UMEM Educational Pearls - Ultrasound

Category: Ultrasound

Title: Does IV contrast help identify injuries in blunt abdominal trauma patients?

Keywords: Abdomen, ultrasound, trauma, contrast (PubMed Search)

Posted: 5/23/2024 by Robert Flint, MD (Updated: 6/13/2024)
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This very small study looked at the utility of using IV contrast media to enhance abdominal sonography in identifying injuries in blunt abdominal trauma patients. The comparison was CT scanning of the abdomen to identify injuries. The study concluded:

“With the addition of contrast and careful inspection of solid organs, abdominal sonography with contrast performed by the emergency physician improves the ability to rule out traumatic findings on abdominal CT. CEUS performed by emergency physicians may miss injuries, especially in the absence of free fluid, in cases of low-grade injuries, simultaneous injuries, or poor-quality examinations.”

To me, this is a limited study and the technique is not ready for wide spread use but further study is warranted.

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Category: Ultrasound

Title: POCUS for Pleural Effusion

Keywords: Pleural Effusion; POCUS (PubMed Search)

Posted: 4/22/2024 by Alexis Salerno, MD (Emailed: 4/29/2024) (Updated: 4/29/2024)
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How do you look for signs of a pleural effusion with ultrasound?

Place your ultrasound probe in the mid axillary line with the probe marker placed towards the patient's head. 

Find the movement of the diaphragm and scan just above the diaphragm.

In normal lung, air scatters the ultrasound signal, and you are not able to see structures above the diaphragm.

With a pleural effusion, you can see:

  • anechoic fluid above the diaphragm
  • consolidated lung moving like a jelly fish
  • the spine above the diaphragm

Category: Ultrasound

Title: US Guided LP Site Marking

Keywords: POCUS; Lumbar Puncture; Neurology (PubMed Search)

Posted: 4/15/2024 by Alexis Salerno, MD (Updated: 6/13/2024)
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Simple tool to help improve your next lumbar puncture: Use ultrasound for site marking.

This can be done in a patient sitting up or laying on their side.

-First start with the probe marker midline towards the patient's head and use the ultrasound to identify the L4/L5 and L3/L4 space.

-Use a surgical pen away from the gel to mark midline on both sides of the probe, using the midline marker on the ultrasound probe. You can use m mode to help you identify the middle of the image when using a curvilinear probe. 

-Then rotate the probe towards the patient's left and use the ultrasound to identify the midline point (spinous process)

-Use a surgical pen away from the gel to mark midline on both sides of the probe, using the midline marker on the ultrasound probe.

-Clean off the gel, connect the skin markings and use a 3 cc syringe to mark the center of the crosshair. 

-Sterilize and start your LP!

Category: Ultrasound

Title: Ultrasound Artifacts: The April Fool's of Ultrasound

Keywords: POCUS; Ultrasound Artifacts (PubMed Search)

Posted: 4/1/2024 by Alexis Salerno, MD (Updated: 6/13/2024)
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Ultrasound artifacts can sometimes be helpful, but sometimes they can be misleading. 

For example:

1)Does this patient have a gallstone?

No, this is edge artifact! This is due to the ultrasound signals refracting off the side of the gallbladder wall.

  1. Does this patient have sludge?

No, this is side lobe artifact! This is due to a bright reflector outside of the central beam of the ultrasound signal that the machine mistakenly places with in the center of the beam. Side lobe artifact can occur near fluid filled masses such as the gallbladder and bladder. 

  1. Is there tissue above the liver?

No, this is mirror artifact!! This is due to ultrasound signals bouncing off a highly reflective surface such as the diaphragm.  The ultrasound machine misinterprets the time delay from the reflected ultrasound signal as a structure deeper in the image.

What happens if you have a patient who steps on a nail? How can you make this procedure easier for you and the patient? 

– Use a Posterior Tibial Nerve Block! !

To Perform This Procedure:

  • Have the patient lay on a stretcher and externally rotate their hip and have their knee flexed.
  • Clean the area  
  • Use a linear probe with a sterile probe cover on
  • Place the probe with the marker towards the patient’s right, just above the medial malleolus and positioned posteriorly.
  • Identify the posterior tibial nerve next to the posterior tibial artery and center the probe on the nerve
  • Use a 22–30-gauge needle in an out of plane technique, slowly inject about 5 cc of anesthetic, making sure you are just above the nerve and not in the artery.

