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 1h each to 75% (CO75%), 50% (CO50%), and 35% (CO35%) 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 CO50% in the intervention groups. The decrease in superior mesenteric arterial blood flow was non-linear and exaggerated at CO35%. Systemic, venous mesenteric, and intraperitoneal lactate concentrations increased in the intervention groups from CO50%. Global and mesenteric oxygen uptake decreased at CO35%. 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.
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