J Trauma Acute Care Surg. 2018 May 2. doi: 10.1097/TA.0000000000001964. [Epub ahead of print]

# Extending the golden hour for Zone 1 REBOA: improved survival and reperfusion injury with intermittent versus continuous REBOA in a porcine severe truncal hemorrhage model.

Kuckelman J, Barron M, Moe D, Derickson M, Phillips C, Kononchik J, Lallemand M, Marko S, Eckert M, Martin M

BACKGROUND: Non-compressible hemorrhage can be controlled using resuscitative endovascular occlusion of the aorta (REBOA). Prolonged ischemia limits REBOA application during Zone 1 deployment. Intermittent inflation/deflation may effectively mitigate this problem.

METHODS: A lethal abdominal vascular injury was created in 28 swine. Animals were randomized to controls (n=7), 60min full REBOA (FR, n=5), time-based intermittent REBOA (iRT, n=7), and pressure-based REBOA (iRP, n=9). Intermittent groups had an initial inflation for 15min, followed by 10min inflation: 3min deflation cycles (iRT) or an inflate/deflate schedule based on blood pressure (MAP)<40mmHg (iRP). Experiments were concluded after 120min or death (MAP<20mmHg).

RESULTS: Intermittent REBOA animals all survived to 120min versus 15min for controls and 63min for FR(p<0.001). After 60min, FR animals were more hypotensive(MAP 20mmHg vs 80mmHg(iRP) and 100mmHg(iRT), p<0.001), had lower cardiac output(1.06mL/min vs 5.1L/min(iRP) and 8.2L/min(iRT), p<0.001), higher lactate(12.5mg/dL vs 8.5mg/dL(iRP), p=0.02), and decreased clot firmness on ROTEM than iRP/T(64mm vs 69mm(iRP) and 69mm(iRT), p=0.04). Acidosis was worse in iRT versus iRP at 120min (pH 7.28 vs 7.12, p=0.02), improved lactate (11.9mg/dL vs 16.3mg/dL, p=0.04), and decreased whole blood resuscitation (452cc vs 646cc, p=0.05). Blood loss (clot weight) was higher in controls (2.0kg) versus iRT and iRP(1.16kg and 1.23kg, p<0.01) and not different from FR(0.87kg, p=0.10).

CONCLUSION: Intermittent REBOA can maintain supraceliac hemorrhage control while decreasing distal ischemia in a swine model. Prolonged survival times, decreased acidosis, and lower resuscitation requirements indicate that this technique could potentially extend Zone 1 REBOA deployment times. Schedules based on MAP may be superior to time-based regimens.

LEVEL OF EVIDENCE: Not applicable as an animal study.

STUDY DESIGN: Original article.