The subcostal view of the inferior vena cava (IVC) assesses respirophasic variation and overall size as a way of gauging venous volume status. I obtain this view by palpating the xiphoid process, moving just inferior to it, and aiming my ultrasound probe straight down to the spine with the probe indicator facing the patient’s head.
The superior and inferior vena cavas are “right-sided” structures, whereas the thoracoabdominal aorta is a “left-sided” structure. Because the IVC and aorta both run longitudinally in this view, it’s important to distinguish one structure from the other. Panning the ultrasound beam rightward will reveal the IVC with the hepatic vein(s) draining into it as well as the IVC-right atrium (RA) junction. Panning the ultrasound beam leftward will reveal the thicker-walled aorta, which runs alongside the spine and does not show respiratory variation. Remember, pulsatility alone is unreliable (think about patients on mechanical circulatory support, severe tricuspid regurgitation, etc.)!
In this video, I pan back-and-forth between the IVC and descending aorta on my Butterfly iQ+ to show the subtle but important differences between these structures. Point-of-care ultrasound (POCUS) is something I often use as a cardiothoracic anesthesiologist and intensivist, and it’s definitely a vital skill in my OR and ICU practices.
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