Unvexing the VExUS Score – An Overview

Posted on April 22, 2023 by David Lewis

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

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.
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.
Koratala A, Reisinger N. Venous excess doppler ultrasound for the nephrologist: Pearls and pitfalls. Kidney Medicine. 2022 May 19:100482.
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.
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.
Mattoon JS, Berry CR, Nyland TG. Abdominal ultrasound scanning techniques. Small Animal Diagnostic Ultrasound-E-Book. 2014 Dec 2;94(6):93-112.
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
Dinh V. POCUS101 Vexus ultrasound score–fluid overload and venous congestion assessment.
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.
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.
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.
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.
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.
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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Infraorbital Rim Fracture – PoCUS Fellowship Journal Club

Posted on March 10, 2023 by David Lewis

Dr. Rawan Makhdom

DalEMSJ PoCUS Fellow

Consultant Emergency Medicine

King Fahad Hospital of the University, Al Khobar KSA

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Bicuspid Aortic Valve – An important incidental PoCUS finding?

Posted on December 8, 2022 by David Lewis

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 dissection^2.3.

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.

Known bicuspid aortic valve patients presenting with possible associated complications
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 3^rd or 4^th 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 valve^5-9

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

Braverman, A. C., & Cheng, A. (2013). The bicuspid aortic valve and associated aortic disease. Valvular heart disease. Philadelphia: Elsevier, 179-218.
Verma, S., & Siu, S. C. (2014). Aortic dilatation in patients with bicuspid aortic valve. N Engl J Med, 370, 1920-1929.
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.
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.
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.
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.
Shapiro, L. M., Thwaites, B., Westgate, C., & Donaldson, R. (1985). Prevalence and clinical significance of aortic valve prolapse. Heart, 54(2), 179-183.
Gebhardt, C., Hegazy, A.F., Arntfield, R. (2015). Chapter 16: Valves. Point-of-Care Ultrasound. Philadelphia: Elsevier, 119-125.
Kimura, B. J. (2017). Point-of-care cardiac ultrasound techniques in the physical examination: better at the bedside. Heart, 103(13), 987-994.
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.
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.
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.
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.

Vascular Access In Children: Solve the Puzzle

Posted on July 18, 2022 by Rawan Alrashed

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

Prepare instruments: cleansing solution, tourniquet, catheter needle, connecting tube, flush, dressing, gauze, and stabilizer tape.
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.
Apply tourniquet proximal to the site of insertion to enhance visualization
Identify proper vein by visualization, palpation and utilizing the transilluminator or infrared light
Clean the skin as per the facility protocol
Hold the needle between the thumb and forefinger with the dominant hand and stretch the skin with the other hand
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.
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

Technique⁷

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 20-30^o 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 45^o 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:

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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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

Volume Status Assessment in ED: Beyond the Vitals

Posted on June 8, 2022 by Rawan Alrashed

Dr. Rawan Alrashed (@rawalrashed)

PEM Physician

PoCUS Fellow

Reviewed and edited by: Dr. David Lewis

Case

A 55 year old man known to have hypertension, diabetes, atrial fibrillation, chronic kidney disease presenting with 1 week H/O fever, SOB, chest pain, cough, fatigability, looking distressed on exam with HR 110, SpO2 of 86% on RA and BP of 87/45. No audible crackles or gallop rhythm, bilateral pitting edema noticed.

So, you are asking yourself should your next step be Fluids or Diuresis ??

Background

Patient presenting to the emergency department as critically ill with shock status presents a challenge in the initial hour to balance their fluid requirements with their volume status to reach an improvement in hemodynamics without causing harm.

Volume status assessment and fluid responsiveness have been investigated using multiple measures ranging from physical examination to laboratory work up to invasive measures. Despite all that, no single or multiple factor have been sensitive or specific enough to guide further fluid management. Currently, PoCUS is progressing widely in aiding the emergency physician to take a decision in assessing patient’s fluid vs vasopressor vs diuretic needs and guide further resuscitation. PoCUS is noninvasive, readily available, reproducible test that can be augmented with other measures to guide fluid management (1).

Pathophysiology

To simplify fluid responsiveness, patients are assessed on accordance of the Frank-Starling curve. Patients will respond to fluid administration if they are on the ascending portion of the Starling curve and no benefit will be added if they are at a plateau where more harm can occur which is difficult to be predict form physical examination solely (2).

Figure 1: Frank Starling Law

Fluid Challenge

Traditionally volume responsiveness has been assessed by small fluid bolus challenge. A safer alternative to this is passive leg raise (PLR) which is an autotransfusion where you mobilize about 300-500 ml of intravascular volume from the lower limb to the heart by raising the patient legs from 0^o to 45^o. A Pre-Post assessment of stroke volume within 30-90 sec from PLR can be done to measure the difference where change of 10% consider to be responsive.

This have been shown to have a sensitivity of 77% to 100%, and a specificity of 88% and 99% (1).

Figure 2: Passive Leg raising technique (uptodate)

Volume Status Assessment

PoCUS have been used in volume status assessment and fluid responsiveness using multiple surrogates which can be classified as follows for simplification:

Cardiac PoCUS: core and advanced.
Stroke volume Assessment: VTI of LVOT/Carotid artery.
Vascular Assessment: IVC, IJV.
Venous Congestion: Hepatic, portal, & intra-renal doppler.
Lung PoCUS.

1) Cardiac PoCUS

The target of Cardiac PoCUS is to assess for possible causes of hypotension and shock status using the RUSH or SHoC protocol (3).

Figure 3: SHoC Protocol (3).

2) Cardiac Output Assessment

Two measures can be used to assess fluid responsiveness: the left ventricular outlet tract (LVOT) and the carotid artery where you assess the velocity time integral (VTI) representing the column of blood passing through the vessel through time. This can be used as surrogate of fluid responsiveness before and after the PLR where a change of 10-15% consider as fluid responsive (4).

a. LVOT measurements

Cardiac output variation of greater than 14% has a high positive predictive value for the patient being fluid responsive while values less than 10% are associated with a high negative predictive value (1)

Cardiac output (mL/min) = Stroke Volume (mL/cycle) x Heart Rate (bpm)

Stroke Volume= LVOT area x LVOT VTI

PoCUS Technique (4)

Using the cardiac phased array probe to get apical 5 chamber view and parasternal long axis view.
Apical five chamber view, with visualization of the LVOT (A).
Pulsed wave Doppler interrogation of the LVOT. The interrogation window is placed just above the aortic valve, and the line of interrogation is positioned parallel to the long-axis of the LVOT itself (B).
Measuring the area under the curve of the LVOT Doppler waveform to derive the velocity time integral (C) .
Diameter of the LVOT, measured from a parasternal long-axis view (D)

Figure 4: Stroke volume measurement at the LVOT.

b. Common Carotid Artery

Two measurement are applied to the carotid artery: the carotid blood flow and the corrected carotid flow time index. These measure are recently established in the field of cardiac output assessment and accuracy is still under debate with further studies needed.

The carotid blood flow is the integral of blood volume that is ejected through the carotid artery with each cardiac cycle. An increase of carotid blood flow by 20% after PLR is indicative of fluid responsiveness with a sensitivity of 94% and specificity of 86% (6).

The corrected carotid flow time index (CFTI) representing the flow time between the onset of systole and the closure of the aortic valve as the duration of the full cardiac cycle. A change in the CFTI of 25% following PLR was found to have high specificity but a low sensitivity accordingly a cutoff values of 10% to 15% are more typical, still further studies are needed to specify the accurate cut off value (4).

PoCUS Technique (4,5)

a. The linear transducer is placed at approximately at the level of the thyroid cartilage, with the orientation marker pointed toward the patient’s head (A).

b. The Carotid artery identified in long-axis and the bulb before the bifurcation visualized and the doppler is applied within 2–3 cm proximal to the carotid bulb, interrogation line (green) has also been angled to make it more parallel to the long-axis of the artery.

c. The Doppler angle correction cursor is placed parallel to the direction of blood flow with insonation angles <60° .

d. Carotid artery Doppler waveform with measurement of the systolic flow time (SFT) and total cycle time (CCT).

e. Calculate the corrected flow time index using the following formula (Figure-5):

CFTI=SFT/√CCT

f. Calculate the carotid blood flow using velocity time integral tracing and carotid diameter (Intima to intima) then apply it in this formula (Figure-6):

blood flow=π×(carotid diameter)2/4×VTI×heart rate

Figure-5: Corrected Carotid Flow Time Index Measurement (4).

Figure-6: Carotid Blood Flow measurement (5).

3) Vascular Assessment

a. Inferior vena cava (IVC)

Measurements of IVC diameter and respiratory variation with the collapsibility index as a predictor of fluid responsiveness was found to be having pooled sensitivity and specificity of 63% and 73% respectively (7).

PoCUS Technique (8)

Use the curvilinear or phased array probe.
placed in the sub-xiphoid space with the transducer flat against the abdomen identifying RA and gradually fanning the probe until the intrahepatic IVC can be identified.
The probe is then rotated 90 degrees with the marker toward patient head to obtain the IVC in long axis view.
IVC diameter is measured 2 cm inferior to the cavo-atrial junction or about 1 cm inferior to the branching of the hepatic veins (Figure 7).
M-mode can be used to track IVC collapse during inspiration in spontaneously breathing patients.

Figure-7: IVC and measurement of respiratory variation (Collapsibility Index)

Measurements:

Collapsibility Index (Caval Index)

The collapsibility index=(maximal vessel diameter – minimal vessel diameter)÷maximal vessel diameter

It has been demonstrated that venous collapsibility may be inversely proportional to CVP: a 1 mmHg change in central venous pressure correlates to about 3.3% change in IVC collapsibility (9).

IVC diameter (cm)	CI (%)	CVP (mmHg)
<1.5	100%	<0-5	Volume depleted
1.5-2.5	>50%	<10	Less predictive of responsiveness
1.5-2.5	<50	>10	Less predictive of responsiveness
>2.5	0%	>20	Volume overload

Important to note that sole interpretation of the IVC for volume assessment was found to be poorly correlating and thus should be used in conjunction with other measures and integrated on patient presentation (9).

b. Internal Jugular Vein (IJV)

Internal jugular vein is used for the assessment of the central venous pressure in comparable way to IVC. A small study of non-ventilated patients who were simultaneously undergoing CVP monitoring, a mean IJV diameter of 7 mm correlated with a CVP of 10 mmHg (8).

Collapsibility index of the IJV with change of 39% consider the patient as volume depleted but this carries a limitation of the intrabdominal/ intrathoracic pressure effects (4).

