I’ve previously talked about a case that highlights just how much information subxiphoid views can provide. We often think it’s easy to get great cardiac views in thin patients, but that’s not always the case. I recently encountered a thin person with hypotension who presented challenges in transthoracic windows due to crowded ribs and hyperinflated lungs from chronic obstructive airway disease. But let’s dive into how we can maximize the subxiphoid views we do get!

Starting with the subxiphoid 4-chamber and short axis views, we can rule out significant pericardial effusion. The left ventricle appears to be squeezing well, and the tricuspid annulus is moving nicely (kind of a visual stand-in for TAPSE), although couldn’t get a good look at the right ventricular free wall. I also managed to get tricuspid annular S’ using tissue Doppler, which is normal (>9.5 cm/s). The right ventricular diameter is smaller than the left, and there’s no flattening of the interventricular septum in the short axis view, making right ventricular overload unlikely. We also see a little bit of tricuspid regurgitation.

Plus, the short axis views at the aortic valve level clearly show the pulmonary artery bifurcation, which means a saddle pulmonary embolism is unlikely (but doesn’t exclude the need for CT PE if the clinical suspicion is high for a thromboembolic event).

Since we can’t get an optimal Doppler angle for left ventricular outflow to estimate stroke volume here, we can use the right ventricular outflow tract Doppler instead. The idea is that what goes into the right heart should come out of the left heart—assuming no intracardiac shunts. Here, the VTI is close to 14 cm, which is normal for the right side (compared to 18-22 cm for the left side, since the RVOT is typically wider than the LVOT). So, it seems like the stroke volume is likely normal, suggesting it’s not a volume depletion case. However, things can get tricky if you’re getting borderline VTI numbers while running IV fluids at high rates – always interpret these findings in the right clinical context!

Next, I checked the IVC to estimate right atrial pressure. It looks a bit dilated, but as you know, IVC ultrasound doesn’t correlate well with RAP in mechanically ventilated patients. Portal vein is non-pulsatile, making significant venous congestion unlikely.

One interesting observation I’ve made is that in mechanically ventilated patients who don’t have truly elevated RAP, the internal jugular vein tends to be smaller, which could be a more reliable indicator. But I should note that there’s no published data to back this up this statement. If you’ve noticed anything similar, feel free to comment below! Here’s a bicaval view showing the SVC and a small, oval right IJ vein at the neck base with the head angle at about 20 degrees.

While the subxiphoid view doesn’t allow for diastology measurements, in most real-life situations, especially in the ICU or inpatient settings – you probably don’t need those unless you’re trying to differentiate between cardiogenic and non-cardiogenic pulmonary edema. My patient had A-line pattern (+ good sliding) in the lung, which helped.

The bottom line? Don’t get discouraged if transthoracic windows are challenging. You can still gather a wealth of information if the subxiphoid window is accessible!