Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an endovascular haemorrhage control intervention which was first described in the Korean war. Thanks to the development of smaller and wire-free balloon-tipped catheters, REBOA has recently regained popularity as a replacement to thoracotomy and aortic cross-clamping in human trauma patients. Current research efforts aim at improving occlusion technique to minimize post-deflation complications while maximizing occlusion benefits.

REBOA Indications

REBOA has mainly been used in trauma patients with non-compressible torso haemorrhage, which refers to the presence of hypovolaemic shock in a patient with disruption of a named axial vessel or injured solid organ. REBOA has thus been used in patients with blunt or penetrating trauma with lesions distal to the diaphragm. Such lesions would be abdominal aortic tear, spleen or liver lacerations, pelvic fractures with large vessel disruptions, etc. Evidence of haemorrhage in the chest is a contraindication to the deployment of a REBOA catheter for fear of worsening haemorrhage since upon balloon inflation, arterial blood pressure above the occlusion point is often elevated. Since it is less invasive and safer for the care team than resuscitative thoracotomy with aortic cross-clamping, REBOA has also been used in other settings. For instance, it is sometimes used during oncologic or obstetric surgery to control life-threatening haemorrhages.

REBOA Implementation

While the technique has been described in humans and pigs, there is currently no description of the clinical use of REBOA in dogs or cats. Femoral arterial access can be achieved by either pulse palpation or using anatomical landmarks. Since patients with severe haemorrhagic shock may present with weak or no pulses, ultrasonographic guidance is a popular tool to facilitate prompt catheter insertion. The use of ultrasound also facilitates vessel evaluation to avoid venous catheterization or observe puncture-induced complications such as haematomas. An introducer sheath is placed in the femoral artery. Currently, there are two commercial REBOA catheters, the CODA catheter and the ER-REBOA. The CODA catheter requires a 12 Fr introducer sheath and is advanced over-the-wire, the ER-REBOA catheter is placed through a 7 Fr catheter and does not require wire guidance. The balloon at the tip of the REBOA catheter can be placed at various levels, or zones, of the aorta. Zone 1 encompasses the segment of the aorta between the left subclavian artery and the celiac trunk, zone 2 extends from the celiac trunk to the lowest renal artery, and zone 3 is between the lowest renal artery and the aortic bifurcation. Thus, in patients with profound haemorrhagic shock due to abdominal trauma and haemorrhagic peritoneal effusion, if the source of bleeding is unknown the balloon can be placed in zone 1. If the lesion is deemed infrarenal, the balloon can be placed in zone 3. Zone 2 placement is seldom performed. Proper balloon placement can be verified either via fluoroscopy or manual palpation during celiotomy. Measurement of catheter length of insertion using anatomical landmarks has been described in humans and dogs.

Following catheter placement, the balloon is inflated using 0.9% saline. Initially the balloon should be inflated to fully occlude the aorta. Full occlusion can be confirmed by the absence of distal pulse either by palpation or waveform observation via arterial pressure transduction from the femoral sheath. Full aortic occlusion allows for haemorrhage cessation, clot formation, as well as augmentation of perfusion to organs cranial to the balloon (heart and brain). Complete aortic balloon occlusion (complete REBOA) is associated with a significant ischaemic burden caudal to the balloon. Current REBOA guidelines recommend a maximum complete occlusion time of 30 to 45 minutes. To reduce the ischaemic burden, clinical and translational research has focused on partial REBOA whereby following a brief period of complete REBOA (approximately 10 minutes) a small amount of blood is allowed around the catheter to maintain oxygen delivery to tissue beds caudal to the balloon and reduce the ischaemia-reperfusion burden at the time of balloon deflation. Partial REBOA relies on precise balloon volume titration, which is hard to achieve since small changes in balloon volume result in large increases in aortic blood flow. Our team has therefore developed an automated platform capable of precise titration of balloon volume to control aortic blood flow or proximal and distal mean arterial pressures. The dynamic, automated, and precise control of endovascular aortic balloon has been termed endovascular variable aortic control or EVAC.

