You get a patient who has gradual onset of shortness of breath with a history of cancer, a patient with sudden severe exertional chest pressure and new orthopnea, a patient with known pericarditis with worse pain or breathing difficulty, or a trauma patient with a penetrating stab wound to the chest and you want to evaluate whether they have a pericardial effusion, signs of tamponade, or poor contractility through a bedside echo, but you just can’t seem to obtain a great subxiphoid (SX) view. The SX view of the heart seems like it would be easy to obtain. I mean, it is right there! – right by the probe, and the patient is alive so you know he has a heart! Well, sometimes it’s not so easy. There are several reasons for this: your probe positioning, not seeing the liver, and the patient’s thoracic cage.
Probe position: First off, hold your probe like a TV remote and not like a pencil. Make sure your probe is right under the xiphoid process and flattened down so that the tip of the probe is aiming toward the area of the heart. The reason for this is that distended stomach or bowel can get in the way of your view if your too low and you will not see the heart if your not aiming in the right direction. You may even need to fan anterior to posterior, changing the angle of your probe, slowly in search of the heart.
The Liver: It’s kind of like the saying, your “eyes are the window to your soul.” Well, in this case, your liver is the window to your heart. You must see the liver in order to see the heart. The sound waves go through the nice liver density (top of your screen), instead of pulmonary air or bowel gas (remember, air is the enemy of ultrasound!). If youre in the SX space as bove and you cannot get a good view, slide your probe to the patient’s right subcostally (you’ll need to change the direction of your probe to continue to aim to the mid-chest and adjust your depth) and get more liver in your view. In the video shown, the sonographer had slid toward the patient’s right and you can see that on your left of the screen the SX heart is seen well. On the right of the screen, when the liver is not there as an acoustic window, a air/gas scatter artifact is seen obstructing the view of the heart.
The thoracic cage: Some people have long thoracic cages. Why, I don’t know, but I don’t really care either, I just want to be able to see their heart when I need to with US. In the video below, despite trying the attempts above at getting a good view of the heart, I have found that having the patient take a deep breath in will lower the heart, having it come closer to my probe, and it suddenly appears! You may need to do small adjustments to the angle of your probe, but you’ll see it. In the first second of the video, the patient took a deep breath and the heart went from poorly visible to wonderfully visible!
SonoSpot: Topics in Bedside Ultrasound 