So here is the clip again. This is a transverse epigastric view with the IVC in short axis and the hepatic veins (bunny ears) draining into it. We can see bright hyperechoic material moving up and down, which are air bubbles. Note that this is air in the hepatic veins and NOT the portal veins, which can be “relatively” common due to ischemic bowel and a few unusual causes.
Air in the systemic hepatic circulation is quite unusual. Obviously, air anywhere in the circulation implies a breach of vascular integrity somewhere – in the case of portal venous air, the breach is in the bowel microvasculature as the bowel breaks down. In the case of air in the hepatic veins, we are looking at air coming from (a) the lower body vasculature, so in the absence of trauma the most likely cause is iatrogenic from a femoral line, or (b) the upper body vasculature if associated with tricuspid regurgitation (iatrogenic or lung vascular injury coupled with positive pressure ventilation).
Here is an article discussing hepatic vein air.
Their clinical point is important to note – you have to investigate to get an idea of the amount of air and the possible source.
So this patient was transferred to my ICU from a smaller centre for more aggressive care. He was in profound septic shock felt to be pulmonary in aetiology, on levo/vaso/epi and dobutamine, ventilated on 100% with PEEP 16. My basic CUSE (critical ultrasound examination) done on essentially every critical care patient revealed this rapidly and, concerned that air embolism had occurred (femoral line was in situ at arrival), I scanned him.
Here is the CT:
You can see a small sliver of air in the IVC, and none was noted in the liver or in the heart (which was what I wanted to r/o). Now of course ultrasound is much more sensitive than CT for identifying small air bubbles (a CT image is a composite of several slices so a small bubble is lost) but when he returned form CT and I scanned him again, the hepatic veins no longer had air, but the IVC was full of air below the liver (as in the CT), so I think moving the patient had relocated the air.
More to come on the clinical story and investigations of this particular case, which is still ongoing.
thanks for looking!