EMFirst Q&A: REBOA

So what does REBOA stand for?

REBOA stands for Resuscitative Endovascular Balloon Occlusion of the Aorta!

What does all that mean?

REBOA is a (somewhat) novel technique for stopping catastrophic bleeds in certain anatomic locations and temporarily resolving hemorrhagic shock.  The idea is pretty simple: keep blood flowing to the important stuff (heart, lungs, brain) and cut off blood flow to less important parts until the source of bleeding can be fixed. 

How is it done?

Arterial access is gained in the left or right femoral artery and a vascular sheath is passed.  A balloon catheter is then floated up into the aorta and inflated at the appropriate level.  Blood flow below the balloon is completely cut off, meaning the surgeons have much more time to fix the problem before the patient succumbs to hemorrhagic shock. 

Where is the balloon inflated?

The aorta is divided into three zones: zone 1 (just distal to the left subclavian artery to the celiac artery), zone 2 (celiac artery to the lowest renal artery), and zone 3 (lowest renal artery to the aortic bifurcation).  The balloon is usually inflated with a mixture of saline and contrast so it can be easily seen on bedside X-Ray to confirm placement. 

REBOA placed in zone 3 in the setting of pelvic fracture (a); placement in zone 1 (b).  The difference between filling the balloon with contrast and saline (a) or saline only (b) is also apparent. (Brenner et al., 2014)

REBOA placed in zone 3 in the setting of pelvic fracture (a); placement in zone 1 (b).  The difference between filling the balloon with contrast and saline (a) or saline only (b) is also apparent. (Brenner et al., 2014)

How do we decide which zone to use?

Zone 1 is used for bleeding in the abdomen, and zone 3 is used for pelvic hemorrhage.  If you think about the abdominal vasculature, these make a lot of sense.  When zone 1 is used, blood exits the heart and only has the option of travelling to the brachiocephalic trunk, left common carotid artery or left subclavian; everything beyond these branches (abdominal organs, pelvis, and lower extremities) is cut off by the balloon.  Using zone 3 allows blood to reach as far as the renal arteries, meaning that the balloon blocks flow to the pelvis and lower extremities but the abdominal organs stay perfused.  Zone 2 is not typically used because it would cause blocked perfusion to a mixed bag of abdominal organs.  REBOA is typically being used when the exact source of bleeding has not yet been pinpointed so zone 2 doesn’t offer a lot of benefit.

Inflation in zone 1 and zone 3 is used for massive abdominal and pelvic hemorrhage, respectively.  (Stannard et al., 2011)

Inflation in zone 1 and zone 3 is used for massive abdominal and pelvic hemorrhage, respectively.  (Stannard et al., 2011)

How long can we leave the balloon inflated?

The data still is not great on this question, but right now most programs are saying 60-90 minutes for zone 1 and 4-6 hours for zone 3 occlusion. 

How is this related to intra-aortic balloon pumps?

REBOA is similar in that it greatly increases afterload, but the similarities mostly stop there.  IABPs oscillate while REBOA stays inflated, occluding the aorta until manually deflated.  The indications are also vastly different (heart failure vs refractory hemorrhagic shock). 

Why is this important for EMS providers to know?

Aside from the fact that your next crashing trauma patient may get one of these within a few minutes of being wheeled into the trauma bay, REBOA is actually headed in the direction of prehospital medicine.  Believe it or not, in June 2014 a London Air Ambulance crew performed the first prehospital REBOA on a long fall patient with a complex pelvic fracture, saving the patient’s life and changing REBOA from unachievable futuristic medicine to a practical and essential tool.  To be fair, London HEMS does fly with physicians on all of their aircraft, but this at least shows that REBOA is not as unachievable as was once thought.  In fact, the EMCrit Podcast dedicated a whole episode to it, which can be heard here

We hope you enjoyed our first EMFirst Q&A.  Let us know what you think in the comments!

References

  1. Brenner, Hoehn, Rasmussen.  Endovascular therapy in trauma.  European J Trauma & Emergency Surgery.  Nov 2014; 40(6). 

  2. Stannard, Eliason, Rasmussen. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) as an adjunct for hemorrhagic shock. J Trauma. Dec 2011; 71(6): 1869-72.