Introduction to Transesophageal Echo – Basic Technique

Thanks to Dr. Jennifer Cloutier, Cardiac Anesthesiologist, for delivering a great session.


This beginner guide is designed for those familiar with transthoracic echo and just starting to use TEE. ED indications and TEE utility in the emergency setting are briefly discussed at the end of this post.


Requirements

  • Sterile transducer – This requires a sterilization facility, protocol and collaboration with other departments
  • Patient preparation – In ED usually intubated, unconscious or sedated.
  • Optional – spray the transducer with topical local anesthetic

Contraindications

  • Suspected esophageal perforation, stricture or trauma
  • Varices

Insertion

  • Hold transducer control module with left hand and support against your abdomen (see pic 1)
  • Extend transducer to full length, holding end with right hand
  • Check the control wheels are functioning correctly before inserting the transducer
  • Ensure transducer head is facing upwards (use anterior length markings to maintain orientation)
  • Insert transducer on left side of tongue
  • Use bite guard – e.g cut corrugated airway tubing
  • Advance to mid esophagus
  • Look for left atrium – this is the first window

 

Orientation

The transducer can be manipulated into several orientations:

  • Rotate control module clockwise to orientate to patient right
  • Rotate control module anticlockwise to orientate to patient left
  • Rotate “Big Wheel” clockwise to antiflex and orientate anteriorly
  • Rotate “Big Wheel” anticlockwise to retroflex and orientate posteriorly
  • Rotate “Small Wheel” clockwise to flex right
  • Rotate “Small Wheel” anticlockwise to flex left
  • Advance transducer deeper into esophagus
  • Withdraw transducer less deeply in esophagus

(a) Advance, withdraw: Pushing or pulling the tip of the TEE probe; (b) turn to right, turn to left (also referred as clockwise and anticlockwise): rotating the anterior aspect of the TEE probe to the right or left of the patient; (c) anteflex, retroflex: anteflex is flexing the tip of the TEE probe anteriorly by turning the large control wheel clockwise. Retroflex is flexing the tip of the TEE probe posteriorly by turning the large wheel anticlockwise; (d) Flex to right, Flex to left: flexing the tip of the TEE probe with the small control wheel to the patient’s right or left. The probe flexion to the right and left may not be necessary and should be avoided to minimize trauma to the esophagus 

 

 

Multiplane Imaging Angle

With all modern TEE transducers the transducer beam can be rotated within the probe to generate different beam angles. This is achieved using 2 buttons on the control module, one button rotates from 0 to 180 degrees, the other button rotates it back from 180 to 0 degrees. Using the buttons in combination any desired angle between 0 and 180 degrees can be achieved.

At 0 degrees the transducer beam is transverse (orientated Left screen – Right patient)

At 90 degrees the transducer beam is longitudinal

At 180 degrees the transducer beam is transverse (orientated Left screen – Left patient)

 

Multiplane Imaging angle is depicted on the monitor using a pictogram dial.

In this example the TEE probe is located in the Mid Esophageal location. View A – the multiplane imaging angle is 10 degrees and a 4 chamber view is generated. View B – the multiplane imaging angle is 90 degrees and a 2 chamber view is generated.

 

 


 

Useful video tutorial explaining orientation

 

 


 

Core Views

For the beginner, standard views can be achieved by using a guide that shows the location of the transducer (e.g Mid Esophageal, Trans-Gastric along with the optimal multiplane angle (see below).

Clearly every patient will have slightly different anatomy and cardiac axis, so these guides are just a starting point. Fine tuning of all the above will be required.

The Consensus Statement of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists provides an excellent outline of the basic perioperative TEE examination. Although this examination is likely to be much more comprehensive than what is needed in the Emergency Department (e.g during a code or peri arrest), it provides a useful guide to practicing all the important views that may be required in most situations.

 


 

This short video tutorial provides a useful outline of core views

 


ME 4 Chamber View


 

Indications

  • Cardiac Arrest – continuous echo evaluation of cardiac contractility, without impacting chest compression
  • Peri Arrest – assists with diagnosis and fluid resuscitation,
  • Undifferentiated Hypotension – assists with diagnosis and fluid resuscitation

US Probe: Transesophageal Echocardiography in Cardiac Arrest

The post above and the article below provide a more detailed discussion on the use of TEE in cardiac arrest.

