December 2017 - UCSD Ultrasound

December 16, 2017July 22, 2020

Case # 11: Look and You Will Find

A 32 year old healthy female with no past medical history presents to the emergency department with left sided flank pain x 2 days.

Vitals: T 98.6 HR 72 BP 126/82 RR 12 O2 98% on RA

A bedside ultrasound of the left kidney is performed, what is the next best step in management?

Answer and Learning Points

Answer

The ultrasound image demonstrates a simple cyst located in the cortex of the kidney. The cyst can be described as anechoic, homogenous, with thin and smooth walls, and would be a type I lesion according to the Bosniak classification system (image below). There is no evidence to suggest obstructing hydronephrosis. The Bosniak classification for renal cysts was developed in the 1980s as an attempt to standardize the description and management of complex renal lesions. Based on classification of the renal lesion, the likelihood of malignancy can also be predicted. While the Bosniak classification was initially described and validated with CT imaging, newer data suggests that ultrasound may be sufficient to follow renal cysts that are minimally complex (Bosniak I & II).

Learning Points

- Given the bedside ultrasound demonstrates a Bosniak I lesion in the left kidney, the patient can be reassured that this finding is very unlikely to be malignant and she can be referred to a primary care provider for follow up in several weeks for formal outpatient renal ultrasound.
- Incidental findings are frequently found on point of care ultrasound and while most of them are benign it is of utmost importance to ensure proper follow up when identified. Specifically with renal cysts, this is a common occurrence and most can be followed with renal ultrasound as long as they are simple (Bosniak I or II).
- One pitfall to be aware of is that renal cysts can be mistaken for hydronephrosis and lead to unnecessary imaging and work up (especially in patients presenting with acute flank pain). Therefore it is critical to note the differences between a simple renal cyst and hydronephrosis. As seen in the comparison above renal cysts tend to (but not always) be located in the renal cortex and are both spherical and very well circumscribed. On the other hand, hydronephrosis is centrally located, and tends to branch outwards like a tree. If there is uncertainty, I recommend performing evaluation in both transverse and longitudinal planes to fully characterize your finding. The opposite kidney in the patient can also be used for comparison.

Author

This post was written by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

1. Muglia VF, Westphalen AC. (2014) Bosniak classification for complex renal cysts: history and critical analysis. Radiol Bras 47(6): 368–373.

2. McGuire BB, Fitzpatrick JM. (2010) The diagnosis and management of complex renal cysts. Curr Opin Urol 20:349–354.

3. Case courtesy of Dr Matt Skalski, Radiopaedia.org. From the case rID: 20989

December 7, 2017July 22, 2020

How To: DIY Ultrasound Guided Peripheral IV Phantom

Introduction

Ultrasound-guided venous access has become a core skill for both emergency medicine providers, and nursing staff, to help facilitate difficult access. While clinical experience is critical to learning this technique, phantoms are also a necessary component, specifically with regards to developing both fine-motor skills and spatial orientation. In this post, we provide a step-by-step guide to creating a high-quality, affordable, phantom that can be used for educational purposes at large conferences or for small group training sessions.

1. The Set Up

The Mold: water, metamucil, gelatin, citric acid, blue food coloring

The Veins: animal balloons, red food coloring

The Container: supply case ( 5.08 x 5.25 x 1.9 )

The Tools: sharpie, scissors, syringe, sharp knife or razor blade, large whisk (not shown)

2. Create your Container

We chose the above container because it only requires 500 ml of gelatin mixture, it is plastic (which allows us to cut into it), and it has a lid which allows for easy transport and keeps the phantom fresh.

What you will be doing is creating small slits in the sides of the container to allow for the vessels to "float" and avoid having to pour gelatin in two steps which is both time consuming and messy.

2a. Measure out vessel depth and location

I like to place the vessels 1.5 cm below the surface of the gelatin mold. Using the thick plastic line near the opening of the box, measure 1.5 cm down from here. Measure 4 cm from each side of the box and connect everything with lines. The areas that cross will be where your vessels will go. Repeat this process on opposite side.

2b. Puncture four small slits in container

Now it's time to make small cuts in the plastic container which will allow the vessels to "float." I sit by the stove when doing this and turn on vent above to prevent significant inhalation of burning plastic fumes. Hold the tip of sharp knife or razor knife directly in flame until it turns red. Then quickly push knife into plastic at each line intersection, making approximately a 7-8 mm slit. You may have to re-heat knife between punctures.

Your container is now ready to be used, onto creation of your vessels.

