The Pre-brief
Your team is managing a relatively young male in cardiac arrest. He remains in refractory ventricular fibrillation despite all the tips and tricks you can pull out of your bag. You wish you had ECMO at your hospital, as he seems a perfect candidate. You look around, hoping to find something else that you can try. That’s when you spot the REBOA kit.
“Wait a minute…can I even use that in this case?”
Repurposing REBOA
By now REBOA (resuscitative endovascular balloon occlusion of the aorta) is becoming almost a household name in Emergency Medicine and Trauma – some love it, some hate it, most agree there is some role for it, many know that they will probably not see a need for it in their system.
The research around it continues to develop and is becoming a little stronger – but much, if not all has been focused on use in trauma.
Is there any role in medical cardiac arrest?
That’s a question being asked in a recent review article published in JACEP Open, entitled “The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for non-traumatic cardiac arrest: A review.” by Nowadly et al.
What does this paper say?
This paper raises as its premise that each year, over half a million people in the United States suffer a cardiac arrest, with dismal survival rates to hospital discharge, often cited as under 10%. A fair amount of time and effort has been spent on addressing various aspects of care including the role of ventilation and intubation, the use or timing of epinephrine, and the importance of chest compressions.
Effective chest compressions in particular have been shown to have an important contribution to survival outcomes. However, looking at the physiologic effect of chest compressions reveals that only 20-30% of the baseline cardiac output is generated, resulting in limited blood flow to the cardiocerebral circulation. Can we then use REBOA to help in this instance?
A step back to remind you of the general premise of REBOA – this is a balloon catheter that is inserted through the femoral artery into the descending thoracic aorta, where the balloon is then inflated. In trauma, this temporizes bleeding below the balloon. In non-traumatic arrest, the premise is similar to an aortic cross-clamp, where blood is now diverted away from the rest of the torso preferentially to the heart and brain. When combined with closed chest compressions, can this actually improve perfusion to these vital organs?
In this paper, the authors review the existing evidence through a search of EMBASE and SCOPUS databases, and argue that in animal models, descriptions of improved cardiocerebral perfusion were noted over 20 years ago. One study in particular showed improved cerebral perfusion pressures (CPP; remember, CPP = mean arterial pressure – intracranial pressure) of up to 60%, although this can vary depending on the animal model. The evidence in humans is very limited currently, isolated primarily to case reports, which certainly limits generalizability.
However, the potential for benefit demonstrated has prompted several efforts at more robust study including a current trial in the United States being carried out by Yale University, as well as a prehospital study being carried out in Norway. The latter has already yielded impressive results in their 10 enrolled subjects – at least in the immediate resuscitation phase: 60% ROSC, 30% admission to hospital. Survival to discharge with good neurologic outcome was 10%.
The Debrief
So will REBOA for non-traumatic arrest actually improve neurologically intact survival – or will it be a lot of effort for little gain over current outcomes as the Norwegian paper shows? What about other mechanical circulatory support devices such as Impella, aortic balloon pumps, and ECMO? Should we be putting REBOA in at hospitals already capable of these? Perhaps this can be a bridge if your hospital is not yet capable of these other interventions and requires a secondary transfer? Who is the right candidate?
As you see, many questions remain. Personally I would like to see more robust data to show improvement over the current status quo, and the Yale study looks promising. Nevertheless it is laudable for the authors of this paper to discuss the potential role of REBOA in this pathology, and it will be interesting to see whether this can be a feasible tool in the box for non-traumatic arrest – and also importantly to see what may be the inadvertent costs or risks of doing so.
References
Nowadly CD, Johnson MA, Hoareau GL, et al. The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) for non-traumatic cardiac arrest: a review. JACEP Open August 2020 https://doi.org/10.1002/emp2.12241
Benger RJ, Kirby K, Black S, et al. Effect of a strategy of a supraglottic airway device vs tracheal intubation during out-of-hospital cardiac arrest on functional outcome: the AIRWAYS-2 randomized clinical trial JAMA 2018;320(8):779-791 PMID: 30167701.
Perkins GD, Ji C, Deakin CD, et al. A randomized trial of epinephrine in out-of-hospital cardiac arrest. NEJM 2018;379:711-721 PMID: 30021076
Riva G, Ringh M, Jonsson M, et al. Survival in out-of-hospital cardiac arrest after standard cardiopulmonary resuscitation or chest compressions only before arrival of emergency medical services-nationwide study during three guideline periods. Circulation 2019;139(23) epub ahead of print PMID: 30929457