New Concepts of Ultrasound in the Emergency Department: Focused Cardiac Ultrasound in Cardiac Arrest

 

 


References

Reeves ST, Finley AC, Skubas NJ, et al. Basic perioperative transesophageal echocardiography examination: a consensus statement of the American Society of Echocardiography and the Society of Cardiovascular Anesthesiologists. J Am Soc Echocardiogr. 2013;26(5):443–456. doi:10.1016/j.echo.2013.02.015

Arntfield, Robert et al. Focused Transesophageal Echocardiography by Emergency Physicians is Feasible and Clinically Influential: Observational Results from a Novel Ultrasound Program. Journal of Emergency Medicine, Volume 50, Issue 2, 286 – 294

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PoCUS in Pericardial Effusion

Medical Student Clinical Pearl – October 2019

 

Alex Pupek

Faculty of Medicine
Dalhousie University
CC4
Class of 2020

Reviewed and Edited by Dr. David Lewis

All case histories are illustrative and not based on any individual


Case

A 70F with a history of bladder CA, HTN and 4.9cm AAA presented to the Emergency Department (ED) and was Triaged as Level 3 with a chief complaint of generalized weakness. Initial assessment was significant for hypotension and low-grade fever with dysuria elicited on history; she was started on Ceftriaxone with a working diagnosis of urosepsis. Bloodwork and imaging studies were sent to rule out other potential sources of infection.

She had a mild leukocytosis of 12.4, pH of 7.23 and a lactate of 5.0. Point-of-care urinalysis was unremarkable. The chest x-ray revealed an enlarged cardiothoracic ratio of 0.62 compared to 0.46 ten months previously, concerning for a pericardial effusion.

Upon reassessment, the patient appeared unwell with slight mottling to the skin, cool extremities and tenuous blood pressure; point of care ultrasound revealed a large pericardial effusion.  Interventional cardiology was paged; the patient was moved to the trauma area and an emergent pericardiocentesis was performed: 360cc of bloody fluid was removed. The pericardial drain was left in situ.

Post-procedure bloodwork included a troponin of 216 and CK of 204. The patient was admitted to the Cardiac Care Unit and discharged within a week’s time.

 


Pericardial Effusions and The Role of Point-of-Care Ultrasound (POCUS)

The normal pericardial sac contains up to 50 mL of plasma ultrafiltrate [1]. Any disease affecting the pericardium can contribute to the accumulation of fluid beyond 50mL, termed a pericardial effusion. The most commonly identified causes of pericardial effusions include malignancy and infection (Table 1).

 

Table 1 – UpToDate, 2019 – Diagnosis and Treatment of Pericardial Effusions


 

Evaluation of the pericardium with point-of-care ultrasound includes one of four standard views: parasternal long axis, parasternal short axis, subxiphoid and apical (Figure 1). A pericardial effusion appears as an anechoic stripe or accumulation surrounding the heart. Larger effusions may completely surround the heart while smaller fluid collections form only a thin stripe layering out posteriorly with gravity. Seen most commonly post-cardiac surgery, pericardial effusions may be loculated and compress only a portion of the heart. [1,2] (Table 2)

Figure 1[1]


Table 2 [2]


 

Both the pericardial fat pad and pleural effusions can be mistaken for pericardial effusions. The parasternal long-axis view is most helpful to accurately define the effusion with the descending aorta, posterior to the mitral valve and left atrium, serving as a landmark: the posterior pericardial reflection is located anterior to this structure. Fluid anterior to the posterior pericardial wall is pericardial, whereas a pleural effusion will lie posterior. The pericardial fat pad is an isolated dark area with bright speckles, located anteriorly; unlike fluid, it is not gravity dependent. Rather than competing with the cardiac chambers for space within the pericardial sac, the fat pad moves synchronously with the myocardium throughout the cardiac cycle. [1,2] (Figure 2)

Figure 2[1]


