Month: May 2020

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Case # 21: A 28 Year Old With Shortness of Breath

echo d sign

 

A previously healthy 28-year-old male presents to the Emergency Department complaining of one month of fatigue, shortness of breath, and dyspnea on exertion. These symptoms were preceded by symptoms of a viral illness which initially improved; however, he had recurrence of symptoms two weeks ago. He was seen at urgent care five days ago and was given steroids and albuterol without improvement. The patient otherwise denies any infectious symptoms, leg swelling, or risk factors for pulmonary embolus or deep vein thrombosis.  

VS: T: 97.7F    BP: 129/87.    HR: 109     RR: 16.    SP02: 95%

Patient is alert and oriented, non-toxic in no distress, and behaving appropriately. Cardiac exam shows a RRR, no murmurs, rubs, or gallops. Lung exam is consistent with shallow breaths and dyspnea with conversation, otherwise lungs are CTAB with no wheezing, rales, or rhonchi. The patient has no chest wall tenderness, no JVD, and no lower extremity edema.

You perform a bedside ECHO and you see the following. What do you see and what is your most likely diagnosis? What is your next step in management?

apical 4 rv strain
psla rv strain
pssa rv strain

Answer and Learning Points

Answer:

In all three cardiac views, there is dilation of the right side of the heart. In the parasternal short axis you see septal bowing into the left side of the heart, also known as the “D” sign (named after the shape of the left ventricle). These findings are indicative of elevated right sided pressure, or right heart strain, which can be seen in conditions such as acute pulmonary embolism, pulmonary hypertension, COPD, and right ventricular infarction. Given the relatively thin free wall of the right ventricle, the likely cause of right heart strain in the above scenario is an acute process.

The patient had a CT scan that revealed extensive pulmonary emboli in all segmental and subsegmental arterial divisions of the lung with findings consistent with pulmonary artery hypertension and severe right heart strain. The EKG obtained had evidence of right heart strain including right axis deviation and diffuse T-wave inversions. The patient was started on heparin and admitted to the ICU.

Learning Points

  • The reported sensitivity and specificity of echocardiography in demonstrating right heart dysfunction are around 56% and 42% respectively (1)
  • Described features of right heart dysfunction include (2)
    1. Dilation of the right ventricle
      • The RV normally appears triangular-shaped and is two-thirds the size of the LV in apical four view (3)
    1. Interventricular septal flattening
      • AKA the “D sign” on parasternal short view or paradoxical septal motion on apical four view
    1. Right ventricular hypertrophy (right ventricular free wall thickness >5mm in diastole)
      • When present, implies some degree of chronicity to the inciting hemodynamic insult
    1. Right ventricular hypokensia
      • Typically quantified as a tricuspid annular plane systolic excursion, as measured by M-mode from the apical 4 chamber view, <1.6 cm
    1. Plethoric vena cava

References

  1. He, H., et-al. Computed tomography evaluation of right heart dysfunction in patients with acute pulmonary embolism. J Comput Assist Tomogr. 2006;30 (2): 262-6.
  2. Rudski, L.G., et al. Guidelines for the echocardiographic assessment of the right heart in adults: a report from the American Society of Echocardiography endorsed by the European Association of Echocardiography, a registered branch of the European Society of Cardiology, and the Canadian Society of Echocardiography. (2010) Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography. 23 (7): 685-713
  3. Mallin, M, Dawson, M. Introduction to Bedside Ultrasound: Volume 2. Emergency Ultrasound Solutions, 2013. Apple Books. https://books.apple.com/us/book/introduction-to-bedside-ultrasound-volume-2/id647356692. Accessed April 17th, 2020.


The following authors contributed to this post:

Danika Brodak, MD; Amir Aminlari, MD; Rachna Subramony, MD; Colleen Campbell, MD

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Ultrasound-guided supra-inguinal fascia iliaca block: a cadaveric evaluation of a novel approach

fascia iliaca block

Background

Regional anesthesia of the fascia iliaca is well-documented to be a successful way to control acute pain from hip fractures in the emergency department, particularly in those patients at high risk of complications from repeated doses of IV opioids. However, the majority of existing descriptions on technique for performing fascia iliaca blocks focus on approaching from inferior to the inguinal ligament, relying on supra-inguinal spread to block the lateral femoral cutaneous nerve in the iliac fossa. This study aims to investigate the utility in performing suprainguinal injection of anesthetic agents directly into the iliac fossa to provide regional anesthesia.

Ultrasound-guided supra-inguinal fascia iliaca block: a cadaveric evaluation of a novel approach

Clinical Question

Does injecting dye superior to the inguinal ligament provide significant uptake of dye in the femoral, LCFN, and ilioinguinal nerves in cadaveric models?

