Effects of intraluminal distention and decompression on microvascular permeability and hemodynamics of the equine jejunum

Objective-To determine whether intraluminal distention and subsequent decom pression of the equine jejunum affects intestinal blood flow, hemodynamics, and microvascular permeability. Animals-5 healthy adult horses. Procedure-Horses were anesthestized and underwent exploratory laparotomy. T wo jejunal segments were identified as sham-operated or instrumented segmen ts. After baseline values were obtained, intraluminal distention was create d in the experimental segment to induce an intraluminal pressure of 18 cm H 2O. After 120 minutes of distention, the intestine was decompressed for 120 minutes. Mesenteric blood flow, oxygen delivery, oxygen consumption, micro vascular permeability, we? weight-to-dry weight ratio, neutrophil infiltrat ion, and vascular resistance were determined and comparisons made among con trol, sham-operated, and experimental segments. Results-Mean jejunal blood flow was 21.4 ml/min per kg. There was a signifi cant decrease in mesenteric blood flow to the distended intestine (13.4 ml/ min per kg). Blood flow increased significantly during the decompression pe riod (340% of baseline blood flow). Intraluminal distention and subsequent decompression resulted in a significant increase in microvascular permeabil ity, as determined by the osmotic reflection coefficient. Oxygen delivery a nd oxygen content decreased significantly during the distention period and increased during decompression. Morphologic evaluation revealed a significa nt increase in edema and neutrophil infiltration after distention and decom pression, compared with results for the sham-operated or control segments. Conclusions and Clinical Relevance-Intraluminal distention and decompressio n of the equine jejunum results in low-flow ischemia and edema, which may c ontribute to adhesions and ileus in the postoperative period after surgery for obstructions of the small intestines.