A pericardial effusion discovered on POCUS in the ED may be mistaken for tamponade, leading to inappropriate and invasive management in the form of pericardiocentesis.[2]

Patient tolerance of pericardial effusions depends on the rate by which they accumulate. As little as 150-200 mL of rapidly accumulating effusion can cause tamponade whereas much larger amounts of slowly accumulating fluid can be well tolerated. Pericardial effusions formed gradually are accommodated by adaptations in pericardial compliance. A tamponade physiology is reached once the intrapericardial pressure overcomes the pericardial stretch limit.[2] (Figure 3)

Figure 3[2]


The core echocardiographic findings of pericardial tamponade consist of:

  • a pericardial effusion
  • diastolic right ventricular collapse (high specificity)
  • systolic right atrial collapse (earliest sign)
  • a plethoric inferior vena cava with minimal respiratory variation (high sensitivity)
  • exaggerated respiratory cycle changes in mitral and tricuspid valve in-flow velocities as a surrogate for pulsus paradoxus

In the unstable patient with clinical and echocardiographic findings of tamponade, an emergent pericardiocentesis is indicated.[2]

A retrospective cohort study of non-trauma emergency department patients with large pericardial effusions or tamponade, ultimately undergoing pericardiocentesis, found that effusions identified by POCUS in the ED rather than incidentally or by other means saw a decreased time to drainage procedures, (11.3 vs 70.2 hours, p=0.055).[3]

Point of care ultrasound is a valuable tool during the initial evaluation of the undifferentiated hypotensive emergency department patient but should be interpreted judiciously and within clinical context to avoid unnecessary emergency procedures.


Additional Images

From GrepMed


 

echocardiogram-pericardial-tamponade-alternans-effusion

 


References

  1. Goodman, A., Perera, P., Mailhot, T., & Mandavia, D. (2012). The role of bedside ultrasound in the diagnosis of pericardial effusion and cardiac tamponade. Journal of emergencies, trauma, and shock, 5(1), 72.
  2. Alerhand, S., & Carter, J. M. (2019). What echocardiographic findings suggest a pericardial effusion is causing tamponade?. The American journal of emergency medicine, 37(2), 321-326.
  3. Alpert, E. A., Amit, U., Guranda, L., Mahagna, R., Grossman, S. A., & Bentancur, A. (2017). Emergency department point-of-care ultrasonography improves time to pericardiocentesis for clinically significant effusions. Clinical and experimental emergency medicine, 4(3), 128.

 

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Pediatric Hip PoCUS

Pediatric Hip PoCUS

PoCUS Pearl

Dr. Sultan Ali Alrobaian

Dalhousie EM PoCUS Fellowship

Saint John, NB

@AlrobaianSultan

 

Reviewed and Edited by Dr. David Lewis


 

Case:

A 5 year old healthy boy, came to ED with history of limping since waking that morning. He had worsening right hip discomfort. No history of trauma. He had history of cold symptoms for the last 3 days associated with documented low grade fever.

On physical examination, he looked uncomfortable and unwell looking, he had temperature of 38.1 C, HR 130, BP 110/70, RR 20 and O2 saturation of 98% on RA. He was non-weight-bearing with decreased ROM of right hip because of pain.

Pelvis x-ray was unremarkable, he had WBC of 14.4 x 103  and CRP of 40 .

PoCUS of the right hip was performed.


 

Pediatric Hip Ultrasound

Ultrasonography is an excellent modality to evaluate pathologies in both the intra-articular and extra-articular soft tissues including muscles, tendons, and bursae. PoCUS to detect hip effusion can serve as an adjunct to the history and physical examination in case with hip pain.  It is easily accessible, no radiation exposure and low cost.

Technique:

The child should be in supine position. Expose the hip with drapes for patient comfort. If the patient will tolerate it, position the leg in slight abduction and external rotation. A high frequency linear probe is the preferred transducer to scan the relatively superficial pediatric hip, use the curvilinear probe if increased depth is required.

With the patient lying supine, identify the greater trochanter on the symptomatic hip of the patient. Place the linear probe in the sagittal oblique plane parallel to the long axis of the femoral neck (with the indicator toward the patient’s head).

