This paper is from the group at ShockTrauma in Baltimore, who are really pushing the envelope of REBOA. We always worry about distal ischemia after balloon inflation, because the ischemia produced can be detrimental to the gut and lower extremities. This group was curious about what the flow patterns looked like with  inflation of the balloon. So in select cases, they obtained CT scans with contrast in patients while the balloon was fully inflated (!!).

They reviewed their experience over a four year period, looking at patients receiving a CT scan with the REBOA balloon partially or fully inflated.

Here are the factoids:

• Nine patients were included. This makes sense because unstable patients should not go to CT scan, so this should be a very limited group.
• Mean injury severity score (ISS) was 48, which makes sense. These patients are hurt bad!
• Four patients had supraceliac REBOA (aortic zone I) and five had infrarenal (zone III)
• Contrast was seen below the REBOA balloon in all patients, and was seen distal to the insertion site in half
• Collateral flow around the balloon was identified in all patients

Bottom line: The authors found that REBOA decreased blood flow to the distal aorta, but certainly did not stop it. Collateral flow is underestimated, and probably provides a protective effect for the viscera and other structures while inflated. This is good news for REBOA proponents, because it suggests that placement may not cause as much risk from ischemia as originally thought.

But why oh why did they have to go to  CT in the first place?

Reference: Assessment of blood flow patterns distal to aortic occlusion (AO) using computed tomography in patients with resuscitative endovascular balloon occlusion of the aorta. JACS 225(4S1):S50, 2017.