Category Archives: Ultrasound

EMSJ – Transesophageal Echo (TEE) Protocol

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Please refer to our TEE introduction and video guides in the resources at the bottom of this page

EMSJ MD Protocol

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Information for Nursing and Respiratory Therapy

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Reminders:

  • Please ensure the probe is sent for sterilization at the end of the procedure
  • Please ensure it is returned to the Walmart HEPA cupboard when it returns (usually takes 1 hr)
  • Please save the clips to Path and ensure it is coded as a TEE – for our database

Pearls:

  • Resuscitative TEE requires 2 MDs. One to run the code, the other to exchange the EMS airway for an ETT and perform the TEE
  • The TEE probe only works with the XPORTE
  • Attach TEE probe and place the XPORTE at the head of the bed before the patient arrives
  • Exchange Intubate the patient during first pulse check, immediately followed by passing the TEE
  • Laryngoscopy can assist with directing TEE posterior to ETT, but the blade will need to be removed prior to advancing into esophagus (it gets in the way)
  • Stand at the head of the bed to control the probe.
  • Advance probe until the first view is obtained (ME4C)
  • Follow protocol
  • Defibrillation can be done with probe in situ
  • Communicate findings with the team

Videos

Introduction to TEE Guide

Introduction to Transesophageal Echo – Basic Technique

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PoCUS For Maxillary Sinusitis

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PoCUS Clinical Pearl by Dr. Chew Kiat Yeoh

 

 

DalEM PoCUS Fellow

Reviewed by: Dr. David Lewis

 

 

 

Background

  • Acute rhinosinusitis is an inflammatory disease of nasal mucosa and paranasal sinuses. It is one of the most common ED presentations and fifth most common diagnosis for which antibiotics are prescribed (1).
  • It affects more than 30 million adult each year (2).
  • Accurate diagnosis of acute maxillary sinusitis based on clinical examination is unreliable (3) because the signs/symptoms are nonspecific.
  • Although radiographic imaging improves diagnostic accuracy, it is not recommended in uncomplicated sinusitis (4) due to radiation risk, additional costs, and time.

 

How accurate is PoCUS in identifying maxillary sinusitis?

  • Gold standard for diagnosing maxillary sinusitis is positive fluid culture obtained from sinus puncture (5). However, this method is invasive, unnecessary, and often not easily accepted by patient.
  • Ultrasound has been used to diagnose acute maxillary sinusitis as it is rapid, safe, and non-invasive.
  • Ultrasound is very sensitive in identifying fluid in sinus cavities, with accuracies more than 90% for the diagnosis of maxillary sinusitis have been reported in otolaryngology (ENT) practices.
  • While the result from ENT practices might not be applicable to the ED setting due to different patient demographic and severity of disease. When PoCUS performed by Emergency Physician compared to CT in ED patients with suspected maxillary sinusitis, the sensitivity and specificity are 81% and 89%, respectively, for diagnosis of maxillary sinusitis (7). The agreement between the two methods was 86%.
  • Study using MRI as gold standard, ultrasound was found to have 64% sensitivity and 95% specificity, compared to 73% sensitivity and 100% specificity for plain XR (6).
  • Overall – ultrasound is sensitive in detecting fluid in sinus cavities and highly accurate (>90%) in diagnosing maxillary sinusitis.

 

Scanning Technique

  • Position: sitting upright or lean slight forward to ensure sinus fluid if present, would layer out against the anterior wall.
  • Probe: High frequency (4 to 12 MHz) linear array transducer with adequate depth penetration (5-7cm) to visualize the entire sinus cavity Or phased-array probe if depth required.
  • Scan the maxillary sinus in between lateral nose and zygoma in at least two planes: transverse & sagittal (Figure 1).
  • Always scan the contralateral normal side is for comparison.

Ultrasound Features

Normal Ultrasound Appearance of Maxillary Sinus

 

 

The Ultrasound Appearance of Maxillary Sinusitis

  • If the sinus cavity is fluid filled (complete or partial), the ultrasound signal will be able to penetrate through the thin hyperechoic anterior wall, and the surrounding walls (posterior, medial, lateral) of the sinus will be visualized and seen as a bright echogenic line.
  • Positive Ultrasound finding : Presence of posterior wall echo >3.5 cm from the initial echo (3) (anterior maxillary wall)

 

Partially Filled: Partial Sinusogram

 

Completely Filled: Complete Sinusogram

 

 

The significance of the Pathology and how can PoCUS add value?

  • More than 1 in 5 antibiotics prescribed in adults are for sinusitis. It is the fifth most common diagnosis which antibiotics is prescribed.
  • Rhinosinusitis is a common disorder, however, only 50% of patients presenting to the acute care setting with sinus symptoms have acute bacterial sinusitis.
  • Although, ultrasound is not accurate as CT and MRI, it is a more practical adjunct bedside tool that can be rapidly, safely and routinely used to assess those with sinus symptoms and for diagnosing uncomplicated sinusitis in acute care settings and could potentially reduce unnecessary over prescription of antibiotic use.

 

Pearls and Pitfalls

  • Ultrasound is not helpful in differentiating between a viral and or bacterial sinusitis.
  • Positive sinusogram can also be caused by significant mucosal thickening, polyps, fluid-filled cysts, masses and blood from facial trauma or sinus fractures. All these can be mistaken for acute sinusitis.
  • Technical failure includes inadequate depth setting to properly visualize the posterior wall and improper position(supine).

