hi my name is Mike avula and today we will be talking about basic trans thoracic echocardiography including the Imaging windows and various pathologies at the end we will also talk about IVC measurements the probe of choice for this examination is the cardiac probe aka the phased array probe this probe is great for fitting in between the rib spaces if your machine does not have this probe the curval linear probe can be used but really the preferred probe is the phase array probe first we need to talk about probe positioning you will use a standard mode
where the indicator is on the left of the screen for most scans that are non-cardiac in this convention the probe marker will either be to the patient's right side or to the patient's head to get a cross-section of the heart however you need to imagine the heart as an upside down cone in standard mode a cross-sectional view or short AIS view of the heart will have the probe marker pointing to the patient's right hip and in Long AIS view to the patient's left hip as an example this is a parisal long AIS view of the
heart we are in standard mode shown by the red arrow on the left of the screen the probe marker on the body is facing to the patient's left hip contrast standard mode with cardiac mode notice the indicator is on the right of the screen shown by the red arrow in this view again Imagining the heart as an upside down cone the long axis view will have the probe indicator pointing to the patient's right shoulder and in short AIS orientation to the patient's left shoulder this is opposite of standard mode but so is the indicator on
the screen opposite of standard mode therefore the image acquired will be the same basically if you flip the indicator then you need to also flip the probe this is a parisal long AIS view of the heart probe marker is facing to the patient's right shoulder and we are in cardiac mode because the indicator on the screen is on the right side remember that the left ventricle should always be on the left of the screen for parason long axis we will talk about that again so here the image looks different it is actually flipped remember when
I said that the LV should be on the left of the screen well here it's on the right why is this image flipped first see that the indicator on the screen is on the right which tells you that you are in cardiac mode then see where the probe marker is facing and in this case it is facing down to the patient's left hip the orientation in standard mode not cardiac mode remember in cardiac mode for parison long axis probe indicator should point to the right shoulder this image also looks different again it is flipped why
is it flipped first see that the indicator on the screen is on the left which tells you that you are in standard mode then see where the probe marker is facing and in this case it is facing to the patient's right shoulder the orientation in cardiac mode not standard mode remember in standard mode probe indicator should point to the left hip so to summarize in cardiac mode the indicator on the screen should be on the right side and the probe marker should be be facing the right shoulder the LV should be on the left of
the screen don't worry there's an easy way to remember that which we'll get to in a moment in case you got lost here's another summary when troubleshooting your image first check the screen for the indicator position for personal long axis make sure the probe is either pointing to the right shoulder in cardiac mode or left hip standard mode also make sure the LV is on the left of the screen for par long AIS if you do the previous two and are still unsatisfied with the image it may help to ask the patient to assume a
left lateral decubitus position this brings the heart forward and closer to the chest surface which could help in acquiring your image have them lay on their left side it may help to ask the patient to place his or her arm above the head now we will talk about obtaining the cardiac views you can practice your Echo skills by developing a systematic protocol a suggested approach can begin with the parasal long axis view rotate the probe 90° for short axxis move on down to the apical four chamber and then finish up with the subid window let's
start with the parisal long AIS view start out in cardiac mode the indicator should be on the right of the screen and then the probe indicator on the patient's body should be facing the right shoulder start by placing the probe at the nipple line or fourth interner Cal space or in women the infr memory line right next to the sternum keep the probe perpendicular to the skin and hug the sternum as you go up and down the chest searching for the best window so I told you I would give you an easy way to remember
the paral long AIS view you can remember it by the 3 L's to success the personal long axis should have the left ventricle on the left side of the screen so for a visual here's what we're looking at for the personal long AIS view make sure the left ventricle is on the left of the screen before we go identifying what we see on the image it may be helpful to see a schematic representation on the ultrasound image toward the top of the screen we will see the right ventricle with the left ventricle beneath or deeper
to it and the interventricular septum in between in the left ventricle you can see the mitro valve and sometimes the papillary muscles to the right of the mitro valves you will see the left atrium in this image you can also see the aortic Valves and the aortic outflow track going back to the ultrasound image if we again imagine the heart as a cone the Apex is at the upper left of the screen with the base towards lower right anteriorly is at the top of the screen which makes sense because that is where you physically have
