Procedure: Radial Artery Catheter Insertion

Although radial artery catheter insertion can be done as a palpation-guided procedure, it can sometimes be difficult to perform successfully. This video provides a general overview on how to perform this procedure with ultrasound guidance.

When performing this procedure, the radial artery appears as an anechoic circle that is pulsatile. Unlike the surrounding veins, the radial artery should not be compressible. If you are having difficulty finding the radial artery, the use of colour doppler can help with localization.

Clinical Case: Myocardial Infarction

A 56 year old gentleman presents to the emergency department with a 2 hour history of crushing central chest pain.

On physical exam, blood pressure is 90/55 with a pulse of 90. Oxygen saturations are 98% on 2 litres nasal prongs. JVP is elevated and there is peripheral edema. Heart sounds are normal with no murmurs appreciated. Lungs are clear on auscultation.

You review the initial ECG:

You perform a quick bedside cardiac ultrasound, and the subcostal view reveals the following image:

This is an example of an inferior myocardial infarction with RV involvement. The physical exam demonstrating predominately symptoms of right-sided heart failure in combination with an ECG with ST elevation in inferior leads would suggest RV involvement. 

The bedside cardiac ultrasound can help in confirming RV dysfunction, which is present in the ultrasound image above. The RV sits inferiorly and anteriorly, therefore in the subcostal view it appears closest to the probe at the top of the screen. As you can see, it is not contracting well during systole which confirms the suspected RV involvement. 

It is important to consider RV involvement in patients with an inferior STEMI since these patients are usually preload dependent. This modifies how they are treated, and they more often require intravenous fluids to increase their pre-load as well as the avoidance of medications that cause vasodilation (ie: nitrates). Since the presence of RV involvement changes how these patients are managed, bedside cardiac ultrasound can assist with management. 

FOCUS App

The Toronto General Hospital Department of Anesthesia has an app for Cardiac Ultrasound. Their FOCUS (FOcused Cardiac UltraSound) app is also available to download in the App Store.

This app has several different features. Firstly, it gives a great overview on the different ultrasound views of the heart, including how to obtain these views, how to optimize these views and which structures are assessable with each view. Another great feature of this app is that is provides a great overview of the anatomy with the use of educational diagrams with key anatomical structures labelled. The images and diagrams are clear and easy to read.

The FOCUS app also provides an overview and examples of normal and abnormal pericardium, left ventricular funciton, right ventricular function, and volume status. 

This is a great user-friendly and interactive app for anyone who is just starting to learn how to perform bedside cardiac ultrasound, as well as anyone who needs a quick reminder on the essential points. 

Procedure: Pericardiocentesis

This video provides an overview of how to use an ultrasound to perform a pericardiocentesis using the cardiac probe.

As with most ultrasound guided procedures, it's important to visualize the needle on insertion and correctly identify the surrounding anatomy. The video provides a good overview of cardiac anatomy as well as the location of a pericardial effusion on echo.

Clinical case: Cardiac Tamponnade

A 43 year old gentleman presents to the emergency department via ambulance with significant shortness of breath. 

On clinical exam, he is in respiratory distress, and his blood pressure is 80/40 with a heart rate of 114. The JVP is quite elevated on exam, and there is significant pedal edema. Heart sounds are difficult to appreciate on auscultation, and there are crackles bilaterally on lung auscultation. 

You perform a quick bedside ultrasound which reveals the following images:

These images represent a significant pericardial effusion causing cardiac tamponade. Although tamponade is a clinical diagnosis, bedside ultrasonography can aid in the diagnosis (Grade 1C recommendation, Society of Critical Care Medicine 2016).

In these images, both the presence of a significant pericardial effusion as well as right ventricular collapse in diastole support the diagnosis of cardiac tamponade. 

Critical Care Guidelines - Part 2

The second part of the Society of Critical Care Medicine's guidelines regarding bedside ultrasonography have recently been posted on their website. This part of the guidelines, by Levitov et al., focuses on cardiac bedside ultrasonography in the critical care setting.

The link can be found here: SCCM: Cardiac Ultrasonography

This guideline lists several class 1 recommendations for the use of bedside cardiac ultrasonography based on the GRADE system, which demonstrates that there is evidence to support the use of beside cardiac ultrasonography in the evaluation of the critically ill patient.