If the femoral neck cannot easily be found, it can be approached using the proximal femur. Place the probe transversely across the upper thigh. Identify the cortex of the proximal femur and then move the probe proximally until the femoral neck appears medially, then slightly rotate the probe and move medially to align in the long axis of the femoral neck.

Assistance is often required from a parent who may be asked to provide reassurance, apply the gel and help with positioning.

Both symptomatic and asymptomatic hips should be examined.

Negative hip ultrasound in a limping child should prompt examination of the knee and ankle joint (for effusion) and the tibia (for toddler’s fracture)

Hip X-ray should be performed to rule out other causes (depending on age – e.g. Perthes, Osteomyelitis, SCFE, Tumour). Limb X-ray should be performed if history of trauma or NAI.

 

Anatomy of the Pediatric Hip:

The ED Physician should readily identify the sonographic landmarks of the pediatric hip. These landmarks include the femoral head, epiphysis and neck, acetabulum, joint capsule and iliopsoas muscle and tendon.

 

A normal joint may have a small anechoic stripe (normal hypoechoic joint cartilage) between cortex and capsule. This will measure less than 2mm and be symmetrical between hips.

 

Ultrasound Findings:

Measure the maximal distance between the anterior surface of the femoral neck and the posterior surface of the iliopsoas muscle. An effusion will result in a larger anechoic stripe (>2mm) that takes on a lenticular shape as the capsule distends. Asymmetry between hips is confirmatory. Synovial thickening may also be visualized.

FH- Femoral Head, S- Synovium, E – Effusion, FN – Femoral Neck

Criteria for a pediatric hip effusion is:

  • A capsular-synovial thickness of 5 mm measured at the concavity of the femoral neck, from the anterior surface of the femoral neck to the posterior surface of the iliopsoas muscle
  • OR a 2-mm difference compared to the asymptomatic contralateral hip

Right hip effusion, normal left hip, arrow heads – joint capsule, IP – iliopsoas


Interpretation

PoCUS has high sensitivity and specificity for pediatric hip effusion.

  • —
  • Sensitivity of 90%
  • Specificity of 100%
  • Positive predictive value of 100%
  • Negative predictive value of 92%

 

PoCUS cannot determine the cause of an effusion. It cannot differentiate between transient synovitis and septic arthritis. Diagnosis will be determined by combining history, pre-test probability, examination, inflammatory markers and PoCUS findings. If in doubt, septic arthritis is the primary differential diagnosis until proven otherwise.

Several clinical prediction algorithms have been proposed. This post from pedemmorsels.com outlines these nicely:

 

Septic Arthritis

 

 


 

Back to our case:

Ultrasonography cannot definitively distinguish between septic arthritis and transient synovitis, the ED physician’s concern for septic arthritis should be based on history, clinical suspicion and available laboratory findings.

The patient was diagnosed as case of septic arthritis. The patient received intravenous antibiotics empirically. Pediatric orthopedic consultation was obtained, and ED arthrocentesis was deferred as the patient was immediately taken to the operating room for hip joint aspiration and irrigation, confirming the diagnosis.


 

References

 

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Color Flow Doppler to Assess Cardiac Valve Competence

Color Flow Doppler to Assess Cardiac Valve Competence

Resident Clinical Pearl (RCP) April 2019

Dr. Scott Foley – CCFP-EM PGY3 Dalhousie University, Halifax NS

Reviewed by Dr. David Lewis

 


 

Background:

When colour Doppler is initiated, the machine uses the principals of the Doppler effect to determine the direction of movement of the tissues off which it is reflecting.

The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to a wave source. It was named after the Austrian physicist Christian Doppler who first described the phenomenon in 1842. The classic example is the change in pitch of a siren heard from an ambulance as it moves towards and away from an observer.

These principles are applied to POCUS in the form of colour Doppler where direction of flow is reflected by the colour (Red = moving towards the probe, Blue = moving away from the probe), and the velocity of the flow is reflected by the intensity of the colour (brighter colour = higher velocity).
*Note: the colour does not represent venous versus arterial flow.

