Background: Noncompressible hemorrhage can be controlled using resuscitative endovascular balloon 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 swines. Animals were randomized to controls (n = 7), 60 minutes 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 15 minutes, followed by 10-minute inflation: 3-minute deflation cycles (iRT), or an inflate/deflate schedule based on mean arterial pressure (MAP) less than 40 mm Hg (iRP). Experiments were concluded after 120 minutes or death (MAP < 20 mm Hg).
Results: Intermittent REBOA animals all survived to 120 minutes versus 15 minutes for controls and 63 minutes for FR (p < 0.001). After 60 minutes, FR animals were more hypotensive (MAP 20 mm Hg vs. 80 mm Hg [iRP] and 100 mm Hg [iRT]; p < 0.001), had lower cardiac output (1.06 mL/min vs. 5.1 L/min [iRP] and 8.2 L/min [iRT]; p < 0.001), higher lactate (12.5 mg/dL vs. 8.5 mg/dL [iRP], p = 0.02), and decreased clot firmness on rotational thromboelastometry than iRP/T (64 mm vs. 69 mm [iRP] and 69 mm [iRT], p = 0.04). Acidosis was worse in iRT versus iRP at 120 minutes (pH 7.28 vs. pH 7.12; p = 0.02), improved lactate (11.9 mg/dL vs. 16.3 mg/dL; p = 0.04), and decreased whole blood resuscitation (452 mL vs. 646 mL, p = 0.05). Blood loss (clot weight) was higher in controls (2.0 kg) versus iRT and iRP (1.16 kg and 1.23 kg; p < 0.01) and not different from FR (0.87 kg; 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.