the Probe on the chest and deeper or towards the bottom of the image is the posterior portion of the heart the items to identify in the parasal Long exis View are the left ventricle the right ventricle the aortic valve and the mitro valve the left atrium the interventricular septum the descending aorta which will be important for distinguishing between a pericardial fusion and a plural Fusion we'll talk about that later the aortic outflow tract and the pericardium the parisal long AIS view is great for estimating e ection fraction there are a few studies that show that
eyeballing the ejection fraction by looking at the squeeze of the heart and how closely the anterior mitro valve leaflet gets to the interventricular septum is a good estimate of the gold standard Cardiology method of evaluating the EF additionally it is much faster and can easily be done in the emergency setting in this ultrasound image you can see that the anterior mitro valve leaflet is slapping up against the interventricular septum you can also see that there is good squeeze of the ventricle and that the ventricular walls are almost touching with each contraction this is indicative of
a normal ejection fraction of greater than 50% in this ultrasound image the anterior mitro valve leaflet does not quite make it to the inter ventricular septum Additionally the squeeze of the ventricles just isn't as good as the last image this EF is consistent with moderately depressed at 30 to 50% how do we know it is not severely depressed look at the next image in this image there's very little motion of the mitro valve leaflets and hardly any squeeze of the ventricles at all this is a sick heart with an ejection fraction of probably less than
30 if you want to quantitatively measure the ejection fraction and not exactly eyeball it you can do so using epss or E Point sepal separation this is a heart in the parasal long AIS view if we want to use epss we just throw down an M mode Spike at the tip of the anterior mitro valve leaflet you can freeze the image and this is what you will see the thicker white line represents the interventricular septum and the squiggly wavy lines beneath that represents the motion of the anterior mitro valve leaflet I don't know if you
noticed but the anterior mitro valve leaflet slaps twice on the interventricular septum in A Normal Heart the E represents the passive filling of the ventricles and a represents the atrial contraction the distance between the IVs and the squiggly lines show just how close the anterior mitro valve leaflet gets to the interventricular septum a distance of less than 7 mm is considered normal and greater than 10 is considered LV dysfunction or reduced EF 7 to 10 is sort of a gray area and needs to be taken into context notice this distance is greater than 10 mm
and is consistent with CHF this is another example of reduced ejection fraction CHF is not the only way that your patient can end up with a reduced EF if your patient has atic regurgitation the back flow of blood will inhibit the anterior mitro valve leaflet from opening fully this will make your epss larger even though there is no CHF or if your patient has mitro stenosis the poor Excursion of the mitro valve leaflets will give you a large epss falsely predicting cardiac ejection fraction now I mentioned earlier that the descending aorta is important for distinguishing
between a pericardial fusion and a plural effusion you can see in this image that this patient has a paracardial fusion because the fluid is within the pericardium anterior to the descending a y shown by the bottom arrow in this Echo you can see that the effusion is posterior to the pericardium and posterior to the descending aorta this is actually a plural affusion we can't talk about paracardial Fusion without talking about paracardial tanod traditionally the diagnosis of tamponade is made when you have diastolic collapse of the ventricle with clinical symptoms of hypo profusion such as hypotension
tachicardia Syncopy shortness of breath chest pain Etc what's happening is the pressure of the fusion is great enough to impair filling of the RV blood in equals blood out so there will also be impaired filling of the LV you can tell that there is diastolic collapse of the RV because it happens when the mitro valves are open right ventricular strain can be assessed in this view as well strain can be due to any acute event usually a PE that causes sudden pulmonary hypertension causing resistance to the outward flow of the RV this can cause the
RV to enlarge now we're going going to talk about the parisal short axis from the parisal long axis view rotate the probe 90° clockwise towards the patient's left shoulder then fan towards the Apex and up towards the base Fanning up towards the base of the heart to the patient's head will get you more of the mitro valve even the aortic valve in view in this image we are more inferior or towards the Apex in the mid papillary view the circle in the middle is a left ventricle on the other side of the IVs is the
right ventricle the arrows are pointing to the papillary muscles and the mitro valve Fanning superior to the patient's head you can see the mitro valve leaflets and the fish mouth view Fanning even more superiorly and you can see the aidic valve called the Mercedes-Benz sign here's a schematic that will help identify the images in the parach long AIS view with the atic valve in view most anteriorly is the right ventricle with the ra feeding through the tricuspid valve the tricuspid aortic valve is right in the middle the left atrium is the deepest structure feeding down
into the screen out of plane of the probe the LA is the deepest structure so in review more inferiorly or towards the Apex is the mid papillary view fing up towards the head you can see the fishmouth mitro valve most superiorly you can begin to see the atic valve you can also assess for right ventricular strain in the peristal short axis view here we see an enlarged RV and sepal Boe showing something called the D sign where the pressure of the right ventricle is great enough during cyly to actually cause the IVs to bend in