 

The use of colour Doppler ultrasound can be useful in the emergency department to determine vascular flow in peripheral vessels as well as through the heart. It is one way to determine cardiac valve competency by focusing on flow through each valve.


 

Obtaining Views:

To optimize valve assessment, proper views of each valve must be obtained. It is best to have the direction of the ultrasound waves be parallel to the direction of flow. External landmarks for the views used are seen below:

  • Mitral Valve and Tricuspid Valve: The best view for each of these is the apical 4 chamber view. If unable to obtain this view, the mitral valve can be seen in parasternal long axis as well.
  • Aortic Valve: The best view is the apical 5 chamber or apical 3 chamber but are challenging to obtain. Instead, the parasternal long axis is frequently used.
  • Pulmonic Valve: Although not commonly assessed, the parasternal short axis can be used.
  • Visit 5minutesono.com for video instruction on obtaining views

Parasternal long axis: MV, AV

Parasternal short axis: PV, TV

Apical 4 chamber: TV, MV


 

Assessing Valvular Competency:

How to examine valvular competency:

  1. Get view and locate valve in question
  2. Visually examine valve: opening, closing, calcification
  3. Use colour Doppler:
    1. Place colour box over valve (as targeted as possible (resize select box) to not include other valves)
    2. Freeze image and scroll through images frame by frame
    3. Examine for pathologic colour jets in systole and diastole
  4. Estimating severity:
    1. Grade 1 – jet noticeable just at valve
    2. Grade 2 – jet extending out 1/3 of atrium/ventricle
    3. Grade 3 – jet extending out 2/3 of atrium/ventricle
    4. Grade 4 – jet filling entire atrium/ventricle

See video tutorial below for more


Mitral Regurgitation A4C

Tricuspid Regurgitation A4C

Aortic Stenosis PSLA


Bottom line:

Color flow Doppler on POCUS is a straightforward way to assess for valvular competency in the Emergency Department. A more detailed valvular assessment requires skill, knowledge and experience.

 


Useful Video Tutorials:

Mitral Regurgitation

 

Aortic Stenosis vs Sclerosis

Tricuspid Valve


References:

  1. https://www.radiologycafe.com/medical-students/radiology-basics/ultrasound-overview
  2. By Patrick J. Lynch and C. Carl Jaffe – http://www.yale.edu/imaging/echo_atlas/views/index.html, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=21448310
  3. 5minutesono.com
  4. ECCU ShoC 2018 powerpoint, Paul Atkinson, David Lewis
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A focus on PoCUS – A reflection on the value of a PoCUS elective as a medical student

Medical Student PoCUS Elective Reflection

Nick Sajko

Class 2019 Dalhousie Medicine

@saj_ko

 

Nick Sajko, reflects on his experience after completing the SJRHEM PoCUS Elective. Nick is now a PGY1 in Emergency Medicine at the University of Alberta.


 

When my fourth and final year of medical school came around, I was at a crossroads: What did I want to do for the rest of my life? As many will attest, this question influences the choices you make in your clerkship years, especially in deciding on fourth year electives. I was ironically unfortunate in the fact that I had a broad range of interests in a system that does not always benefit those in my situation. I chose electives in Emergency Medicine, Internal Medicine, and Family Medicine – all of them providing valuable learning opportunities and a chance to hone my skills as a junior clinician. However, these “classic” or “bread and butter” electives paled in comparison to the experiences I obtained through my Point of Care Ultrasound (PoCUS) elective at SJRH – a unique elective opportunity relevant to any medical trainee.

 

It is my hope that this reflection piece will provide insight into those deciding on their elective choices and convince some of you to choose a few electives that are off the beat and path and unique. In particular, an elective in the field of PoCUS – a tool that is more useful than some may consider.

 


 

What does a PoCUS elective at SJRH entail? What can I expect?

 

My elective consisted of regularly scheduled shifts within the Emergency Department, paired with senior staff who have specialized training in PoCUS. During these shifts, I would see patients as if I was conducting a bread and butter Emergency Medicine elective, however, cases would be chosen based on the potential for ultrasound practice. This allowed me to gain a remarkable appreciation for the breadth of PoCUS applications within the primary care setting, while also allowing me to gain extremely valuable hands on time with ultrasound in a supervised setting.