 

References

  1. Summary E. Otolaryngology – Head and Neck Surgery Antimicrobial treatment guidelines for acute bacterial rhinosinusitis. 2004;130(January):1-45. doi:10.1016/j.otohns.2003.12.003
  2. Rosenfeld RM, Andes D, Bhattacharyya N, et al. Clinical practice guideline : Adult sinusitis. Published online 2007:1-31. doi:10.1016/j.otohns.2007.06.726
  3. Varonen H, Mäkelä M, Savolainen S, Läärä E, Hilden J. Comparison of ultrasound , radiography , and clinical examination in the diagnosis of acute maxillary sinusitis : a systematic review. 2000;53:940-948.
  4. Aring ANNM, Chan MM. Acute Rhinosinusitis in Adults. Published online 2011:1057-1063.
  5. Carolina S, Sur- N, Hospital HF, Cen- HM, Carolina S. Maxillary sinus puncture and culture in the diagnosis of acute rhinosinusitis : The case for pursuing alternative culture methods. Published online 2000:7-12. doi:10.1067/mhn.2002.124847
  6. Puhakka T, Heikkinen T, Makela MJ, et al. Validity of Ultrasonography in Diagnosis of Acute Maxillary Sinusitis. Arch Otolaryngol Head Neck Surg 126(12):1482–1486, 2000.
  7. Price D, Park R, Frazee B, et al. Emergency department ultrasound for the diagnosis of maxillary sinus fluid. Acad Emerg Med. 2006;13(3):363-4

 

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PoCUS Guided Nerve Blocks in EM

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Recommended resources  for PoCUS Guided Nerve Blocks in EM

This page is under maintenance – future updates will include a ‘Plan A‘ list of blocks with associated guides.

EMSJ Resources

Collection of our nerve block guidelines, clinical pearls and rounds

Fascia Iliaca Block

Serratus Anterior Plane Block

Dental Block

Regional Anesthesia of the Hand

Other Resources

Local Anesthetic Dose

LAST

Overview of Common Nerve Blocks in the ED

Recommended Nerve Block Resources

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Unvexing the VExUS Score – An Overview

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Unvexing the VExUS Score – An Overview

 

PoCUS Clinical Pearl

Dr Steven Chen

DalEM PoCUS Elective

PGY2 Internal Medicine, University of Toronto

Reviewed: Dr David Lewis

Copyedited: Dr David Lewis

Introduction:

The pursuit of a rapid and objective measure of volume status has always been a vexing problem for clinicians as proper fluid management is pivotal for patient outcomes. In recent years, there has been increased attention towards the concept of “fluid-responsive” as liberal fluid boluses can often be associated with poor outcomes as a result of systemic congestion. 1

In the POCUS community, while Inferior Vena Cava (IVC) measurements have promise in assessing central venous pressure, the subsequent translation towards “volume responsiveness” has been met with many other limitations. For one, it did not account for venous congestion at other organ levels such as the pulmonary, renal, or hepatic systems. 2,3

Venous excess ultrasound (VExUS) is a growing bedside ultrasound-based approach that aims to provide a more comprehensive assessment of venous congestion. This was initially described by Beaubien-Souligny et al. (2020) from a post-hoc analysis correlating ultrasound grading parameters with risk in development of AKI in cardiac surgery patients.4 The protocol serves to assess multiple sites of venous congestion, including the IVC, hepatic veins, portal veins and intrarenal veins. By assessing congestion in these multiple sites, the VExUS score has gained attraction in providing a more comprehensive assessment of systemic congestion. 4,5

View Acquisition:

The VExUS protocol is composed of four main components outlined below:

  • IVC diameter
  • Hepatic Vein Doppler Assessment
  • Hepatic Portal Vein Doppler Assessment
  • Intrarenal Vein Doppler Assessment

This can be performed using either the curvilinear probe (preferred) or the phased array probe. The patient should be positioned flat and supine on the bed to acquire the views. The table below depicts some suggested views where larger regions of the veins may be accessible for pulse wave doppler gating in reference to standardized sonography protocols. 6,7

Note: Reviewing the basics of pulse wave doppler will be needed prior to completing VExUS scans (not covered in this article).

 

 

 

 

 

Interpretation:

Interpretation of the VExUS grading system is well summarized in diagram below (sourced from POCUS1018) and takes some practice to differentiate normal from abnormal waveforms. Pulse wave doppler assessment is pursued only if the inferior vena cava is found plethoric, defined as greater or equal to 2cm. 4,5

Each of the hepatic, portal and renal veins are subsequently examined and classified as normal, mildly congested, or severely congested. The VExUS system has four grades: Grade 0 represents no congestion in any organ, Grade 1 represents only mild congestive findings, Grade 2 represents severe congestive findings in only one organ, and Grade 3 represents severe congestive findings in at least two out of three organ systems. 4,5

Source: POCUS1018

Some sample waveforms are shown below with comments to help with distinguishing normal from abnormal waveforms.

 

Evidence:

VExUS has also been shown to be reliable and reproducible, with good interobserver agreement in trained individuals and correlation with other measures of volume status such as central venous pressure.4,5 As the technique is growing in the POCUS literature, below is a table summarizing several recent studies exploring its application across numerous settings.

Study Purpose Results
Beaubien-Souligny W, et al. (2020)4

 

Post-hoc analysis of a single centre prospective study in 145 patients

 

 

 

 Initial model of VExUS grading system looking at association in development of AKI in cardiac surgery population Association with subsequent AKI:

 

HR: 3.69 CI 1.65–8.24 p = 0.001;

+LR: 6.37 CI 2.19–18.50 when detected at ICU admission, which outperformed central venous pressure measurements

 
Bhardwaj V, et al. (2020)9

 

Prospective cohort study of 30 patients in ICU setting

 

 Prospective study on application of VExUS scoring on staging of AKI in patients with cardiorenal syndrome Resolution of AKI injury significantly correlated with improvement in VExUS grade (p 0.003).

 

There was significant association between changes in VExUS grade and fluid balance (p value 0.006).
Varudo R, et al. (2022)10

 

Case report of ICU patient with hyponatremia

 Application of VExUS in case report as rapid tool to help with volume status assessment in patient with complex hyponatremia Overall VExUS grade 2, prompting strategy for diuresis with improvement
Rolston D, et al. (2022)11

 

Observational study of 150 septic patients in single centre

 VExUS score performed on ED septic patients prior to receiving fluids with chart review done to determine if there is association with poorer outcomes Composite outcome (mortality, ICU admission or rapid response activation):

 

VExUS score of 0: 31.6% of patients

VExUS score of 1: 47.6% of patients

VExUS score >1: 67.7% of patients

(p: 0.0015)
Guinot, PG, et al. (2022)12

Prospective observational study of 81 ICU patients started on loop diuretic therapy

 Evaluation of multiple scores to predict appropriate diuretic-induced fluid depletion (portal pulsatility index, renal venous impedance index, VExUS) Baseline portal pulsatility index and renal venous impedance index were found to be superior predictors compared to VExUS.

