Indications for the use of REBOA are summarized below. These indications mirror the indications for resuscitative thoracotomy with the exception that shock or arrest secondary to penetrating chest trauma is a relative contraindication to REBOA (See the JTS Emergency Resuscitative Thoracotomy, 18 Jul 2018 CPG 13 As stated above, there is no high grade evidence defining the specific indications for REBOA. Data is, at best, mixed when comparing survival and outcomes of REBOA versus ERT.14,23 However, there is at least one major trial that demonstrates that REBOA improves survival beyond the emergency department as well as to hospital discharge when compared to ERT for patients who are in hemorrhagic shock, but are pre-cardiac arrest.23 For this reason, early recognition of hemorrhagic shock is vital when identifying patients who may benefit from REBOA.

INITIAL MANAGEMENT

Initial management priorities for patients with traumatic arrest or impending arrest include early control of hemorrhage and hemostatic resuscitation as described in the JTS Damage Control Resuscitation CPG. 50 The initial focus in patients presenting in profound hemorrhagic shock, to include loss of pulses, is to determine the best resuscitative strategy, and whether resuscitation is appropriate or futile in a moribund patient. The following must be rapidly determined:

- Mechanism and pattern of injury
- Presence of a pulse
- Duration of cardiac arrest
- Presence or absence of an organized, narrow complex cardiac rhythm and/or organized cardiac activity by ultrasound.
- Resources available
- Number of concurrent casualties

Patients exsanguinating from abdominal, pelvic, or junctional lower extremity bleeding may be candidates for REBOA. Such patients are identified by penetrating mechanism of injury to abdomen or pelvis, blast or blunt mechanism with positive FAST or suspected pelvic fracture, or massive proximal lower extremity trauma with signs of impending cardiovascular collapse.

Exsanguinating hemorrhage in the chest must be ruled out prior to placing REBOA—this can be done with chest tube placement, thoracostomy, x-ray, or thoracic ultrasound. In cases of major chest hemorrhage, occlusion of the aorta may increase thoracic bleeding and is thus best addressed via thoracotomy or sternotomy.

A decision algorithm for Resuscitative Aortic Occlusion (RAO) is found in Appendix A. If RAO is performed, concurrent hemostatic resuscitation and closed chest cardiac massage should continue while the procedure is performed.51 If RAO is not performed, resuscitative efforts should cease unless there is a compelling reason to consider a non-traumatic arrest.

RESUSCITATIVE THORACOTOMY

The gold standard for aortic occlusion in traumatic arrest remains a left anterolateral thoracotomy (See JTS Emergent Resuscitative Thoracotomy CPG.)

TRANS-ABDOMINAL AORTIC OCCLUSION

The aorta can also be occluded trans-abdominally at any point along its length. It can be occluded with either application of a clamp or compression with a retractor or manually. Alternatively, balloon occlusion can be considered (below) as this can decrease instruments in the upper abdomen, depending on where the focus of bleeding is located. In obese patients with a large volume of hemoperitoneum or other intra-abdominal pathology, a trans-thoracic approach or a balloon approach to the aorta may be preferable. As with all other forms of RAO, restoration of aortic perfusion should be carefully coordinated with the rest of the team to minimize the effects of reperfusion and blood volume shifts.

REBOA STEPS

REBOA can be considered in 6 sequential steps:

1. Arterial access and positioning of sheath
2. Positioning of the balloon
3. Inflation of the balloon
4. Operative/procedural control of bleeding
5. Deflation of the balloon
6. Sheath removal

REBOA can be performed preemptively in patients with high-risk injury patterns and unstable physiologic parameters as described above. In this way, REBOA can be proactive rather than reactive in appropriate patients. The indications for REBOA are summarized in Appendix A for traumatic arrest and Appendix B in cases of profound shock. A schematic of the aortic anatomy is presented in Appendix C.52 If proximal aortic occlusion is required, this is termed Zone 1, whereas distal aortic occlusion is termed Zone 3. Zone 1 REBOA deployment will be used in most patients presenting with hemorrhagic shock, and may be used in all patients with traumatic arrest, regardless of injury pattern, due to the benefits on a patient’s mean arterial pressure (MAP).53

In clinical situations where REBOA is being considered, pre-emptive placement of an arterial line in the common femoral artery (CFA) is recommended. CFA access has consistently been identified as the rate limiting step to REBOA deployment.30 Obtaining early CFA access in the form of an arterial line can greatly decrease REBOA placement time as a preplaced common femoral arterial line can quickly be re-wired to a REBOA introducer in the event of patient deterioration.

