TYPES OF REBOA
Perhaps one of the first questions that come to mind when REBOA is mentioned is: "We cut off the blood flow to the distal part of the balloon inflated, but how will the lower extremity perfusion be?". But when we look at what is the main question to be asked, we can say that the situation changes somewhat. The main question mark in our minds should be “what will happen to the patient when we deflate the balloon while it is bad enough that the distal part of the balloon remains ischemic?”. Before starting REBOA types, it would be useful to talk a little bit about ischemia-reperfusion injury.
Ischemia – Reperfusion Injury
Restoration of the blood flow to a previously ischemic tissue or organ is called reperfusion. Oxygen entering the cell with reperfusion quickly creates free oxygen radicals, proactive cytokines are produced, which causes cell damage and death. This condition is called reperfusion injury. Distant organ damage and multi-organ dysfunction syndrome (MODS) may occur with a vicious cycle that starts with reperfusion.
The REBOA procedure is important to save lives, but it is essential to inflate the catheter balloon to the smallest volume possible and deflate as soon as possible to minimize reperfusion injury.
tREBOA (total REBOA):
Total REBOA is also known as complete REBOA (cREBOA). It is the REBOA type in which the catheter balloon provides complete occlusion in the aorta. In cREBOA, blood flow can not pass distal of the catheteter balloon. Therefore, it can be considered as a less invasive alternative to thoracotomy and cross-clamping. There is a high risk of complications due to complete ischemia. Obstructions over 30 minutes, which are much more pronounced after the 60th minute, are associated with increased reperfusion injury (1).
Apart from reperfusion injury, elevated values such as pancreatic enzymes, kidney function tests, liver function tests, skeletal muscle enzymes can be detected as complications. An increase in lactate and other proinflammatory cytokines may be observed secondary to prolonged ischemia. In addition, there is a risk of paraplegia and amputation in the lower extremity due to distal ischemia and compression of the spinal cord.
An important race against time begins due to the expected complications in a patient who is treated with tREBOA. Therefore, the use of pREBOA should be preferred over the use of tREBOA, except for massive and life-threatening bleeding.
pREBOA (partial REBOA):
Partial REBOA is the REBOA procedure performed by providing partial occlusion of the aorta. In addition to minimizing the complications that may develop with tREBOA, it is becoming accepted in the world in terms of saving time for the bleeding patient.
It will be sufficient to set the systolic blood pressure measured from the proximal to 80-90 mmHg. The volume of the balloon should be adjusted according to the systemic blood pressure monitoring, and blood pressure titration should be ensured in this way.
There is distal blood flow in pREBOA, so the risk of ischemic injury is much lower than in tREBOA. It is also possible to monitor and control the blood pressure going to the lower extremity by means of a 5 french sheath to be placed in the femoral artery on the opposite side of the REBOA catheter.
Since perfusion is provided continuously in pREBOA, both the lower extremity is perfused and adequate blood flow reaches the proximal organs. Thus, both bleeding control is provided and the risk of complications and general metabolic disorders are significantly reduced.
Russo et al., in a study by creating a bleeding model in 15 pigs, found that pigs who underwent pREBOA had less rebound hypotension after deflating the balloon. In the same study, lactate levels were found to be higher in pigs treated with tREBOA (2). On the other hand, Forte et al. showed that the aortic flow velocity can be titrated at fine levels in patients who underwent pREBOA, the tolerability time for zone-1 REBOA is prolonged and the burden of ischemic injury is limited (3).
iREBOA (intermittent REBOA):
iREBOA is the REBOA type in which the REBOA balloon is inflated intermittently and deflated when necessary. Bleeding control is provided intermittently and at a certain level, and it also allows the interventional radiologist or surgeon to see the location of the bleeding during the inflation of the balloon. However, this process must be done in a controlled manner. It should not be forgotten that the patient may start bleeding again with the deflating of the balloon. Therefore, it is necessary to be ready for hemostatic maneuvers. If the patient is stable, the balloon can be followed in the deflated position, but if it is unstable, reinflating the balloon should be considered.
dREBOA (deflated REBOA):
It is the situation where the REBOA catheter is in the aorta but is followed in the deflated position. It can be used in patients who may be at risk of re-bleeding, who have not yet undergone the necessary interventions, but who are currently stable.
REBOA is a life-saving procedure and it is important to know and manage its indications and complications. It can be life-saving in the process up to surgical intervention. The use of pREBOA is being accepted more and more in the world day by day and studies are being carried out in this area. Since the rate of death due to trauma is extremely high in Turkey, it would be beneficial for every physician who encounters trauma to be aware of REBOA and learn how to apply it.
References
1. Heindl SE, Wiltshire DA, Vahora IS, Tsouklidis N, Khan S. Partial Versus Complete Resuscitative Endovascular Balloon Occlusion of the Aorta in Exsanguinating Trauma Patients With Non-Compressible Torso Hemorrhage. Cureus. 2020 ve 2020, 12(7):e8999. Published.
2. Russo RM, Neff LP, Lamb CM, Cannon JW, Galante JM, Clement NF, Grayson JK, Williams TK. Partial Resuscitative Endovascular Balloon Occlusion of the Aorta in Swine Model of Hemorrhagic Shock. J Am Coll Surg. 2016 Aug ve 10.1016/j.jamcollsu, 223(2):359-68.
3. Russo RM, Williams TK, Grayson JK, Lamb CM, Cannon JW, Clement NF, Galante JM, Neff LP. Extending the golden hour: Partial resuscitative endovascular balloon occlusion of the aorta in a highly lethal swine liver injury model. J Trauma Acute Care Surg. 201.
