Partial Resuscitative Endovascular Balloon Occlusion of the Aorta Limits Ischemia-Reperfusion Injury After Simulated Aeromedical Evacuation.

INTRODUCTION: One of the advantages of partial Resuscitative Endovascular Balloon Occlusion of the Aorta (pREBOA) compared to the original model is the mitigation of reperfusion injury. The safety and efficacy of pREBOA have not been demonstrated in the setting of aeromedical evacuation. We hypothesized that the pREBOA would result in less ischemia-reperfusion injury after altitude exposure. METHODS: Twenty-four swine underwent femur fracture with hemorrhage for 20 min, followed by resuscitative endovascular balloon occlusion of the aorta (REBOA) deployment to Zone 1 and were randomized to pREBOA-PRO (Prytime Medical Devices Inc) full inflation, partial inflation, or sham inflation and then an altitude exposure of ground level or 8000 ft for 15 min. The primary endpoint was to examine if the balloon functioned at altitude. Our secondary endpoint was investigating evidence of ischemia-reperfusion by hemodynamic instability, electrolyte derangements, and acidosis. Comparisons were made by ANOVA. RESULTS: After deflation, the partially inflated group maintained a higher mean arterial pressure (MAP) compared to fully inflated group (P = 0.026). Full REBOA pigs were more tachycardic compared to sham pREBOA at ground (P < 0.001) and this was exacerbated at altitude (P < 0.001). Full REBOA pigs were more acidotic than sham and pREBOA at ground pigs (P = 0.0006 and P = 0.0002, respectively). Altitude increased the acidosis in full REBOA pigs, resulting in a greater base deficit (P < 0.0001), lactate (P < 0.0001), and IL-6 (P = 0.006). CONCLUSIONS: PREBOA resulted in less severe ischemia-reperfusion injury at both altitude and ground, while full balloon inflation at altitude exacerbated acidosis and ischemia-reperfusion injury. Efforts should therefore be made to utilize partial balloon occlusion when employing the REBOA catheter.

Can Resuscitative Endovascular Balloon Occlusion of the Aorta Fly? Assessing Aortic Balloon Performance for Aeromedical Evacuation.

BACKGROUND: Noncompressible torso hemorrhage remains a leading cause of death. Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) placement may occur before transport; however, its efficacy has not been demonstrated at altitude. We hypothesized that changes in altitude would not result in blood pressure changes proximal to a deployed REBOA. METHODS: A simulation model for 7Fr guidewireless REBOA was used at altitudes up to 22,000 feet. Female pigs then underwent hemorrhagic shock to a mean arterial pressure (MAP) of 40 mm Hg. After hemorrhage, a REBOA catheter was deployed in the REBOA group and positioned but not inflated in the no-REBOA group. Animals underwent simulated aeromedical evacuation at 8000 ft or were left at ground level. After altitude exposure, the balloon was deflated, and the animals were observed. RESULTS: Taking the REBOA catheter to 22,000 ft in the simulation model resulted in a lower systolic blood pressure but a preserved MAP. In the porcine model, REBOA increased both systolic blood pressure and MAP compared with no-REBOA (P < 0.05) and was unaffected by altitude. No differences in postflight blood pressure, acidosis, or systemic inflammatory response were observed between ground and altitude REBOA groups. CONCLUSIONS: REBOA maintained MAP up to 22,000 feet in an inanimate model. In the porcine model, REBOA deployment improved MAP, and the balloon remained effective at altitude.

Full Nutrition or Not?

Enteral nutrition (EN) is widely used in intensive care units around the world, but the optimal dosing strategy during the first week of critical illness is still controversial. Numerous studies in the past decade have provided conflicting recommendations regarding the roles of trophic and permissive/intentional underfeeding strategies. Further complicating effective medical decision making is the widespread, yet unintentional and persistent underdelivery of prescribed energy and protein, in addition to the trend for recommending ever-higher amounts of protein delivery. We postulate that the key to appropriate enteral strategy lies within an accurate and patient-specific assessment. Patients with a baseline high nutrition risk and those with increased nutrition demands, such as those with wounds, surgery, or burns, likely require full nutrition support, in contrast with medical patients, such as those with acute respiratory distress syndrome, who may selectively be appropriate for trophic strategies. In this analysis, we review several key trials for and against full EN in the first week of critical illness, as well as key issues such as the role of autophagy and immunonutrition in enteral dose selection.