PoCUS Technique

Use the linear Probe
Identify the IJV in transverse plane then rotate the probe 90^o toward the patient head.
Image of IJV is obtained where it narrows into a paintbrush appearance (Figure 8).
The height where the IJV tapers correlates with jugular venous distension.
The IJV diameter is measured using M-mode through several respiratory cycles, and the end expiratory diameter is used as the final measurement.

Figure-8: Internal Jugular vein

4)Venous Congestion (VEXUS):

This includes assessment of the Hepatic/Portal/Intrarenal veins wave forms which has been correlated to the level of venous congestion thus estimating the end organ volume effects.

Hepatic Vein Doppler mainly reflects the right atrium filling pattern, portal and intrarenal venous Doppler provide additional information about right atrial filling pressure and its correlation with congestive organ injury (10).

PoCUS Technique (9)

Hepatic Vein Doppler

The probe is placed over the liver in the subcostal position to visualize the middle hepatic vein. Pulsed-wave Doppler is used 2-4 cm from where the hepatic vein drains into the IVC.

Findings: The waveform of the hepatic vein is reversed with higher velocities seen in diastole in states of volume overload. In severe volume overload, retrograde flow is seen in systole (Figure 9)

Figure-9: Hepatic vein doppler different wave forms (11).

Portal Vein Doppler

Moving towards the portal vein, the transducer is placed in the right mid-axillary line

Findings: Flow through the portal vein is normally monophasic, but in the presence of hypervolemia, pulsatility will be present. This can be quantified using the pulsatility index where a pulsatility index greater than 50% indicates severe volume overload.

Figure 10: Portal vein doppler wave forms (11).

Intra-renal Doppler

The curvilinear transducer is placed on the posterior axillary line

Findings: A normal Doppler waveform is continuous. With increasing venous congestion, there is a decrease in the systolic component of the wave with progression to biphasic (systolic/diastolic phases), and with severe renal congestion, there is complete absence of systolic flow showing only diastolic phase.

Figure 11: Intra-renal doppler wave forms (11).

Figure-12: the change in the venous doppler according to progression of venous congestion (10).

Figure -13: VExUS grading system for venous congestion using IVC and different venous doppler wave form for categorization.

5)Lung Ultrasound

A meta-analysis showed that LUS is 88% sensitive and 90% specific for acutely decompensated heart failure and was more sensitive at detecting pulmonary edema than CXR (8).

Another meta-analysis determined the sensitivity and specificity of ultrasound for detection of pleural effusions as 93% and 96% respectively. The sensitivity approaches 100% with pleural effusions >100 mL in volume (8).

PoCUS Technique

Use the linear or curvilinear probe.
In longitudinal plane, along the midclavicular, midaxillary line then the posterior-lateral point.

Findings:

B-lines are hyperechoic vertical lines extending from the pleura down to the bottom of the US image (Figure 14). Two or fewer B-lines in each section is considered normal
Pleural effusion can be identified with presence of V-sign (extension of vertebral line proximal to the diaphragm (Figure-15) .

Figure 14: B-Lines

Figure 15: Pleural effusion

Case Conclusion

Patient was found to have reduced LV function with Dilated IVC and CI of 15%, VExUS grade 2. Assessment of COP after PLR didn’t show a proper change thus patient was started on diuretic and respiratory support with consideration of inotropic support.

Conclusion

The table below (8) shows a summary of the evidence related to the different used marker for volume assessment from physical exam to the use of PoCUS. Thus, it is imperative that we do not rely on one single tool, but rather integrate both pertinent physical examination and POCUS findings for better probability of coming to the right decision.

References

Pourmand A, Pyle M, Yamane D, Sumon K, Frasure SE. The utility of point-of-care ultrasound in the assessment of volume status in acute and critically ill patients. World J Emerg Med. 2019;10(4):232-238. doi:10.5847/wjem.j.1920-8642.2019.04.007.
Praveen P., Shanmugam L., Prasath, P. A review of role of lung ultrasound and clinical congestion score in acute left ventricular failure. International Journal of Advances in Medicine. 2020;7. 720. 10.18203/2349-3933.ijam20201130.
Atkinson P, Bowra J, Milne J, et al. 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 – CORRIGENDUM. CJEM. 2017;19(4):327. doi:10.1017/cem.2017.31.
Millington SJ, Wiskar K, Hobbs H, Koenig S. Risks and Benefits of Fluid Administration as Assessed by Ultrasound. Chest. 2021;160(6):2196-2208. doi:10.1016/j.chest.2021.06.041.
Ma IWY, Caplin JD, Azad A, et al. Correlation of carotid blood flow and corrected carotid flow time with invasive cardiac output measurements. Crit Ultrasound J. 2017;9(1):10. doi:10.1186/s13089-017-0065-0.
Marik PE LA, Young A, Andrews L. The use of bioreactance and carotid Doppler to determine volume responsiveness and blood flow redistribution following passive leg raising in hemodynamically unstable patients. Chest. 2013;143(2):364-370. doi:10.1378/chest.12-1274.
Long E, Oakley E, Duke T, Babl FE. Does Respiratory Variation in Inferior Vena Cava Diameter Predict Fluid Responsiveness: A Systematic Review and Meta-Analysis. Shock (Augusta, Ga). 2017;47(5):550-559.
Kearney, D., Reisinger, N., & Lohani, S. (2022). Integrative Volume Status Assessment. POCUS Journal, 7(Kidney), 65–77.
Argaiz Eduardo R, Koratal A., Reisinger N. Comprehensive Assessment of Fluid Status by Point-of-Care Ultrasonography. Kidney360 Aug 2021, 2 (8) 1326-1338; DOI: 10.34067/KID.0006482020.
Galindo P, Gasca C, Argaiz ER, Koratala A. Point of care venous Doppler ultrasound: Exploring the missing piece of bedside hemodynamic assessment. World J Crit Care Med. 2021;10(6):310-322. Published 2021 Nov 9. doi:10.5492/wjccm.v10.i6.310.
Dinh, V. (n.d.). Vexus ultrasound score – fluid overload and venous congestion assessment. POCUS 101. Retrieved March 29, 2022, from https://www.pocus101.com/vexus-ultrasound-score-fluid-overload-and-venous-congestion-assessment/.

Scrotal Pain – Scrotal PoCUS in a nutshell

Posted on January 22, 2022 by Rawan Alrashed

Rawan Alrashed (@rawalrashed)

PEM Physician

PoCUS Fellow

Background

Acute Scrotal pain represent 0.5% of Emergency department visit, less than 25% of those are due to testicular torsion (1). Clinical history and physical examination don’t consist a definitive tool to diagnose the problem especially when presentation of different causes of scrotal pain can overlap. Testicular torsion doesn’t always present with the typical acute onset of pain as gradual onset was found in 25% of presentation which is described for the epididymo-orichitis (2-3). Scrotal pathology is divided into the 4 following groups: torsion, trauma, infection, and tumors, often described as the scrotum’s “4 T’s (4).

Review on how to approach Acute scrotal pain can be found on this post:

The Acute Scrotum

Anatomy

The testicles originate in the posterior abdominal wall in embryonic life then migrates to the scrotum, in case of failure of migration presentation of acute scrotum can be along the abdomen, inguinal canal.

Figure-1 Anatomy on Transverse and Longitudinal plane (Radiology Key)(5)

The testicle is enveloped by a fibrous capsule called the tunica albuginea, which projects into the testis to form the mediastinum testis. The tunica vaginalis is a two-layered membrane that covers the tunica albuginea. Multiple testicular seminiferous tubules run toward the mediastinum and coalesce into a network of channels called the rete testis. These channels pass through the mediastinum and tunica albuginea to form the epididymal head, body, and tail ducts, which continue as the vas deferens. The spermatic cord contains the vas deferens, testicular vessels, pampiniform venous plexus, and nerve (6).

PoCUS Technique

Patient should be in supine position.
Use a towel under the scrotum for elevation and support and a second towel to cover and retract the penis of the scrotum.
Use a linear high-frequency (>7MHz) transducer with broad bandwidth.
Scan in transverse and sagittal planes.
Assess the size and texture of each testicle and look to the surroundings including the epididymis and tunica vaginalis for fluids.
Use comparison by visualizing both testicle in transverse plane.
Use Color and spectral Doppler imaging for the assessment of blood flow.
Images of the inguinal canal and spermatic cord can be obtained in the upright position during Valsalva maneuver to evaluate for inguinal hernias and varicoceles, respectively.

N.B. Doppler settings should be optimized to maximize detection of low-velocity flow. Color Doppler gain should be adjusted to eliminate artifacts. This can be done by adjusting the scale of flow on the normal testis then use it to visualize the abnormal one. (6)

Video on how to do the scan (7):

Normal Findings

Figure 2- Ultrasound Anatomy: a- Transverse view, b- sagittal view (6)

Scrotal wall is heterogeneous and the wall thickness ranges from 2 to 8mm.
The normal adult testicle is oval and measures approximately 5×3×2 cm, with a homogeneous echotexture and diffuse intermediate level echogenicity.
The tunica albuginea appears as a thin hyperechoic rim encasing the testicle, which invaginates in the central testicle as a hyperechoic band corresponding to the mediastinum testis.
The tunica vaginalis can be identified as a thin hyperechoic line, but this structure is not routinely visualized in the absence of hydrocele.
The epididymis is best visualized on longitudinal views and appears isoechoic to slightly hypoechoic relative to the adjacent testis.
The spermatic cord has a straight course from the external inguinal ring along the posterior border of the testicle, with a normal transverse diameter of less than 5mm. (6)

– Comparing testicular echogenicity bilaterally (Q-path)

– Comparing bilateral Testicular blood supply and notice the low flow scale (Q-path)

PATHOLOGY

1.VASCULAR

Testicular Torsion (Torsion of the spermatic cord)

Testicular Torsion is a clinical diagnosis mainly affecting children with two age peaks at 1 year and adolescence (6). TWIST score can help in risk stratifying the patients which was developed by urologist and validated in pediatric age group in emergency setting (8).

REMEMBER

Time is testicle, So once suspected involve surgical specialty for De-torsion. As the salvage rate is as high as 80%-100% if it was repaired within 6 hours of symptom onset then drops to 20% after 12 hours (9).

If diagnosis couldn’t be made clinically, Scrotal ultrasound can help with the use of color and spectral doppler to rule in this diagnosis.