 

The baseline VExUS score (AUC of 0.66 CI95% 0.53–0.79, p = 0.012) was poorly predictive of appropriate response to diuretic-induced fluid depletion.
Menéndez‐Suso JJ, et al. (2023)13

 

Cross-sectional pilot study of 33 children in pediatric ICU setting

 Association of VExUS score with CVP in pediatric ICU VExUS score severity was strongly associated with CVP (p<0.001) in critically ill children.
Longino A, et al. (2023)14

 

Prospective validation study in 56 critically ill patients

 Validation looking at association of VExUS grade with right atrial pressure. VExUS had a favorable AUC for prediction of a RAP ≥ 12 mmHg (0.99, 95% CI 0.96-1) compared to IVC

diameter (0.79, 95% CI 0.65–0.92).

Pitfalls:

It should be kept in mind that numerous factors may affect interpretation of VExUS gradings.

For the IVC component, increased intra-abdominal pressure can affect measurements independently of the pressure in the right atrium or may be affected by chronic pulmonary hypertension. The hepatic vein may not show significant changes even in severe tricuspid regurgitation if the right atrium can still expand and contract normally. In thin healthy people and those with arteriovenous malformations, the portal vein can have a pulsatile flow without venous congestion. It is also important to note that for patients with underlying disease renal or liver parenchymal disease, venous doppler recordings may be less reliable. 3-5

Outside of physiologic factors, another limitation is the need for adequate training and familiarity in performing and interpreting the technique. While VExUS is fairly well protocolized, it requires proficiency with pulse wave doppler to perform accurately. As with any new technique, there is a risk of variability in technique and interpretation. To avoid misinterpretation, it is important to consider repeat tracings to ensure consistency of results and to consider findings within the overall clinical context of the patient.

Bottom line:

VExUS is a non-invasive ultrasound method for assessing venous congestion across multiple organ systems. While there are several physiologic limitations and results need to be used in adjunct with the clinical picture, studies have shown promise for VExUS to be incorporated as part of a physician’s toolkit to help with clinical decision making. 3-5

References

  1. Atkinson P, Bowra J, Milne J, Lewis D, Lambert M, Jarman B, Noble VE, Lamprecht H, Harris T, Connolly J, Kessler R. International Federation for Emergency Medicine Consensus Statement: Sonography in hypotension and cardiac arrest (SHoC): An international consensus on the use of point of care ultrasound for undifferentiated hypotension and during cardiac arrest. Canadian Journal of Emergency Medicine. 2017 Nov;19(6):459-70.
  2. Corl KA, George NR, Romanoff J, Levinson AT, Chheng DB, Merchant RC, Levy MM, Napoli AM. Inferior vena cava collapsibility detects fluid responsiveness among spontaneously breathing critically-ill patients. Journal of critical care. 2017 Oct 1;41:130-7.
  3. Koratala A, Reisinger N. Venous excess doppler ultrasound for the nephrologist: Pearls and pitfalls. Kidney Medicine. 2022 May 19:100482.
  4. Beaubien-Souligny W, Rola P, Haycock K, Bouchard J, Lamarche Y, Spiegel R, Denault AY. Quantifying systemic congestion with point-of-care ultrasound: development of the venous excess ultrasound grading system. The Ultrasound Journal. 2020 Dec;12:1-2.
  5. Rola P, Miralles-Aguiar F, Argaiz E, Beaubien-Souligny W, Haycock K, Karimov T, Dinh VA, Spiegel R. Clinical applications of the venous excess ultrasound (VExUS) score: conceptual review and case series. The Ultrasound Journal. 2021 Dec;13(1):1-0.
  6. Mattoon JS, Berry CR, Nyland TG. Abdominal ultrasound scanning techniques. Small Animal Diagnostic Ultrasound-E-Book. 2014 Dec 2;94(6):93-112.
  7. Standardized method of abdominal ultrasound [Internet]. Japanese society of sonographers. [cited 2023Apr12]. Available from: https://www.jss.org/english/standard/abdominal.html#Longitudinal%20scanning_2
  8. Dinh V. POCUS101 Vexus ultrasound score–fluid overload and venous congestion assessment.
  9. Bhardwaj V, Vikneswaran G, Rola P, Raju S, Bhat RS, Jayakumar A, Alva A. Combination of inferior vena cava diameter, hepatic venous flow, and portal vein pulsatility index: venous excess ultrasound score (VExUS score) in predicting acute kidney injury in patients with cardiorenal syndrome: a prospective cohort study. Indian journal of critical care medicine: peer-reviewed, official publication of Indian Society of Critical Care Medicine. 2020 Sep;24(9):783.
  10. Varudo R, Pimenta I, Blanco JB, Gonzalez FA. Use of Venous Excess UltraSound (VExUS) score in hyponatraemia management in critically ill patient. BMJ Case Reports CP. 2022 Feb 1;15(2):e246995.
  11. Rolston D, Li T, Huang H, Johnson A, van Loveren K, Kearney E, Pettit D, Haverty J, Nelson M, Cohen A. 204 A Higher Initial VExUS Score Is Associated With Inferior Outcomes in Septic Emergency Department Patients. Annals of Emergency Medicine. 2021 Oct 1;78(4):S82.
  12. Guinot PG, Bahr PA, Andrei S, Popescu BA, Caruso V, Mertes PM, Berthoud V, Nguyen M, Bouhemad B. Doppler study of portal vein and renal venous velocity predict the appropriate fluid response to diuretic in ICU: a prospective observational echocardiographic evaluation. Critical Care. 2022 Dec;26(1):1-1.
  13. Menéndez‐Suso JJ, Rodríguez‐Álvarez D, Sánchez‐Martín M. Feasibility and Utility of the Venous Excess Ultrasound Score to Detect and Grade Central Venous Pressure Elevation in Critically Ill Children. Journal of Ultrasound in Medicine. 2023 Jan;42(1):211-20.
  14. Longino A, Martin K, Leyba K, Siegel G, Gill E, Douglas I, Burke J. Prospective Validation of the Venous Excess Ultrasound “(VExUS)” Score.

