:

  • Pleural effusion
  • Lung
  • Diaphragm
  • Liver

Bubble test

bubbles 300x225 Bubble testWe already know it is helpful to use ultrasound to guide placement of central venous catheters.

How can we use ultrasound to help confirm proper placement of an internal jugular catheter?

There are several methods which have been described:

  • Visualize the needle entering the vein (optimally in the long axis)
  • Visualize the guide wire in the vein
  • Visualize the tip of the triple lumen catheter in the right atrium, then pull back 2 cm
  • Bubble test (more on this below)

In addition there are non-ultrasound-related methods to confirm placement (but who cares about those?):

  • Chest x-ray
  • Blood gas drawn through central venous catheter port
  • Pressure transduction (quantitative- manometry)
  • Pressure transduction (qualitative- attach IV tubing and check height of blood column)

So let’s get back to that bubble test. In order to confirm that the catheter has been placed in the superior vena cava, inject 5-10 cc normal saline through the catheter while visualizing the right heart on a subxiphoid 4-chamber view.  When done right should look something like this :

Saline flush right heart from Sinai EM Ultrasound on Vimeo.

So this is a neat trick after the catheter is in, but the horse is out of the barn at that point. Ideally you should confirm proper venous placement prior to dilating the vessel and placing the central line. You could do this while the needle is in the vessel, but that’s a bit unstable. Instead consider using the long angiocatheter found in most central line kits to puncture the internal jugular vein.

After the flash (and ultrasound confirmation of venous puncture) advance the catheter and remove the needle. You then have an angiocatheter in the central venous system, which can be used for manometry, blood gas analysis, or the saline push necessary for the bubble test. Some people have used this angiocatheter during ACLS situations to administer a few doses of code medications in a shorter time than it would take to complete a “full” central line.

Once proper venous placement is confirmed, you can advance the guide wire through the angiocatheter and continue the procedure as normal.

For a great overview of central venous catheterization, check out this post by Haru Okuda and Scott Weingart at EMCrit.org.

Further Reading

Prekker ME, Chang R, Cole JB, Reardon R.  “Rapid confirmation of central venous catheter placement using an ultrasonographic “Bubble Test.” Acad Emerg Med 2010;17(7):e85-6. (PMID: 20653578)

Presentations-slide sorter view

We mostly focus on ultrasound here, but a large part of what we do is information exchange, adult education, and the like. We give a lot of presentations, and many of our faculty are interested in the art of speaking, the aesthetics of presentation design, and adult education.

So from time to time we’ll post on presentation-related topics; I hope you find them as useful as we do.

Slide Sorter View

When I’m polishing a talk, I like to look at the slides in Slide Sorter view. I use PowerPoint; Keynote calls this view Light Table. If you are using Prezi, just close your eyes and spin around 20 times really fast. That’s how your audience feels. Now stop it.

Slide sorter has many uses- right now I want to focus on using it as a final litmus test for how interesting your talk is going to be. If you have crafted an engaging presentation, you’ll be able to tell pretty quickly based on this “big picture” view of your content.

Before

Here’s the slide sorter view of a talk I gave during residency. The topic was cyanide poisoning, but it doesn’t really matter. Do you want to hear this talk? I don’t. Take a minute and imagine what this talk will sound like. SlideSorterCyanide Presentations slide sorter viewIf you pull out this slide deck (I’m deliberately using that archaic term), you have lost before you started. You could read this in your best Ben Stein monotone, or bend over and speak the words out of your butt like Ace Ventura. It doesn’t matter. We’ve all seen this type of talk a million times. A resident reads some articles, pastes data into the slides without fully assimilating the information themselves. Then we have to listen to them tell us something we could read for ourselves. The resident (in this case, my past self), has taken a dry topic and kept it dry.

After

In contrast, here’s a talk I recently gave as part of Sinai’s White Coat ceremony day. What was the topic? Again it doesn’t matter. Look at the slides. Are you curious to find out what was said?

SlideSorterWhiteCoat 500x266 Presentations slide sorter view

What’s that wooden tube? Will the boat catch the submarine? Why is that guy in a bathtub? The visuals here are just a part of the process. Hopefully they are designed to augment what is being said by the speaker. Hopefully there is real content here and it’s not just a bunch of pictures. But at least the speaker and audience are not engaged in a race to read through the words on the slides. That’s a race no one wins.

How to use this

The Slide Sorter test is among the last things I check. It’s like looking at yourself in the mirror as you leave the house. You should already have combed your hair and buttoned your fly by then, but the mirror will let you know before it’s too late. There’s an art and science to slide design, which starts way before this. But this is a simple final check.

Slide Sorter view is also very helpful in rearranging slide order and keeping the threads of your talk together. Garr Reynolds, the presentation zen master, uses Slide Sorter view to storyboard his talks as he builds them.

If you haven’t tried this trick, compare your favorite and your worst talk using this view and see if you can spot any differences.

 

Straight Suture Safety

finger bandage 300x271 Straight Suture SafetyHopefully you are using ultrasound to guide your insertion of central venous catheters. Once they are in, you still have to suture them at some point. Straight suture needles are often used to secure arterial and venous catheters to the skin. These types of suture needles have been demonstrated to be more dangerous than curved or blunt suture needles, with up to seven times higher rate of injury for health care workers. By utilizing the plastic needle sheath present in most central venous line kits as a “thimble,” counter pressure and skin puncture may be achieved without bringing the fingers near the sharp end of the suture. Here’s an image from Bret Nelson’s article on the technique.

Straight Sutre Safe 500x213 Straight Suture Safety

Panel A shows counter-pressure being applied with the cap to direct the tip of the needle. Panel B shows the needle tip safely sheathed within the cap.

The video below demonstrates this technique in real time:

 

Safety technique for straight suture needle from Sinai EM Ultrasound on Vimeo.

 

Other authors have illustrated alternative techniques to reduce the risk of self-injury when using straight suture needles.  Steven Bauer uses a 5-mL syringe to ensconce the emerging straight needle. This can provide even more distance, and he also uses it to guide tying an ‘air knot’ when needed!

syringe needle cap Bauer Straight Suture Safety

Haney Mallemat has just posted a video where he demonstrates using the paper envelope the suture is packaged in to distance the needle tip from your fingers.

Keep in mind NONE of these techniques has been studied- there is no evidence that they reduce needlesticks. We DO know that using curved, blunt-tip suture needles used with needle drivers and forceps is safer than using straight sutures. Whichever method you use please be careful!

References

  • Nelson BP. Making straight suture needles a little safer: a technique to keep fingers from harm’s way. J Emerg Med. 2008 Feb; 34(2):195-7. Epub 2007 Oct 1. (PMID: 18282537)
  • Bauer S, Tauferner D, Carlson D. Improving straight needle safety: an alternate method. J Emerg Med. 2011 Jul; 41(1):e19-20. Epub 2009 Sep 17. (PMID: 19765943)
  • Centers for Disease Control and Prevention. Evaluation of blunt suture needles in preventing percutaneous injuries among healthcare workers during gynecologic surgical procedures—New York City, March 1993–June 1994. MMWR Morb Mortal Wkly Rep 1997;46:25–9. (PMID: 9011779)
  • Edlich RF, Wind TC, Hill LG, Thacker JG, McGregor W. Reducing accidental injuries during surgery. J Long Term Eff Med Implants 2003;13:1–10. (PMID: 12825744)