Effects of Intra-Aortic Balloon Occlusion on Intestinal Perfusion, Oxygen Metabolism and Gastric Mucosal PCO2 during Experimental Hemorrhagic Shock

Background: Aortic occlusion has been suggested for the initial treatment of severe uncontrolled hemorrhagic shock. Our objective is to determine the impact of aortic occlusion, during hemorrhagic shock, on splanchnic mucosal perfusion and to correlate these findings with other systemic and regional markers of splanchnic ischemia. Methods: Fourteen dogs (17 ± 1.7 kg) anesthetized with pentobarbital were bled to a mean arterial pressure (MAP) of 40 mm Hg. After 30 min, the animals were randomly assigned to controls (no aortic occlusion, n = 7) and transfemoral aortic occlusion (TAO) at T9 level (n = 7). Superior mesenteric artery blood flow (SMABF, ultrasonic flow probe), gastric mucosal PCO 2 (gastric tonometry) and splanchnic oxygen extraction ratio (O 2 ERsplanc) were evaluated for 120 min. Results:Hemorrhage caused a marked reduction in SMABF and increases in PCO 2 -gap and O 2 ERsplanc in both groups. TAO significantly improved MAP and further increased the PCO 2 -gap and O 2 ERsplanc, with a decreased SMABF. After reperfusion, SMABF, MAP and O 2 ERsplanc returned to pre-occlusion values, although the PCO 2 -gap remained higher in the TAO group. Conclusion: Aortic occlusion promotes blood pressure restoration with an additional insult to mucosal perfusion, which could be adequately predicted by global and/or splanchnic oxygen-derived variables during ischemia, but not during the early reperfusion period.