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Bicuspid Aortic Valve – An important incidental PoCUS finding?

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Bicuspid Aortic Valve – An important incidental PoCUS finding?

Medical Student Pearl

 

Khoi Thien Dao

MD Candidate – Class of 2023

Dalhousie Medicine New Brunswick

Reviewed by: Dr. David Lewis

Case:

A 58-year-old male presents to Emergency Department with sudden onset of chest pain that is radiating to the back. He was also having shortness of breath at the same time of chest pain. The patient later reveals that his past medical history only consists of “bicuspid valve”, and he takes no medication. On examination, he was uncomfortable, but no signs of acute distress. His respiratory and cardiac exam were unremarkable for reduced air sound, adventitious sound, heart murmur, or extra heart sound. ECG was normal and initial cardiac markers were within normal range. His chest x-ray is normal.

You are aware that with his medical presentation and a history of bicuspid aortic valve, you need to consider associated concerning diagnosis (aortic root aneurysm and aortic dissection) within the differential (myocardial infarct, congestive heart failure, pneumonia, etc.).

Bicuspid Aortic Valve

Bicuspid aortic valve is one of the most common types of congenital heart disease that affects approximately one percent of population. There is a strong heritable component to the disease. Bicuspid aortic valve occurs when two leaflets fused (commonly right and left coronary leaflets) and form a raphe, a fibrous ridge1. The fusion of the leaflets can be partial, or complete, with the presence or absence of a raphe1. Bicuspid aortic valve disease is associated with increasing risks for valve calcification, which lead to aortic stenosis or regurgitation secondary to premature degeneration1. This congenital heart defect is also a well-known risks factor for aortic dissection and aortic dilatation. Reports have estimated prevalence of aortic dilation in patients with bicuspid aortic valve ranging between 20 to 80 percent, and that the risks of aortic dilation increase with age2. Increases risk of aortic dilatation in bicuspid valve disease also leads to a significantly greater risk for aortic dissection2.3.

The majority of patients with bicuspid aortic valve are asymptomatic with relatively normal valve function and therefore can remain undiagnosed for many years. However, most patients with bicuspid aortic valve will develop complications and eventually require valve surgery within their lifetime. Early diagnosis, while asymptomatic, can enable close follow-up for complications and early intervention with better outcomes. However, asymptomatic individuals are rarely referred for echocardiography.

With increasing use of cardiac PoCUS by Emergency Physicians, there are two scenarios where increased awareness of the appearance of bicuspid aortic valve and its complications may be of benefit.

  1. Known bicuspid aortic valve patients presenting with possible associated complications
  2. Undiagnosed bicuspid aortic valve patients presenting with unrelated symptoms undergoing routine cardiac PoCUS

This clinical pearl provides a review of the clinical approach to bicuspid aortic valve and its associated complications and provides guide to enhancing clinical assessment with PoCUS.

Clinical Approach:

Although bicuspid aortic valve commonly presents as asymptomatic, a detailed focused cardiac history can assess for clinical signs and symptoms related to valve dysfunction and its associated disease, such as reduced exercise capacity, angina, syncope, or exertional dizziness1. Information about family history with relation to cardiac disease is essential for a clinician’s suspicion of heritable cardiovascular disease. Red flag symptoms that shouldn’t be missed such as chest pain, back pain, hypertensive crisis, etc. should be specifically identified. They are indicators for possible emergent pathologies that should not be missed (for example: acute MI, aortic dissection, ruptured aortic aneurysm, etc.)

Physical examination findings in patients with bicuspid aortic valve include, but not limited to, ejection sound or click at cardiac apex/base, murmurs that have features of crescendo-decrescendo or holosystolic. Clinical signs of congestive heart failure such as dyspnea, abnormal JVP elevation, and peripheral edema may also be present.

Core Cardiac PoCUS:

With cardiac PoCUS, it is important to obtain images from different planes and windows to increase the complexity of the exam and to be able to be confidently interpreting the exam. There are four standard cardiac view that can be obtained: parasternal short axis (PSSA), parasternal long axis (PSLA), subxiphoid (sub-X), and apical 4-chamber view (A4C). Each cardiac view has specific benefits.

Parasternal Long Axis

With the PSLA, the phased-array transducer is placed to the left sternum at 3rd or 4th intercostal with transducer orientation pointing toward patient’s right shoulder. Key structures that should be seen are Aortic Valve (AV), Mitral Valve (MV), Left Ventricle (LV), pericardium, Right Ventricle (RV), Left Ventricular Outflow Tract (LVOT), and portion of ascending and descending aorta8. It is primarily used to assess left ventricular size and function, aortic and mitral valves, left atrial size8. Furthermore, pericardial effusions and left ventricular systolic function can be assessed.

Parasternal Long Axis

 

Parasternal Short Axis

Using the same transducer position as the PSLA the transducer can be centered to the mitral valve and rotated 90 degrees clockwise to a point where the transducer marker points to patient’s left shoulder to obtain the PSSA. With this orientation, one can assess for global LV function and LV wall motion8. Furthermore, with five different imaging planes that can be utilized with this view, aortic valve can be visualized in specific clinical contexts.

Parasternal Short Axis

 

Apical 4-Chamber

The apical 4-chamber view is generated by placing the transducer at the apex, which is landmarked just inferolateral to left nipple in men and underneath inferolateral of left breast in women. This view helps the clinician to assess RV systolic function and size relative to the LV8.

Apical 4-Chamber

 

Subxiphoid

The subxiphoid view can be visualized by placing a transducer (phased-array or curvilinear) immediately below the xiphoid process with the transducer marker points to patient’s right. The movements of rocking, tilting, and rotation are required to generate an optimal 4-chamber subcostal view. A “7” sign, which consists of visualizing the border between liver and pericardium, the septum, and the RV and LV that looks like number 7. This view allows user to assess RV functions, pericardial effusion, and valve functions8. In emergency setting, it can be used for rapid assessments in cardiac arrest, cardiac tamponade, and global LV dysfunction8.