towards the LV here's another image demonstrating the D sign now we will talk about the apical four chamber view make sure the probe indicator is pointing towards the patient's left axila and from the parasal short axis view slide down towards the Apex until you see the chamber size getting smaller and smaller then when you get to the Apex or when you see the chamber size getting smaller fan up towards the patient's head the probe at this point should be at the point of maximal impulse the bottom right image displays the LA and the LV on
the right of the screen and the RV and the RA are on the left of the screen as a general rule taking the ventricles as one the LV should take up about 2/3 of the total and the RV 1/3 of the total consider PE or another acute event causing pulmonary hypertension if the RV is greater than the size of the LV you can also assess for pericardial Fusion in this view as shown in the image at the top left the fourth and final window of trans thoracic echocardiography is the subho view with the patient's knees
bent place the probe in the subid region make sure the indicator on the probe still points with the patient's left side assume an overhand grip on the probe this will help you get more level and parallel with the skin and will allow you to visualize the heart start on on the patient's right locate the liver and sweep to the patient's left using the liver as an acoustic window basically acoustic window just means using an organ that doesn't contain gas and allows sound waves to travel through in the subid region bowel gas can sometimes mess up
your image so using the liver as an acoustic window will help avoid this you can have the patient take a deep breath to help bring the heart into view so here the liver is being used as an acoustic window remember the RV is closest thing to the liver in this View you can see the LV the LA the RV the ra mitro valve and tricuspid valve and the pericardium this is a video clip of the same thing up here you can see the liver and right next to the liver you see the RV the subai
foot view is pretty good for seeing a paracardial affusion here's another image of it remember that the traditional definition of pericardial tamponade is RV collapse with symptoms of hypo profusion here in these images we see a paracardial affusion and in the the image to the right we see RV compression and collapse this is a clip of cardiac standstill seems obvious like why do we need to Ultrasound that but if you have a patient without a pulse it helps to know that this isn't because of an arhythmia but instead because the heart isn't actually pumping if
it was an arhythmia you would see motion of the heart even though we talked about the four views of the heart it would be prudent to also talk about the IBC as this can help you gather more information that is very important about the patient's fluid stat St in a nutshell IVC measurements are important because they help guide fluid management the respiratory Cycles correlate with changes in IVC diameter in someone that can receive fluid giving estimates of CVP during deep inspiration the diameter gets smaller and during expiration the diameter gets larger we will get into
this a little bit more in a few slides but if the diameter does not change and remains open remains dilated this is a suspicion that the patient is pretty Prett overfilled with fluid the cable index is the percent collapsibility of the IVC throughout the respiratory cycle and is considered a predictor of preload Reserve or in other words a predictor of how much fluid the patient can receive before you run the risk of plural edema or a fusion let's talk about how to obtain the correct image of the IBC start in the subcostal region the collapsibility
is measured by obtaining a long AIS view of the IVC aim towards the head which would be over here until you see the IVC entering the ra right here changes in size throughout the respiratory cycle are identified with the machine and M mode measure the diameter 2 to 3 cm distal to the Confluence of the hepatic vein and the IVC so here's the hepatic vein and here's the IVC the cable index is measured by taking the maximum IVC diameter during expiration and subtracting the minimum diameter of the IVC during inspiration from that then dividing all
of that by the maximum IVC diameter this table was taken from asap.org and shows the correlations between the IVC size and the CVP small diameters with greater than 50% cable index correlates with a relatively low CVP compared to a dilated IVC with little to no change in the cable index which correlates with a high CVP in the first case probably the patient can receive fluid whereas the second case probably should not receive as much fluid all right so that was a lot we talked about the cardiac views forming a protocol that you go through each
time so that you don't miss anything start in the parisal long AIS view rotate 90° to the parasal short AIS view go down to the Apex for the apical four chamber view then assuming an overhand approach go to the subid view we talked about troubleshooting your image first check the screen indicator then check the probe positioning then if that doesn't work put the patient in a left lateral decubitus if the patient is able to do so to remember the paral long axis view remember the three L is Success the paral long axis view should have
the LV on the left side of the screen we talked about ejection fraction and how that can be a predictor of the patient's cardiac status whether it's a strong functioning heart or whether it's a poor functioning heart you can do that qualitatively by just looking at it which takes little to no time or you can quantitatively do it by using epss we talked about pericardial fusion and how that's different from paric cardial tanod we talked about right ventricular strain and how a pulmonary embolism or other cause of acute pulmonary hypertension can cause the right ventricle
to enlarge and we also talked about IVC measurements we talked about the caveal index and how that can be a predictor of the fluid status of the patient here are the references that I used and that is it I hope you enjoyed that I hope you learn something have a great day