REBOA Challenges and Future Avenues

While REBOA is a life-saving intervention that rapidly temporizes patients in or with impending cardiac arrest, it comes with a host of downsides and complications that require cautious management. Ischaemia-reperfusion is a significant concern and minimizing the time of occlusion is of the utmost importance. Furthermore, ischaemic damage to organs caudal to the balloon, to include the gastrointestinal tract, kidney, and spine, have been documented. Similarly, organs above the balloon may suffer from supraphysiologic arterial pressure. Myocardial damage has been documented with extended occlusion period and our team has documented myocardial injury in clinically relevant occlusion periods (data not published as of this date). REBOA should be carefully implemented in patients with traumatic brain injury as ongoing haemorrhage sustained by supraphysiologic arterial blood pressure may worsen intracranial pressure and precipitate herniation of intracranial tissue.

Patients that received REBOA have almost universally sustained significant injury, which in conjunction with REBOA-induced ischaemia-reperfusion injury makes them prone to significant vasoplegia requiring careful fluid and vasopressor resuscitation. Artificial intelligence-driven balloon volume may prove helpful in tightly controlling patients’ aortic flow.

References

1.  Osborn LA, Brenner ML, Prater SJ, Moore LJ. Resuscitative endovascular balloon occlusion of the aorta: current evidence. Open Access Emerg Med. 2019;11:29–38.

2.  Ribeiro Junior MAF, Feng CYD, Nguyen ATM, Rodrigues VC, Bechara GEK, de-Moura RR, Brenner M. The complications associated with resuscitative endovascular balloon occlusion of the aorta (REBOA). World J Emerg Surg. 2018;13:20.

3.  Hoareau GL, Cassiday PA, Stewart IJ, Studer A, DuBose JJ, Neff LP, Williams TK, Johnson MA. Acute kidney injury following resuscitative aortic occlusion. Journal of Endovascular Resuscitation and Trauma Management.

4.  Wasicek PJ, et al. Extended resuscitative endovascular balloon occlusion of the aorta (REBOA)-induced type 2 myocardial ischemia: a time-dependent penalty. Trauma Surg Acute Care Open. 2019;4:e000194.

5.  Tibbits EM, Hoareau GL, Simon MA, Davidson AJ, Desoucy ES, Faulconer ER, Dubose JJ, Neff LP, Grayson JK, Johnson MA, Williams TK. Stepwise reperfusion after zone 1 REBOA: is repositioning to zone 3 a useful maneuver. Journal of Endovascular Resuscitation and Trauma Management.

6.  Tibbits EM, Hoareau GL, Simon MA, Davidson AJ, Desoucy ES, Faulconer ER, Dubose JJ, Neff LP, Grayson JK, Williams TK, Johnson MA. Location is everything: the hemodynamic effects of REBOA in zone 1 versus zone 3 of the aorta. J Trauma Acute Care Surg.

7.  Williams TK, Neff LP, Tibbits EM, Hoareau GL, Simon MA, Davidson AJ, DeSoucy ES, Robert Faulconer R, Grayson JK, Johnson MA. A novel automated endovascular variable aortic control device to expand function of standard REBOA catheters. Journal of Endovascular Trauma Management.

8.  Johnson MA, Tibbits EM, Hoareau GL, Simon MA, Davidson AJ, DeSoucy ES, Faulconer ER, Grayson JK, Neff LP, Williams TK. Endovascular perfusion augmentation for critical care: partial aortic occlusion for treatment of severe ischemia-reperfusion shock. Shock. 2018.

9.  Williams TK, Tibbits EM, Hoareau GL, Simon MA, Davidson AJ, DeSoucy ES, Robert Faulconer R, Grayson JK, Neff LP, Johnson MA. EVAC versus REBOA in a swine model of hemorrhage and ischemia reperfusion injury. J Trauma Acute Care Surg. 2018.