From –  the PoCUS Atlas

Subxiphoid labelled

 

7 Sign

PoCUS Views for Aortic Valve Assessment

In assessing the aortic valve, the PSSA and PSLA can be best used to obtain different information, depending on clinical indications. Both views can be used to assess blood flows to assess stenosis or regurgitation. However, the PSLA view includes the aorta where clinician can look for aortic valve prolapse or doming as signs of stenosis and its complications, like aortic dilatation. On the other hand, PSSA are beneficial when assessing the aortic valve anatomy.

Parasternal Long Axis

From PoCUS 101

Parasternal Short Axis

From – the PoCUS Atlas

PoCUS Appearance of Normal Aortic Valve (Tricuspid) vs Bicuspid Aortic Valve

With PSSA view, the normal aortic valve will have three uniformly leaflets that open and form a circular orifice during most of systole. During diastole, it will form a three point stars with slight thickening at central closing point. The normal aortic valve is commonly referred to as the Mercedes Benz sign.

Parasternal Short Axis – Normal Tricuspid AV – Mercedes Benz Sign and 3 cusp opening

Pitfall

However, the Mercedes Benz Sign sign can be misleading bicuspid valve disease when three commissure lines are misinterpreted due to the presence of a raphe. A raphe is a fibrous band formed when two leaflets are fused together. It is therefore important to visualize the aortic valve when closed and during opening, to ensure all 3 cusps are mobile. Visualization of The Mercedes Benz sign is not enough on its own to exclude Bicuspid Aortic Valve.

Apparent Mercedes sign when AV closed due to presence of raphe. Fish mouth appearance of the same valve when open confirming bicuspid aortic valve

Bicuspid Aortic Valve

Identification requires optimal valve visualization during opening (systole). Appearance will depend on the degree of cusp fusion. In general a ‘fish mouth’ appearance is typical for bicuspid aortic valve.

Parasternal Short Axis – Fish Mouth Opening – Fusion L & R Coronary Cusps – Bicuspid Aortic Valve

In the parasternal long axis view the aortic valve can form a dome shape during systole, and prolapse during diastole, rather than opening parallel to the aorta. This is called systolic doming. Another sign that can be seen in PSLA view is valve prolapse, when either right or non-coronary aortic valve cusps showed backward bowing towards the left ventricle beyond the attachment of the aortic valve leaflets to the annulus. This can be estimated by drawing a line joining the points of the attachment.

Systolic doming

 

Diastolic prolapse and systolic doming

 

 

 

PoCUS Appearance of the Complications of Bicuspid Valve Disease

In patients presenting with chest/back pain, shock or severe dyspnea who have either known or newly diagnosed bicuspid valve disease, PoCUS assessment for potential complications can be helpful in guiding subsequent management.

Complications of bicuspid aortic valve include aortic dilatation at root or ascending (above 3.8cm) and aortic dissection 5-9.

Dilated aortic root, from – sonomojo.com

Aortic root dilatation – Normal maximum = 40mm

 

Aortic root dilatation with dissection

Valve vegetations or signs of infective endocarditis are among the complications of severe bicuspid valve5-9

Aortic valve vegetations

General Management of Patients with Bicuspid Valve in the Emergency Department

Management of bicuspid aortic valve disease is dependent on the severity of the disease and associated findings.

For a patient with suspicious diagnosis of bicuspid valve disease, a further evaluation of echocardiography should be arranged, and patient should be monitored for progressive aortic valve dysfunction as well as risk of aortic aneurysm and dissection. Surgical intervention is indicated with evidence of severe aortic stenosis, regurgitation, aneurysm that is > 5.5cm, or dissection1.

How accurate is PoCUS for Aortic Valve assessment?

Bicuspid aortic valve disease is usually diagnosed with transthoracic echocardiography, when physical examination has revealed cardiac murmurs that prompt for further investigation. However, patients with bicuspid valve disease frequently remain asymptomatic for a prolonged periods. Michelena et al. (2014) suggested that auscultatory abnormalities account for 60 to 70% diagnostic echocardiograms for BAV in community10.

While there are no published studies on the utility of PoCUS for the diagnosis of bicuspid aortic valve, there are studies on the use of PoCUS as part of the general cardiac exam. Kimura (2017) published a review that reported early detection of cardiac pathology when PoCUS was used as part of the physical exam 9. Abe et al. (2013) found that PoCUS operated by expert sonographer to screen for aortic stenosis has a sensitivity of 84% and a specificity of 90% in 130 patients 11. In another study by Kobal et al. (2004), they found that PoCUS has a specificity of 93% and sensitivity of 82% in diagnosing mild regurgitation12.

There are also limitations of using PoCUS to assess for bicuspid aortic valve disease, or valve disease in general. Obtaining images from ultrasound and interpretation are highly dependent on user’s experiences to assess for the valve9. Furthermore, research is needed to investigate the use of PoCUS in lesser valvular pathology.

 

When a new diagnosis of bicuspid aortic valve is suspected, a formal echocardiogram should be arranged, and follow-up is recommended.

Summary 

  • Bicuspid aortic valve is often asymptomatic and undiagnosed until later in life
  • Patients with known bicuspid aortic valve disease are closely followed and may require surgical intervention in the event of complications
  • Diagnosis of bicuspid aortic valve requires careful visualization of valve closing and opening during diastole and systole
  • The increased use of PoCUS by Emergency Physicians as an adjunct to cardiac examination may result in increased diagnosis of bicuspid  aortic valve. These may be related to the presentation or incidental findings
  • In patients presenting to the Emergency Department with known or newly diagnosed bicuspid aortic valve disease, consider if a complication is related to their presentation
  • In patient with incidental finding of bicuspid aortic valve disease refer for cardiology follow up

 

