Point of Care Ultrasound- POCUS
Cardiac Ultrasound
The use of ultrasound is now becoming more commonplace in the diagnosis and treatment of our patients. This is proving very valuable as it is quick to use at the bedside, is relatively cheap and quick to interpret allowing us to gain much greater insights much more easily.
Cardiac ultrasound can be very complicated or reasonably simple and this really depends on what it is you are trying to diagnose. Some of the more simple function of the heart can be assessed using bedside ultrasound and with practice, experience and a good mentor this can become a very useful tool in your medical armoury.
Here, in the UK, we can access the Focused Intensive Care Echo (FICE) course to enable us to become accredited with some of the basic skills that an make such a difference. This requires that we register with the Intensive Care Society and undertake a face to face course (one day) and do 50 scans 10 of which must be with a mentor.
I am currently undertaking such learning and thought it might be useful for my own learning and to help others to get the green screen out and try to understand what it is I am actually looking at! As a consequence I am only going to talk about those views and the issues within those views that are within the scope of FICE accreditation.
The videos are my efforts to move forward. I hope they are of value to you.
Parasternal Long Axis View
This view is obtained by placing the cardiac probe (or phased array) on the chest at the 3-5th intercostal space just lateral to the sternum on the left side. The marker on the probe needs to be pointing to the patients right shoulder. As with all these views you may need to do a little "window shopping" to get the view you need.
Keep the following in mind:
- Attempt to display the left ventricle as long stretched as possible. You should not be able to see the apex in this view.
- Ideally try to get the mitral valve in the middle of the image.
- Adjust the screen so that there is about 1 cm at the bottom for the structures behind the left ventricle. They may be important.
- The right ventricle is the first structure seen. This should be about half the size of the left ventricle. You will not see the right atrium in this view.
- You will get a good view of the intraventricular septum.
- You will be able to see the aortic root and the left atrium.
- You should be able to get a good view of the mitral and aortic valves with their posterior and anterior leaflets.
- The left ventricle should be evident by its muscular walls. The walls of the left ventricle should shorten as it contracts which is a measure of its function.
- Another important structure to try to identify is the descending aorta behind the heart. The pericardium comes off this structure on ultrasound and the presence of fluid in front of or behind the aorta will indicate whether that fluid is pericardia or pleural.
Parasternal Short Axis View
When you have completed your parasternal short axis view, see above, then you need to rotate the probe 90 degrees clockwise. Keep the mitral valve in the middle of the screen as you do.
The marker on the probe should now be pointing to the patients left shoulder. Again, do a bit of "window shopping" to get the best view.
Keep the following in mind:
- You should be able to see an almost perfect circle as you look down through the left ventricle in the lower right of the image.
- Above and to the left of the ventricle should be the crescent shape of the right ventricle.
- In between these structures is the intraventricular septum.
- At the level below the mitral valve (see video) you will be able to see the papillary muscles.
- The contraction of the left ventricle should be even all the way round. Imagine you have put your finger in it and it is squeezing. Will it squeeze evenly?
- If you then tilt the probe superiorly then the "fish mouth" of the mitral valve should come in to view. The leaflets should be thin and mobile.
- If you continue to tilt upwards then you may eventually get a view of the aortic valve, distinguished by its 3 leaflets (usually). Because of this 3 leaflet system it is sometimes referred to as the Mercedes Benz sign.
Apical Four Chamber
AWAITING VIDEO- WATCH THIS SPACE
The Apical views are achieved by having the probe at the 5th intercostal space, midclavicular line.
The index marker is directed towards the patients left axilla.
One can achieve both a 4 chamber and 5 chamber view. If you first gain the four chamber view, then a tilt of the transducer downwards will bring in the 5 chamber view which will include the aortic valve in the middle.
Keep the following in mind:
- Relative sizes of the chambers can be assessed as they are laid out side by side.
- Right ventricle should be about two thirds the size of the left.
- Atria should be similar sizes and considerably smaller than the ventricles.
- Right ventricular free wall is quite trabeculated.
- You may see the moderator band across the apex of the right ventricle.
- Realtive to each other the tricuspid valve tends to sit slightly closer to the apex than the mitral valve (approx 5mm, so may be hard to see).
- Are the walls of the ventricles moving equally?
- You can also look around the heart to see if there is any pericardial fluid.
Subcostal Four Chamber
AWAITING VIDEO- WATCH THIS SPACE
This view is obtained by placing the cardiac probe (or phased array) on the chest inferior to the sternum. The marker on the probe needs to be pointing to the patients left axilla.
Remember also that you are pointing the probe up towards the patients head rather than at their spine. This should get you a good view through the liver.
As with all these views you may need to do a little "window shopping" to get the view you need.
Keep the following in mind:
- The first structure you will see will be the liver.
- Immediately below that will be the right ventricle.
- Below that will be the left ventricle with the wall of the intraventricular septum between them..
- You should also get good views of the atria to the right of both ventricles.
- Both triscuspid and mitral valves should be visible .
- There should be good contractility observed throughout the heart and again the relative sizes of the ventricles can be assessed. .
- The pericardium should be visible as a bright line and there should not be any fluid visible around the heart which may indicate a pericardial effusion..
Guidelines for the management of tracheal intubation in critically ill adults
Having read the guidelines I made these infographics. They are FREE. Just click on the button below.