Findings:

It will depend on the timing of presentation

Early (within 6 hours):

Abnormal position.
Normal echogenicity could be seen early.
Twisting of the spermatic cord (most specific) (“whirlpool sign”)
Reduced venous flow.
Later testicular enlargement within the 6 hours due to tissue edema.
Scrotal wall thickening, and secondary hydrocele may also be observed. (6,9)

After 6 hours Reduced arterial blood supply with high resistance flow pattern compared to normal flow.

Late(After 24 h):

Testicular heterogeneity, hypo-echogenicity due to infarction and hemorrhage (at this stage salvageability is less likely (10).

Normal right testis (Q-path)

Abnormal echogenicity of left testis (Q-path)

Absence of color flow on this image (Q-path)

Whirlpool sign (11)

Important to keep in mind:

-In case of Partial torsion, the previous findings might not fully manifest and the scan could be falsely negative, still the abnormal spermatic cord can be seen as well on spectral doppler the arterial flow will be either absent or reversed diastolic flow.

-In Case of Torsion- De-torsion, rebound reperfusion with hyperemia may make the diagnosis difficult and confusing, so regular monitoring and re-scan could help in reaching the diagnosis (6,9).

Video explaining the findings on PoCUS and spectral doppler wave :

Torsion of testicular appendage

It’s the commonest presentation of pediatric testicular pain. This appendage is usually pedunculated and is present in more than 80% of children. It is located at the superior aspect of the testis in the groove between the testicle and the epidydimal head.

Findings:

Appendages are more readily apparent in the presence of a hydrocele.
Enlarged, rounded, extra-testicular masses, with mixed hyperechoic and heterogeneous echotexture depending on the degree of ischemia.
Absent flow on color Doppler, and hyperemia of the surrounding structures. (6)

normal appearing testicular appendix with hydrocele (11)

Hyperechoic torsion appendage (11)

Absent blood supply inside the appendage with hyperemia around it (11)

2. INFECTIOUS

Epididymitis and epididymo‑orchitis

Always try to scan the Epididymis from head to tail (some infection may be limited to the tail) then compare the findings to the unaffected site.

Findings:

Heterogenous echogenicity.
Enlargement in size.
Increase in color flow doppler.
Secondary findings includes Hydrocele and scrotal wall thickening.

The primary infection might get complicated and develop Abscess or Pyocele or end up with infarction and reversal arterial diastolic flow (6,9).

Enlarged epididymis (Q-path)

Increase flow on color doppler (Q-path)

Fournier gangrene

It’s a polymicrobial necrotizing fasciitis of the perineal, perianal, or genital areas. This diagnosis is clinical though the characteristic crepitus could only be found in 19-64% of cases. It’s critical that if this diagnosis is suspected, treatment should not be delayed for imaging confirmation. The modality of choice for diagnosis is CT scan (12).

Findings on US:

Diffuse subcutaneous tissue thickening.
Perifascial fluid accumulation.
Bright echogenic foci with dirty shadowing and reverberation artifacts corresponding to the underlying soft tissue gas. (12)

Thickening of scrotal wall with hydrocele and air reverberation artifact (13)

3. TRAUMA

The American Urological Association recommends surgical exploration in case of testicular trauma to delineate the extent of injury and should be within 72 hours as the rate of salvage up to 90% of blunt testicular rupture cases; But when surgery is delayed beyond this time point, the orchiectomy rate is 45%. (6,9)

Testicular Rupture:

A tear in the tunica albuginea that results in extrusion of testicular contents.
Radiology US sensitivity 100% Specificity 93.5%.
Images will show heterogeneous testicle, contour abnormality, and disruption of the tunica albuginea.
Color Doppler imaging demonstrates focal or diffuse loss of vascularity.

Testes look heterogenous with irregular wall and abnormal blood supply (11)

Complete loss of the testicle contour (13)

Testicular fracture

Disruption of the testicular parenchyma with preserved testicular shape and integrity of the hyperechoic tunica albuginea. The fracture plane appears as an avascular linear hypoechoic band extending across the parenchyma.

It’s critical to identify blood flow on color doppler to determine salvageability(9,10).

Scrotal hematoma

Depend on the chronicity of the evolving blood products; hematoceles and focal testicular, epididymal, and scrotal wall hematomas are acutely hyperechoic with decreasing echogenicity and increasing complexity (septa, loculations, and fluid levels) as they evolve to subacute and chronic phases. Hematomas have no internal flow on color and power Doppler images(9,10).

4. OTHERS

Testicular tumors:

Well-defined, hypoechoic or heterogeneous echogenicity intra-testicular lesion.
Might also see calcifications, micro-lithiasis, and necrosis.
Low level echoes with increased blood flow on color Doppler.(9)

multiple hypoechoic area with micro-lithiasis (11)

Varicocele:

Normal diameter of the pampiniform plexus veins range from 0.5 to 1.5 mm, the diameter of the main draining vein measuring up to 2 mm.
When this diameter increases, the collection of tortuous elongated veins seen posterior to testes.
Primary varicocele is almost always (98%) left sided due to venous drainage into the renal vein, contrary to direct drainage of the right vein into the inferior vena cava.
Secondary varicoceles are bilateral in up to 70%.

Dilated vein (worm like appearance) (14)

augmented vascularity with Valsalva (14)

The Evidence

Color and power Doppler ultrasonography reported sensitivity ranges between 86% and 98%, specificity up to 100%, and accuracy up to 97% by radiologist(9).
Friedman et.al. reported an agreement rate of 70% accuracy of all performed acute scrotum point-of-care ultrasound with final diagnosis(15).
Testicular torsion showed a sensitivity of 100% and Specificity of 99.1% with 73 minutes difference between the emergency physician and the radiologist acquiring the results(15).
For the other applications, still the evidence to be established but Blaivas et al. in a sample of 36 patients found the accuracy of emergency physician diagnosis compared to radiological studies was 95% sensitive and 94% specific(16).

Limitation and pitfalls

Normal variant
Overlapping of pathological findings might interfere with diagnosis, so clinical correlation is needed.
PoCUS in the emergency department is mainly a Rule In NOT out, So if no testicular torsion is identified it doesn’t mean that it’s ruled out.
Absence of scrotal pathology might signify an abdominal one especially if you identified undescended testes.

Bottom line:

Presentation of scrotal pathology could overlap greatly, and PoCUS can aid in delineating the diagnosis.
Most critical for emergency physician is to identify testicular torsion as time here is your enemy so PoCUS can assist in Ruling in this diagnosis with accuracy reaching 100%.

References

Blaivas M, Sierzenski P, Lambert M. Emergency evaluation of patients presenting with acute scrotum using bedside ultrasonography. Acad Emerg Med. 2001;8(1):90-93.
Cos LR, Rabinowitz R. Trauma-induced testicular torsion in children. J Trauma. 1982; 22:244–6.
Melekos MD, Asbach HW, Markou SA. Etiology of acute scrotum in 100 boys with regard to age distribution. J Urol.1988; 139:1023–5.
Wittenberg AF, Tobias T, Rzeszotarski M, et al. Sonography of the acute scrotum: The four T’s of testicular imaging. Curr Probl Diagn Radiol 2006;35:12-21.
Testicular Ultrasound | Radiology Key.
Sweet DE, Feldman MK, Remer EM. Imaging of the acute scrotum: keys to a rapid diagnosis of acute scrotal disorders. Abdom Radiol (NY). 2020;45(7):2063-2081.
Badar Bin Bilal Shaf, 2018, Testicular Evaluation using Bedside Ultrasonography. (Testicular Evaluation using Bedside Ultrasonography: Practice Essentials, Indications, Positioning (medscape.com)
Frohlich LC, Paydar-Darian N, Cilento BG Jr, Lee LK. Prospective Validation of Clinical Score for Males Presenting With an Acute Scrotum. Acad Emerg Med. 2017;24(12):1474-1482.
Cokkinos DD, Antypa E, Tserotas P, et al. Emergency ultrasound of the scrotum: a review of the commonest pathologic conditions. Curr Probl Diagn Radiol. 2011;40(1):1-14.
Rebik K, Wagner JM, Middleton W. Scrotal Ultrasound. Radiol Clin North Am. 2019;57(3):635-648.
Radiopedia (Radiopaedia.org, the wiki-based collaborative Radiology resource).
Levenson RB, Singh AK, Novelline RA (2008) Fournier gangrene: role of imaging. Radiographics 28:519-528.
The Pocus Atlas (TPA (thepocusatlas.com)
Liftl (Ultrasound Case 105 • LITFL • POCUS Top 100).
Friedman N, Pancer Z, Savic R, et al. Accuracy of point-of-care ultrasound by pediatric emergency physicians for testicular torsion. J Pediatr Urol. 2019;15(6):608.e1-608.e6.
Blaivas M, Sierzenski P, Lambert M. Emergency evaluation of patients presenting with acute scrotum using bedside ultrasonography. Acad Emerg Med. 2001;8(1):90-93.

DVT PoCUS: When?, Where?, How? and What to do next?

Posted on January 22, 2022 by Rawan Alrashed

Dr. Kyle Traboulsee

EM Physician, PoCUS Fellow

Reviewed by Dr. David Lewis

Copyedited by Dr. Rawan Alrashed

Background

Lower extremity deep vein thrombosis (DVT) is a common, and potentially life-threatening vascular condition, with an annual incidence of 1 per 1000 adults. If left untreated, it may progress to pulmonary embolism, which is associated with a higher mortality. Therefore, accurate and timely diagnosis and treatment are incredibly important. (1,2,3)

An initial approach to the diagnosis of DVT involves risk stratification, often with the clinical risk score “Well’s score”, in conjunction with D-dimer assays. Based on the associated pre-test probability of the above risk stratification, further imaging may be required.

Although the gold standard for the diagnosis of DVT has traditionally been contrast venography, Duplex ultrasonography has become the standard of care due (in large part) to its lack of radiation and intravenous contrast, as well as widespread availability. This elective scan evaluates from groin to ankle and can take upwards of 1 hour depending on the difficulty of the individual exam. Studies have shown that a simplified ultrasound technique, limited to proximal segments of the femoral and popliteal veins using compression alone has a high sensitivity and specificity for proximal DVT detection. (2,4)

Point of care ultrasound (POCUS) has been increasingly used by emergency room physicians to assess for proximal lower extremity DVTs, with studies finding comparable diagnostic accuracy to radiology or vascular lab-performed duplex ultrasonography for detection of proximal DVT. (2)

Anatomy

Figure 1: Veins of the lower extremity (5)

The venous anatomy of the lower limb is relatively simple. The most proximal vein of interest is the Common Femoral Vein (CFV), which gives off the great saphenous vein (a superficial branch). Distal to this, the Common Femoral Vein should bifurcate into the Deep Femoral Vein, and Femoral Vein.