References

  1. Braverman, A. C., & Cheng, A. (2013). The bicuspid aortic valve and associated aortic disease. Valvular heart disease. Philadelphia: Elsevier, 179-218.
  2. Verma, S., & Siu, S. C. (2014). Aortic dilatation in patients with bicuspid aortic valve. N Engl J Med, 370, 1920-1929.
  3. Della Corte, A., Bancone, C., Quarto, C., Dialetto, G., Covino, F. E., Scardone, M., … & Cotrufo, M. (2007). Predictors of ascending aortic dilatation with bicuspid aortic valve: a wide spectrum of disease expression. European Journal of Cardio-Thoracic Surgery, 31(3), 397-405.
  4. Tirrito, S. J., & Kerut, E. K. (2005). How not to miss a bicuspid aortic valve in the echocardiography laboratory. Echocardiography: A Journal of Cardiovascular Ultrasound and Allied Techniques, 22(1), 53-55.
  5. Baumgartner, H., Donal, E., Orwat, S., Schmermund, A., Rosenhek, R., & Maintz, D. (2015). Chapter 10: Aortic valve stenosis. The ESC textbook of cardiovascular imaging. European Society of Cardiology.
  6. Fowles, R. E., Martin, R. P., Abrams, J. M., Schapira, J. N., French, J. W., & Popp, R. L. (1979). Two-dimensional echocardiographic features of bicuspid aortic valve. Chest, 75(4), 434-440.
  7. Shapiro, L. M., Thwaites, B., Westgate, C., & Donaldson, R. (1985). Prevalence and clinical significance of aortic valve prolapse. Heart, 54(2), 179-183.
  8. Gebhardt, C., Hegazy, A.F., Arntfield, R. (2015). Chapter 16: Valves. Point-of-Care Ultrasound. Philadelphia: Elsevier, 119-125.
  9. Kimura, B. J. (2017). Point-of-care cardiac ultrasound techniques in the physical examination: better at the bedside. Heart, 103(13), 987-994.
  10. Michelena, H. I., Prakash, S. K., Della Corte, A., Bissell, M. M., Anavekar, N., Mathieu, P., … & Body, S. C. (2014). Bicuspid aortic valve: identifying knowledge gaps and rising to the challenge from the International Bicuspid Aortic Valve Consortium (BAVCon). Circulation, 129(25), 2691-2704.
  11. Abe, Y., Ito, M., Tanaka, C., Ito, K., Naruko, T., Itoh, A., … & Yoshikawa, J. (2013). A novel and simple method using pocket-sized echocardiography to screen for aortic stenosis. Journal of the American Society of Echocardiography, 26(6), 589-596.
  12. Kobal, S. L., Tolstrup, K., Luo, H., Neuman, Y., Miyamoto, T., Mirocha, J., … & Siegel, R. J. (2004). Usefulness of a hand-carried cardiac ultrasound device to detect clinically significant valvular regurgitation in hospitalized patients. The American journal of cardiology, 93(8), 1069-1072.
  13. Le Polain De Waroux, J. B., Pouleur, A. C., Goffinet, C., Vancraeynest, D., Van Dyck, M., Robert, A., … & Vanoverschelde, J. L. J. (2007). Functional anatomy of aortic regurgitation: accuracy, prediction of surgical repairability, and outcome implications of transesophageal echocardiography. Circulation, 116(11_supplement), I-264.
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Resuscitative Transesophageal Echo

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Resuscitative TEE – the whats, the whys and the hows…. A brief review of the literature, examples of use and a proposed cardiac arrest protocol

Dr. David Lewis

Professor, Dalhousie Department of Emergency Medicine

Download Slides – PoCUS Rounds – TEE – Nov 2022

Further Reading

Introduction to Transesophageal Echo – Basic Technique

   http://pie.med.utoronto.ca/tee/

ACEP NOW – How to Perform Resuscitative Transesophageal Echocardiography in the Emergency Department

 

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Vascular Access In Children: Solve the Puzzle

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Dr. Rawan Alrashed (@rawalrashed)

PEM Physician

PoCUS Fellow

Reviewed and edited by: Dr. David Lewis

 

Background

Pediatric vascular access is one of the challenging skills in the medical field especially during an emergency, different guidelines have been established to facilitate the choice of the proper IV access one of which is the miniMAGIC that was published in 2020.1 Choosing the right access is crucial for success taking in consideration the urgency of access, patient safety, infused fluid characteristic  to determine the right one especially with a peripheral IV catheter failure rate of 77% in the first attempt.2 Difficult intravenous Access score (DIVA) is one of the tool that can be used to evaluate the feasibility of a peripheral IV and accordingly, the best next step for IV line insertion where Subjects with a DIVA score of 4 or more were more than 50% likely to have failed intravenous placement on first attempt.3

 

Figure-1: DIVA score.4

Types of vascular access

  • Peripheral IV catheters (PIVCS)
  • Intraosseous Access
  • Central Venous Catheters (CVCs) (Non-tunneled) 
  • US guided Access
  • Umbilical Catheter
  • Surgical cutdown

 

Figure 2: Vascular Access Locations.5

Consideration in pediatrics4

  • Pain management is a critical step for the success of IV cannulation

Multiple choices are available starting from non-pharmacological distraction technique and non-nutritive sucking to the utilization of local anesthetic such as EMLA and LMX as well the needle-free lidocaine jet-injection

  • Enhancing visualization of vein by using tourniquet, transilluminator with any available light source.
  • Ultrasound guided peripheral IV access is the recommended current practice in difficult access.
  • Ultrasound guided central IV access is the standard of care currently in comparison to anatomical landmark in critical care setting.

Indication of IV access

Patient resuscitation.

Delivering fluids, medication, Blood sampling.

Hemodynamics monitoring as well arterial blood gas.

Contraindications

Infection at the insertion site.

Thrombosis of the vein.

Bleeding diathesis in central line is a relative contraindication.

In IO Access, fracture on the same bone as well pathological disorder predisposing to fractures is a contraindication.

Peripheral IV catheter (PIVC)

Different veins can be used for PIVC starting with dorsal veins of the hand, then the feet and then proceeding to other choices including scalp vein in infants, external jugular vein, antecubital and the great saphenous vein as in Figure-2.5

Technique:5

  1. Prepare instruments: cleansing solution, tourniquet, catheter needle, connecting tube, flush, dressing, gauze, and stabilizer tape.
  2. Size of catheter as in the table: utilize the smallest gauge and shortest catheter as possible with exception in resuscitation where larger bore gauge is preferable or in case of midline cannulation where longer catheter is preferable.
  3. Apply tourniquet proximal to the site of insertion to enhance visualization
  4. Identify proper vein by visualization, palpation and utilizing the transilluminator or infrared light
  5. Clean the skin as per the facility protocol
  6. Hold the needle between the thumb and forefinger with the dominant hand and stretch the skin with the other hand
  7. Enter with an angle of 10-30 degree then if blood seen shallow your angle to advance 1-2 mm then advance the catheter and once in pull your needle or retract it.
  8. Flush to confirm patency and no swelling at the site then stabilize your catheter

 

 Neonate  Infant   Children Length
PIV 24-26G 22G 20G 2-6cm
Midline Access 22G 22G 20G 15-30cm

 

Table-1: Size of PIV catheter.