Preclinical research has shown a Zone 1 aortic occlusion time of 60 minutes or more results in significant metabolic derangement and organ damage that may offset any gain obtained by early hemorrhage control. 30 minute occlusion times had significantly improved outcomes without evidence of severe physiologic costs. Based on this data, Zone I REBOA should be deployed for no greater than 30 minutes. Zone III REBOA historically has been considered acceptable for up to 4-6 hours.54-55 However, recent analysis in preclinical models have led to the revised recommendation to target Zone III balloon occlusion times of less than 30, and no greater than 60 minutes.54-56,36

After placing a REBOA, careful management of the femoral sheath is imperative. The majority of complications associated with REBOA use are related to the sheath and access site complications. Reported femoral access complications include arterial disruption, dissection, pseudoaneurysms, hematoma, thromboembolic phenomenon, and extremity ischemia. These complications have resulted in limb loss.27,28 Due to the risk of sheath dislodgement or vessel wall damage excessive patient movement should be avoided. Patients with indwelling sheaths should be positioned supine or reverse Trendelenburg only. If the patient must be moved or turned, they should be kept in a flat position and log-rolled.

The provider, or assistant, should promptly document placement time, pre-/post-placement blood pressure and MAP, and REBOA insertion distance. Please use the Aortic Occlusion (AO) Procedure Note that is found in Appendix H of this CPG for specific REBOA documentation. It is also available on the JTS Website at https://jts.amedd.army.mil/index.cfm/documents/forms_after_action under CPG Forms. Balloon volume and inflation time should be noted at the insertion site for reference by all providers caring for the patient. The provider is responsible for prevention of catheter migration, particularly during patient transport. A provider who is knowledgeable about the management of REBOA should attend to the patient while awaiting definitive surgical repair, to include during transport. The trained provider is responsible for ensuring a safe and competent hand off.

While the sheath is in place, hourly neurovascular assessments of the bilateral lower extremities should be completed. These assessments should continue for 24 hours after removal of the sheath to allow for early identification and intervention of access site complications. In addition, follow-on duplex imaging (24-48 hours post REBOA) of the access site allows for early identification and treatment of any access site complications. This may be performed either at the Role 3 facility or as soon as possible after arrival at a Role 4 facility, depending on resources available to perform and interpret the ultrasound.

Once definitive hemorrhage control has been obtained, the REBOA sheath should be removed and 30 minutes of direct pressure applied to the CFA access site. If arterial pressure monitoring is still required an alternate line site should be considered. An angiogram through the sheath to document distal limb perfusion is best practice, though not always available. If a large sheath size is used, a patient is coagulopathic, or there is technical difficulty in sheath removal a cut down and arterial repair, patch or graft may be required. This may be best accomplished in the Role 3 environment with access to specialists and/or surgical backup.21

The balloon should be deflated once specific vascular control or definitive hemorrhage control has been obtained. Communication with the assistant holding the apparatus securing the catheter and the anesthesia team is critical before consideration of deflating the balloon. When deflating the balloon turn the three-way stopcock and withdraw saline slowly and deflate the balloon slowly as this step can be anticipated to result in a significant decrease in afterload and hypotension and may result in cardiac collapse. Additional resuscitation may be needed while the balloon is slowly deflated. After balloon deflation, the team should anticipate hemodynamic changes related to reperfusion, washout of metabolic byproducts, and acidosis. As such, intermittent balloon inflation and deflation may be necessary during ongoing resuscitation until hemodynamic stability is restored.

Even in an austere environment, protocols for use and follow on care should be planned and discussed prior to implementation. Team training and awareness of pitfalls are critical to ensure the best possible outcomes.

If definitive hemorrhage is not obtained, leaving the sheath in place without aortic occlusion may be a valid option. By leaving the sheath in place, the REBOA can easily be reinserted and aortic occlusion can quickly be obtained if rebleeding occurs or hemorrhage continues.38 In general, and situation/resource dependent, the sheath should be left in during any active or ongoing resuscitation. The sheath should not be removed immediately prior to transport, and is best removed where vascular complications can be treated and managed.

A sheath MUST NEVER be left in for transfer to a host nation facility.