Therapeutic cardiac arrest as an adjunct to resuscitative endovascular balloon occlusion of the aorta: Bridging the gap from fatal hemorrhage to definitive surgical control in swine.

Abstract

Uncontrolled hemorrhage is the leading cause of potentially survivable combat casualty mortality, with 86.5% of cases resulting from noncompressible torso hemorrhage. Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a minimally invasive technique used to stabilize patients with noncompressible torso hemorrhage; however, its application can take an average of 8 minutes to place. One therapeutic capable of bridging this gap is adenosine-lidocaine-magnesium (ALM), which at high doses induces a reversible cardioplegia. We hypothesize by using ALM as an adjunct to REBOA, the ALM-induced cardiac arrest will temporarily halt exsanguination and reduce blood loss, allowing for REBOA placement and control of bleeding. Male Yorkshire swine (60-80 kg) were randomly assigned to REBOA only or ALM-REBOA (n = 8/group). At baseline, uncontrolled hemorrhage was induced via a 1.5-cm right femoral arteriotomy, and hemorrhaged blood was quantified. One minute after injury (S1), ALM was administered, and 7 minutes later (T0), zone 1 REBOA inflation occurred. If cardiac arrest ensued, cardiac function either recovered spontaneously or advanced life support was initiated. At T30, surgical hemostasis was obtained, and REBOA was deflated. Animals were resuscitated until they were humanely euthanized at T90. During field care phase, heart rate and end-tidal CO2 of the ALM-REBOA group were significantly lower than the REBOA only group. While mean arterial pressure significantly decreased from baseline, no significant differences between groups were observed throughout the field care phase. There was no significant difference in survival between the two groups (ALM-REBOA = 89% vs. REBOA only = 100%). Total blood loss was significantly decreased in the ALM-REBOA group (REBOA only = 24.32 ± 1.89 mL/kg vs. ALM-REBOA = 17.75 ± 2.04 mL/kg, p = 0.0499). Adenosine-lidocaine-magnesium is a novel therapeutic, which, when used with REBOA, can significantly decrease the amount of blood loss at initial presentation, without compromising survival. This study provides proof of concept for ALM and its ability to bridge the gap between patient presentation and REBOA placement.