Updates in Trauma – REBOA and SAAP

GSA HEMS Wollongong CGDAugust 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.

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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– 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