 

US guided peripheral vascular access

A recent RCT by Vinograd et.al. evaluated 167 children showed 85% success rate of first attempt with US guidance compared to 45% with traditional methods. Also US guidance resulted in shorter cannulation time, less redirection and fewer attempts.6 

Important consideration in US- guided PIV

  • The diameter and depth of the vein have been found determinate factors for success of cannulation in adult studies where very superficial (< 0.3 cm) and very deep (> 1.5 cm) veins are difficult to cannulate.7
  • The suggested veins are the cephalic vein in the forearm or the saphenous vein at the medial malleolus, while the antecubital vein might be an easy approach but the risk of brachial artery cannulation and the elbow bending make it less favorable. 7

Technique 7

  • Use a linear probe with 5-15 MHz ( Alternatively a hockey stick or MicroConvex might be useful)
  • Identify the vein and assess patency by being compressible and non pulsatile, for further confirmation utilize color or pulse wave doppler with augmentation to identify low status flow.

Longer catheter are preferable when using ultrasound guided insertion especially with a vein deeper then 0.5 cm to minimize the risk of dislodgment and infiltration (suggested to be longer than 2 cm). In a pilot study by Paladini, long catheter > 6 cm were associated with lower risk of failure in pediatric patients more than 10 years comparable to the short one <6 cm.8

  • Static or dynamic guidance are acceptable with preference of the latter. 
  • Two approach technique available with best outcome observed with out-of-plane in PIVC.

 

Out-of-plane (Short-Axis):
  • Consider using the middle point on the ultrasound machine to enhance alignment
  • The US wave perpendicular at right angle to the vessel.
  • The needle is inserted close to the probe at 20-30o angle then advance with meet and greet technique or dynamic needle tip positioning technique as in video

 

 

Pitfalls:

  • The needle shaft might be misidentified as the needle tip thus the importance of advancing the probe then the needle to maintain visualization of the tip only.  Also sweeping in the same plane can help to follow the needle proximal and distal to confirm the tip from the shaft.
  • Risk of posterior wall penetration and failure of cannulation.

 

In-Plane (Long-Axis):
  • The US beam is parallel to the vessel.
  • The whole needle shaft is visualized during insertion and advancement to the vein.
  • To facilitate visualization of needle “Ski left” technique can be used.

 

 

Pitfalls:

  • Maintaining the transducer static without any movement is difficult in small children as any movement would lead to loss of needle visualization, thus insertion will not be accurate (side lobe artifact)

No evidence of preferable technique in pediatrics but in adults out-of-plane proven to be superior for PIVC insertion.

 

How to Use US for PIVC:

https://www.coreultrasound.com/ultrasound-guided-peripheral-iv-access/

 

Intraosseous Access

It’s considered the best alternative IV access in emergencies (peri-arrest and arrest condition) after 2 failed attempts of PIVC within 60-90 seconds, AHA recommends IO catheter as first line access in cardiac arrest. Still the outcome of out of hospital cardiac arrest and best access need more delineation.4,5

Technique4

  • IO access can be accomplished using a manual needle or battery powered device such as EZ-IO or even a regular large bore needle.
  • Place the knee in slight flexion with padding.
  • Clean the skin and consider analgesia according to the urgency of the situation.
  • Insert the needle at 900 over the skin.
  • Remove the stylet and aspirate then infuse saline.
  • Confirmation of proper insertion by the needle standing still even if no backflow seen with lack of extravasation during fluid infusion.

Figure-2 (on green)  shows the possible site for IO insertion where the commonest one is the proximal tibial shaft about 1-2 cm from the tibial tuberosity avoiding the growth plate.

Complication4

  • IO needle is a temporary access that can not last for more than 24 hours
  • Longer use can predispose the child to complication including infection, thrombosis, fat embolism
  • Other complications of insertion include through-and-through penetration of the bone, physeal plate injury, pressure necrosis of the skin, compartment syndrome, osteomyelitis, subcutaneous abscess

 

Confirmation of IO by POCUS2

  • Use linear probe distal to the insertion site
  • Apply color doppler and observe for saline flush site
  • If above the bony cortical site or lateral or deep may indicate misplacement

 

Figure-3: POCUS confirmation of IO site.

 

 

Central IV Catheter (CIVC)

This an alternative longer duration route that can be utilized as an emergency line but less favorable compared to the IO during initial resuscitation. It is still considered a good choice in ill patients with difficulty of PIVC and failure of US guided peripheral access as well IO when fluid, high concentrated electrolytes and vasopressors are needed.4

The common site for insertion of non-tunneled CVC in pediatric is the internal jugular in critical care setting with higher success rate compared to femoral vein9 , but the femoral vein might be the first choice in PEM as it’s easily accessible and don’t interfere with resuscitation measures.10

Technique10

Always prepare your equipment and check them, also get consent when possible before attempting a central line

 

Age(years) weight (kg) Catheter gauge French gauge length (cm)
<1y 4-8 24 3 5-12
<1y 5-10 22 3-3.5 5-12
1-3y 10-15 20 4 5-15
3-8y 15-30 18-20 4-5 5-25
>8y 30-70 16-20 5-8 5-30

Table-2: CVC sizes.4

Anatomical Landmark5

Internal Jugular vein:

  • Under aseptic technique with proper draping, put the patient in Trendelenburg position and turn the head slightly to the other side.
  • Use the medial head of the sternocleidomastoid muscle or between the tow head at the level of the thyroid cartilage just lateral to the carotid artery guide your needle on a 45o  toward the ipsilateral nipple while aspirating during insertion until you feel loss of resistance and have a backflow.
  • follow with the guidewire into your needle and then dilator
  • Complete by  inserting the catheter line and fixing it.

