The duration of use and efficacy of resuscitative endovascular balloon occlusion of the aorta (REBOA) is limited by distal ischemia. We developed a hybrid endovascular-extracorporeal circuit variable aortic control (VAC) device to extend REBOA duration in a lethal model of hemorrhagic shock to serve as an experimental surrogate to further the development of endovascular VAC (EVAC) technologies.
Nine Yorkshire-cross swine were anesthetized, instrumented, splenectomized, and subjected to 30% liver amputation. Following a short period of uncontrolled hemorrhage, REBOA was instituted for 20 minutes. Automated variable occlusion in response to changes in proximal mean arterial pressure was applied for the remaining 70 minutes of the intervention phase using the automated extracorporeal circuit. Damage-control surgery and whole blood resuscitation then occurred, and the animals were monitored for a total of 6 hours.
Seven animals survived the initial surgical preparation. After 20 minutes of complete REBOA, regulated flow was initiated through the extracorporeal circuit to simulate VAC and provide perfusion to distal tissue beds during the 90-minute intervention phase. Two animals required circuit occlusion for salvage, while five animals tolerated sustained, escalating restoration of distal blood flow before surgical hemorrhage control. Animals tolerating distal flow had preserved renal function, maintained proximal blood pressure, and rapidly weaned from complete REBOA.
We combined a novel automated, extracorporeal circuit with complete REBOA to achieve EVAC in a swine model of uncontrolled hemorrhage. Our approach regulated proximal aortic pressure, alleviated supranormal values above the balloon, and provided controlled distal aortic perfusion that reduced ischemia without inducing intolerable bleeding. This experimental model serves as a temporary surrogate to guide future EVAC catheter designs that may provide transformational approaches to hemorrhagic shock.
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From the Department of Vascular and Endovascular Surgery (T.K.W.), Clinical Investigation Facility (T.K.W., L.P.N.), and Department of General Surgery (L.P.N.), David Grant USAF Medical Center, Travis Air Force Base; and Departments of Emergency Medicine (M.A.J.) and Surgery (R.M.R., S.-A.F., A.J.D.), UC Davis Medical Center, Sacramento, California; and US Combat Casualty Care Research Program (T.E.R.), US Army Medical Research and Materiel Command, Fort Detrick, Maryland.
Submitted: February 11, 2016, Revised: February 27, 2016, Accepted: March 9, 2016, Published online: April 8, 2016.
The animals involved in this study were procured, maintained, and used in accordance with the Laboratory Animal Welfare Act of 1966, as amended, and NIH 80–23, Guide for the Care and Use of Laboratory Animals, National Research Council.
The views expressed in this material are those of the authors and do not reflect the official policy or position of the US Government, the Department of Defense, the Department of the Air Force, or the University of California Davis. The work reported herein was performed under US Air Force Surgeon General approved Clinical Investigation No. FDG20150002A.
Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jtrauma.com).
Address for reprints: Timothy K. Williams, MD, Department of Vascular, Endovascular Surgery, David Grant USAF Medical Center, Travis AFB, CA 94535; email: email@example.com.