 

In addition to the above, I was provided with numerous resources so as to allow for self-directed learning. One of the most valuable resources provided was the opportunity to use the SJRH EM state-of-the-art PoCUS simulator – an invaluable tool for any level of PoCUS experience. Closer to the end of this elective experience, I was offered opportunities to write PoCUS focused case-reports, as well as undergo PoCUS competency exams to solidify my skills within this setting.

The skills I learned in this elective carried forward with me into my various other electives, and provided me with a unique skill-set as a junior learner. Whether it was doing point of care ECHO in my cardiology elective, FAST scans during trauma-codes in my other Emergency Medicine electives, or assessing volume status in complex general internal medicine patients, my competency in these PoCUS applications definitely impressed both residents and staff alike during my fourth year!

 


Why is PoCUS relevant to me as a medical student wanting to specialize in: (insert hyper-specific / niche specialty here)

One question many people may have at this point is, “why would I do this if I wasn’t interested in Emergency Medicine?”. PoCUS is a constantly evolving field, with new and innovative applications being seen in clinical practice constantly. With this, PoCUS can play a huge role in many different specialties: Internal Medicine physicians use PoCUS to provide support to presumed diagnoses and perform certain procedures (such as placing central lines), while surgeons can utilize PoCUS in the examination of traumas, as well as to support diagnoses in the pre- and post-operative patient. PoCUS is steadily becoming a sought after skill in most of the medical and surgical specialties, where proficiency in its use and interpretation can set you apart from other trainees, and more importantly, add to the competency of your patient care!

The value of having this elective through the Emergency Department allows for students to test their skills in the undifferentiated patient – something that will provide learners with enhanced deduction and reasoning skills, no matter what specialty they are interested in. It also allows learners to have access to a huge pool of patients, with a wide breadth of medical problems, thus optimizing this unique elective’s value.

 


 

Is choosing a “unique”, “niche”, or “extra-focused” elective, such as PoCUS, detrimental to my CaRMS application?

Fourth year electives and CaRMS amalgamate into a cruel and unusual game – while most medical school staff and administrators will tell you that your fourth year electives are to be used to “try new things”, this is often not the reality. With the competitiveness of specialties on a constant upward trend, more and more learners choose to conduct the majority of their electives in the single specialty they are interested in. This is great for those who are certain about the field they want to practice in, but creates a predicament for those of us who want to explore a number of options before making a decision.

As I mentioned above, I was in the latter group – with interests spanning 3 different specialties, including some very competitive ones. I chose to go against the grain, so to speak, and opted to conduct a variety of electives in different specialties – including some niche electives in things such as PoCUS. Not only were these opportunities fantastic from a learning point of view, I would argue that they allowed me to stand out amongst a sea of similar applicants and provided me with a unique skill set – something that I think most programs will find enticing! But most importantly, they were fun, exciting, and allowed me to experience my fourth year of medical school the way its advertised.

For those that know their specialty of choice, I would provide the same advice – use this year to experience new things and create a unique learning identity that will set you apart from the rest.

 


 

After all the worry and panic with my elective choices, feeling like I wasn’t committed enough to one specific specialty, I ended up matching to my first-choice field and location. I think this is in large part due to the fact that I was well-rounded in my experiences and had taken the chance to explore unique learning opportunities through this fantastic elective at SJRH. The staff, the environment, and the resources that come with the PoCUS elective at SJRH EM are second to none – I am confident in saying that this elective was the most beneficial and enjoyable component to my fourth year training. Hopefully my thoughts and reflections on this experience will allow some of you to follow a similar path.

 

Nicholas Sajko, B.Sc, MD

Emergency Medicine PGY1

University of Alberta

 


 

Click here for more information on the SJRHEM PoCUS Electives and Fellowships

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PoCUS – Dilated Aortic Root

Medical Student Clinical Pearl

James Kiberd

Class 2019 Dalhousie Medicine

Reviewed and Edited by Dr. David Lewis


Case:

A 66 year-old female presented to the Emergency Department with shortness of breath and back pain. She had a known dilated aortic root, which was being followed with repeat CT scans. Given the nature of her presenting complaint, a PoCUS was performed to assess her aorta.