2. Create your Vessels

The red food coloring adds an extra element to your phantom by making the "flash" in the angio-catheter chamber visible.

Fill your syringe with colored water and inject into balloon until it is plump. Next, make sure to get all the air out of the balloon that may have become trapped by holding the balloon vertical, allowing the air to rise to the top, and then tying this off. Continue to tie off the ends of the balloon and trim down with scissors until the vessel is just longer than the width of your container.

Make sure to leave around 1 cm of balloon on each side of your knots as you will need this to pull the vessels through the slits in the container.

3. Cannulate your Container

Take each balloon vessel and thread the ends through the slits in your container. Note as shown in the image that the knot will get caught up on the slit. I use the end of my scissors to pry open the slit slightly, allowing the knot to be pulled through with a little bit of force.

Once the knot is through, pull the balloon vessel out about 1 cm. This will allow the container to "auto-seal." so you do not have to worry about leaking when pouring in the gelatin mold.

This is the hardest step in constructing your phantom so do not be dissuaded if it takes you a few tries.

4. Make your Gelatin Mold

Now it's time to make your gelatin mold. Here are the amounts required for a 500 ml gelatin mold. You can multiply these amounts as needed if making multiple models at a time:

Water: 500 ml

Gelatin: 40 grams (~3.5 Tbsp)

Metamucil: 20 grams (~1.75 Tbsp)

Citric Acid: 1 Tbsp

Blue Food Coloring: 1 tsp

4a. Combine ingredients

Heat up the water in a large pot until it just begins to boil. At this point turn down heat so that water stays warm but is not bubbling. Too much heat will cause the mixture to froth and overflow.

Now add your ingredients, I do the gelatin first as this is the most difficult. It is critical to whisk the water the entire time while adding the gelatin slowly. If you dump the gelatin in all at once, it will form large clumps and ruin your phantom. I would also follow this same technique when adding the other ingredients.

Once all ingredients have been well combined and your mixture has thickened you are ready to pour your gelatin mold into your container.

4b. Pour the mold

Pour gelatin mold into your container, up to the thick plastic line. Allow the mold to cool for 10-15 minutes, then close lid and place in the fridge overnight to set.

The next day your mold will be ready to use!

5. Use your Mold

The mold is probably good for ~ 50-100 IV insertion attempts and can be used at multiple training sessions, though I probably would not keep it for more than 2 weeks. Here are a few other tips:

- The gelatin mold should be chilled until just prior to use to keep it firm; clean surface with water after use, pat completely dry, and store back in fridge to increase longevity.

- To optimize movement of probe along the surface of gelatin mold, be sure to apply a generous quantity to the surface.

- If you notice the balloons appear flat after multiple cannulations, you can refill by directly accessing them through the gelatin under ultrasound guidance and injecting slowly until they appear plump again (do not over pressurize or you may damage the phantom or cause a leak).

Questions?

Leave a comment or email us at ucsdultrasound@gmail.com

December 1, 2017July 22, 2020

Review of Lawsuits Related to Point of Care Emergency Ultrasound Applications

Background

Point-of-care (POC) ultrasound has become heavily integrated into clinical practice in emergency departments (ED). Ultrasound training is now standard in emergency medicine (EM) residency programs and most emergency physicians are able to independently perform and interpret bedside ultrasounds exams. With the rise in use of POC ultrasound by emergency physicians, there is an accompanying theoretical increase in malpractice risk. Malpractice risk can potentially arise from failure to perform an adequate study, failure to interpret findings accurately, or misdiagnosis. This increased liability has prompted some emergency physicians to avoid POC ultrasound in their own practice to decrease their personal risk or transfer risk to consulting services, such as radiology. However, the opposite argument could also be made that failure to incorporate ultrasound into one’s emergency medicine practice can leave clinicians susceptible to legal action as well. This study aims to build on the work of Blavais et al, which revealed that from 1987-2007 there was only one identifiable malpractice lawsuit associated with POC ultrasound. Given the increased use of POC ultrasound since the prior study, this article aims to further characterize the nature of malpractice lawsuits associated with POC ultrasound in more recent years.

Review of lawsuits related to POC emergency ultrasound applications

Clinical Question

With the increased use and scope of practice of POC ultrasound in EM, is there an associated increased legal risk to emergency physicians performing POC ultrasound?

