In trauma patients, hemorrhage is one of the most fatal conditions, and it is the second leading cause of traumatic mortality [1]. A total of 30-40% of traumatic patients have died from hemorrhage [2]. Worldwide, 1,481,700 people die from traumatic hemorrhage yearly, and the years of life lost from traumatic hemorrhage are 74,568,000 years [3].

Resuscitative endovascular balloon occlusion of the aorta (REBOA) has been developed to control hemodynamically unstable hemorrhagic shock patients and to maintain brain and coronary perfusion [4,5]. Emergency resuscitative thoracotomy (ERT), which was previously performed, can be indicated for a single penetrating injury; however, for blunt injuries, there are many debates on performing ERT [6]. Some authors argue that REBOA can replace ERT in select cases [4,7]. In places, such as the Republic of Korea, where most traumatic patients experience blunt traumas (90.8%), REBOA is becoming important for hemorrhagic shock patients [8]. However, REBOA has several disadvantages [9]: 1) It is extremely time-dependent. 2) It has limited indications in patients with abdominal or pelvic hemorrhage who have a detectable pulse but whose systolic blood pressure remains 80 mmHg or less despite resuscitative efforts [10]. 3) It has many complications, such as distal ischemia and mortality. Nevertheless, because REBOA can play an important role in saving the time required to proceed to the next stage of treatment in blunt trauma patients, discussions to find an appropriate indication for REBOA and reduce its complications are under way.

As a result, in this multicenter retrospective study, we analyzed trauma patients who underwent REBOA according to their mortality, development of complications, and cardiopulmonary resuscitation (CPR). Furthermore, we tried to identify other variables that can affect the risk of complications and mortality. We hypothesized that the type of REBOA and type of catheter used may affect the risk for complications and mortality.

When we compared the CPR and No-CPR groups in trauma patients who underwent REBOA within our study, no variables, except mortality and following treatment, showed significant differences between the two groups. Chen et al. [11] reported that only 2.2% of traumatic cardiac arrest patients survived for at least 30 days, and ISS above 16 and total resuscitation length above 20 minutes were unfavorable factors for mortality. In our study, the mean ISS was 34.9±15.0. Consequently, CPR is an independent factor influencing mortality. In the CPR group, six patients could not receive the following treatment because the patients had expired. More patients in the No-CPR group received other treatments, such as surgery, angiographic embolization, or both than those in the CPR group.

The main reason for REBOA is intra-abdominal injury (57.4%). However, if we check each injury type, pelvic bone fracture (44.4%) was the most common reason for REBOA, and liver injury was the second most common reason. The injury type distribution by the detailed organ is described in Table 2. Fourteen patients (25.9%) had multiple organ injuries, and there was no significant difference between the CPR and the No-CPR groups (p=1.000). The majority of our cases showed intra-abdominal organ injury or pelvic bone fracture. In 3 cases we performed REBOA on patients with lung injury. Two of them had multiple organ (spleen, liver, and lung) injuries, and the other had solitary lung injury. REBOA is indicated mostly in patients with life-threatening hemorrhagic injuries below the diaphragm [12], and the performance of REBOA in thoracic trauma patients with or without other torso injuries has been debated [13]. Ordoñez et al. [14] suggested that the combination of REBOA and ERT could be useful in patients with non-compressible torso hemorrhage secondary to penetrating chest trauma in their 7-case series report. However, in our study, all patients with lung injury were injured from blunt trauma; therefore, it is better to be careful about implementation of REBOA in patients with thoracic injuries.

Fourteen patients developed complications, as described in Table 3. Postoperative bleeding was the highest in four cases, followed by lower limb ischemia in two cases. There was one case each for bowel ischemia, sigmoid colon perforation, acute respiratory distress syndrome, lung atelectasis, pleural effusion, pulmonary thromboembolism, stress-induced cardiomyopathy, and pseudoaneurysm. There are many complications associated with REBOA. The reported complications of REBOA included femoral arterial complications (disruption, dissection, pseudoaneurysm, hematoma, thromboembolism), extremity ischemia, aortoiliac complication (intimal tear, dissection, rupture), and bowel ischemia [12,15]. The conditions in which complications occur during REBOA implementation are: 1) the physical damage inflicted on the accessing vessel (femoral artery or iliac vessels); and 2) ischemia and inflammation caused by blockage of downstream blood flow [15,16]. Vessels can be injured by the catheter itself or by overinflation of the REBOA balloon. Sadeghi et al. [16] reported that REBOA could cause severe systemic and intra-abdominal metabolic disturbances, organ damage, and inflammatory activation at 30 minutes of occlusion in a non-hemorrhagic porcine model.

In this study, we attempted to identify the variables that affect the occurrence of complications (Fig. 2). In the LRA model, the occurrence of the complication is the dependent variable, and male sex and total occlusion have a statistically significant effect. However, this result is different from what we hypothesized. Males tend to have a higher risk of complications than females. This may have resulted from a bias that may have occurred during collection of data or due to the small amount of data (total number of patients was 54). In other studies, there is no evidence that males have a higher risk of occurrence of complications [13,15,17]. The judgment of this phenomenon should be withheld until more data is accumulated. The total occlusion of the REBOA balloon has a protective effect on complications than intermittent or partial occlusion. Usually, total occlusion is known to have a higher ischemic burden than partial occlusion [18]. The current guideline for REBOA recommends that total occlusion time in Zone 1 does not exceed 30-45 minutes [19]. However, there were three patients with ischemic complications in this study who received partial or intermittent occlusive REBOA, two of which were in Zone 3 and the other was in Zone 1. These ischemic complications occurred in a relatively early period of this study. It seems to be the complication caused by the patient’s condition or procedural immaturity, rather than problems associated with the type of REBOA. There was only one case in which the complication occurred in total occlusion. This result needs to be analyzed by considering the time that has been occluded rather than the REBOA type, and follow-up studies with data on the proficiency of REBOA and how to implement REBOA is also needed.

The type of REBOA catheter is not statistically significant for the LRA model for complications. However, considering the 95% CI of this variable, Rescue catheters may have a dangerous effect on the occurrence of complications. The Rescue catheter is a 7 Fr catheter that reduces access-related complications and is safer than the previously used thick catheter [9,20,21]. Therefore, it cannot be concluded that the Rescue catheter has a dangerous effect on the occurrence of complications. During the study period, the Rescue catheter was used relatively later and had the largest number. Therefore, this result should be analyzed considering the time and frequency of use. Accordingly, it seems that this phenomenon is the result of insufficient proficiency in the overall REBOA procedure.

In the LRA model for death, we could not find any statistically significant variables except whether CPR was performed (Fig. 3). It should be considered that CPR itself is a powerful predictor of death, and REBOA is being implemented to buy time for the next treatment in patients with a high risk of death [9,22,23]. Therefore, further research with more accumulated data is necessary.

REBOA is a technique that can improve hemodynamic stability in patients with life-threatening hemorrhagic shock. It seems that it can replace ERT in selective cases, but exact indications and protocols for REBOA have not been established. This study was conducted in the early stages of REBOA implementation in the Republic of Korea and showed conflicting results from studies conducted by multiple institutions. Therefore, additional research with more accumulated data is needed. Establishing appropriate protocols for REBOA and training for physicians is necessary.