Intra-abdominal hypertension--an experimental study of early effects on intra-abdominal metabolism

The main aim of this experimental study was to investigate the early effects of intra-abdominal hypertension (IAH) on intra-abdominal metabolism and intestinal mucosal blood flow to evaluate whether metabolites can serve as markers for organ dysfunction during IAH.

A swine model was used, and the animals were anesthetized and ventilated. Fifteen animals were subjected to IAH of 30 mm Hg for 4 hr by carbon dioxide insufflation. Seven animals served as controls. Hemodynamic data, arterial blood samples, and urine output were analyzed. Intraluminal laser Doppler flowmetry measured intestinal mucosal blood flow. Glucose, glycerol, lactate, and pyruvate concentrations and lactate-to-pyruvate (l/p) ratio were measured intraperitoneally and intramurally in the small intestine and rectum using microdialysis.

IAH lowered the abdominal perfusion pressure by 12-18 mm Hg, reduced the intestinal mucosal blood flow by 45-63%, and decreased urine output by 50-80%. In the intervention group, glycerol concentrations increased at all locations, pyruvate concentrations decreased, and the l/p ratio increased intraperitoneally and intramurally in the small intestine. Control animals remained metabolically stable. Glucose and lactate concentrations were only slightly affected or unchanged in both the groups.

IAH reduces intestinal blood flow and urinary output and causes early metabolic changes, indicating a discrete shift toward anaerobic metabolism. Intraperitoneal microdialysis may be useful in the early detection of impaired organ dysfunction with metabolic consequences in IAH and abdominal compartment syndrome.