Methods & Study Design

Design
- Retrospective review of Westlaw database for reported decisions in state and federal malpractice cases involving POC ultrasound
  - Westlaw database include state and federal case law and statutes, and public records
Population
- Published case law in the US from Jan 2008 – Dec 2012 in the Westlaw database
Inclusion criteria
- Cases were included if:
  - Physician was accused of misconduct
  - Patient encounter was in ED
  - Interpretation or failure to perform ultrasound was discussed to any degree
  - Ultrasound application was within ACEP ultrasound core applications (trauma, intrauterine pregnancy, AAA, cardiac, biliary, DVT, urinary tract, soft tissue/MSK, thoracic, ocular, procedure)
  - Ultrasound exam performed or ordered through a radiology department was within scope of ACEP core emergency ultrasound applications
Exclusion criteria
- There were no specific exclusion criteria. However, cases settled out of court, cases with unreported decisions, and cases not publically available (private negotiations, arbitration, sealed records, etc) were not available for analysis through the Westlaw database.
Intervention
- Westlaw database was reviewed for published case law (federal and state) in the US from Jan 2008 – Dec 2012
- Search terms included “ultrasound”, “sonography”, “emergency”, “physician”, “doctor”
- Emergency physicians with emergency ultrasound fellowship training reviewed case records that were identified via search. Specific case information was collected. Any discrepancies were discussed between the two reviewers to reach a consensus.
Outcomes
- - The follow case information was collected:
    - Basic clinical narrative of case
    - Exam type involved
    - Department that performed exam
    - Broad category of type of allegation (i.e. misdiagnosis, failure to interpret, failure to perform, failure to perform in timely manner)

Results

- 120 records matched initial search criteria; 7 of these matched inclusion criteria
  - 2 out of 7 were reviewed and found to be outside the scope of ACEP core ultrasound applications
- 5 identified malpractice cases relating to POC ultrasound in the ED
  - No cases resulted from misdiagnosis with POC ultrasound or failure to interpret POC ultrasound
  - All cases involved failure to perform a complete ultrasound study or failure to perform in a timely manner
  - Most common exam type was DVT study
  - Majority of cases involved patient death

Strengths & Limitations

Strengths
- Provides valuable data on legal landscape of POC ultrasound
- Study was designed to identify cases where emergency physicians not only performed but could have performed an ultrasound exam. This allows for potential assessment of “deferred risk”.
Limitations
- Small n – Small number of cases limits ability to approximate any measure of risk to emergency physicians using POC ultrasound
- Selection bias – Cases settled out of court, cases with unreported decisions, cases not publically available (private negotiations, arbitration, sealed records, etc) not included in Westlaw database
- Limited assessment of other factors associated with each case: emergency physician ultrasound skills, access to ultrasound, level of facility support, barriers to perform ultrasound, medical decision making process

Author's Conclusions

“From 2008 to 2012, the Westlaw database reported no judicial decisions against an emergency physician performing POC ultrasound. The database reports five cases related to failure to perform an ultrasound examination that was within the scope of ACEP core emergency ultrasound applications in a timely manner. Further analyses using other legal data sources and insurance claim data are desired and further work is necessary to confirm these preliminary findings.”

Our Conclusions

This study provides reassuring evidence that emergency physicians are not significantly burdened by malpractice lawsuits relating to POC ultrasound use in their clinical practice. In a comprehensive search of publicly available federal and state US malpractice claims, only five cases were found to be associated with POC ultrasound. However, this number must be interpreted with caution. Rubin et al demonstrated that a very small percentage of paid malpractice claims in the US are judged in court (3.1%) while the majority are settled outside (96.9%). The Westlaw database used in this study was able to access only publicly available case data, or cases that were judged in court. Thus, it is difficult to draw generalizable conclusions about the legal risks associated with POC ultrasound from this study. Overall, this study reveals that within publicly available malpractice claims data, lawsuits relating to POC ultrasound are in the minority. While there is legal risk associated with use and failure to use available diagnostic modalities, emergency physicians should feel encouraged to incorporate POC ultrasound exams into their clinical practice.

The Bottom Line

Though the data is limited, there is some reassuring evidence that there is no significant legal burden associated with POC ultrasound used within the scope of ACEP core emergency ultrasound applications. Emergency physicians should continue to incorporate POC ultrasound into their clinical practice.

Authors

This post was written by Neha Chandra, MS4 at University of California, San Diego. It was reviewed by Michael Macias, MD, Ultrasound Fellow at UCSD.

References

1. 1. Rubin, Jessica B., and Tara F. Bishop. "Characteristics of paid malpractice claims settled in and out of court in the USA: a retrospective analysis." BMJ open 3.6 (2013): e002985.
  2. Stolz, Lori, et al. "A review of lawsuits related to point-of-care emergency ultrasound applications." Western Journal of Emergency Medicine 16.1 (2015): 1.