Myoelectric Activity Of The Small Bowel Of Dogs Submitted To Partial Occlusion Of The Portal Vein

Background - Temporary occlusion of the portal vein causes splancnic venous stasis and intestinal disfunction, that can produce alterations in the motility, and this fact is not vastly known. Aim -To evaluate the small bowel myoelectric activity and histology in the six dogs, also covering mean arterial blood pressure (AP), pulse rate (PR), central venous pressure (CVP) e portal pressure (PP), in two phases: pre-occlusion and occlusion. Methods - It was done general anesthesia, invasive monitorization of the AP, PR e CVP, laparotomy, measure of the PP, fixation of the three pairs of electrodes in the intestinal wall, jejunal biopsy and parcial occlusion of the portal vein, being programmed the increase of the PP between 2.5 and 3 times baseline. Electrodes were connected to a computer system that captured electrical signals from the intestine. The computer has a software of acquisition to store and analyse the myoelectric activity after registering, what happened in 30 minutes of the preocclusion phase and in 60 minutes of occlusion. The variance and the mean RMS (root mean square) of the myoeletric activity were determined. The statistical analysis was done with Friedman, Dunn, Cochran and Students t tests. Results - Mean RMS of myoeletric activity showed significant decrease in the phase of portal occlusion, in comparison to pre- occlusion phase. The frequency of hemorrhage of the lamina propria was major during occlusion. It was proportional at stasis time, with significant difference between the pre-occlusion and the occlusion of 60 minutes. Inflammatory infiltration, vascular dilation and epithelial detachment did not show any differences between two phases. During the stasis, AP, PR and CVP decreased (p= 0,326; 0,375 e 0,008, respectively), and PP increased (p= 0,015). Conclusions - Parcial occlusion of the portal vein produced reduction of the myoeletric activity and elevation of the percentage frequency of hemorrhage in lamina propria, and a fall of CVP, with relative hemodynamic stabilization.