Methods & Study Design

• Design 

This is an informational study made to illustrate the utility of an alternative supra-inguinal approach for providing regional anesthesia in those patients presenting with acute hip or knee pain.

• Population 

Bilateral injections of 20 mL of 0.25% aniline blue dye were administered to six unembalmed cadavers, for a total of 12 injections available for analysis.

• Intervention 

Bilateral injections of 20 mL of 0.25% aniline blue dye were administered to six unembalmed cadavers via an ultrasound guided approach, and dye uptake was analyzed in anatomic nerve distributions.

Steps of superior approach to fascia iliaca block:

  • Place sterile probe over the inguinal ligament, close to the anterior superior iliac spine
  • Orient linear probe in parasagittal oblique orientation (superior aspect facing medially)
  • Rock the probe so beam faces laterally to enhance fascia iliaca
  • Move probe infero-medially along the line of inguinal ligament until femoral artery is imaged
  • Moving probe supero-laterally helps identify anterior inferior iliac spine (site of rectus femoris attachment)
  • As you move laterally, you see “rising” of ilium towards transducer
  • Identify deep circumflex artery 1-2cm superficial to fascia iliaca
  • Needle introduced 2-4cm inferior to inguinal ligament, and advanced through the fascia iliaca at the level of inguinal ligament.
  • “pop” as needle passes through fascial iliaca and into the iliacus muscle
  • Needle withdrawn to the fascia, and position confirmed by 1cc of local anesthetic.
  • Injection of fluid produces a“lens”that appears. The fluid should then hydro-dissect as it migrates into the iliac fossa
  • End point is when local anesthetic passes freely superiorly over the iliacus muscle and into the iliac fossa.

• Outcomes  

Dye uptake in the femoral, lateral femoral cutaneous nerve, and ilioninguinal nerves after supra-inguinal injection.

Results

    • There was extensive spread of dye identified in the iliac fossa. (50 to 144mm of spread)
    • 10 out of 12 injections also resulted in spread into the thigh along the femoral nerve
    • The femoral nerve was surrounded by dye in all cases
    • The LFCN was identified bilaterally in 5 cadavers, but one cadaver lacked both LFCN. LCFN was surrounded by dye in all cases in which it was present.
    • It is important to realize that the ilioinguinal nerve has significant anatomic variation. The ilioinguinal nerve passed over iliac crest onto iliacus muscle and re-emerged into the abdominal wall anteriorly in 8 cases. In the other four cases it remained in the abdominal wall. It was stained blue 7 out of 8 times in this procedure as it passed over iliac crest.

Strength & Limitations

    • There was no comparison group in this study (supra-inguinal approach was used in all cases).
    • There were significant anatomic variations between cadavers. One cadaver was found to have no lateral femoral cutaneous nerve. There were also significant anatomic variations in positioning of the ilioinguinal nerve.
    • Throughout the article, there were multiple references that the authors institution has performed over 150 supra-inguinal fascia iliata blocks without any short term complications, however no retrospective data was available in the article to confirm this.
    • Low sample population (6 cadavers, 12 nerve blocks)

Authors Conclusion

“Our cadaveric dye-injection study confirms that the ultrasound-guided supra-inguinal approach result in significant spread of injectate with simultaneous involvement of both the femoral nerve and LFCN, in the iliac fossa, in the all the cadavers in which we identified theses nerves by dissection.”

Our Conclusion

This article outlines an interesting alternative approach to providing regional anesthesia for acute pain control of the hip or knee. The majority of existing descriptions on technique for performing fascia iliaca blocks focus on approaching from inferior to the inguinal ligament, relying on supra-inguinal spread to block the lateral femoral cutaneous nerve in the iliac fossa. This study demonstrates consistent bathing of the LFCN and femoral nerve with dye in cadaveric subjects with a supra-inguinal approach. However, this study does not directly demonstrate superior efficacy of the suprainguinal approach when compared to infrainguinal fascia iliaca block. Further patient-oriented studies would be needed to make such a suggestion.

The Bottom Line 

Ultrasound guided suprainguinal fascia iliaca injection of dye in cadaveric subjects shows consistent and significant uptake of injectate of the femoral nerve and LFCN in the iliac fossa. Further studies are needed to show if this provides improved analgesia as compared to the conventional infrainguinal approach. 

Authors

This post was written by Casey Smith, MD. Review and further commentary was provided by Danika Brodak, MD, Emergency Ultrasound Fellow at UCSD and Amir Aminlari, MD, Ultrasound Faculty at UCSD.

References

  1. Hebbard P, Ivanusic J, Sha S. Ultrasound-guided supra-inguinal fascia iliaca block: a cadaveric evaluation of a novel approach. Anaesthesia. 2011;66(4):300‐305. doi:10.1111/j.1365-2044.2011.06628.x

 

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