 

 

 

Long Axis Parasternal View:

PoCUS for Cardiac imaging has been studied in the acute care setting; focusing on the assessment for pericardial effusion, chamber size, global cardiac function, and volume status, and cardiac arrest.1

In the setting of acute aortic dissection, further evaluation is often recommended depending on the practitioner’s skill level.2 There have been case reports where ultrasound has been used to assess both Type A and Type B aortic dissections.3–5

In order to assess the aortic root, have the patient in a supine position. Either the phased array or the curvilinear probe can be used depending on examiner’s preference. The probe should be positioned with the marker towards the patient’s right shoulder on the anterior chest to the left of the patient’s lower left sternal border. By tilting the transducer between the left shoulder and right hip, long axis views are obtained at different levels with the goal of identifying four main structures; the aorta, the left atrium, and the right and left ventricles. The parasternal long axis view of our patient is shown in Figure 1, where her aortic root measured 3.83cm.

 

Figure 1: Parasternal Long Axis View of Heart: Patient’s root diameter was found to be 3.83cm.

More generally, this view can be used to assess left ventricular contractility and the presence of pericardial effusion, which were not present in this patient. She went on to have a confirmatory CT scan where her aortic root was found to be unchanged from her last scan and was 3.8 cm in diameter as assessed by PoCUS.

In Summary:

Although not rigorously studied to assess aortic root dilatation at the bedside, we present a case where PoCUS was reliable in the assessment of the aortic root. There have been other cases of aortic dissection identified by ultrasound in the emergency department setting, however confirmatory studies (either CT scan or formal echocardiography) are still recommended.


References:

  1. Labovitz AJ, Noble VE, Bierig M, et al. Focused cardiac ultrasound in the emergent setting: A consensus statement of the American society of Echocardiography and American College of Emergency Physicians. J Am Soc Echocardiogr. 2010;23(12):1225-1230. doi:10.1016/j.echo.2010.10.005.
  2. Andrus P, Dean A. Focused cardiac ultrasound. Glob Heart. 2013;8(4):299-303. doi:10.1016/j.gheart.2013.12.003.
  3. Perkins AM, Liteplo A, Noble VE. Ultrasound Diagnosis of Type A Aortic Dissection. J Emerg Med. 2010;38(4):490-493. doi:10.1016/j.jemermed.2008.05.013.
  4. Bernett J, Strony R. Diagnosing acute aortic dissection with aneurysmal degeneration with point of care ultrasound. Am J Emerg Med. 2017;35(9):1384.e3-1384.e4. doi:10.1016/j.ajem.2017.05.052.
  5. Kaban J, Raio C. Emergency department diagnosis of aortic dissection by bedside transabdominal ultrasound. Acad Emerg Med. 2009;16(8):809-810. doi:10.1111/j.1553-2712.2009.00448.x.
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PoCUS – Pleural Effusion

Medical Student Clinical Pearl

James Kiberd

Class 2019 Dalhousie Medicine

Reviewed and Edited by Dr. David Lewis


Case: 

A 90 year-old male presented with worsening shortness of breath on exertion, crackles bilaterally at the bases on auscultation with known history of congestive heart failure. Bedside ultrasound was performed to assess for pleural effusion

Lung Views:

In order to perform ultrasound of the lungs, there are four views that are obtained (see Figure 1). Place the patient supine. The high frequency linear array transducer is often used, but either the phased array or curvilinear transducers can be used. The first views are taken at both right and left mid-clavicular lines of the anterior chest. With the marker of the transducer pointed toward the patient’s head, a minimum of 3-4 rib spaces should be identified. The next views are of the posterior-lateral chest. The patient can be supine or in the sitting position. It is these views where a pleural effusion can be identified.

