Atividade mioelétrica do intestino delgado de cães submetidos à oclusão parcial da veia porta

Abstract

-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.Resumo -Racional -A oclusão temporária da veia porta causa estase esplâncnica e pode causar dismotilidade intestinal. Objetivo -Avaliar as alterações da atividade mioelétrica e da histologia do intestino delgado, além da pressão arterial média (PAM), frequência cardíaca (FC), pressão venosa central (PVC) e pressão portal (PP), na fase de pré-oclusão e de oclusão portal. Método -Realizou-se anestesia geral em seis cães, seguido de monitorização da PAM, FC e PVC, laparotomia, aferição da PP, fixação de três pares de eletrodos na parede intestinal, biópsias jejunais e oclusão parcial da veia porta, sendo programado aumento da PP entre 2,5 e 3 vezes. Os eletrodos foram conectados a um microcomputador com software de aquisição para armazenamento e análise da atividade mioelétrica, cujo registro ocorreu nos 30 minutos da fase de pré-oclusão e nos 60 minutos de oclusão. Determinouse a variância e a média do RMS (root mean square) da atividade mioelétrica. Resultados -Na fase de oclusão, houve diminuição significativa da...