N.B: the Femoral Vein also known as the Superficial Femoral Vein, but because it is still considered a deep vein with respect to the diagnosis of deep vein thrombosis, it is usually referred to as simply the Femoral Vein.

As the femoral Vein travels distally, it enters the adductor canal, passing posterior to the knee, and becomes the popliteal vein. The popliteal vein gives rise to three deep veins at the level of the calf: the perineal vein, anterior tibial vein, and posterior tibial vein. (5)

DVT POCUS protocols

There are multiple POCUS protocols with respect to lower extremity DVT evaluation, ranging from a 2-point ultrasound scan to a whole leg protocol. The more commonly studied, and utilized, protocols in the emergency department are referred to as the 2-point compression study and 3-point compression study. (1,2,5)

(It should be noted that the “points” are regions being scanned, opposed to distinct, singular points).

Figure 2: DVT protocols (5)

2-point compression study

This study evaluates the:

common femoral vein
popliteal vein

The common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein, including the junction of the common femoral vein and greater saphenous vein (CFV-GSV). Ensure this scan includes at least 1-2cm above and below the CFV-GSV junction. (2)

The popliteal vein is assessed from the popliteal fossa until it trifurcates. (2)

3-point compression study

This technique evaluates the:

Common femoral vein
Femoral vein
Popliteal vein.

Like the “2-point” examination, the common femoral vein is evaluated from the inguinal ligament until it becomes the femoral vein (including the CFV-GSV junction). The femoral vein is then further evaluated at least 2 cm distal to the bifurcation of the femoral vein and deep femoral vein. Some variations on the 3-point protocol may suggest continued evaluation of the femoral vein distally as it transitions to the popliteal vein. (2,4,5)

PoCUS Technique (3-point compression technique)

The linear array is the probe of choice for this scan.

Femoral Veins

Position the patient by raising the head of the stretcher 30 degrees and placing the patient in reverse Trendelenburg (if able). This allows distension of the lower limb veins. Slightly flex the knee and externally rotate the hip. (4,5)
Place the probe along the inguinal ligament in the transverse plane midway between the pubic symphysis and anterior superior iliac spine and identify the common femoral vein (CFV). The common femoral artery and vein should be side by side, with the artery lateral to the vein.
Ensure that you are at the most proximal part by sliding the probe proximally towards the abdomen until the CFV become in the far field obscured by bowel gases (most proximal point) then slide the probe distally and Apply firm pressure with the probe until the vein collapses completely, or the artery begins to collapse without full collapse of the vein (which could indicate a DVT). (4,5)

Fig 3: Common femoral vein (5)

CFA: Common femoral artery
CFV: Common femoral Vein (5)

CFV compression (5)

4. After that slowly slide the probe distally, stopping every centimeter (or every width of the probe head), to compress the vein, ensuring it flattens completely. The end point of the scan is 1-2 cm distal to the bifurcation of the common femoral vein into the deep femoral vein and femoral vein. (4,5)

a. Within the first 1-2 cm, the great saphenous vein will branch off from the common femoral vein, usually medially and near field. Monitor the compressibility of both the common femoral vein, as well as the first 1-2 cm of the great saphenous vein.

Fig. 4: Branching of great saphenous vein (5)

CFA: common femoral artery
CFV: common femoral vein
SV: Great Saphenous Vein (5)

b. The common femoral vein should bifurcate into the deep femoral vein, and femoral vein 1-2 cm distal to the CFV-GSV junction. Ensure compressibility is assessed at least 1-2 cm distal to the bifurcation if the common femoral vein. Consider continuing to scan distally until the femoral vein becomes the popliteal vein or are no longer able to assess.

Fig.5: Femoral vein (5)

FA: Femoral Artery
FV: Femoral Vein (5)

Popliteal vein

If the posterior aspect of the knee (popliteal fossa) can be easily accessed in the patient’s current position (i.e., hip externally rotated, knee slightly flexed), no further positioning changes are needed. Other options include having the patient turn to a lateral decubitus position, with the leg of interest above the other, or, have the patient sit on the side of the stretcher, with their legs dangling. (4,5)
Place the probe into the posterior crease of the knee (popliteal fossa), in a transverse plane and scan 2 cm above and below to locate the popliteal vein. If the structure is not immediately identified, slide the probe slightly medially and laterally to attempt to locate it. The vein should be near field, and directly over, the popliteal artery. Once located, assess compressibility of the vessel (4,5)

Fig. 6: Popliteal Vein (5)

PA: Popliteal Artery
PV: Popliteal Vein (5)

Popliteal Vein compression (5)

Continue scanning distally (assessing compressibility along the way), until the popliteal vein trifurcates into the anterior tibial, posterior tibial, and peroneal vein. This marks the end of the examination. (4,5)

Fig.7: Popliteal Vein trifurcation (5)

PA: Popliteal artery
V: Popliteal Vein Trifurcation (5)

Doppler flow augmentation

If the veins are difficult to identify or compress, color doppler can be applied. With the probe held stationary over the vessel in question, gently squeeze the calf distal to the probe. This should augment blood flow into the vein of interest and appear (briefly) as a brighter signal. If there is no increase in blood flow seen, a DVT could be present. (3,5)

Of note, normal venous flow will also change with the respiratory cycle. As the intrabdominal pressure increases with inspiration, venous return from the lower extremities will decrease, while with expiration, flow increases. This can be appreciated with spectral doppler. (3)

Positive Scan

Failure to completely collapse the vein (with enough pressure to partially compress the adjacent artery), at any level, is highly suggestive for the presence of a clot.

Depending on the chronicity of the clot, it may appear echogenic enough to directly visualize under ultrasound, but this is not always the case. (3,4,5)

Direct clot visualization (5)

Non-compressible popliteal vein (own image)

Doppler flow around a DVT, popliteal vein (own image)

The Evidence

A meta-analysis published in 2019, looked at 16 articles utilizing either 2-point compression or 3-point compression and found comparable sensitivities and specificities for proximal DVT, with no statistically significant difference (1):

2-point compression technique

Sensitivity 91%

Specificity 98%

3-point compression technique

Sensitivity 90%

Specificity 95%

Although there was no statistically significant difference between tests, many clinicians still recommend performing the 3-point compression, to include visualization of the femoral vein.

Other studies have quoted sensitivities ranging from 93% to as high as 100% (3).

It’s important to note that compression ultrasound alone is not accurate at picking up below-knee DVT. It is rare for below-knee DVT to progress to pulmonary embolism without first extending to an above-knee DVT. Therefore, although proximal DVT is of more clinical significance in the emergency department, a negative proximal PoCUS DVT scan should be followed by a repeat scan in 5-7 days to ensure a below-knee DVT was not missed. (3)

Pitfalls (false positives and negatives)

False negatives

Small, non-occlusive DVTs may near completely compress under applied probe pressure. Ensure complete vein occlusion when applying pressure during scan.
Excessive probe pressure. If enough pressure is applied to compress the adjacent artery, then a DVT may also be compressed.
A pelvic vein DVT may be missed either due to starting the scan to distally or being unable to compress the vein due to its location. Further imaging may be required if high clinical suspicion including venography, MRI, or extended ultrasound to include the iliac vessels and IVC (3,4).

False positives

Lymph nodes can appear as non-compressible vessels. If in doubt, rotating the probe in a longitudinal orientation will reveal the spherical nature of the lymph node.
Superficial thrombophlebitis. These non-compressible superficial veins may be mistaken for deep veins. The major difference is superficial veins should not accompany arteries.
Recanalized DVT. Old thrombi that have recanalized may not compress appropriately under probe pressure, but flow should be apparent on color doppler imaging. (3,4,5)

Approach to DVT Diagnosis/exclusion

One in three patients with untreated DVTs will progress to clinically significant pulmonary emboli, thus diagnosis and treatment of DVT is vitally important.

Although a positive scan is very helpful, a negative scan does not rule out a thrombus, specifically a below-knee DVT, which can propagate to an above-knee DVT, and eventually a PE given time.

Multiple diagnostic approaches have been described, incorporating the DVT PoCUS scan, well established risk stratification tools (Such as Well’s criteria), and repeat imaging. Below is one such approach, adapted from Mazzolai 2017. (5,6)

DVT diagnostic algorithm (5)

Bottom Line

DVT PoCUS is a (relatively) simple scan, that can be performed quickly and used to assess for proximal DVT. Its utility is well recognized, and it is considered one of the core ultrasound applications for emergency medicine physicians by the American College of Emergency Physicians.

When assessing for DVT, the PoCUS scan should be incorporated into a diagnostic algorithm along with other risk stratification tools, and due to its low sensitivity for below-knee DVT, repeat imaging in the context of a negative scan may be warranted.

References

Lee, J. H., Lee, S. H., & Yun, S. J. (2019). Comparison of 2-point and 3-point point-of-care ultrasound techniques for deep vein thrombosis at the Emergency Department. Medicine, 98(22).
Varrias, D., Palaiodimos, L., Balasubramanian, P., Barrera, C. A., Nauka, P., Melainis, A. A., Zamora, C., Zavras, P., Napolitano, M., Gulani, P., Ntaios, G., Faillace, R. T., & Galen, B. (2021). The use of point-of-care ultrasound (Pocus) in the diagnosis of deep vein thrombosis. Journal of Clinical Medicine, 10(17), 3903.
Atkinson, P., Bowra, J., Harris, T., Jarman, B., & Lewis, D. (2019). Point-of-care ultrasound for Emergency Medicine and Resuscitation. Oxford University Press
Socransky, S., & Wiss, R. (2016). Essentials of point-of-care ultrasound: The ede book. The EDE 2 Course, Inc.
Dinh, V. (n.d.). DVT Ultrasound made easy: Step-by-step guide. POCUS 101. Retrieved November 26, 2021, from https://www.pocus101.com/dvt-ultrasound-made-easy-step-by-step-guide/.
Mazzolai, L., Aboyans, V., Ageno, W., Agnelli, G., Alatri, A., Bauersachs, R., Brekelmans, M. P., Büller, H. R., Elias, A., Farge, D., Konstantinides, S., Palareti, G., Prandoni, P., Righini, M., Torbicki, A., Vlachopoulos, C., & Brodmann, M. (2017). Diagnosis and management of acute deep vein thrombosis: A joint consensus document from the European Society of cardiology working groups of aorta and peripheral vascular diseases and pulmonary circulation and right ventricular function. European Heart Journal, 39(47), 4208–4218.
Deep vein thrombosis (DVT). ACEP Symbol. (n.d.). Retrieved November 29, 2021, from https://www.acep.org/sonoguide/basic/dvt/.