Figure 1: Chest views with ultrasound. ‘A’ are anterior chest view positions and ‘B’ are posterolateral view positions

Pleural Effusion

Pleural effusion is assessed by ultrasound placing the transducer in the midaxillary line with the marker oriented toward the patient’s head. On the patient’s right side the diaphragm, the liver, and the vertebral line can be seen. On the left, the diaphragm, spleen, and vertebral line should be in view. In a patient without pleural effusion, one should not be able to visualize the lung as it is mostly air and scatters the sound produced by the transducer. However, in the presence of pleural effusion, the area above the diaphragm is filled with fluid and therefore will appear anechoic. In addition, the vertebral line will be present past the diaphragm as the fluid allows the sound waves to propagate and not scatter. This is known as the ‘spine sign’ (also known as the ‘V-line’). Finally, one is often able to see the atelectatic lung float and move with respirations in the fluid, this is known as the ‘sinusoid sign.’ These are the three criteria outlined by consensus statements in the identification of pleural effusions.1 Occasionally, the area above the diaphragm may look like spleen or liver, but this is known as ‘mirror image’ artifact and is normal.2 Figure 2 shows both the right and left views of our patient.

Figure 2: Pleural effusion showing anechoic pleural fluid, atelectatic lung, and ‘spine sign

Accuracy with Ultrasound

Ultrasound is more accurate than either chest x-ray or physical exam in the identification of small pleural effusions.3 For a chest x-ray to identify fluid there usually needs to be more than 200cc present.2 A meta-analysis found that ultrasound had a mean sensitivity of 93% (95%CI: 89-96%) and specificity of 96% (95%CI: 95-98%).4

 

Our patient went on to have a chest x-ray where he was found to have bilateral pleural effusions (see Figure 3).

Figure 3: Bilateral pleural effusions seen on chest radiography in our patient.

In Summary

Three criteria are used to identify pleural effusion on ultrasound; anechoic fluid above the diaphragm, the ability to visualize the spine above the diaphragm (‘spine sign’), and atelectatic lung moving with respirations (‘sinusoid sign’). Lung ultrasound for the detection of pleural effusion is more reliable to identify small effusions in comparison to both radiography and physical exam.


References:

  1. Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591. doi:10.1007/s00134-012-2513-4.
  2. Liu RB, Donroe JH, McNamara RL, Forman HP, Moore CL. The practice and implications of finding fluid during point-of-care ultrasonography: A review. JAMA Intern Med. 2017;177(12):1818-1825. doi:10.1001/jamainternmed.2017.5048.
  3. Wong CL, Holroyd-leduc J, Straus SE. CLINICIAN ’ S CORNER Does This Patient Have a Pleural Effusion ? PATIENT SCENARIO. Jama. 2010;301(3):309-317. doi:10.1001/jama.2008.937.
  4. Grimberg AI, Carlos Shigueoka DI, Nagib Atallah III Á, et al. Diagnostic accuracy of sonography for pleural effusion: systematic review Acurácia diagnóstica da ultrassonografia nos derrames pleurais: revisão sistemática
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ECCU IP School 24th November – New Places Now Available!

Are you finding it difficult to get your supervised scans for CPoCUS Core IP. We are here to help!

We have just been able to open up a few spaces on the ECCU IP School 24th November in Saint John, NB.

CPoCUS IP instructors will supervise up to 90 scans in this 1-day session.

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ECCU IP School – Application and Payment

Staff Physicians – $850

Residents – $550

 

 

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Fall ECCU Conference Workshop – 28th September

We still have availability for delegates wanting to attend the Fall ECCU Conference Workshop on the 28th September at the beautiful Algonquin Resort in St. Andrews, New Brunswick.


  • International PoCUS experts from South Africa, USA and Canada
  • PoCUS hot topics and updates
    • PoCUS in Rural Health
    • Why aren’t you doing THIS with PoCUS?
    • How to be a leader in PoCUS
  • Top PoCUS research
  • IP2 Diagnostic stream lectures
  • Hands-on scanning workshops


  • Choose your own workshop
    • Pediatrics, Cardiac, Lung, IVC, DVT, Gallbladder, DVT, Aorta, FAST, Obstetric
  • CPoCUS approved
  • CCFP CME approved
  • Bring the family and stay for the weekend
    • Top golf resort, whale watching, explore the islands

 

Click Here for More information and Booking

 


 

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