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Category: Ultrasound

Title: POCUS for hydronephrosis

Keywords: POCUS; Renal Colic; Flank Pain; Hydronephrosis (PubMed Search)

Posted: 2/5/2024 by Alexis Salerno, MD
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Ultrasound is the first line diagnostic tool to evaluate younger patients who present to the ED with flank pain. 

Most of the time on ultrasound, you will not see the actual kidney stone. More often, you will see associated signs such as hydronephrosis.

In a patient with hydronephrosis, the normally hyperechoic renal pelvis will become anechoic. With increased severity of the hydronephrosis, you can have complete distortion of the kidney. 

You can tell the difference between hydronephrosis and a renal vein by placing color doppler over the image. Hydronephrosis will not have flow. 

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Category: Ultrasound

Title: POCUS for Ankle Effusion

Keywords: POCUS, musculoskeletal, ankle, arthrocentesis (PubMed Search)

Posted: 1/29/2024 by Alexis Salerno, MD (Updated: 6/13/2024)
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Many patients present to the emergency department for ankle swelling. On way to identify signs of intra-articular swelling is to use POCUS. To perform this, place the linear probe at the tibio-talar junction with the probe marker placed towards the patient’s head. An effusion is identified as anechoic fluid in-between the tibia and talus bone.  

POCUS has been shown to improve first-pass success and overall success as compared to a landmark based approach for medium-sized joints. When performing an ankle arthrocentesis with POCUS, care should be taken to avoid blood vessels and tendons.

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Category: Ultrasound

Title: Ultrasound Signs of Cardiac Tamponade

Keywords: POCUS; Cardiac Tamponade; Cardiology; Critical Care (PubMed Search)

Posted: 1/15/2024 by Alexis Salerno, MD (Updated: 6/13/2024)
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What are the signs of Cardiac Tamponade on ultrasound? 

Think of them as a pyramid with clinical importance decreasing as you rise to the top of the pyramid.  

  • To have tamponade you need a pericardial effusion. 

  • The most specific sign of tamponade is RV collapse in diastole.  

  • The earliest and most sensitive sign is RA collapse over 1/3 of the cardiac cycle from late diastole into systole, which is why we say RA collapse during systole. 

  • IVC dilation also occurs but is not sensitive. 

  • Placing the pulse wave Doppler over the mitral valve and evaluating the change with respirations is an advanced technique. It’s positive if you have 25% change. 

Don’t know if you are in systole or diastole? Connect your telemetry leads to the ultrasound machine. Don't have leads? Then you can also cine scroll on a subxiphoid view or parasternal view to look at when the valves are open and closed, then compare to the cardiac wall positioning.

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Category: Ultrasound

Title: How to Perform a Transvaginal Ultrasound for OB

Keywords: Obstetrics; POCUS; Transvaginal Ultrasound (PubMed Search)

Posted: 12/18/2023 by Alexis Salerno, MD
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By performing a Point-of-Care Transvaginal Ultrasound (TVUS), we can decrease length of stay for patients with early pregnancy. Moreover, if an ectopic pregnancy is identified, we can decrease time to the OR for these patients. 

Begin by discussing the exam with the patient and ensuring they have emptied their bladder.  Apply a probe cover and add sterile lubricant to the outside of the probe tip. You can save time by performing a TVUS immediately after the pelvic speculum exam for swab collection.

  • Obtain a Sagittal View of the Uterus:

Gently introduce the transducer with the marker upward, directed towards the ceiling. As you slowly advance, the uterus will be visualized in a sagittal orientation. Fan through the uterus by moving the probe handle left and right.

Image From: doi: 10.1016/j.emc.2022.12.006.

  • Obtain a Coronal View of the Uterus:

Rotate the transducer so that the marker is directed towards the patient's right side. Fan through the uterus by lifting the probe handle up and down. 

Image From: doi: 10.1016/j.emc.2022.12.006.

  • Perform Measurements:

If a gestational sac is found, you should measure the gestational age and if present, fetal heart rate. 

  • Evaluate the Adnexa:

Tilt the transducer towards the patient's left or right side to visualize the adnexa. The adnexa will be located medially to the iliac vessels. 

  • End the Exam:

Remove the transducer and follow your department protocol for high level disinfection.

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