Updates in Trauma – REBOA and SAAP GSA HEMS Wollongong CGD August 13th

REBOA Resuscitative Endovascular Balloon Occlusion of the Aorta. First described in 1954 in the Korean War. Haemorrhage control below the level of the chest without having to do an open procedure (thoracotomy with aortic cross clamping)

REBOA Simple procedure – gain arterial access and insert a balloon into the aorta and inflate to control bleeding. Endovascular procedure – vascular surgeons having been using techniques like REBOA for the last 20 years for ruptured AAA

REBOA Now has expanded into the areas of trauma and hemorrhagic shock. Used as a bridge in haemodynamically unstable patients to theatre or interventional radiology.

REBOA - Technique Gain access to the CFA (avoid the SFA as this is too weak to hold a dilator and will rupture) Most common site is the right CFA Best level to access the CFA is at the inguinal crease In cardiac arrest, open procedure is preferred to percutaneous approach due to difficulty in cannulating femoral artery in cardiac arrest (alternatively can use ultrasound approach)

REBOA - Technique Float the wire Measure externally to the level of the umbilicus and the second rib Advance wire to the measured depth Confirm placement with X-Ray Place sheath (12F) – will require a dilator

REBOA - Technique Float the balloon, measure externally first; Zone 1 is to the level of the xiphoid Zone 3 is to the level of the umbilicus Inflate the balloon until there is moderate resistance - no set pressure determined as yet. This is dependent on the size of the patient but averages between 12-24 mL. Inflate the balloon with saline and contrast agent.

Secure Everything for Transport

When to use REBOA Patients who arrive recently dead Patients who are actively trying to die Patients with injuries making them prone to try to die.

REBOA Once arterial access is gained, time for insertion is usually less than 5 minutes (average is 90 seconds) Duration of inflation (based on experimental animal models) Zone 1; 1.5 hours Zone 3; 5 hours

REBOA - Effectiveness Literature limited to case reports currently. On average the blood pressure increased by 55 mmHg when REBOA was used in one case series. In the other case series of 13 patients, the blood pressure increased from 41 +/- 26 to 111 +/- 47 mmHg.

REBOA - Prehospital London’s HEMS performs the worlds first prehospital REBOA in July of this year. Plans for Sydney HEMS to start using technology in the next few years.

SAAP Selective aortic arch perfusion (SAAP) is an experimental resuscitative intervention that involves the placement of a large-lumen balloon occlusion catheter in the descending thoracic aorta via a femoral artery. Allows relatively isolated perfusion of the heart and brain – useful in resuscitation from medical and traumatic cardiac arrest.

SAAP It differs from REBOA in that the catheter has ports for infusing oxygen carrying fluids and vasoactive drugs. Inflation of the balloon serves as a functional aortic cross- clamp and provides for relatively isolated perfusion of the heart and brain with an oxygen-carrying perfusate.

SAAP Oxygen carrying fluids include; Haemoglobin based oxygen carrier (HBOC) Fluorocarbon based carriers (PFC) Blood (current prototype) SAAP also can be used to deliver metabolic substrates, vasoactive drugs, and agents to limit ischemic damage and reperfusion- induced injury.

SAAP Involves insertion of femoral sheath into femoral artery. Catheter is slightly larger than the CODA balloon used with REBOA to allow for perfusion and administration of vasoactive drugs. Balloon inflated to pressure of 150-180 mmHg.

SAAP Blood is infused at 10 ml/kg/min 750 mL/min (3 units of blood per minute) Infuse for up to 3 minutes in medical cardiac arrest without volume overload. Get venous access at the same time Allows you to pull off blood Limited body ECMO

SAAP Infuse vasoactive drugs directly to heart and brain Results in improved ROSC Intra-aortic adrenaline has minor effect on coronary and cerebral vasculature. Thought to shunt blood by vasoconstriction from upper limbs to heart and brain. IA Adrenaline dose is 1/3 of normal.

SAAP - Trauma Feasible to float the balloon in the field blindly. Balloon works as a functional cross clamp and allows selective perfusion of heart and brain. Allows volume replacement Next step following a failed REBOA procedure.

EPR – Emergency Preservation & Resuscitation Suspended Animation Induced hypothermia – cold saline infused to core temperature of 10 degrees. Vital surgery performed to repair injury and then patient rewarmed on heart-lung bypass machine Estimated downtime of 4 hours ER-CAT trial starting with 10 patients (penetrating trauma)

Summary - REBOA Balloon occlusion of the aorta – equivalent to cross clamping aorta Effective in haemorrhagic shock as a bridge to definitive therapy. Has been used clinically in vascular surgery for the last 20 years – recent expansion into other areas including trauma Planned introduction into NSW prehospital system soon.

Summary - SAAP Experimental procedure with inflation of balloon in descending aorta. Allows selective perfusion and oxygenation of heart and brain. Allows administration of O2 carrying fluid and vasoactive drugs directly to brain and heart. Proposed next step following failed REBOA.

References REBOA review article REBOA case series SAAP J Trauma. 2011; 71(6);1869 REBOA case series J Trauma. 2010; 68(4);942 J Trauma Acute Care Surg. 2013;75(3);506 SAAP Critical Care Med. 2001;29(11);2067