Splanchnic Circulation and Intraabdominal Metabolism in Two Porcine Models of Low Cardiac Output

The impact of acute cardiac dysfunction on the gastrointestinal tract was investigated in anesthetized and instrumented pigs by sequential reductions of cardiac output (CO). Using a cardiac tamponade (n = 6) or partial inferior caval vein balloon inflation (n = 6), CO was controllably reduced for 1 h each to 75% (CO(75%)), 50% (CO(50%)), and 35% (CO(35%)) of the baseline value. Cardiac output in controls (n = 6) was not manipulated and maintained. Mean arterial pressure, superior mesenteric arterial blood flow, and intestinal mucosal perfusion started to decrease at CO(50%) in the intervention groups. The decrease in superior mesenteric arterial blood flow was non-linear and exaggerated at CO(35%). Systemic, venous mesenteric, and intraperitoneal lactate concentrations increased in the intervention groups from CO(50%). Global and mesenteric oxygen uptake decreased at CO(35%). In conclusion, gastrointestinal metabolism became increasingly anaerobic when CO was reduced by 50%. Anaerobic gastrointestinal metabolism in low CO can be detected using intraperitoneal microdialysis.