Advanced cardiac echo – a review of E-point septal separation

Posted on November 13, 2021 by Mandy Peach

Dr. Kyle Traboulsee, PoCUS Fellow

Reviewed by Dr. David Lewis

Copyedited by Dr. Mandy Peach

Background:

Often hypotensive, or acutely dyspneic patients, present to the emergency department in significant distress, and emergency physicians must work quickly to evaluate, stabilize, and treat these patients. In the past, determining whether there was a cardiac etiology to these presentations often relied solely on history, physical exam, and varies biochemical markers. Point-of-care ultrasound has increasingly been adopted as a tool to assess cardiac function, and specifically left ventricular ejection fraction (LVEF). Different methods can be used to estimate LVEF (such as “eyeballing”, and the Simpson method), but they can have large inter-reader variability, and require significant cardiac PoCUS experience. E-point septal separation is a measurement of how close the anterior mitral valve leaflet comes towards the interventricular septum and has been shown to be a quick and easy method for estimating LVEF. (1)(2)

Anatomy/pathophysiology

Blood flow is determined by pressure gradients, where blood will travel from areas of high pressure to low pressure. Such a pressure gradient exists between the left atrium and left ventricle. During diastole, the left ventricle relaxes, and the intraventricular pressure decreases until the pressure falls below that of the left intra-atrial pressure. When the left atrial pressure exceeds the left ventricular pressure, the mitral valve opens, and blood passively flows from the high(er) pressure atrium to the lower pressure ventricle. This occurs early in diastole, and the flow of blood from atrium to ventricle is further assisted by an atrial contraction (termed atrial kick) later in diastole. In a healthy individual the atrial-ventricular (A-V) gradient is sufficient to open the mitral valves and bring the anterior mitral leaflet in proximity (or contact) with the intraventricular septum. (1)(2)(3)

In the case of reduced LVEF, the diastolic pressure inside the left ventricle increases due to a decreased ability to eject blood during systole. This can occur due to several reasons, but often result in left ventricular dilation to compensate and preserve LVEF. As LVEF decreases, the ventricular diastolic pressure increases, and the atrial-ventricular (A-V) gradient decreases, leading to a decreased flow rate from atrium to ventricle during diastole, and thus a decreased mitral valve opening. That, paired with LV dilation, leads to an increased (measurable) distance between the anterior mitral valve leaflet and the intraventricular septum during diastole, which can be used as a surrogate marker for left ventricular function. (1)(2)(3).

PoCUS Technique

The E-point septal separation measurements will be made using a parasternal long axis (PLAX) view

Obtaining PLAX view

Steps:

Place probe at the left parasternal border, just caudal to manubrium (second intercostal space), perpendicular to the chest. Ensure the probe indicator is placed towards to the patient’s right shoulder.
Slowly slide the probe down each successive intercostal space, as well as medially (not exceeding patient midline), and laterally, until the highest quality images are obtained (this will likely be around 3-5^th intercostal space, left parasternal border, but may differ from patient to patient)
Once the best view has been located from step 2, slowly rotate the probe to elongate the left ventricle as much as possible. The probe may need to be rocked (heeled) to center the image.

The optimal PSL image includes the left ventricle (LV) in continuity with the aortic outflow tract. The right ventricle will be near field, the left atrium far field, and the mitral valve, aortic valve, and LV cavity are in between (in the middle of the field). The apex of the left ventricle will be screen left. (4)(5).

Parasternal long axis view- probe orientation (6) Parasternal long axis view-anatomy (7)

Parasternal long axis view: normal (own image)

EPSS measurements

EPSS measurements are commonly obtained using M-mode.

Once a parasternal long axis view (PLAX) is obtained, turn on M-mode, and place the cursor over the apical tip of the anterior mitral valve leaflet.
The M-mode will demonstrate movement of the anterior mitral leaflet, with respect to the intraventricular septum. The image should show 2 peaks per heart cycle, under a hyperechoic line. The first, larger peak (E), represents the initial opening of the mitral valve from passive blood flow in early diastole caused by the A-V gradient. The second, usually smaller peak (A), represents the atrial kick, occurring later in diastole. This M mode image is commonly referred to as a “cloudy sky over two hills”
Measure the distance from the top of the E wave to the intraventricular septum. (1)(5)

A normal EPSS measurement with M-mode (8)

PSL: normal EPSS, M-mode (own image)

An abnormal EPSS measurement with M-mode (8)

EPSS measurements can alternatively be measured in B mode

Once a parasternal long axis view (PLAX) is obtained, ensure anterior mitral valve leaflet and septum are well visualized over 3-5 cardiac cycles
Freeze the image and cycle through the previous 3-5 cardiac cycles, stopping on the image where the anterior mitral valve leaflet lies closest to the intraventricular septum.
Measure the distance between the tip of the anterior mitral valve leaflet and the intraventricular septum.

PSL-Poor mitral valve opening (own image)

PSL view- abnormal EPSS measurement in B mode (9)

Interpretation

An EPSS < 7mm is considered normal

An EPSS >7 mm has been suggested as 87% sensitive and 75% specific for an EF <50% (10)

Another study suggested that an EPSS >7 mm was 100% sensitive and 51.6% specific for an EF<30% (11).

One MRI study came up with the following formula to calculate EF (4):

EF=75.5 – (2.5 x EPSS in mm)

Pitfalls

Although a quick and relatively simple surrogate measurement for LVEF, there are some patient populations and situations in which EPSS may give in inaccurate estimate of cardiac function. Patients with mitral stenosis may have poor valve opening, leading to a high EPSS, in the context of an otherwise normally functioning left ventricle. Patients with aortic regurgitation may also have poor anterior mitral valve leaflet motion, and thus have a falsely high EPSS. For these reasons, it would be reasonable to apply color doppler across the mitral and aortic valves to assess for signs of regurgitant jets, as well as close assessment of the valves for signs of calcification. Off-axis measurement, regional wall motion abnormalities, and left ventricular hypertrophy may also result in false interpretations concerning LVEF (1)(3)(4).

Bottom line

E-point septal separation is a relatively easy and reproducible technique that can be used to generate a quick estimation of left ventricular function and can help point towards a cardiac etiology in the undifferentiated patient. It is important to keep in mind factors (as discussed) that may lead to false EPSS interpretations, and EPSS results should not preclude a more global cardiac assessment.

References:

Boon, S. C., Lopez Matta, J. E., Elzo Kraemer, C. V., Tuinman, P. R., & van Westerloo, D. J. (2020). POCUS series: E-point septal separation, a quick assessment of reduced left ventricular ejection fraction in a POCUS setting. Netherlands Journal of Critical Care, 28(3), 139–141.
Cisewski , D., & Alerhand, S. (2018, December). Fellow corner: E-point septal separation in the patient with congestive heart failure. ACEP // Home Page. Retrieved October 18, 2021, from https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/dece/fellow-corner-e-point-septal-separation-in-the-patient-with-congestive-heart-failure/.
Miller, T., Salerno, A., & Slagle, D. (2021, May 25). Advanced Critical Care Ultrasound: E-Point Septal Separation to Estimate Left Ventricular Ejection Fraction. EM resident . Retrieved October 2021, from https://www.emra.org/emresident/article/epss/.
Atkinson, P., Bowra, J., Harris, T., Jarman, B., & Lewis, D. (2019). Point-of-care ultrasound for Emergency Medicine and Resuscitation. Oxford University Press.
Socransky, S., & Wiss, R. (2016). Essentials of point-of-care ultrasound: The ede book. The EDE 2 Course, Inc.
SonoSpot, & SonoSpot. (2012, September 17). Sonotip&Trick: “I can’t get a good parasternal long view.” really? well, try this… Retrieved October 18, 2021, from https://sonospot.wordpress.com/2012/08/07/sonotiptrick-i-cant-get-a-good-parasternal-long-view-really-well-try-this/.
Roma, Ak, Sparks, M., Kelly, C., (@NephroP), A. K., Dowd, R., Crosson, D. A., Deepali, D., Singh, N., Andreea, Aya, S.A., A., Panchal, L. M. R., & Murthy, J. (2019, June 7). Introduction to focused cardiac ultrasound: The parasternal long axis view. Renal Fellow Network. Retrieved October 18, 2021, from https://www.renalfellow.org/2019/06/07/introduction-to-focused-cardiac-ultrasound-the-parasternal-long-axis-view/.
Miller, T., Salerno, A., & Slagle, D. (2021, May 25). Advanced Critical Care Ultrasound: E-Point Septal Separation to Estimate Left Ventricular Ejection Fraction. EM resident . Retrieved October 2021, from https://www.emra.org/emresident/article/epss/.
Satılmış Siliv, N., Yamanoglu, A., Pınar, P., Celebi Yamanoglu, N. G., Torlak, F., & Parlak, I. (2018). Estimation of cardiac systolic function based on mitral valve movements: An accurate bedside tool for emergency physicians in DYSPNEIC patients. Journal of Ultrasound in Medicine, 38(4), 1027–1038. https://doi.org/10.1002/jum.14791
Ahmadpour H, Shah AA, Allen JW, et al. Mitral E point septal separation: a reliable index of left ventricular performance in coronary artery disease. Am Heart J. 1983;106(1 Pt 1):21-8
McKaigney, C. J., Krantz, M. J., La Rocque, C. L., Hurst, N. D., Buchanan, M. S., & Kendall, J. L. (2014). E-point septal separation: A bedside tool for emergency physician assessment of left ventricular ejection fraction. The American Journal of Emergency Medicine, 32(6), 493–497. https://doi.org/10.1016/j.ajem.2014.01.045

Rib Fractures and Serratus Anterior Plane Block

Posted on March 23, 2021 by David Lewis

Saint John EM Rounds – March 2021

Dr. David Lewis

@e_med_doc

View PDF here

Scaphoid Fracture – Can PoCUS disrupt the traditional ‘splint and wait’ pathway?