Subclavian vein:

Directly below the clavicle at the junction of the lateral one third with the medial two third directing the needle toward the sternal notch

Femoral vein:

1-2 cm below the inguinal ligament medial to the femoral artery, guide the needle toward the umbilicus

 

US Guided CVC

The use of ultrasound guided insertion is considered the standard of care for central line insertion. Ultrasound use reduces the number of attempts and procedure duration, increases the successful insertion rate, and reduces complications compared to the skin surface anatomic landmarks technique.9

This can facilitate visualization, increase the success rate with 95% first attempt success rate of ultrasound-guided venous punctures compared to 34% of the anatomical landmark and decrease the rate of complication that would occur with the anatomical landmark.11

 

  • Always start by identifying the land mark on US before starting the procedure (vein is compressible and less pulsatile than the adjacent artery)
  • Probe position according to the site of insertion.  
  • Prepare the patient under aseptic technique as well the probe with sterile sheet and the ultrasound counsel unless you have assistance.
  • Infiltrate local anesthesia to the skin puncture site.
  • Utilize sterile gel on the outside of the sterile sheet or alternatively sterile water or saline
  • Use an out of plane technique to guide the needle into the vein (higher success rate).
  • Start by inserting the needle at 45 degree angle from the probe and the same distance away as the vein from the skin
  • Follow the dynamic needle tip positioning technique (meet &greet) to keep visualizing the needle tip while guiding it toward the vein
  • If confusing the needle tip with the shaft try to slide the probe proximal and distal until confirmation
  • Use the same steps in aspirating while inserting until having a backflow and confirming the needle is inside the vein lumen
  • Complete the steps as before and confirm the position of the guidewire by ultrasound.
  • Insert the central catheter and fix it with sutures and transparent dressing.

 

Internal jugular vein:

Subclavian vein

Femoral vein

 

Complication12

Confirm proper placement by US as well X-Ray

R/O complication as pneumothorax, hemothorax or hematoma, mis-displacement

Artery puncture, air embolism, thoracic duct injury, arrhythmia are possible complications.

 

Umbilical Catheter

  • Can be used in neonate up to 7 days old.
  • Apply tourniquet to umbilical stump then cut the upper dried part.
  • Identify the vein which is single and thin walled while arteries are two and thick wall.
  • Stent the vessel with a forceps then insert the catheter up to 3-4 cm until blood return (Do NOT advance further as the risk of complication and adverse events are high)

 

Venous Cutdown

It is uncommon access in pediatric patients with the availability of IO needle, if needed the classic site is the saphenous vein which is 2 cm superior and anterior to the medial malleolus.

 

 

Resources:

  1. Ullman AJ, Bernstein SJ, Brown E, et al. The Michigan Appropriateness Guide for Intravenous Catheters in Pediatrics: miniMAGIC. Pediatrics. 2020;145(Suppl 3):S269-S284. doi:10.1542/peds.2019-3474I.
  2. Delacruz N, Malia L, Dessie A. Point-of-Care Ultrasound for the Evaluation and Management of Febrile Infants. Pediatr Emerg Care. 2021;37(12):e886-e892. doi:10.1097/PEC.0000000000002300.
  3. Yen K, Riegert A, Gorelick MH. Derivation of the DIVA score: a clinical prediction rule for the identification of children with difficult intravenous access. Pediatr Emerg Care. 2008;24(3):143-147. doi:10.1097/PEC.0b013e3181666f32.
  4. Whitney R, Langhan M. Vascular Access in Pediatric Patients in the Emergency Department: Types of Access, Indications, and Complications. Pediatr Emerg Med Pract. 2017;14(6):1-20.
  5. Naik VM, Mantha SSP, Rayani BK. Vascular access in children. Indian J Anaesth. 2019;63(9):737-745. doi:10.4103/ija.IJA_489_19.
  6. Vinograd AM, Chen AE, Woodford AL, et al. Ultrasonographic guidance to improve first-attempt success in children with predicted difficult intravenous access in the emergency department: a randomized controlled trial. Ann Emerg Med. 2019;74:19–27.
  7. Nakayama Y, Takeshita J, Nakajima Y, Shime N. Ultrasound-guided peripheral vascular catheterization in pediatric patients: a narrative review. Crit Care. 2020;24(1):592. Published 2020 Sep 30. doi:10.1186/s13054-020-03305-7.
  8. Paladini A, Chiaretti A, Sellasie KW, Pittiruti M, Vento G. Ultrasound-guided placement of long peripheral cannulas in children over the age of 10 years admitted to the emergency department: a pilot study. BMJ Paediatr Open. 2018;2(1):e000244. Published 2018 Mar 28. doi:10.1136/bmjpo-2017-000244.
  9. Pellegrini S, Rodríguez R, Lenz M, et al. Experience with ultrasound use in central venous catheterization (jugular-femoral) in pediatric patients in an intensive care unit. Arch Argent Pediatr. 2022;120(3):167-173. doi:10.5546/aap.2022.eng.167.
  10. Skippen P, Kissoon N. Ultrasound guidance for central vascular access in the pediatric emergency department. Pediatr Emerg Care. 2007;23(3):203-207. doi:10.1097/PEC.0b013e3180467780.
  11. De Souza TH, Brandão MB, Santos TM, Pereira RM, Nogueira RJ. Ultrasound guidance for internal jugular vein cannulation in PICU: a randomised controlled trial. Arch Dis Child. 2018; 103(10):952-6.
  12. Georgeades C, Rothstein AE, Plunk MR, Arendonk KV. Iatrogenic vascular trauma and complications of vascular access in children. Semin Pediatr Surg. 2021;30(6):151122. doi:10.1016/j.sempedsurg.2021.151122

 

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CanPoCUS May 2022

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CanPoCUS May 2022

New to Point of Care Ultrasound (PoCUS)? Been scanning for a while but wanted some formal, hands on training? Join us for the CanPoCUS Core Course in Saint John, NB this upcoming May 2022. 

This introductory PoCUS course has been designed for doctors, nurse practitioners, physician assistants who work in acute care e.g Emergency Medicine, Family Medicine, Internal Medicine, Critical Care, Surgery.

It provides the core knowledge and hands-on training required to confidently add PoCUS to your practice.

Our course fills up quickly – what are you waiting for? Register today 

 

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