Following traumatic brain injuries, acute traumatic hemorrhage is the main causes of early death, after severe blunt trauma [
1]. Although hemorrhagic control by external pressure, tourniquet [
2], or open surgery [
3] are the commonly used interventions, endovascular techniques have recently gained considerable more acceptance. Similarly, open procedures for acute bleeding control have decreased as endovascular catheter-based techniques have continued to demonstrate efficacy and durability [
4]. The use of endovascular techniques for managing traumatic vascular lesions in solid organ injury is, therefore, gaining greater popularity [
5]. At the turn of the century, an approximate 30-fold increase in the use of endovascular techniques in trauma was observed [
6], with approximately 13.2% of all blunt vascular injuries treated using endovascular methods [
7]. The use of resuscitative endovascular balloon occlusion of the aorta (REBOA) as a modern clinical practice, adds a promising adjunct to the acute treatment of major blood loss in the abdomen or the pelvis [
8], with successful elevation of central blood pressure during shock [
9]. REBOA also serves as a hemorrhage control and resuscitation adjunct to prevent cardiovascular collapse [
9]. Depending on the bleeding source, REBOA may be performed at three different zones: Zone 1 ranges from the left subclavian artery to the coeliac trunk; Zone 2 ranges from the celiac trunk to the most caudal renal artery, and Zone 3 extends from the most caudal renal artery to the aortic bifurcation [
8,
9]. There are still discussions on the duration of REBOA. Studies included in a systematic review [
9] presented REBOA occlusion times of 63 min (Inter-Quartile-Range (IQR) 33–88 min) in zone 1, and 45 min (IQR 30–105 min) in zone 3, including patients with occlusion times up to 6 and 10 h. Thus, REBOA increases resuscitation times, preventing hemorrhaging by up to 60 min [
8,
10].
The introduction of REBOA has led to a growing number of experimental studies, assessing different parameters on REBOA [
11]. However, acute organ-specific microcirculatory changes during REBOA have not yet been described. Therefore, in this study we aimed to analyze zone-depending microcirculatory changes in abdominal organs and the extremity during REBOA. We hypothesized that REBOA at different zones would influence regional ischemia–reperfusion changes in intra-abdominal organs.