Posted on March 19, 2021 by David Lewis

PoCUS Fellow Pearl

Dr. Melanie Leclerc, CCFP-EM

MSK PoCUS Fellow

Dalhousie University Department of Emergency Medicine

@MelanieLecler19

Reviewed & Edited by Dr David Lewis (@e_med_doc)

All case histories are illustrative and not based on any individual

Case:

A 37 year old, right hand dominant, carpenter presents to your local ED with a complaint of right wrist pain. He was on a step-stool and lost his balance earlier today. He fell landing on his outstretched arm and had an acute-onset of radial-sided wrist pain. He denies any other injury. There are no neurologic complaints.

On exam, there is no visible deformity. The skin is closed and there is some swelling noted. The patient is tender over the anatomic snuff box as well as volarly over the scaphoid. There is pain noted with axial loading of the thumb. There is no other tenderness. ROM is within normal limits. The limb is distally neurovascularly intact.

X-rays are normal.

An occult scaphoid fracture is suspected. At this institution, patients with suspected occult scaphoid fracture are placed in a thumb spica splint and referred to the local hand surgeon to be seen in ~10-14 days for repeat assessment and X-ray.

Can Point of Care Ultrasound change this traditional “splint and wait” patient pathway?

Background:

Scaphoid fracture is a common presentation to the Emergency Department accounting for approximately 15% of all wrist injuries and 70% of carpal fractures. Up to 30% of the time, radiographs at initial presentation appear normal making fracture a commonly missed injury for Emergency physicians. A failure to recognize this injury can lead to chronic pain and functional impairment for patients. Particularly, fractures of the proximal pole (most distant to the blood supply) can lead to avascular necrosis (AVN) at high rates. Non-union can lead to scaphoid non-union advanced collapse (SNAC wrist) which can perpetuate further degenerative changes throughout the carpus. This can cause a significant impact on quality of life and occupation. Early detection of fracture could expedite fixation and possibly results in better outcomes. Further study in this area is needed.

Anatomy:

The scaphoid bone lies in the radial aspect of the proximal carpal row. It’s unique shape (“twisted peanut”), lends to easy recognition. It articulates proximally with the distal radius, distally with the trapezium, and on its’ ulnar aspect with the lunate to form the scapho-lunate interval. The blood supply to the scaphoid is unique in that the majority of it is retrograde. The dorsal carpal branch of the radial artery supplies the bone from distal to proximal. A small proportion of the blood supply originates at the proximal end. The boundary between the two supplies creates a “watershed” area prone to non-union and AVN.

Classification of Fractures:

Scaphoid fractures are classified by location. These regions are the proximal, middle and distal thirds which account for 20%, 75%, and 5% of the fractures respectively. The stability of fractures is determined by the displacement (>1mm) and angulation (scapholunate angle >60 and radiolunate angle >15). The Hebert Classification as endorsed by Traumapedia can be found below.

Traditional Imaging:

Imaging of these suspected injuries varies. Traditionally serial X-rays were used, but have been found to be poorly sensitive even several weeks after injury. Bone scan has also been used as an alternative due to it’s high sensitivity, but has poor specificity and provides no further information regarding the nature of the fracture. CT is relatively sensitive and specific and provides information for pre-operative planning. MRI is considered the gold standard, but is difficult to obtain in a timely manner in Canada.

Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020 Feb;9(1):81-89. doi: 10.1055/s-0039-1693147. Epub 2019 Jul 21. PMID: 32025360; PMCID: PMC7000269.

PoCUS Technique:

Linear probe
Consider waterbath, gel standoff pad, or bag of IV fluid
Scan with the wrist ulnarly deviated
Scan in the longitudinal and transverse orientations of volar, lateral and dorsal aspects
Place the probe in longitudinal orientation dorsally over lister’s tubercle of the radius and scan distally until the scaphoid is visualized in the snuff box. Scan radial to ulnar.
Rotate to the transverse orientation and scan through proximal to distal
Volarly, in the transverse plane, identify the tendon of the flexor carpi radialis (this lies radial to the easily identifiable palmaris longus tendon on exam). The scaphoid is found deep to this. Scan proximal to distal.
Rotate to the longitudinal orientation and scan radial to ulnar

Video Demonstration:

Findings:

Cortical disruption
Periosteal elevation
Hematoma

The Evidence:

Early advanced imaging (CT or MRI) compared to initial 2 week immobilisation proved more cost effective and had better patient oriented outcomes (ie. missed work).(7)
A systematic review and meta analysis of moderate to high quality studies published in 2018 found that ultrasound had a mean sensitivity of ~89% and specificity of ~90% for detection of occult scaphoid fractures.(1)
Similar results were also reported by another systematic review in 2018.(8)
Pocus was shown to have a comparable sensitivity to CT for occult scaphoid in a systematic review published in 2020.(2)

Limitations:

Only useful if positive
Operator experience dependent
US probe and frequency dependant
Potential for false positives due to injury of nearby structure causing hematoma
Potential for false positives in context of arthritis or remote trauma

Bottom line:

Useful if positive
Still need definitive test to further delineate fracture (ie: for operative planning)
Could expedite CT
Could expedite specialist follow-up
May improve ER physician diagnostic certainty
May improve patient trust and compliance with splinting
Further study is needed

Case Conclusion:

Scaphoid cortical disruption was visualized using PoCUS. After discussion with the hand surgeon, a CT Scan of the wrist was performed which confirmed a minimally displaced waste fracture of the scaphoid. The patient was splinted and seen the next day in clinic for discussion regarding operative management.

Further Review:

References

Ali M, Ali M, Mohamed A, Mannan S, Fallahi F. The role of ultrasonography in the diagnosis of occult scaphoid fractures J Ultrason 2018; 18: 325–331.
Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020 Feb;9(1):81-89.
Bakur A. Jamjoom, Tim R.C. Davis. Why scaphoid fractures are missed. A review of 52 medical negligence cases, Injury, Volume 50, Issue 7, 2019, Pages 1306-1308.
Carpenter CR et al. Adult Scaphoid Fracture. Acad Emerg Med 2014; 21(2): 101-121.
Gibney B, Smith B, Moughty A, Kavanagh EC, Hynes D and MacMahon PJ American Journal of Roentgenology 2019 213:5, 1117-1123

Jenkins PJ, Slade K, Huntley JS, Robinson CM. A comparative analysis of the accuracy, diagnostic uncertainty and cost of imaging modalities in suspected scaphoid fractures. Injury. 2008;39:768–774.
Karl, John W. MD, MPH1; Swart, Eric MD1; Strauch, Robert J. MD1 Diagnosis of Occult Scaphoid Fractures, The Journal of Bone and Joint Surgery: November 18, 2015 – Volume 97 – Issue 22 – p 1860-1868.
Kwee, R.M., Kwee, T.C. Ultrasound for diagnosing radiographically occult scaphoid fracture. Skeletal Radiol 47, 1205–1212 (2018).
Malahias MA, Nikolaou VS, Chytas D, Kaseta MK, Babis GC. Accuracy and Interobserver and Intraobserver Reliability of Ultrasound in the Early Diagnosis of Occult Scaphoid Fractures: Diagnostic Criteria and a Way of Interpretation. Journal of Surgical Orthopaedic Advances. 2019 ;28(1):1-9.
Mallee WH, Wang J, Poolman RW, Kloen P, Maas M, de Vet HCW, Doornberg JN. Computed tomography versus magnetic resonance imaging versus bone scintigraphy for clinically suspected scaphoid fractures in patients with negative plain radiographs. Cochrane Database of Systematic Reviews 2015, Issue 6.
Mallee, W.H., Mellema, J.J., Guitton, T.G. et al. 6-week radiographs unsuitable for diagnosis of suspected scaphoid fractures. Arch Orthop Trauma Surg 136, 771–778 (2016).
Melville, D., Jacobson, J.A., Haase, S. et al. Ultrasound of displaced ulnar collateral ligament tears of the thumb: the Stener lesion revisited. Skeletal Radiol 42, 667–673 (2013).
Meyer, P., Lintingre, P.-F., Pesquer, L., Poussange, N., Silvestre, A., & Dallaudiere, B. (2018). Imaging of Wrist Injuries: A Standardized US Examination in Daily Practice. Journal of the Belgian Society of Radiology, 102(1), 9.
Mohomad et al. 2019. Accuracy of the common practice of doing X-rays after two weeks in detecting scaphoid fractures. A retrospective cohort study. Hong Kong Journal of Orthopaedic Research 2019; 2(1): 01-06.
Neubauer J, Benndorf M, Ehritt-Braun C, et al. Comparison of the diagnostic accuracy of cone beam computed tomography and radiography for scaphoid fractures. Sci Rep 2018; 8:3906.
Ravikant Jain, Nikhil Jain, Tanveer Sheikh, Charanjeet Yadav. 2018. Early scaphoid fractures are better diagnosed with ultrasonography than X-rays: A prospective study over 114 patients, Chinese Journal of Traumatology, Volume 21, Issue 4, Pages 206-210.
Senall, JA, Failla, JM, Bouffard, JL. 2004. Ultrasound for the early diagnosis of clinically suspected scaphoid fracture. J Hand Surg Am, 29:400-405.
https://essr.org/content-essr/uploads/2016/10/wrist.pdf
http://www.bonetalks.com/scaphoid
https://radiopaedia.org/articles/scaphoid-fracture
https://sketchymedicine.com/2014/07/scaphoid-bone-anatomy-and-fractures/
https://radiopaedia.org/cases/scaphoid-fracture-11?lang=gb
https://www.orthobullets.com/hand/6034/scaphoid-fracture
https://meeting.handsurgery.org/abstracts/2018/EP15.cgi
https://www.researchgate.net/figure/Bone-scintigraphy-patient-C-of-the-hands-the-patient-with-a-scaphoid-fracture-on-the_fig4_50399987
https://www.youtube.com/watch?v=7pCXiRQMRKo&t=5s&ab_channel=UltrasoundPod
https://litfl.com/terry-thomas-sign

Lisfranc Injury – We have PoCUS but do we still need the cavalry?

Posted on February 1, 2021 by David Lewis

PoCUS Fellow Pearl

Dr. Melanie Leclerc, CCFP-EM

MSK PoCUS Fellow

Dalhousie University Department of Emergency Medicine

@MelanieLecler19

Reviewed & Edited by Dr David Lewis (@e_med_doc)

All case histories are illustrative and not based on any individual

Case Report

A 32 year old male presents to a rural Emergency Department with a complaint of traumatic left foot pain. He was playing recreational football this evening. While crouching, the patient was tackled by another player who landed on his hyper-plantar flexed left foot from behind. The patient had immediate onset of pain in the middle of his foot and was unable to weight-bear.

