Overview
Definition:
Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is an endovascular technique used in emergent settings to control massive hemorrhage from the torso and lower extremities by occluding the aorta with a balloon catheter
It is primarily employed in patients with refractory hemorrhagic shock where traditional resuscitation has failed.
Epidemiology:
REBOA is increasingly utilized in centers managing severely injured patients
Its application is often in cases of penetrating or blunt trauma with signs of irreversible shock, where conventional damage control resuscitation is insufficient.
Clinical Significance:
REBOA provides a temporizing measure to restore proximal aortic pressure and perfuse vital organs, buying critical time for definitive surgical control of hemorrhage
Proper zone selection is paramount to maximize benefits and minimize risks.
Zone Selection
Zone I Occlusion:
Includes the descending thoracic aorta, distal to the left subclavian artery and proximal to the celiac artery
This zone is typically used for hemorrhage originating from the abdominal aorta, pelvic vasculature, or bilateral lower extremities.
Zone Ii Occlusion:
Includes the descending thoracic aorta between the left subclavian artery and the diaphragm
This zone is generally avoided due to potential interference with cerebral and upper extremity perfusion, and is rarely indicated.
Zone Iii Occlusion:
Includes the abdominal aorta, distal to the renal arteries
This zone is indicated for hemorrhage originating from the infrarenal aorta, iliac vessels, or lower extremities
Careful placement is required to avoid occluding the renal arteries.
Factors Influencing Selection:
The primary determinant is the suspected source of hemorrhage
Location of injury, hemodynamic response to occlusion, and anatomical considerations (e.g., presence of visceral artery origin) guide the choice
Imaging, if available and rapidly obtainable, can aid decision-making.
Imaging Guidance:
While REBOA is often a rapid, bedside procedure, pre-REBOA imaging like FAST or CT angiography can help identify the bleeding source, although this is frequently not feasible in the immediate resuscitation phase.
Procedure And Placement
Access:
Typically via percutaneous femoral artery access, though surgical cutdown may be necessary in cases of extremity trauma or compromised access.
Catheter Selection:
Various REBOA catheters are available, differing in balloon design and shaft length
Catheter length must be adequate to position the balloon in the desired zone with the introducer sheath remaining outside the body.
Angiography:
Intra-aortic balloon inflation is often preceded by angiography to confirm aortic anatomy and delineate the intended occlusion site.
Balloon Inflation:
Gradual inflation to a specific pressure (e.g., 5-10 mmHg above systolic BP) or until proximal flow is occluded is recommended
Continuous pressure monitoring is crucial.
Monitoring:
Hemodynamic parameters (BP, HR, ECG), urine output, and distal perfusion (e.g., pedal pulses, capillary refill) must be closely monitored throughout the period of occlusion.
Pitfalls And Complications
Incorrect Zone Selection:
Occluding Zone II can compromise cerebral circulation, while inadvertent occlusion of visceral or renal arteries in Zone III can lead to organ ischemia
Inadequate occlusion can fail to control hemorrhage.
Catheter Malposition:
The balloon may drift distally or proximally, leading to ineffective occlusion or unintended ischemia of vital branches
The catheter must be secured properly.
Ischemic Injury:
Prolonged occlusion can lead to limb ischemia, spinal cord ischemia (especially with Zone I), visceral organ ischemia, and end-organ damage
Duration of occlusion should be minimized.
Revascularization Syndrome:
Rapid reperfusion after balloon deflation can lead to a surge in inflammatory mediators, acidosis, coagulopathy, and potential organ dysfunction
Gradual deflation and aggressive resuscitation are key.
Access Site Complications:
Bleeding, hematoma formation, pseudoaneurysm, or dissection at the femoral access site can occur
Meticulous technique and appropriate closure devices are essential.
Management Post Reboa
Definitive Hemorrhage Control:
REBOA is a temporizing measure
definitive surgical control of the bleeding source must be achieved as soon as possible.
Reperfusion Strategy:
Gradual deflation of the balloon is preferred to mitigate reperfusion injury
Reassess hemodynamics and perfuse diligently.
Hemodynamic Management:
Aggressive fluid resuscitation, blood product transfusion, and vasopressor support are critical to manage shock and acid-base derangements post-REBOA.
Monitoring And Support:
Continuous cardiac monitoring, ventilatory support, and monitoring for signs of organ dysfunction (e.g., renal failure, abdominal compartment syndrome) are vital.
Key Points
Exam Focus:
Understand the rationale for REBOA, indications (refractory shock), contraindications (e.g., severe limb ischemia, known aortoiliac dissection), and the distinct anatomical zones (I, II, III) with their respective bleeding sources and risks
Focus on the temporizing nature of the intervention.
Clinical Pearls:
Always have a plan for definitive hemorrhage control before or immediately after REBOA deployment
Minimize occlusion time
Monitor distal pulses and end-organ perfusion vigilantly
Gradual deflation is crucial.
Common Mistakes:
Misidentifying the bleeding source leading to incorrect zone selection
Prolonged occlusion time
Inadequate monitoring post-inflation or deflation
Failure to plan for definitive surgical intervention
Access site complications.