On physical examination, you notice significant bruising and swelling of the mid-foot. There is tenderness to the medial mid-foot specifically at the 1st-2nd tarsal-metatarsal articulations. X-rays of the foot appear normal. You are concerned about the possibility of a ligamentous Lisfranc injury.

https://www.footandanklesurgery.com.au/lisfranc-injuries

Lisfranc injuries

Lisfranc injuries are those that involve the tarsal-metatarsal joints. A spectrum of injury exists from ligamentous to fracture-dislocation. Up to 20% – 40% of injuries to the Lisfranc complex are missed in the Emergency Department. Unrecognized and untreated injuries can lead to long-term instability through the midfoot. As this region of the foot is responsible for a significant load during weight bearing, instability can accelerate degenerative changes in the foot resulting in chronic pain and disability

The injury is named after Jacques Lisfranc de St. Martin, a French surgeon and gynecologist performed forefoot amputations at the tarsometatarsal joint on cavalrymen, during the 1815 Napoleonic wars. Although he didn’t specifically describe the injury, it has since been recognised in equestrians and occurring as a result of a trapped plantar flexed foot in the stirrup during a fall.

Other mechanisms have been described including high velocity injuries (sports injuries, foot on brake pedal MVA) and low velocity injuries (Stepping off a curb awkwardly). Low velocity injuries are more likely to be missed than high velocity injuries.

Anatomy

The Lisfranc ligament complex is comprised of 3 ligaments. The dorsal (red), interosseous (blue) and the plantar (green) Lisfranc ligaments. The Interosseous ligament is the largest and the dorsal ligament is the smallest.

The first and second rays have unique ligamentous anatomy wherein no intermetatarsal ligaments exist, but extreme strength is imparted by dorsal, interosseous, and plantar bundles of ligament binding the lateral aspect of the medial cuneiform bone with the medial head of the second metatarsal bone—the Lisfranc ligamentous complex. Only the dorsal and plantar Lisfranc ligaments are accessible to ultrasound.

PoCUS of the Lisfranc joint and dorsal lisfranc ligament (DLL)

Lisfranc injuries are one of the most commonly missed orthopaedic injuries in the Emergency Department. Normal X-rays are often falsely reassuring to providers and patients are discharged with a diagnosis of “soft-tissue injury”. These injuries result in midfoot instability and often require definitive surgical management.

PoCUS has been studied as a method of early detection of these injuries. Specifically, assessment of the dorsal lisfranc ligament (DLL) between the second metatarsal (M2) and the medial cuneiform(C1). PoCUS also has the advantages of being significantly cheaper and more accessible than CT and MRI. Further investigation is needed to validate this method of diagnosis, however ultrasound findings of a disrupted DLL and a widened C1-M2 interval compared to the contralateral side may increase your suspicion when pre-test probability is high.

Technique

Linear probe-MSK setting starting at a depth of 2cm
Place probe in transverse orientation over the proximal aspect of the 1st-2nd metatarsals with the probe indicator to the patient’s right
Slide the transducer proximally until you locate the medial cuneiform and identify the junction between the medial cuneiform (C1) and the 2nd metatarsal (M2)
The medial cuneiform will have an angulated contour appearance in contrast to the round appearance of the metatarsals
Sweep to identify the dorsal lisfranc ligament (DLL)
Assess the DLL for a fibrillar pattern, normal echogenicity and contour
Measure the DLL width and the C1-M2 distance compare to the contralateral side
Measure the C1-M2 distance with weightbearing (if patient tolerates) to compare
Apply colour doppler to assess for hyperemia

PoCUS Findings

Medial Cuneiform (C1), 2nd Metatarsal (M2)

Note the angulated contour of C1 and the smooth contour of M2 – this sectional plane is important when locating the dorsal Lisfranc ligament. The ligament appears hypoechoic with a fibrillar pattern, typical for other ligaments more commonly visualized with PoCUS e.g MCL, ATFL.

1. Normal image – Arrows = dorsal Lisfranc ligament

2. Normal Clip and annotated image. Note how the dorsalis pedis a. frequently overlies the dorsal Lisfranc ligament (yellow lines)

3. Normal clip. Note how there is no separation of C1/M2 while counterstressing the 1st and 2nd rays

4. Thickened, convex contour

5. DLL disrupted, wide joint space

6. Widening C1-M2 with weightbearing

Video Case

Limitations

Anisotropy – Irregular dorsal contour of foot can result in difficult perpendicular imaging of doral Lisfranc ligament. Stand-off gel pad may help.
History of prior trauma – chronic Lisfranc injury may result in joint widening
Bilateral injuries – inability to compare sides to judge joint space widening

Application

Standard foot radiographs should be performed in all cases of suspicion for Lisfranc Injury. Weight bearing radiographs should also be performed if tolerated (the ability to fully weight bear is often limited in the acute setting)

HIgh velocity injuries result in significant soft tissue swelling, and although non-weight bearing radiographs may not be diagnostic, the index of suspicion for Lisfranc injury will be high. Immobilization +/- early CT and follow up with foot and ankle specialist is recommended. For these, high pretest probability injuries, PoCUS findings are unlikely to change management significantly. A clear Lisfranc ligament rupture on PoCUS may trigger a request for CT/MRI earlier than otherwise considered. In most cases advanced imaging and a clear diagnosis is not usually possible until the swelling has subsided.

In low velocity injuries, soft tissue swelling is less pronounced. in the acute presentation the ability to perform weight bearing radiographs is limited by pain. Index of suspicion for Lisfranc injury may be low-moderate and the decision to immobilize and refer for specialist follow up can be difficult. While there is limited published evidence for PoCUS test characteristics in Lisfranc injury, a positive scan (injury + disrupted ligament / widening of C1/M2) is likely to be highly specific. Patients with positive PoCUS findings should therefore be immobilized and referred for specialist follow up. In those with negative or inconclusive findings, management and disposition will depend on degree of clinical suspicion and correlated with radiographic findings.

In summary, PoCUS provides a useful additional piece of information that can be plugged into a bayesian diagnostic pathway. What is the pretest probability of a particular diagnosis? After reviewing radiographs and performing PoCUS is the diagnosis more or less likely?

More evidence is required to fully understand the test characteristics of PoCUS for Lisfranc injury. Would the addition of plantar views improve sensitivity?

Although the performing the scan takes only a few minutes, it is quite technically challenging for the novice. As with all MSK PoCUS, repeated practice in numerous patient presentations will increase operator speed and accuracy.

Finally, although we still need the cavalry, PoCUS can help us decide which regiment and how quickly we need them!

References

Mayich DJ, Mayich MS, Daniels TR. Effective detection and management of low-velocity Lisfranc injuries in the emergency setting: principles for a subtle and commonly missed entity. Can Fam Physician. 2012;58(11):1199-e625. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498011
Woodward, S., Jacobson, J.A., Femino, J.E., Morag, Y., Fessell, D.P. and Dong, Q. (2009), Sonographic Evaluation of Lisfranc Ligament Injuries. Journal of Ultrasound in Medicine, 28: 351-357.
Döring, S., Provyn, S., Marcelis, S., Shahabpour, M., Boulet, C., de Mey, J., De Smet, A., De Maeseneer, M. (2018). Ankle and midfoot ligaments: Ultrasound with anatomical correlation: A review. Eur J Radiol.107:216-226.
Kaicker, J., Zajac, M., Shergill, R., & Choudur, H. N. (2016). Ultrasound appearance of the normal Lisfranc ligament. Emergency Radiology, 23(6), 609-614.
DeLuca, M.K., Walrod, B. and Boucher, L.C. (2020). Ultrasound as a Diagnostic Tool in the Assessment of Lisfranc Joint Injuries. J Ultrasound Med, 39: 579-587.
Marshall, J., Graves, N.C., Rettedal, D.D., Frush, K., Vardaxis. V. (2013). Ultrasound Assessment of Bilateral Symmetry in Dorsal Lisfranc Ligament. The Journal of Foot and Ankle Surgery, 52(3): 319-323.
Rettedal, D.D., Graves, N.C., Marshall, J.J. et al. Reliability of ultrasound imaging in the assessment of the dorsal Lisfranc ligament. J Foot Ankle Res 6, 7 (2013).

Detection of Foreign Bodies in Soft Tissue – A PoCUS-Guided Approach

Posted on January 23, 2021 by David Lewis

Medical Student Clinical Pearl

Sophia Miao, CC4

MD Candidate, Class of 2021

Dalhousie University

Reviewed & Edited by Dr David Lewis (@e_med_doc)

All case histories are illustrative and not based on any individual.

Case Report

A 33-year-old woman presents to the ED with pain and swelling over the third digit of her right hand. One week prior to this, she had shattered a jar and a small glass splinter lodged into her finger. This was promptly removed at home, and the puncture wound healed without intervention.

She presented to the emergency room 7 days later with new pain and swelling surrounding the initial puncture wound. There is no significant past medical history and most recent Td booster was given 2 years ago. On examination, there was some mild erythema, swelling, and tenderness on palpation of the lateral aspect of the middle phalanx of the right hand. She is otherwise well. You wonder about the possibility of a retained foreign body.

PoCUS-Guided Approach to the Detection of Foreign Bodies in Soft Tissue

Foreign bodies in soft tissue are a common complaint in the emergency department, with open wounds comprising 5.7 million (or 4.5% of total) visits to the ED in 2010.[1] Foreign bodies were found in up to 15% of wounds.[2] If retained, complications of these include allergic reaction, inflammation, delayed wound healing, damage to adjacent tissue structures, neurovascular damage, tetanus, and infectious complications including cellulitis, necrotizing fasciitis, synovitis, and abscess formation.[3],[4] Proper detection, and subsequent removal, of retained foreign bodies is therefore essential to evaluate the wound and prevent associated complications.

Diagnosis of a retained FB requires a high index of suspicion. Clinical suspicion should be raised when there is a compelling history and physical exam. The latter may include signs of inflammation and/or infection, including warmth, swelling, erythema, tenderness, abscess formation, and discharging wound).[5],[6]

Conventional radiography is known to commonly miss radiolucent materials such as wood and plastic. It has been shown that plain radiographs have only a 7.4% sensitivity in the detection of wood foreign bodies.⁵ Remarkably, even glass – a radiopaque material – has been demonstrated to have been missed in up to 35% of x-ray film studies.[7] There is increasingly compelling evidence for the clinical usefulness and accuracy of bedside ultrasonography in the detection of soft-tissue foreign bodies. It has been shown to have a specificity of 92% (95% CI = 88%-95%) and sensitivity ranging from 83.3% to 100%.[8],[9]

PoCUS Technique

Probe selection: the use of a high-frequency ultrasound probe is recommended. This allows for greater axial resolution at the expense of less penetration, which is suitable for the detection of small foreign bodies, as they typically lodge in superficial tissues.[10]

If the wound is open, a transparent covering such as a Tegaderm or probe cover can be used to cover either the wound or probe before scanning.[11]

Medium: standard technique for assessment of soft-tissue structures by ultrasound involves the use of a standoff pad or gel mound. However, this is not always possible due to the irregular curvature of extremities such as fingers and feet, which may result in poor contact between the probe and skin, decreased field of view, and patient discomfort. A water-bath technique can circumvent this and has been shown to be superior in such cases.[12]

Method: the area of interest should be scanned in both longitudinal and transverse planes. Foreign bodies are best detected when the transducer aligns with the longitudinal axis of the foreign body, and therefore revealing the span of the object.[13] As foreign bodies tend to embed less than 2 cm below the surface of the skin, the depth of field should remain superficial in order to avoid false positives.

US Probe: Ultrasound Water Bath for Distal Extremity Evaluation

Findings

Ultrasonography and plain film findings of foreign bodies in soft tissue are summarized in the table below.

Table 1. Ultrasound and x-ray findings of foreign bodies.⁶^{,[14],[15],[16]}

Material	Ultrasound findings	X-ray findings
Wood	Hyperechoic; may become isoechoic with surrounding tissue as it denatures over time Posterior acoustic shadowing	Radiolucent, often undetectable
Glass	Hyperechoic, bright Posterior acoustic shadowing ± Posterior comet tail reverberation, diffuse beam scattering	Radiopaque
Plastic	Hyperechoic Posterior acoustic shadowing	Radiolucent, often undetectable
Metal	Hyperechoic, bright Posterior acoustic shadowing ± Posterior comet tail reverberation	Radiopaque

Foreign bodies may also display a straight or regular contour.⁶

Image 1 – Wood splinter in volar aspect digit, mildly hyperechoic, surrounding hypoechoic halo, irregular acoustic shadowing

Image 2 – Plastic FB, within tendon sheath, volar aspect digit, brightly hyperechoic, long axis

Image 3 – Plastic FB, within tendon sheath, volar aspect digit, brightly hyperechoic, short axis

Image 4 – Glass FB – brightly echogenic, posterior reverberation, FB long axis

Image 5 – Metal FB – brightly echogenic, posterior reverberation, FB long axis

It is important to note that the acoustic shadowing may be complete or partial, as this is dependent on the angle of sonography and foreign body material.[17] It is also possible to see a hypoechoic halo around the FB, which may be suggest edema, abscess formation, granulation tissue, or other inflammatory process.[18] As the inflammatory reaction develops, the halo effect becomes more apparent; therefore the foreign body is therefore best visualized by PoCUS several days after the initial injury.⁶

PoCUS-Guided Foreign Body Removal

There are several options for removal of a foreign body with PoCUS:[19]

Needle localization. Once the foreign body has been identified on PoCUS, a hollow injection needle can be inserted under ultrasound guidance and local anesthetic is delivered through this. This can be done in either the transverse or longitudinal plane. The ultrasound probe is then removed, and an incision is made along the needle. Through the incision site, tweezers or forceps can be used to remove the foreign body.
Real-time ultrasound-guided extraction. This technique is similar to the needle localization method. However, rather than removing the transducer following the needle insertion, the entire procedure is done under direct ultrasound visualization. The probe is held in the longitudinal plane to visualize both the forceps and the foreign body during the extraction process.

There is a risk of obscuring the view of the foreign body on ultrasound with air as a result of the incision itself or through anesthetic delivery. Saline may be used to irrigate and therefore mitigate the issue.¹⁹

The patient’s tetanus status should be verified and updated, if required. Antibiotic therapy may also be provided, should the risk of infection justify it.

Limitations

There is the possibility of false positives. Foreign bodies must be differentiated from other hyperechoic body structures, including ossified cartilage, sesamoid bones, scar tissue, gas bubbles, and intermuscular fascia.¹⁴ Visualization is therefore important in both longitudinal and transverse planes, as well as comparison with the opposite side. Acoustic shadowing, hypoechoic halo, and posterior comet tails, if present, can also be indicative of a FB rather than organic body tissue.

Traumatic air injection as a result of penetrating injury can create a scatter artifact on ultrasound, which can be misinterpreted as an acoustic shadow associated with a foreign body. To differentiate this from a true acoustic shadow, pressure may be applied through the transducer to displace the scatter artifact.⁶

As is commonplace with all emergency ultrasonography, limitations also include the technical skill of the operator.[20] A foreign body may also be too small to be detectable by ultrasound. It is therefore important to remember that a negative scan does not necessarily rule out the possibility of a retained foreign body, and the history and physical examination must be considered in conjunction with the ultrasound findings.

References

[1] National Center for Health Statistics. Emergency Department Visits. Available from: http://www.cdc.gov/nchs/fastats/emergency-department.htm.

[2] Steele MT, Tran LV, Watson WA, Muelleman RL. Retained glass foreign bodies in wounds: predictive value of wound characteristics, patient perception, and wound exploration. Am J Emerg Med. 1998 Nov;16(7):627-30. DOI: 10.1016/s0735-6757(98)90161-9. PMID: 9827733.

[3] Skinner EJ, Morrison CA. Wound Foreign Body Removal. In:StatPearls. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK554447/.

[4] Ebrahimi A, Radmanesh M, Rabiei S, Kavoussi H. Surgical removal of neglected soft tissue foreign bodies by needle-guided technique. Iran J Otorhinolaryngol. 2013 Winter;25(70):29-36. PMID: 24303416; PMCID: PMC3846242.

[5] Levine MR, Gorman SM, Young CF, Courtney DM. Clinical characteristics and management of wound foreign bodies in the ED. Am J Emerg Med. 2008 Oct;26(8):918-22. DOI: 10.1016/j.ajem.2007.11.026. PMID: 18926353.

[6] Atkinson P, Bowra J, Harris T, Jarman B, Lewis D. Point of Care Ultrasound for Emergency Medicine and Resuscitation. Oxford, United Kingdom: Oxford University Press; 2019. DOI: 10.1093/med/9780198777540.001.0001.

[7] Kaiser, C. William MD; Slowick, Timothy MBA; Spurling, Kathleen Pfeifer RN, JD; Friedman, Sissie MA. Retained Foreign Bodies, The Journal of Trauma: Injury, Infection, and Critical Care: July 1997 – Volume 43 – Issue 1 – p 107-111.

[8] Davis J, Czerniski B, Au A, Adhikari S, Farrell I, Fields JM. Diagnostic Accuracy of Ultrasonography in Retained Soft Tissue Foreign Bodies: A Systematic Review and Meta-analysis. Acad Emerg Med. 2015 Jul;22(7):777-87. DOI: 10.1111/acem.12714. Epub 2015 Jun 25. PMID: 26111545.

[9] Atkinson P, Madan R, Kendall R, Fraser J, Lewis D. Detection of soft tissue foreign bodies by nurse practitioner-performed ultrasound. Crit Ultrasound J. 2014 Jan 29;6(1):2. DOI: 10.1186/2036-7902-6-2. PMID: 24476553; PMCID: PMC3922659.

[10] Dean AJ, Gronczewski CA, Costantino TG. Technique for emergency medicine bedside ultrasound identification of a radiolucent foreign body. The Journal of Emergency Medicine. 2003;24(3):303–8. DOI: 10.1016/S0736-4679(02)00765-5.

[11] Chen KC, Lin AC, Chong CF, Wang TL. An overview of point-of-care ultrasound for soft tissue and musculoskeletal applications in the emergency department. J Intensive Care. 2016 Aug 15;4:55. DOI: 10.1186/s40560-016-0173-0. PMID: 27529031; PMCID: PMC4983782.

[12] Krishnamurthy R, Yoo JH, Thapa M, Callahan MJ. Water-bath method for sonographic evaluation of superficial structures of the extremities in children. Pediatr Radiol. 2013 Mar;43 Suppl 1:S41-7. DOI: 10.1007/s00247-012-2592-y. Epub 2013 Mar 12. PMID: 23478918.

[13] Rooks VJ, Shiels WE 3rd, Murakami JW. Soft tissue foreign bodies: A training manual for sonographic diagnosis and guided removal. J Clin Ultrasound. 2020 Jul;48(6):330-336. DOI: 10.1002/jcu.22856. Epub 2020 May 8. PMID: 32385865.

[14] Mohammadi A, Ghasemi-Rad M, Khodabakhsh M. Non-opaque soft tissue foreign body: sonographic findings. BMC Med Imaging. 2011 Apr 10;11:9. DOI: 10.1186/1471-2342-11-9. PMID: 21477360; PMCID: PMC3079678.

[15] Lewis D, Jivraj A, Atkinson P, Jarman R. My patient is injured: identifying foreign bodies with ultrasound. Ultrasound. 2015 Aug;23(3):174-80. DOI: 10.1177/1742271X15579950. Epub 2015 Mar 26. PMID: 27433254; PMCID: PMC4760591.

[16] Campbell EA, Wilbert CD. Foreign Body Imaging. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020. Available from: https://www.ncbi.nlm.nih.gov/books/NBK470294/.

[17] Anderson MA, Newmeyer WL 3rd, Kilgore ES Jr. Diagnosis and treatment of retained foreign bodies in the hand. Am J Surg. 1982 Jul;144(1):63-7. DOI: 10.1016/0002-9610(82)90603-1. PMID: 7091533.

[18] Little CM, Parker MG, Callowich MC, Sartori JC. The ultrasonic detection of soft tissue foreign bodies. Invest Radiol. 1986 Mar;21(3):275-7. DOI: 10.1097/00004424-198603000-00014. PMID: 3514541.

[19] Paziana K, Fields JM, Rotte M, Au A, Ku B. Soft tissue foreign body removal technique using portable ultrasonography. Wilderness Environ Med. 2012 Dec;23(4):343-8. DOI: 10.1016/j.wem.2012.04.006. Epub 2012 Jul 25. PMID: 22835803.

[20] Pinto A, Pinto F, Faggian A, Rubini G, Caranci F, Macarini L, Genovese EA, Brunese L. Sources of error in emergency ultrasonography. Crit Ultrasound J. 2013 Jul 15;5 Suppl 1(Suppl 1):S1. DOI: 10.1186/2036-7902-5-S1-S1. Epub 2013 Jul 15. PMID: 23902656; PMCID: PMC3711733.